A new clinical trial has found that adding repeated intravenous ketamine infusions to standard care for hospitalized patients with serious depression did not provide a significant additional benefit. The study, which compared ketamine to a psychoactive placebo, suggests that previous estimates of the drug’s effectiveness might have been influenced by patient and clinician expectations. These findings were published in the journal JAMA Psychiatry.

Ketamine, originally developed as an anesthetic, has gained attention over the past two decades for its ability to produce rapid antidepressant effects in individuals who have not responded to conventional treatments. Unlike standard antidepressants that can take weeks to work, a single infusion of ketamine can sometimes lift mood within hours. A significant drawback, however, is that these benefits are often short-lived, typically fading within a week.

This has led to the widespread practice of administering a series of infusions to sustain the positive effects. A central challenge in studying ketamine is its distinct psychological effects, such as feelings of dissociation or detachment from reality. When compared to an inactive placebo like a saline solution, it is very easy for participants and researchers to know who received the active drug, potentially creating strong expectancy effects that can inflate the perceived benefits.

To address this, the researchers designed their study to use an “active” placebo, a drug called midazolam, which is a sedative that produces noticeable effects of its own, making it a more rigorous comparison.

“Ketamine has attracted a lot of interest as a rapidly-acting antidepressant but it has short-lived effects. Therefore, its usefulness is quite limited. Despite this major limitation, ketamine is increasingly being adopted as an off-label treatment for depression, especially in the USA,” said study author Declan McLoughlin, a professor at Trinity College Dublin.

“We hypothesized that repeated ketamine infusions may have more sustained benefit. So far this has been evaluated in only a small number of trials. Another problem is that few ketamine trials have used an adequate control condition to mask the obvious dissociative effects of ketamine, e.g. altered consciousness and perceptions of oneself and one’s environment.”

“To try address some of these issues, we conducted an independent investigator-led randomized trial (KARMA-Dep 2) to evaluate antidepressant efficacy, safety, cost-effectiveness, and quality of life during and after serial ketamine infusions when compared to a psychoactive comparison drug midazolam. Trial participants were randomized to receive up to eight infusions of either ketamine or midazolam, given over four weeks, in addition to all other aspects of usual inpatient care.”

The trial, conducted at an academic hospital in Dublin, Ireland, aimed to see if adding twice-weekly ketamine infusions to the usual comprehensive care provided to inpatients could improve depression outcomes. Researchers enrolled adults who had been voluntarily admitted to the hospital for moderate to severe depression. These participants were already receiving a range of treatments, including medication, various forms of therapy, and psychoeducation programs.

In this randomized, double-blind study, 65 participants were assigned to one of two groups. One group received intravenous ketamine infusions twice a week for up to four weeks, while the other group received intravenous midazolam on the same schedule. The doses were calculated based on body weight. The double-blind design meant that neither the patients, the clinicians rating their symptoms, nor the main investigators knew who was receiving which substance. Only the anesthesiologist administering the infusion knew the assignment, ensuring patient safety without influencing the results.

The primary measure of success was the change in participants’ depression scores, assessed using a standard clinical tool called the Montgomery-Åsberg Depression Rating Scale. This assessment was conducted at the beginning of the study and again 24 hours after the final infusion. The researchers also tracked other outcomes, such as self-reported symptoms, rates of response and remission, cognitive function, side effects, and overall quality of life.

After analyzing the data from 62 participants who completed the treatment phase, the study found no statistically significant difference in the main outcome between the two groups. Although patients in both groups showed improvement in their depressive symptoms during their hospital stay, the group receiving ketamine did not fare significantly better than the group receiving midazolam. The average reduction in depression scores was only slightly larger in the ketamine group, a difference that was small and could have been due to chance.

Similarly, there were no significant advantages for ketamine on secondary measures, including self-reported depression symptoms, cognitive performance, or long-term quality of life. While the rate of remission from depression was slightly higher in the ketamine group (about 44 percent) compared to the midazolam group (30 percent), this difference was not statistically robust. The treatments were found to be generally safe, though ketamine produced more dissociative experiences during the infusion, while midazolam produced more sedation.

“We found no significant difference between the two groups on our primary outcome measure (i.e. depression severity assessed with the commonly used Montgomery-Åsberg Depression Rating Scale (MADRS)),” McLoughlin told PsyPost. “Nor did we find any difference between the two groups on any other secondary outcome or cost-effectiveness measure. Under rigorous clinical trial conditions, adjunctive ketamine provided no additional benefit to routine inpatient care during the initial treatment phase or the six-month follow-up period.”

A key finding emerged when the researchers checked how well the “blinding” had worked. They discovered that it was not very successful. From the very first infusion, the clinicians rating patient symptoms were able to guess with high accuracy who was receiving ketamine.

Patients in the ketamine group also became quite accurate at guessing their treatment over time. This functional unblinding complicates the interpretation of the results, as the small, nonsignificant trend favoring ketamine could be explained by the psychological effect of knowing one is receiving a treatment with a powerful reputation.

“Our initial hypothesis was that repeated ketamine infusions for people hospitalised with depression would improve mood outcomes,” McLoughlin said. “However, contrary to our hypothesis, we found this not to be the case. We suspect that functional unblinding (due to its obvious dissociative effects) has amplified the placebo effects of ketamine in previous trials. This is a major, often unacknowledged, problem with many recent trials in psychiatry evaluating ketamine, psychedelic, and brain stimulation therapies. Our trial highlights the importance of reporting the success, or lack thereof, of blinding in clinical trials.”

The study’s authors acknowledged some limitations. The research was unable to recruit its planned number of participants, partly due to logistical challenges created by the COVID-19 pandemic. This smaller sample size reduced the study’s statistical power, making it harder to detect a real, but modest, difference between the treatments if one existed. The primary limitation, however, remains the challenge of blinding.

The results from this trial suggest that when tested under more rigorous conditions, the antidepressant benefit of repeated ketamine infusions may be smaller than suggested by earlier studies that used inactive placebos. The researchers propose that expectations for both patients and clinicians may play a substantial role in ketamine’s perceived effects. This highlights the need to recalibrate expectations for ketamine in clinical practice and for more robustly designed trials in psychiatry.

Looking forward, the researchers emphasize the importance of reporting negative or null trial results to provide a balanced view of a treatment’s capabilities. They also expressed concern about a separate in the field: the promotion of ketamine as an equally effective alternative to electroconvulsive therapy, or ECT.

“Scrutiny of the scientific literature shows that this includes methodologically flawed trials and invalid meta-analyses,” McLoughlin said. “We discuss this in some detail in a Comment piece just published in Lancet Psychiatry. Unfortunately, such errors have been accepted as scientific evidence and are already creeping into international clinical guidelines. There is a thus a real risk of patients and clinicians being steered towards a less effective treatment, particularly for patients with severe, sometimes life-threatening, depression.”

The study, “Serial Ketamine Infusions as Adjunctive Therapy to Inpatient Care for Depression: The KARMA-Dep 2 Randomized Clinical Trial,” was authored by Ana Jelovac, Cathal McCaffrey, Masashi Terao, Enda Shanahan, Emma Whooley, Kelly McDonagh, Sarah McDonogh, Orlaith Loughran, Ellie Shackleton, Anna Igoe, Sarah Thompson, Enas Mohamed, Duyen Nguyen, Ciaran O’Neill, Cathal Walsh, and Declan M. McLoughlin.

A new study indicates that Donald Trump’s frequent shrugging is a deliberate communication tool used to establish common ground with his audience and express negative evaluations of his opponents and their policies. The research, published in the journal Visual Communication, suggests these gestures are a key component of his populist performance style, helping him appear both ordinary and larger-than-life.

Researchers have become increasingly interested in the communication style of right-wing populism, which extends beyond spoken words to include physical performance. While a significant amount of analysis has focused on Donald Trump’s language, particularly on social media platforms, his live performances at rallies have received less systematic attention. The body is widely recognized as being important to political performance, but the specific gestures used are not always well understood.

This new research on shrugging builds on a previous study by one of the authors that examined Trump’s use of pointing gestures. That analysis found that Trump uses different kinds of points to serve distinct functions, such as pointing outwards to single out opponents, pointing inwards to emphasize his personal commitment, and pointing downwards to connect his message to the immediate location of his audience. The current study continues this investigation into his non-verbal communication by focusing on another of his signature moves, the shrug.

“The study was motivated by several factors,” explained Christopher Hart, a professor of linguistics at Lancaster University and the author of Language, Image, Gesture: The Cognitive Semiotics of Politics.

(1) Political scientists frequently refer to the more animated bodily performance of right wing populist politicians like Trump compared to non-populist leaders. We wanted to study one gesture – the shrug – that seemed to be implicated here. (2) Trump’s shrug gestures have been noted by the media previously and described as his “signature move”. We wanted to study this gesture in more detail to examine its precise forms and the way he uses it to fulfil rhetorical goals.”

“(3) To meet a gap: while a great deal has been written about Donald Trump’s speech and his use of language online, much less has been written about the gestures that accompany his speech in live settings. This is despite the known importance of gesture in political communication.”

To conduct their analysis, the researchers examined video footage of two of Trump’s campaign rallies from the 2016 primary season. The events, one in Dayton, Ohio, and the other in Buffalo, New York, amounted to approximately 110 minutes of data. The researchers adopted a conservative approach, identifying 187 clear instances of shrugging gestures across the two events.

Each shrug was coded based on its physical form and its communicative function. For the form, they classified shrugs based on the orientation of the forearms and the position of the hands relative to the body. They also noted whether the shrug was performed with one or two hands and whether it was a simple gesture or a more complex, animated movement. To understand the function, they analyzed the spoken words accompanying each shrug to determine the meaning being conveyed.

Hart was surprised “just how often Trump shrugs – 1.7 times per minute in the campaign rallies analyzed. Trump is a prolific shrugger and this is one way his communication style breaks with traditional forms of political communication.”

The analysis of the physical forms of the shrugs provided evidence for what has been described as a strong “corporeal presence.” Trump tended to favor expansive shrugs, with his hands positioned outside his shoulder width, a form that physically occupies more space.

The second most frequent type was the “lateral” shrug, where his arms extend out to his sides, sometimes in a highly theatrical, showman-like manner. This use of large, exaggerated gestures appears to contribute to a performance style more commonly associated with live entertainment than with traditional politics.

The researchers also noted that nearly a third of his shrugs were complex, meaning they involved animated, oscillating movements. These gestures create a dynamic and sometimes caricatured performance. While these expansive and animated shrugs help create an extraordinary, entertaining persona, the very act of shrugging is an informal, everyday gesture. This combination seems to allow Trump to simultaneously signal both his ordinariness and his exceptionalism.

When examining the functions of the shrugs, the researchers found that the most common meaning was not what many people might expect. While shrugs are often associated with expressing ignorance (“I don’t know”) or indifference (“I don’t care”), these were not their primary uses in Trump’s speeches. Instead, the most frequent function, accounting for over 44 percent of instances, was to signal common ground or obviousness. Trump often uses a shrug to present a statement as a self-evident truth that he and his audience already share.

For example, he would shrug when asking rhetorical questions like “We love our police. Do we love our police?” The gesture suggests the answer is obvious and that everyone in the room is in agreement. He also used these shrugs to present his own political skills as a given fact or to frame the shortcomings of his opponents as plainly evident to all. This use of shrugging appears to be a powerful tool for building a sense of shared knowledge and values with his supporters.

“Most people think of shrugs as conveying ‘I don’t know’ or ‘I don’t care,” Hart told PsyPost. “While Trump uses shrugs to convey these meanings, more often he uses shrugs to indicate that something is known to everyone or obviously the case. This is one of the ways he establishes common ground and aligns himself with his audience, indicating that he and they hold a shared worldview.”

The second most common function was to express what the researchers term “affective distance.” This involves conveying negative emotions like disapproval, dissatisfaction, or dismay towards a particular state of affairs. When discussing trade deals he considered terrible or military situations he found lacking, a shrug would often accompany his words. In these cases, the gesture itself, rather than the explicit language, carried the negative emotional evaluation of the topic.

Shrugs that conveyed “epistemic distance,” meaning ignorance, doubt, or disbelief, accounted for about 17 percent of the total. A notable use of this function occurred during what is known as “constructed dialogue,” where Trump would re-enact conversations. In one instance, he used a mocking shrug while impersonating a political opponent to portray them as clueless and incompetent, a performance that drew laughter from the crowd.

The least common function was indifference, or the classic “I don’t care” meaning. Though infrequent, these shrugs served a strategic purpose. When shrugging alongside a phrase like “I understand that it might not be presidential. Who cares?,” Trump used the gesture to dismiss the conventions of traditional politics. This helps him position himself as an outsider who is not bound by the same rules as the political establishment.

The findings highlight that “what politicians do with their hands and other body parts is an important part of their message and their brand,” Hart told PsyPost. However, he emphasizes that “gestures are not ‘body language.’ They do not accidentally give away one’s emotional state. Gestures are built in to the language system and are part of the way we communicate. They carry part of the information speakers intend to convey and that information forms part of the message audiences take away.”

The study does have some limitations. Its analysis is focused exclusively on Donald Trump, so it remains unclear whether this pattern of shrugging is unique to his style or a broader feature of right-wing populist communication. Future research could compare his gestural profile to that of other populist and non-populist leaders.

Additionally, the study centered on one specific gesture, and a more complete picture would require analyzing the full range of a politician’s non-verbal repertoire. The authors also suggest that future work could examine other elements, like facial expressions and the timing of gestures, in greater detail.

Despite these limitations, the research provides a detailed look at how a seemingly simple gesture can be a sophisticated and versatile rhetorical tool. Trump’s shrugs appear to be a central part of a performance style that transgresses political norms, creates entertainment value, and forges a strong connection with his base. The findings indicate the importance of looking beyond a politician’s words to understand the full, embodied performance through which they communicate their message.

“We hope to look at other gestures of Trump to build a bigger picture of how he uses his body to distinguish himself from other politicians and to imbue his performances with entertainment value,” Hart said. This might include, for example, his use of chopping or slicing gestures. I also hope to explore the gestural performances of other right wing populist politicians in Europe to see how their gestures compare. ”

The study, “A shrug of the shoulders is a stance-taking act: The form-function interface of shrugs in the multimodal performance of Donald Trump,” was authored by Christopher Hart and Steve Strudwick.

A new study examining nine consecutive birth years in Sweden indicates that the dramatic rise in clinical diagnoses of autism spectrum disorder is not accompanied by an increase in autism-related symptoms in the population. The research, published in the journal Psychiatry Research, also found that while parent-reported symptoms of ADHD remained stable in boys, there was a small but statistically significant increase in symptoms among girls.

Autism spectrum disorder, or ASD, is a neurodevelopmental condition characterized by differences in social communication and interaction, along with restricted or repetitive patterns of behavior and interests. Attention-Deficit/Hyperactivity Disorder, or ADHD, is another neurodevelopmental condition marked by persistent patterns of inattention, hyperactivity, and impulsivity that can interfere with functioning or development. Over the past two decades, the number of clinical diagnoses for both conditions has increased substantially in many Western countries, particularly among teenagers and young adults.

This trend has raised questions about whether the underlying traits associated with these conditions are becoming more common in the general population. Researchers sought to investigate this possibility by looking beyond clinical diagnoses to the level of symptoms reported by parents.

“The frequency of clinical diagnoses of ASD and ADHD has increased substantially over the past decades across the world,” said study author Olof Arvidsson, a PhD student at the Gillberg Neuropsychiatry Centre at Gothenburg University and resident physician in Child and Adolescent Psychiatry.

“The largest prevalence increase has been among teenagers and young adults. Therefore, we wanted to investigate if symptoms of ASD and ADHD in the population had increased over time in 18-year-olds. In this study we used data from a twin study in Sweden in which parents reported on symptoms of ASD and ADHD when their children turned 18 and investigated whether symptoms had increased between year 2011 to 2019.”

To conduct their analysis, the researchers utilized data from a large, ongoing project called the Child and Adolescent Twin Study in Sweden. This study follows twins born in Sweden to learn more about mental and physical health. For this specific investigation, researchers focused on information collected from the parents of nearly 10,000 twins born between 1993 and 2001. When the twins reached their 18th birthday, their parents were asked to complete a web-based questionnaire about their children’s behaviors and traits.

Parents answered a set of 12 questions designed to measure symptoms related to autism. These items correspond to the diagnostic criteria for ASD. For ADHD, parents completed a 17-item checklist covering problems associated with inattention and executive function, which are core components of ADHD.

Using this data, the researchers employed statistical methods to analyze whether the average symptom scores changed across the nine different birth years, from 1993 to 2001. They also looked at the percentage of individuals who scored in the highest percentiles, representing those with the most significant number of traits.

The analysis showed no increase in the average level of parent-reported autism symptoms among 18-year-olds across the nine-year span. This stability was observed for both boys and girls. Similarly, when the researchers examined the proportion of individuals with the highest symptom scores, defined as those in the top five percent, they found no statistically significant change over time. This suggests that the prevalence of autism-related traits in the young adult population remained constant during this period.

The results for ADHD presented a more nuanced picture. Among boys, the data indicated that parent-reported ADHD symptoms were stable. There was no significant change in either the average symptom scores or in the percentage of boys scoring in the top 10 percent. For girls, however, the study identified a small but statistically detectable increase in ADHD symptoms over the nine birth years. This trend was apparent in both the average symptom scores and in the proportion of girls who scored in the top 10 percent for ADHD traits.

Despite being statistically significant, the researchers note that the magnitude of this increase in girls was small. The year of birth explained only a very small fraction of the variation in ADHD symptom scores. The results suggest that while there may be a slight upward trend in certain ADHD symptoms among adolescent girls, it is not nearly large enough to account for the substantial increase in clinical ADHD diagnoses reported in this group. The study provides evidence that the steep rise in both autism and ADHD diagnoses is likely influenced by factors other than a simple increase in the symptoms themselves.

“Across the nine birth years examined, there was no sign of increasing symptoms of ASD in the population, despite rising diagnoses,” Arvidsson told PsyPost. “For ADHD, there was no increase among boys. However, in 18-year-old girls we saw a very small but statistically significant increase in ADHD symptoms. The increase in absolute numbers was small in relation to the increase in clinical diagnoses.”

The researchers propose several alternative explanations for the growing number of diagnoses. Increased public and professional awareness may lead more people to seek assessments. Diagnostic criteria for both conditions have also widened over the years, potentially including individuals who would not have met the threshold in the past. Another factor may be a change in perception, where certain behaviors are now seen as more impairing than they were previously. This aligns with other research indicating that parents today tend to report higher levels of dysfunction associated with the same number of symptoms compared to a decade ago.

Changes in societal demands, particularly in educational settings that place a greater emphasis on executive functioning and complex social skills, could also contribute. In some cases, a formal diagnosis may be a prerequisite for accessing academic support and resources, creating an incentive for assessment. For the slight increase in ADHD symptoms among girls, the authors suggest it could reflect better recognition of how ADHD presents in females, or perhaps an overlap with symptoms of anxiety and depression, which have also been on the rise in this demographic.

“The takeaway is that the increases in clinical diagnoses of both ASD and ADHD need to be explained by other factors than increasing symptoms in the population, such as increased awareness and increased perceived impairment related to ASD and ADHD symptoms,” Arvidsson said. “Taken together we also hope to curb any worries about a true increase in ASD or ADHD.”

The study has some limitations. The response rate for the parental questionnaires was about 41 percent. While the researchers checked for potential biases and found that their main conclusions about the trends over time were likely unaffected, a higher participation rate would strengthen the findings. Additionally, the questionnaire for ADHD primarily measured symptoms of inattention and did not include items on hyperactivity. The results, therefore, mainly speak to the inattentive aspects of ADHD.

Future research could explore these trends with different measures and in different populations. The researchers also plan to investigate trends in clinical diagnoses more closely to better understand resource allocation for healthcare systems.

“We want to better understand trends of clinical diagnoses, such as trends of incidence of diagnoses in different groups,” Arvidsson said. “With increasing clinical diagnoses of ASD and ADHD and the resulting impact on the healthcare system as well as on the affected patients, it is important to characterize these trends in order to motivate an increased allocation of resources.”

The study, “ASD and ADHD symptoms in 18-year-olds – A population-based study of twins born 1993 to 2001,” was authored by Olof Arvidsson, Isabell Brikell, Henrik Larsson, Paul Lichtenstein, Ralf Kuja-Halkola, Mats Johnson, Christopher Gillberg, and Sebastian Lundström.

Recent research published in the journal Evolution and Human Behavior offers new insights into how broad environmental conditions may shape “dark” personality traits on a national level. The study suggests that harsh or unpredictable ecological factors experienced during childhood, such as natural disasters or skewed sex ratios, are linked to higher average levels of traits like narcissism in adulthood. These findings indicate that forces largely outside of an individual’s control could play a key role in the development of antisocial personality profiles across different cultures.

The “Dark Triad” consists of three distinct but related personality traits: narcissism, Machiavellianism, and psychopathy. Individuals with high levels of narcissism often display grandiosity, entitlement, and a constant need for admiration. Machiavellianism is characterized by a cynical, manipulative approach to social interaction and a focus on self-interest over moral principles. Psychopathy involves high impulsivity, thrill-seeking behavior, and a lack of empathy or remorse for others.

While these traits are often viewed as undesirable, evolutionary perspectives suggest they may represent adaptive strategies in certain environments. Psychological research frequently focuses on immediate social causes for these traits, such as family upbringing or individual trauma. However, this new study aimed to broaden that lens by examining macro-level ecological factors that affect entire populations.

“There were several reasons to do this study,” explained Peter Jonason, a professor at Vizja University, creator of the Your Stylish Scientist YouTube Channel, and editor of Shining Light on the Dark Side of Personality: Measurement Properties and Theoretical Advances.

“First, there is limited understanding how ecological factors predict personality at all, let alone the Dark Triad. That is, most research focuses on personal, familial, or sociological predictors, but these are embedded in larger ecological systems. If the Dark Triad traits are mere pathologies of defunkt parenting or income inequality, one would not predict sensitivity to ecological factors in determining people’s adult Dark Triad scores let alone sex differences therein.”

“Second, most research on the Dark Triad traits focuses on individual-level variance but here we examined what you might call a culture of each trait and what might account for it. Third, and, less interestingly perhaps, the team happened to meet, get along, have the skills needed, and had access to the data to examine this.”

The researchers employed a theoretical framework known as life history theory to guide their investigation. This theory proposes that organisms, including humans, unconsciously adjust their reproductive and survival strategies based on the harshness and predictability of their environment. In dangerous or unstable environments, “faster” life strategies (characterized by greater risk-taking, short-term mating, and higher aggression) tend to be more advantageous for evolutionary fitness.

To test this idea, the researchers utilized existing personality data from 11,504 participants across 48 different countries. The data for these national averages were collected around 2016 using the “Dirty Dozen,” a widely used twelve-item questionnaire designed to briefly measure the three Dark Triad traits. The researchers then paired these personality scores with historical ecological data from the World Bank and other international databases.

They specifically examined ecological conditions during three developmental windows: early childhood (years 2000–2004), mid-childhood (years 2005–2009), and adolescence (years 2010–2015). The ecological indicators included population density, life expectancy (survival to age 65), and the operational sex ratio, which measures the balance of men to women in society. They also included data on the frequency of natural disasters, the prevalence of major infectious disease outbreaks, and levels of income inequality.

“When considering what makes people different from around the world, it is lazy to say ‘culture,'” Jonason told PsyPost. “Culture is a system that results from higher-order conditions like access to resources and ecological threats. If you want to understand why someone differs from you, you must consider more than just her/his immediate–and obvious–circumstances.”

The analysis used advanced statistical techniques known as spatial autoregressive models. These models allowed the researchers to not only test the direct associations within a country but also to account for “spillover” effects from neighboring nations. This approach recognizes that countries do not exist in isolation and may be influenced by the conditions and cultures of sharing borders.

The results indicated that different ecological factors were associated with distinct Dark Triad traits. Countries that had more male-biased sex ratios during the participants’ childhoods tended to have higher average levels of adult narcissism. The researchers suggest that an excess of males may intensify intrasexual competition, prompting men to adopt grander, more self-promoting behaviors to attract mates.

Conversely, a higher prevalence of infectious diseases during childhood and adolescence was associated with lower national levels of Machiavellianism and psychopathy. In environments with a high disease burden, strict adherence to social norms and greater group cohesion are often necessary for survival. In such contexts, manipulative or antisocial behaviors that disrupt group harmony might be less adaptive and therefore less common.

The study also found that ecological conditions might influence the magnitude of personality differences between men and women. Exposure to natural disasters during developmental years was consistently linked to larger sex differences across all three Dark Triad traits in adulthood. High-threat environments may cause men and women to adopt increasingly divergent survival and reproductive strategies, thereby widening the psychological gap between the sexes.

Furthermore, the research provided evidence for regional clustering of these personality profiles. Conditions in neighboring countries frequently predicted a focal country’s personality scores. For example, higher income inequality or natural disaster impact in bordering nations was associated with higher narcissism or Machiavellianism in the country being studied.

This suggests that dark personality traits may diffuse across borders. This could happen through mechanisms such as migration, shared regional economic challenges, or cultural transmission. The findings highlight the importance of considering regional contexts when studying national character.

“Do not assume that good parenting, safe schools, and successful social experiences are all that matter in determining who goes dark,” Jonason explained. “Larger factors, well beyond our control, have influence as well. By removing the human from the equation, we can better see how people are subject to forces well beyond their will, self-reports, and even situated in larger socioecological systems.”

As with all research, the study has some limitations that should be considered when interpreting these results. The personality data were largely derived from university students, who may not be fully representative of their national populations. Additionally, because the study relied on historical aggregate data, it cannot establish a definitive causal link between these ecological factors and individual personality development. It is possible that other unmeasured variables contribute to these associations.

Future research could aim to replicate these findings using more diverse and representative samples from the general population. The researchers also express an interest in investigating the specific psychological and cognitive mechanisms that might link broad environmental conditions to individual differences in motives and morals. Understanding these mechanisms could provide a clearer picture of how macro-level forces shape the human mind.

“We hope to pursue projects that try to understand the specific conditions that allow for not just personality, but also motives, morals, and mate preferences to be calibrated to local conditions providing more robust tests of not just cross-national differences, but, also, what are the cognitive mechanisms and perceptions that drive those differences,” Jonason said. “This is assuming we get some grant money to do so!”

“This is a study attempting to understand how lived experiences in people’s mileu can correlate with their personality and sex differences therein. This is an important step forward because while manipulating the conditions in people’s lives is nearly impossible, we can get a strong glimpse of how conditions in people’s generalized past can cause adaptive responses to help them solve important tasks like securing status and mates–two motivations highly valued by those high in the Dark Triad traits.”

The study, “Towards an ecological model of the dark triad traits,” was authored by Peter K. Jonason, Dritjon Gruda, and Mark van Vugt.

Researchers in Japan have documented the case of a teenager whose psychotic symptoms consistently appeared before her menstrual period and resolved immediately after. A case report published in Psychiatry and Clinical Neurosciences Reports indicates that a medication typically used to treat seizures and bipolar disorder was effective after standard antipsychotic and antidepressant drugs failed to provide relief. This account offers a detailed look at a rare and often misunderstood condition.

The condition is known as menstrual psychosis, which is characterized by the sudden onset of psychotic symptoms in an individual who is otherwise mentally well. These episodes are typically brief and occur in a cyclical pattern that aligns with the menstrual cycle. The presence of symptoms like delusions or hallucinations distinguishes menstrual psychosis from more common conditions such as premenstrual syndrome or premenstrual dysphoric disorder, which primarily involve mood-related changes. Menstrual psychosis is considered exceptionally rare, with fewer than 100 cases identified in the medical literature.

The new report, authored by Atsuo Morisaki and colleagues at the Tokyo Metropolitan Children’s Medical Center, details the experience of a 17-year-old Japanese girl who sought medical help after about two years of recurring psychological distress. Her initial symptoms included intense anxiety, a feeling of being watched, and auditory hallucinations where she heard a classmate’s voice. She also developed the belief that conversations around her were about herself. She had no prior psychiatric history or family history of mental illness.

Initially, she was diagnosed with schizophrenia and prescribed antipsychotic medication, which did not appear to alleviate her symptoms. Upon being transferred to a new medical center, her treatment was changed, but her condition persisted. While hospitalized, her medical team observed a distinct pattern. In the days leading up to her first menstrual period at the hospital, she experienced a depressive mood and restlessness. This escalated to include delusional thoughts and the feeling that “voices and sounds were entering my mind.” These symptoms disappeared completely four days later, once her period ended.

This cycle repeated itself the following month. About twelve days before her second menstruation, she again became restless. Nine days before, she reported the sensation that her thoughts were “leaking out” during phone calls. She also experienced auditory hallucinations and believed her thoughts were being broadcast to others. Her antipsychotic dosage was increased, but the symptoms continued until her menstruation ended, at which point they once again resolved completely.

A similar pattern emerged before her third period during hospitalization. Fourteen days prior, she developed a fearful, delusional mood. She reported that “gazes and voices are entering my head” and her diary entries showed signs of disorganized thinking. An increase in her medication dosage seemed to have no effect. As her period began, the symptoms started to fade, and they were gone by the time it was over. This consistent, cyclical nature of her psychosis, which did not respond to conventional treatments, led her doctors to consider an alternative diagnosis and treatment plan.

Observing this clear link between her symptoms and her menstrual cycle, the medical team initiated treatment with carbamazepine. This medication is an anticonvulsant commonly used to manage seizures and is also prescribed as a mood stabilizer for bipolar disorder. The dosage was started low and gradually increased. Following the administration of carbamazepine, her psychotic symptoms resolved entirely. She was eventually able to discontinue the antipsychotic and antidepressant medications. During follow-up appointments as an outpatient, her symptoms had not returned.

The exact biological mechanisms behind menstrual psychosis are not well understood. Some scientific theories suggest a link to the sharp drop in estrogen that occurs during the late phase of the menstrual cycle. Estrogen influences several brain chemicals, including dopamine, and a significant reduction in estrogen might lead to a state where the brain has too much dopamine activity, which has been associated with psychosis. However, since psychotic episodes can occur at various points in the menstrual cycle, fluctuating estrogen levels alone do not seem to fully explain the condition.

The choice of carbamazepine was partly guided by the patient’s age and the potential long-term side effects of other mood stabilizers. The authors of the report note that carbamazepine may work by modulating the activity of various channels and chemical messengers in the brain, helping to stabilize neuronal excitability. While there are no previous reports of carbamazepine being used specifically for menstrual psychosis, it has shown some effectiveness in other cyclical psychiatric conditions, suggesting it may influence the underlying mechanisms that produce symptoms tied to biological cycles.

It is important to understand the nature of a case report. Findings from a single patient cannot be generalized to a larger population. This report does not establish that carbamazepine is a definitive treatment for all individuals with menstrual psychosis. The positive outcome observed in this one person could be unique to her specific biology and circumstances.

However, case reports like this one serve a significant function in medical science, especially for uncommon conditions. They can highlight patterns that might otherwise be missed and introduce potential new avenues for treatment that warrant further investigation. By documenting this experience, the authors provide information that may help other clinicians recognize this rare disorder and consider a wider range of therapeutic options. This account provides a foundation for future, more systematic research into the causes of menstrual psychosis and the potential effectiveness of medications like carbamazepine.

The report, “Menstrual psychosis with a marked response to carbamazepine,” was authored by Atsuo Morisaki, Ken Ebishima, Akira Uezono, and Takashi Nagasawa.

A new study published in the Journal of Affective Disorders provides evidence that a brief but structured physical exercise program can help reduce stress levels in adolescents diagnosed with attention-deficit/hyperactivity disorder. The researchers found that after just three weeks of moderate to vigorous physical activity, participants reported lower levels of stress and showed a measurable increase in salivary cortisol, a hormone linked to the body’s stress response.

Adolescence is widely recognized as a time of dramatic psychological and biological development. For teens with ADHD, this period often comes with heightened emotional challenges. In addition to the typical symptoms of inattention and hyperactivity, many adolescents with the condition also struggle with internal feelings such as anxiety and depression. These emotional difficulties can interfere with daily functioning at school and at home, placing them at greater risk for long-term mental health problems.

Although stimulant medications are commonly used to manage symptoms, they often cause side effects such as sleep problems and mood shifts. Due to these complications, many families and young people stop using medication or seek alternative approaches. One such approach gaining traction is physical exercise. Prior research suggests that structured activity may benefit brain function and emotional regulation. However, most studies have focused on children rather than adolescents, and few have examined whether exercise influences cortisol, a stress hormone thought to be dysregulated in young people with ADHD.

Cortisol plays an important role in how the body manages stress. Low levels of cortisol in the morning have been found in children and adolescents with ADHD, and this pattern has been associated with fatigue, anxiety, and greater symptom severity. The researchers behind the new study wanted to know whether a short physical exercise intervention could influence both subjective stress levels and objective stress markers like cortisol in teens with ADHD.

“Adolescents with ADHD face stress-related challenges and appear to display atypical cortisol patterns, yet most exercise studies focus on younger children and rarely include biological stress markers,” explained study author Cindy Sit, a professor of sports science and physical education at The Chinese University of Hong Kong.

“We wanted to test a practical, low-risk intervention that schools and families could feasibly implement and to examine both perceived stress and a physiological marker (salivary cortisol) within a randomized controlled trial design. In short, we aimed to examine whether a brief, feasible program could help regulate stress in this under-researched group through non-pharmacological methods.”

The researchers recruited 82 adolescents, aged 12 to 17, who had been diagnosed with ADHD. Some of the participants also had a diagnosis of autism spectrum disorder, which often co-occurs with ADHD. The teens were randomly assigned to one of two groups. One group participated in a structured physical exercise program lasting three weeks. The other group served as a control and continued with their normal routines.

The exercise group attended two 90-minute sessions each week, totaling 540 minutes over the course of the program. These sessions included a variety of activities designed not only to improve physical fitness but also to engage cognitive functions such as memory, reaction time, and problem-solving. Exercises included circuit training as well as games that required strategic thinking and teamwork. Participants were guided to maintain moderate to vigorous intensity throughout much of the sessions, and their heart rates were monitored to ensure appropriate effort.

To measure outcomes, the researchers used both self-report questionnaires and biological samples. Stress, depression, and anxiety levels were assessed through a validated scale. Cortisol was measured using saliva samples collected in the afternoon before and after the intervention, as well as three months later.

The findings showed that immediately following the exercise program, participants in the exercise group reported lower levels of stress compared to their baseline scores. At the same time, their cortisol levels increased.

The increase in cortisol following exercise was interpreted not as a sign of increased stress but as a reflection of more typical hormonal activity. The researchers noted that this pattern aligns with the idea of exercise as a “positive stressor” that helps train the body to respond more effectively to real-life challenges. Importantly, the teens felt less stressed, even as their cortisol levels rose.

“The combination of lower perceived stress alongside an immediate rise in cortisol was striking,” Sit told PsyPost. “It supports the idea that exercise can feel stress-relieving while still producing a normal physiological stress response that may help calibrate the HPA axis. We also noted a baseline positive association between anxiety and cortisol in the control group only, which warrants further investigation.”

However, by the three-month follow-up, the improvements in self-reported stress had faded, and cortisol levels had returned to their initial levels. There were no significant changes in self-reported depression or anxiety in either group at any point.

“A short, three-week exercise program (90-minute sessions twice a week at moderate to vigorous intensity) reduced perceived stress in adolescents with ADHD immediately after the program,” Sit said. “Cortisol levels increased right after the intervention, consistent with a healthy, short-term activation of the stress system during exertion (often called ‘good stress’). The positive effects on perceived stress did not last for three months without continued physical exercise, and we did not observe short-term changes in depression or anxiety. This suggests that ongoing participation is necessary to sustain these benefits.”

Although the results suggest benefits from the short-term exercise program, there are some limitations to consider. Most of the participants were male, and this gender imbalance could affect how the findings apply to a broader group of adolescents. The study also relied on self-report questionnaires to assess stress, anxiety, and depression, which can be affected by personal bias. Additionally, there was no “active” control group, meaning the control participants were not given an alternate activity that involved social interaction or structure, which might have helped isolate the effects of the exercise itself.

Future studies might benefit from longer intervention periods to examine whether extended participation can produce lasting changes. Collecting saliva samples multiple times during the day could also help map out how cortisol behaves in response to both daily routines and interventions. Incorporating interviews or observer-based assessments could provide a more complete understanding of emotional changes, especially in teens who have difficulty expressing their feelings through questionnaires.

“Our team is currently conducting a large randomized controlled trial testing physical‑activity interventions for people with intellectual disability, with co‑primary outcomes of mood and physical strength,” Sit explained. “The broader aim is to develop scalable, low‑cost programs that can be implemented in schools, day services, and community settings. Ultimately, we aim to increase access for underserved populations so that structured movement becomes a feasible part of everyday care and improves their quality of life.”

“We see exercise as a useful adjunct, not a replacement, for standard ADHD care,” she added. “In practice, that involves incorporating structured movement alongside evidence-based treatments (e.g., medication, psychoeducation, behavioural supports) and working with families, schools, and healthcare providers. Exercise is accessible and generally has low risk; it can assist with stress regulation, sleep, attention, and fitness. However, it should be individualized and monitored, especially for individuals with special needs like ADHD, to support rather than replace routine care.”

The study, “Efficacy of a short-term physical exercise intervention on stress biomarkers and mental health in adolescents with ADHD: A randomized controlled trial,” was authored by Sima Dastamooz, Stephen H.S. Wong, Yijian Yang, Kelly Arbour-Nicitopoulos, Rainbow T.H. Ho, Jason C.S. Yam, Clement C.Y. Tham, Liu Chang, and Cindy H.P. Sit.

A new study in the Archives of Sexual Behavior suggests that how people react to sexual versus emotional infidelity is shaped by more than just biological sex. While heterosexual men were more distressed by sexual betrayal and women by emotional betrayal, the findings indicate that traits like masculinity, femininity, and sexual attraction also influence these responses in flexible ways.

For several decades, psychologists have observed that men and women tend to react differently to infidelity. Men are more likely to be disturbed by sexual infidelity, while women are more upset by emotional cheating. Evolutionary psychologists have suggested that this might reflect reproductive pressures. For men, the risk of raising another man’s child might have favored the development of stronger reactions to sexual betrayal. For women, the loss of a partner’s emotional commitment could mean fewer resources and support for offspring, making emotional infidelity more threatening.

But this difference is not universal. Studies have shown that it becomes much less pronounced among sexual minorities. Gay men and lesbian women often report similar levels of distress over emotional and sexual infidelity, rather than showing a clear difference based on biological sex. This has raised the question of whether the difference between men and women is really just about being male or female—or whether other psychological traits might be involved.

The researchers behind the current study wanted to examine this question in more detail. They were interested in whether traits often associated with masculinity or femininity might influence how people respond to infidelity. They also wanted to test whether sexual orientation, measured not just as a label but as a continuum of attraction to men and women, could account for some of the variation in jealousy responses.

“We have for many years found robust sex difference in jealousy, but we have also been interested in any factors that could influence this pattern. Other researchers discovered that sexual orientation might influence that pattern. We also were influence by David Schmitt’s ideas on sexual dials vs. switches — how masculinization/feminization might be much better described as dimensional than categorical, including sexual orientation and jealousy triggers,” said study author Leif Edward Ottesen Kennair, a professor at the Norwegian University of Science and Technology.

For their study, the researchers collected data from 4,465 adults in Norway, ranging in age from 16 to 80. The sample included people who identified as heterosexual, gay, lesbian, bisexual, and pansexual. Participants were recruited through social media advertisements and LGBTQ+ websites. Each person completed a survey about their responses to hypothetical infidelity scenarios, along with questions about their childhood behavior, personality traits, sexual attraction, and self-perceived masculinity or femininity.

To measure jealousy, the participants were asked to imagine different types of infidelity. In one example, they were asked whether it would be more upsetting if their partner had sex with someone else, or if their partner developed a deep emotional connection with another person. Their answers were used to calculate a jealousy score that reflected how much more distressing they found sexual versus emotional betrayal.

The results supported some long-standing findings. Heterosexual men were much more likely than heterosexual women to be disturbed by sexual infidelity. In fact, nearly 59 percent of heterosexual men said sexual betrayal was more upsetting, compared to only 31 percent of heterosexual women. This pattern was consistent with past research.

But among sexual minorities, the sex difference mostly disappeared. Gay men and lesbian women responded in ways that were more alike, with both groups tending to be more upset by emotional infidelity. Bisexual men and women also reported similar responses. This suggests that sexual orientation plays a key role in how people experience jealousy.

The researchers then examined sexual attraction as a continuous variable. Rather than looking only at how people labeled themselves, they measured how strongly participants were attracted to men and to women. Among men, those who were exclusively attracted to women showed the highest levels of sexual jealousy. Men who had even a small degree of attraction to other men reported less distress about sexual infidelity.

The researchers also measured four different psychological traits related to masculinity and femininity. These included whether participants preferred system-oriented thinking or empathizing, whether they had gender-typical interests as children, whether they preferred male- or female-dominated occupations, and how masculine or feminine they saw themselves. These traits were used to create a broader measure of psychological gender.

In men, higher levels of psychological masculinity were linked to both a stronger attraction to women and a greater tendency to be disturbed by sexual infidelity. But the connection between masculinity and jealousy seemed to depend on whether the man was attracted to women. Masculinity influenced jealousy only when it was also linked to strong gynephilic attraction—that is, attraction to women.

Among women, masculinity was related to sexual orientation, but not to jealousy responses. This suggests that masculinity and femininity may play different roles in shaping sexual psychology for men and women.

Kennair told PsyPost that these findings suggest “that sexual orientation might be best measured dimensionally (as involving both gynephilia and androphilia), that sexual orientation influences sex differences (in this case, jealousy triggers), and that gendering and sex differences are not primarily categorical processes but dimensional processes that are largely influenced by biological sex, but absolutely not categorically determined in an either/or switch pattern. Rather, they function more like interconnected dimensional dials.”

A surprising finding came from a smaller group: bisexual men who were partnered with women. “In the current study, we found that bisexual men with a female partner were still more triggered by emotional than sexual infidelity,” Kennair explained. “Bisexual men should also be concerned about who the father of their partner’s children really is, from an evolutionary perspective, but it seems that only the highly gynephilic men are primarily triggered by sexual infidelity. This needs further investigation and theorizing.”

But the study, like all research, has some caveats. The participants were recruited online, which means the sample might not fully represent the broader population. In addition, the jealousy scenarios were hypothetical, and people’s real-life reactions might differ from what they imagine.

The study raises some new and unresolved questions. One puzzle is why sexual jealousy in men seems to drop off so steeply with even a small degree of androphilic attraction. From an evolutionary standpoint, any man who invested in raising a child would have faced reproductive costs if his partner had been unfaithful, regardless of his own sexual orientation. Yet the findings suggest that the mechanism for sexual jealousy may be tightly linked to sexual attraction to women, rather than simply being male or being partnered with a woman.

It also remains unclear why women’s jealousy responses are less influenced by sexual orientation or masculinity. The results suggest that emotional jealousy is a more stable pattern among women, while sexual jealousy in men appears more sensitive to individual differences in orientation and psychological traits.

“I think this is a first empirical establishment of the dials approach,” Kennair said. “I think it might be helpful to investigate this approach with other phenomena. Also, the research cannot address the developmental and biological processes underlying the psychological level we addressed in the paper. The causal pathways therefore need further investigation. And theorizing.”

He hopes that “maybe in the current polarized discussion of identity and sex/gender, people will find the dimensional and empirical approach of this paper a tool to communicate better than the categorical approaches let us do.”

The study, “Male Sex, Masculinization, Sexual Orientation, and Gynephilia Synergistically Predict Increased Sexual Jealousy,” was authored by Leif Edward Ottesen Kennair, Mons Bendixen, and David P. Schmitt.

Watching a powerful movie may do more than stir emotions. According to a study published in the journal Communication Research, emotionally moving films that explore political or moral issues may encourage viewers to think more deeply about those topics and even engage politically. The researchers found that German television theme nights combining fictional drama with related factual programs were associated with higher levels of information seeking, perceived knowledge, and consideration of political actions related to the issues portrayed.

There is a longstanding debate about whether entertainment harms or helps democracy. Some scholars worry that media such as movies and reality shows distract citizens from more serious political content. But recent research has begun to suggest that certain types of entertainment might actually contribute to political awareness and engagement.

“We were curious about effects of entertainment media on political interest and engagement. Can watching a movie and walking in the shoes of people affected by a political issue raise viewers’ awareness about the issue and motivate them to take action to address the issue?” explained study author Anne Bartsch, a professor at Leipzig University.

“From about a decade of experimental research, we know that moving and thought-provoking media experiences can stimulate empathy and prosocial behavior, including political engagement. In this study, we used television theme nights as an opportunity to replicate these findings ‘in the wild.’ Theme nights are a popular media format in Germany that combines entertainment and information programs about a political issue and attracts a large enough viewership to conduct representative survey research. This opportunity to study political effects of naturally occurring media use was quite unique.”

The researchers conducted three studies around two German television theme nights. The first theme night focused on the arms trade, while the second dealt with physician-assisted suicide. Each theme night included a full-length fictional film followed by an informational program. Across the three studies, more than 2,800 people took part through telephone and online surveys.

In the first study, researchers surveyed a nationally representative sample of 905 German adults by phone after the arms trade theme night. Participants were asked whether they watched the movie, the documentary, or both. They were also asked about their emotional reactions, whether they had thought deeply about the issue, and what actions they had taken afterward.

People who had seen the movie reported feeling more emotionally moved and were more likely to report having reflected on the issue. These viewers also reported greater interest in seeking more information, higher levels of both perceived and factual knowledge, and more willingness to engage in political actions related to arms trade, such as signing petitions or considering the issue when voting.

Statistical analysis indicated that the emotional experience of feeling moved led to deeper reflection, which then predicted greater knowledge and political engagement. However, there was no significant difference in how often viewers talked about the issue with others, compared to non-viewers. Surprisingly, emotional reactions did not appear to encourage discussion on social media, and may have slightly reduced it.

In the second study, the researchers repeated the survey online with a different sample of 877 participants following the same theme night. The results were largely consistent. Again, those who watched the movie felt more moved, thought more about the issue, and were more engaged. In this study, feeling moved was also linked to more frequent interpersonal discussion.

The third study examined the theme night about physician-assisted suicide. Over 1,000 people took part in the online survey. As with the earlier studies, viewers who watched the movie reported being emotionally affected and more reflective. These experiences were linked to higher interest in the topic, greater perceived knowledge, and a higher likelihood of discussing the issue or participating politically. Watching the movie also predicted stronger interest in the subsequent political talk show.

Across all three studies, the researchers found that emotional and reflective experiences were key pathways leading from entertainment to political engagement. People who felt moved by the movies were more likely to think about the issues they portrayed. These thoughts were, in turn, connected to learning more about the issue, talking with others, and taking or considering political action.

The findings suggest that serious entertainment can function as a catalyst, helping viewers process complex social issues and motivating them to become more engaged citizens.

“We found that moving and thought-provoking entertainment can have politically mobilizing effects, including issue interest, political participation, information seeking, learning, and discussing the issue with others,” Bartsch told PsyPost. “This is interesting because entertainment often gets a bad rap, as superficial, escapist pastime. Our findings suggest that it depends on the type of entertainment and the thoughts and feelings it provokes. Some forms of entertainment, it seems, can make a valuable complementary contribution to political discourse, in particular for audiences that rarely consume traditional news.”

Although the findings were consistent across different samples and topics, the authors note some limitations. Most importantly, the studies were correlational, meaning they cannot establish that the movies directly caused people to seek information or take political action. It is possible that people who are already interested in politics are more likely to watch such films and respond emotionally to them.

The researchers also caution that while theme nights seem to offer an effective combination of entertainment and information, these findings might not easily transfer to other types of media or digital platforms. Watching a movie on television with millions of others at the same time may create a shared cultural moment that is less common in today’s fragmented media landscape.

“Our findings cannot be generalized to all forms of entertainment, of course,” Bartsch noted. “Many entertainment formats are apolitical ‘feel-good’ content – which is needed for mood management as well. What is more concerning is that entertainment can also be instrumentalized to spread misinformation, hate and discrimination.”

Future studies could use experimental methods to better isolate cause and effect, and could also explore how similar effects might occur with streaming platforms or social media. Researchers might also investigate how hedonic, or lighter, forms of entertainment interact with political content, and how emotional reactions unfold over time after watching a movie.

“Our study underscores the value of ‘old school’ media formats like television theme nights that can attract large audiences and provide input for shared media experiences and discussions,” Bartsch said. “With the digital transformation of media, however, it is important to explore how entertainment changes in the digital age. For example, we are currently studying parasocial opinion leadership on social media and AI generated content.”

The study, “Eudaimonic Entertainment Experiences of TV Theme Nights and Their Relationships With Political Information Processing and Engagement,” was authored by Frank M. Schneider, Anne Bartsch, Larissa Leonhard, and Anea Meinert.

When people feel emotionally close, their bodies may start to act in tandem. A new study published in Biological Psychology offers evidence that this alignment can reach the level of the heart. Researchers found that married couples from lower socioeconomic backgrounds were more likely to show synchronized heart rate patterns than couples from higher socioeconomic backgrounds. The findings suggest that social and economic conditions may shape not only how people relate to one another emotionally, but also how their bodies respond during social connection.

Previous research has shown that people from lower-income and lower-education backgrounds tend to emphasize relationships more than their more affluent peers. Studies suggest that individuals from these environments often rely more on their social networks for support, given that they face more external challenges such as financial strain and limited access to resources. This emphasis on social interdependence appears in how people think, feel, and behave. But until now, little was known about whether this tendency might also appear in physical processes, such as heart rate.

“Social connection is essential for human well-being and survival. And how we connect with others is shaped by the resources and opportunities we have. When socioeconomic resources are scarce, social relationships can become a refuge and a resource, taking on a particularly important role in people’s lives,” said Tabea Meier, a postdoctoral scholar affiliated with the University of Zurich, and Claudia Haase, an associate professor at Northwestern University, the corresponding authors of the study.

“Prior research has shown that people from less privileged backgrounds tend to be more interdependent and attuned to others, for example, in experiencing greater empathy and compassion. This stands in contrast to the individualism that tends to dominate more privileged social contexts.”

“However, much less is known about whether this attunement to others goes beyond experiences and behavior—whether it shows up in people’s bodies or physiology. Our study of married couples examined this question by probing how socioeconomic status relates to physiological linkage – the way spouses’ heart rates rise and fall together when they interact. In moments of deep connection, people’s hearts can beat in sync.”

For their study, the researchers recruited 48 married couples living in the Chicago area, resulting in a sample of 96 individuals. The couples varied widely in terms of income and education. Some earned less than $20,000 per year, while others made over $150,000. Their education levels also ranged from less than high school to advanced degrees. The sample included people from several racial and ethnic backgrounds.

Each couple participated in a three-hour lab session. After some initial procedures, they took part in two ten-minute conversations: one focused on a topic of conflict in their relationship, and another centered on a mutually enjoyable subject. During these conversations, the participants wore sensors that tracked their heart activity in real time. The researchers focused on a measure called “interbeat interval,” which is the amount of time between heartbeats. These second-by-second measurements allowed the team to assess how each spouse’s heart rate changed throughout the conversation.

The researchers analyzed how closely the spouses’ heart rate patterns mirrored each other. When both people’s heart rates sped up or slowed down together, this was called “in-phase linkage.” When one person’s heart rate increased while the other’s decreased, that was labeled “anti-phase linkage.” In both cases, stronger linkage meant a tighter correlation between spouses’ heart rate shifts. The team looked at how these two types of linkage were related to the couple’s socioeconomic background.

Across both conflict and pleasant conversations, couples from lower socioeconomic backgrounds showed higher in-phase linkage. In other words, their heart rates were more likely to change in the same direction. At the same time, they showed lower anti-phase linkage, meaning their heart rates were less likely to change in opposite directions.

This pattern suggests that less affluent couples tend to experience a stronger bodily connection during interpersonal interactions. Their heart rhythms moved more in unison, regardless of whether they were arguing or sharing positive memories. The difference was particularly strong for anti-phase linkage, which was much lower in lower-income and lower-education couples compared to their more privileged peers.

“When people connect, it’s not just their thoughts, feelings, and behaviors that can align – their bodies can, too,” Meier and Haase told PsyPost. “Our study found that couples’ socioeconomic backgrounds may shape how this connection unfolds at a physiological level. Specifically, the heart rates of spouses from less privileged backgrounds were more likely to change in the same direction (i.e., speeding up or slowing down together) and less likely to change in opposite directions (i.e., one speeding up while the other is slowing down) compared to those from more privileged backgrounds.”

These results held even after the researchers controlled for several other factors, including age and racial background. The effect was also more strongly tied to education than income, although both contributed to the findings.

Importantly, the level of synchrony did not appear to be linked to the emotional tone of the conversation or to how many times the couples used inclusive words like “we.” That suggests that the physiological linkage observed may be operating somewhat independently of what the spouses said or how they rated their emotions.

“These findings build on a long line of research showing that people from less privileged backgrounds tend prioritize relationships and are more attuned to those around them,” the researchers said. “Our study suggests, to our knowledge for the first time, that this connection may not only appear in feelings or behaviors, but also at a physiological level in the form of linked heart rates between spouses. It is a reminder that our social worlds live within us.”

There are a few caveats to consider. The sample size, although consistent with similar lab-based studies, was relatively small. It also focused on heterosexual married couples with children in the United States, which limits how broadly the results can be applied.

The study also did not look at how these heart rate patterns affect the couples over time. It remains unclear whether higher in-phase linkage leads to better relationship satisfaction, improved health, or other benefits. Some previous research suggests that synchrony may be helpful in many cases, but not always. For example, when couples are arguing, syncing up physiologically might sometimes make things worse by escalating conflict. On the other hand, moving in opposite directions might help one partner stay calm while the other is distressed.

“It is important not to oversimplify these results,” Meier and Haase explained. “Linked heart rates do not necessarily mean “better” or healthier relationships. Whether physiological linkage is beneficial or not may really depend on the context in which it occurs, for example, whether spouses are cracking up about an inside joke, are throwing harsh words at each other, or comforting each other in sadness. Future research can explore when and how different heart rate linkage patterns support or harm relationship satisfaction, well-being, and health.”

“Our study is a first step and there are many open questions that we would love the research community to pursue. While we worked hard to recruit a diverse sample of couples from all walks of life from the U.S. Chicagoland area, larger samples will be needed, ideally not just from the US. There are many other open questions. For instance, how does physiological linkage predict how satisfied spouses from less or more privileged backgrounds are with their relationship over time? And what are the consequences for mental and physical health? We look forward to more research in this area that connects the macro and the micro.”

“Socioeconomic status can shape our everyday lives in powerful ways, including how we connect with loved ones,” the researchers added. “Psychological research on couples has traditionally focused mostly on white, middle-class couples. Findings from our study, along with others, highlight the importance of inclusive approaches in the study of social connection. The couples in our study allowed us to gain a deeper understanding of how emotional dynamics and social connection may differ across socioeconomic contexts, and we are grateful that they shared their time and insights with us.”

The study, “Connected at heart? Socioeconomic status and physiological linkage during marital interactions,” was authored by Tabea Meier, Aaron M. Geller, Kuan-Hua Chen, and Claudia M. Haase.

Trigger warnings are meant to help people emotionally prepare for or avoid potentially upsetting material. But new evidence from a week-long study of young adults suggests they often do neither. Instead, most people who encounter these warnings choose to view the content anyway. The findings also indicate that even individuals with trauma histories or mental health concerns are no more likely to avoid warned content than others. The results provide further support for the growing idea that trigger warnings, while widespread, may not function as intended in everyday digital life.

Trigger warnings are now common in both online and offline environments, appearing ahead of everything from social media posts to college course material. They are typically used to signal content that could be distressing, especially for those with past trauma or mental health challenges. Advocates argue that these warnings give vulnerable people the opportunity to prepare for or avoid harmful content.

But a growing body of lab-based studies has cast doubt on the idea that trigger warnings work in the way people hope. While many assume that warnings prompt avoidance, experiments have shown that most people choose to view the content anyway, and that warnings rarely reduce emotional distress. Until now, however, nearly all of this evidence came from controlled settings. Researchers had not yet studied how people actually respond to trigger warnings in their everyday lives.

The new study, published in the Journal of Behavior Therapy and Experimental Psychiatry, aimed to fill that gap. The researchers set out to track when and how often people encounter trigger warnings on social media, whether they choose to view or avoid the associated content, and whether certain psychological traits—such as symptoms of posttraumatic stress or depression—are linked to different patterns of behavior.

“Over the past (almost decade) my research has been concerned with cutting through online debate about trigger warnings and examining them using an experimental framework. This work has found that in the lab, warnings about upcoming negative content do not reduce people’s emotional reactions to material, nor do they seem effective in deterring the majority of people from viewing negative content when given a neutral/non-distressing alternative,” said study author Victoria Bridgland, a lecturer at Flinders University.

“We were interested in seeing if these findings, particularly about avoidance, extend outside of lab environments. Participating in a lab study is inherently coercive, however participants have no obligation to watch or avoid negative content in daily life. However, aligning with lab findings, we found that the most common response to seeing trigger warnings online in daily life was to view the content, and the most common reason given was because of curiosity—which is also something we hear in lab.”

The study followed 261 young adults between the ages of 17 and 25 over a seven-day period. Participants reported their daily experiences with social media, including whether they saw any trigger warnings and what kind of content those warnings accompanied. They also recorded whether they chose to look at or avoid the content after seeing the warning.

To explore whether psychological traits influenced avoidance behavior, participants completed several standardized assessments at the beginning of the study. These included measures of trauma exposure, symptoms of posttraumatic stress disorder, depression, anxiety, and general well-being. The researchers also asked whether participants had a tendency to deliberately seek out reminders of traumatic experiences, a behavior sometimes referred to as self-triggering.

The researchers wanted to see whether people who had higher levels of psychological distress were more likely to avoid warned content, as trigger warning advocates often suggest. They also looked at how frequently participants encountered these warnings and what motivated their decision to view or avoid the content.

Nearly half of the participants reported seeing at least one trigger warning during the week. Among those who did, the average number of warnings seen was about four. The most common platforms for encountering these warnings were Instagram, TikTok, and Twitter, and the most frequent content types were violent or aggressive material, depictions of physical injury, and sexually explicit content.

When asked how they responded to the warnings, the overwhelming majority said they chose to look at the content. On a scale from “never looked” to “always looked,” most people leaned heavily toward viewing. In fact, only around 11 percent reported consistently avoiding warned material throughout the week, while more than a third said they always approached it. When asked why they looked, more than half cited curiosity—the desire to know what was being hidden—as their main motivation.

The results were not a surprise. “We have known for some time from lab experiments that trigger warnings don’t seem to increase rates of avoidance, and we also know that people are morbidly curious and often self-expose themselves to negative material (even when it serves no real benefit),” Bridgland told PsyPost.

The researchers found no evidence that people with higher psychological vulnerability were more likely to avoid the content. Participants with greater posttraumatic stress symptoms, for example, were just as likely to view the material as those with fewer symptoms. This pattern held across several mental health measures, including depression, anxiety, and a history of trauma exposure.

Interestingly, people who did see trigger warnings tended to score higher on mental health symptom scales and lower on general well-being. The authors suggest that this could be because such individuals spend more time in online spaces where trigger warnings are common, or because the warnings feel more personally relevant and memorable to them. But even within this group, the presence of a warning did not increase the likelihood of avoidance.

The content people chose to avoid, when they did avoid it, varied widely. Some said they were simply uninterested, while others avoided it because it involved specific types of content they preferred not to see, such as animal cruelty or depictions of death. A small number of participants reported avoiding material that felt emotionally overwhelming or clashed with their current mood. Still, these decisions were the exception rather than the rule.

“I’d like for people to be conscious consumers of negative material online and be wary of extremes,” Bridgland said. “For example, if you are someone who finds they often need to avoid or becomes overly distressed or triggered by online content or someone who is deliberately searching for and binge consuming negative content in high volumes which is leading to distress—this is likely a sign that there is some underlying issue that likely warrants therapeutic attention. In either of these cases, be aware that a trigger warning may not be serving a beneficial function.”

As with all research, there are some limitations. First, the study did not measure emotional reactions after viewing the content, so it remains unclear whether the warnings helped people feel more prepared or less distressed. Prior research, however, suggests that trigger warnings tend not to influence emotional responses much, if at all.

Another limitation is that people might behave differently depending on the specific context or type of content. For example, someone might avoid a warning about sexual assault but not one about medical procedures. The study also didn’t capture real-time responses, so there may be subtle moment-to-moment factors—such as mood or fatigue—that influence decisions to view or avoid warned content.

“I’d like to clarify that me and my research team aren’t advocating that we should ban trigger warnings, but we just want people to be aware of the lack of benefits they provide,” Bridgland explained. “This way people can take other precautions to safeguard their mental health online.”

“Since it seems hard to improve antecedent based strategies to help people cope with negative content (as various recent studies have tried to “improve” trigger warnings with no success), I’m exploring ways we can help people after they are exposed. This will also help in the case where shocking/traumatic content exposure happens without warning (which is a common experience online).”

The study, “‘I’m always curious’: Tracking young adults exposure and responses to social media trigger warnings in daily life,” was authored by Victoria M.E. Bridgland, Ella K. Moeck, and Melanie K.T. Takarangi.

A new study published in the Journal of Sport and Health Science provides evidence that cardiorespiratory fitness tends to be higher in countries with greater gender equality and higher levels of human development. The findings suggest that social conditions and national policies may shape people’s access to physical activity and their ability to maintain physical health.

There is strong scientific agreement that being physically active helps prevent disease and supports long-term health. Regular movement improves cardiorespiratory fitness, which refers to the ability of the heart and lungs to supply oxygen to the muscles during activity. Higher levels of cardiorespiratory fitness are linked with a lower risk of death from all causes, including heart disease and cancer.

However, researchers have long suspected that fitness levels are not solely determined by individual choices. Factors such as where people live, their income, access to safe outdoor spaces, social support, and even national policies may influence how active they can be. Gender may also play a role. In many societies, women face more barriers to physical activity than men, including caregiving responsibilities, fewer sports opportunities, or concerns about safety.

Despite these observations, the relationship between fitness levels and broader societal factors has not been studied in depth. Previous research has focused mostly on children or used indirect measures of fitness. The current study aimed to close this gap by examining how cardiorespiratory fitness in adults relates to two specific indicators: the Human Development Index, which includes education, income, and life expectancy, and the Gender Inequality Index, which measures disparities between men and women in areas such as health, political power, and the labor market.

The researchers reviewed thousands of studies and selected 95 that included direct measurements of peak oxygen uptake, a key marker of cardiorespiratory fitness, in healthy adults. This measurement, often referred to as VO2peak, is collected during a maximal exercise test in which participants exert themselves on a treadmill or bicycle while their breathing is analyzed. These tests are considered the gold standard for measuring fitness.

The final dataset included over 119,000 adults, with roughly 58 percent men and 42 percent women. The participants came from a diverse group of countries including the United States, Brazil, Germany, China, and Japan. Each study was matched with the relevant Human Development Index and Gender Inequality Index scores for the country and year in which data were collected.

The researchers found that fitness tends to decrease with age and that, on average, women had lower VO2peak values than men. However, when comparing countries, they noticed a pattern: adults in countries with higher levels of human development and lower levels of gender inequality had higher fitness levels.

The relationship between development and fitness was especially pronounced among women. Women living in countries with high human development scores had higher VO2peak levels across all age groups. For men, this trend was mainly observed in those under 40 years old. This suggests that women may benefit more from living in supportive and equitable societies when it comes to maintaining physical fitness.

A similar pattern emerged when looking at gender inequality. In countries with less gender inequality, both men and women had higher cardiorespiratory fitness, but the effect was again stronger for women. The difference was most notable among women under 40. Young women living in countries with low gender inequality had fitness levels that were on average 6.5 mL/kg/min higher than those in countries with high gender inequality. This difference is large enough to matter for health, as even small increases in VO2peak are linked with reduced risks of chronic disease and early death.

These results suggest that policies and social structures that promote equality and development may indirectly support better health by enabling more people, especially women, to engage in regular and vigorous physical activity.

Although this study includes one of the largest datasets of directly measured VO2peak values ever compiled, it is not without its limitations. The researchers were only able to include studies that used standardized testing methods and reported data by age and sex. This meant that many large population studies that estimated fitness indirectly had to be excluded. While this choice improved the reliability of the results, it also limited the diversity of countries included.

Most of the data came from countries with medium to high development levels. There was a lack of data from countries with low development scores, which makes it difficult to understand the full range of global fitness patterns. Additionally, many of the studies did not provide information on participants’ race, ethnicity, or socioeconomic background. These gaps are important because they could affect how fitness relates to social inequality in different contexts.

The authors suggest that future research should aim to collect more data from underrepresented populations and countries. They also recommend investigating how specific social policies, such as workplace fitness programs or community sports initiatives, might improve cardiorespiratory fitness, especially for women and vulnerable groups.

The study, “Human development and gender inequality are associated with cardiorespiratory fitness: A global systematic review of VO2peak,” was authored by Nicolas J. Pillon, Joaquin Ortiz de Zevallos, Juleen R. Zierath, and Barbara E. Ainsworth.

A new pair of large-scale studies finds that while political conservatives and ideological extremists are slightly less likely to update their beliefs when presented with new evidence, these effects are very small. The research, published in the journal Political Psychology, suggests that broad, sweeping claims about a strong connection between a person’s political views and their cognitive rigidity are likely not justified.

The study was conducted as an “adversarial collaboration,” a unique scientific approach where researchers with opposing viewpoints team up to design a study they all agree is a fair test of their competing ideas. This method is intended to reduce the biases that can arise when scientists design studies that might favor their own pre-existing theories. The goal was to find a definitive answer to a long-debated question: Is a rigid way of thinking associated with a particular political ideology?

“There is a rich and longstanding history of examining the relations between political ideology and rigidity,” said corresponding author Shauan Bowes, an assistant professor at the University of Alabama in Huntsville. “Much of this research has been rife with debate, and it is a vast and complex literature. An adversarial collaboration brings together disagreeing scholars to examine a research question, affording the opportunity for more accurate and nuanced research. Here, the adversaries were hoping to provide additional clarity on the nature of the relations between political ideology and rigidity, testing three different primary hypotheses.”

For decades, psychologists have explored the underpinnings of political beliefs. One prominent idea has been the “rigidity-of-the-right” hypothesis. This perspective suggests that conservative ideology is rooted in a less flexible thinking style and a greater need for certainty. According to this view, these traits make conservatives less open to changing their minds.

A second perspective offers a different explanation, known as the symmetry model. Proponents of this view argue that psychological motivations to fit in with a group and avoid social punishment can lead to rigid thinking in people of any political persuasion. They propose that there is no inherent reason to believe one side of the political spectrum would be more or less flexible than the other; any differences would depend on the specific topic being discussed.

A third idea is the “rigidity-of-extremes” hypothesis. This theory posits that inflexibility is not about being left or right, but about being at the ideological fringes. People with extreme political views, whether on the far left or the far right, may be more rigid in their thinking than political moderates. Extreme ideologies often provide simple, clear-cut answers to complex societal problems, which can foster a high degree of certainty and a reluctance to consider alternative viewpoints.

A major challenge in this area of research has been defining and measuring “rigidity.” The term has been used in many different ways, and many popular measures have been criticized for containing questions that are already biased toward a certain political ideology.

To overcome this, the collaborating researchers first reviewed dozens of ways rigidity has been measured. After a thorough process of elimination, they unanimously agreed on one operationalization they all considered valid and unbiased: evidence-based belief updating. This simply means measuring how much a person changes their belief about a statement after being shown evidence that supports it. A person who shows less belief change is considered more rigid.

Before launching their main studies, the team conducted a pretest with over 2,000 participants. Their aim was to find pairs of political statements that were ideologically balanced. They generated statements that made arguments friendly to both liberal and conservative viewpoints on the same topic. For example, one statement suggested that people who are liberal on social issues score higher on intelligence tests, while its counterpart suggested people who are fiscally conservative score higher. By analyzing how people with different ideologies rated these statements, the researchers selected pairs that showed no overall bias, ensuring the main studies would be a fair test.

In the first study, nearly 2,500 American participants were asked to rate their agreement with several political statements. After giving an initial rating, they were shown a short piece of information from a credible source, like a university, that supported the statement. For example, a statement might read, “The U.S. economy performs better under Democratic presidents than under Republican presidents,” followed by evidence from a research institution supporting that claim. Participants then rated the same statement a second time. The researchers measured the change between the first and second ratings to calculate a belief updating score.

The results of this first study showed a weak but statistically significant relationship. People who identified as socially or generally conservative updated their beliefs slightly less than liberals did. The analysis also found that general political extremism was associated with less belief updating. However, the size of these effects was very small. For instance, a one standard deviation increase in conservatism or extremism resulted in a change of less than 1.5 points on a 200-point scale of belief updating.

“I was surprised by how the results were consistently quite small,” Bowes told PsyPost. “Previous studies may have conflated ideology and rigidity measures, which can artificially inflate effect sizes. Because the adversaries intentionally designed an ideology-neutral measure of rigidity, the results were small. And, from my perspective, they were smaller than I would have initially presumed.”

The second study aimed to replicate and build upon the first. This time, the research team recruited more than 3,700 U.S. participants, making a special effort to include more people from the extreme ends of the political spectrum. They also made the evidence presented to participants more engaging, designing it to look like a blog post from a research institution. The fundamental procedure remained the same: participants rated a statement before and after seeing evidence for it.

The findings from the second study mirrored those of the first. Once again, general and social conservatism were weakly associated with less belief updating. In this larger sample with more extremists, all measures of extremism were also significantly linked to less belief updating. People on the far right tended to be slightly more rigid than people on the far left. Despite these consistent patterns, the effects remained tiny and, from a practical standpoint, negligible.

By combining the data from both studies, the researchers created a large dataset of over 6,000 participants. This combined analysis confirmed the earlier findings. Conservatism and extremism were both associated with slightly less willingness to change one’s mind in the face of evidence. But the size of these relationships was consistently very small, suggesting that a person’s political ideology is a very poor predictor of how much they will update their beliefs in this kind of task.

The authors, representing all sides of the original debate, came to a shared conclusion. Centrists and moderates showed the most belief updating, or the least rigidity. When comparing groups, people on the political right, especially the far right, were slightly more rigid. However, the weakness and inconsistency of these effects across different measures of ideology mean that the practical importance of this connection is questionable.

“The relations between political ideology and rigidity, which in this context was belief rigidity (i.e., less willing to update one’s views after being presented with evidence), are generally small, which calls into question the practical importance of ideological differences in rigidity in this context,” Bowes explained. “There was semi-consistent support for the rigidity-of-the-right hypothesis (conservatives are more rigid than liberals) and rigidity-of-extremes (political extremes are more extreme than political moderates) hypothesis.”

“That said, the adversaries acknowledge that because the results are quite small and only semi-consistent, one could reasonably interpret the results as lending support to symmetry perspectives (the left and right are equally rigid but about different topics). ”

The team suggests that instead of asking the broad question of who is more rigid, researchers should focus on identifying the specific contexts and issues that might cause rigidity to appear more strongly in certain groups.

The study did have some limitations. The research was conducted with American participants at a specific point in time, and the findings might not apply to other countries or different political eras. It also focused on only one type of rigidity, belief updating, and did not examine other forms, such as personality traits associated with inflexibility. Future studies could explore these relationships over time or in different cultural contexts to see if the patterns hold.

“We only studied belief rigidity, which is one form of rigidity,” Bowes noted. “We do not want to make sweeping claims about rigidity writ large and encourage others to examine whether our results do or do not held when examining other manifestations of rigidity.”

“I think it would be immensely beneficial to examine additional forms of rigidity in relation to political ideology and consider boundary conditions. That is, there are likely contexts where the relationship is much stronger, and we should be focusing on that question rather than ‘overall, who is more rigid in general?'”

The study, “An adversarial collaboration on the rigidity-of-the-right, symmetry thesis, or rigidity-of-extremes: The answer depends on the question,” was authored by Shauna M. Bowes, Cory J. Clark, Lucian Gideon Conway III, Thomas Costello, Danny Osborne, Philip E. Tetlock, and Jan-Willem van Prooijen.

A new study provides evidence that the human brain constructs our seamless experience of the world by first breaking it down into separate predictive models. These distinct models, which forecast different aspects of reality like context, people’s intentions, and potential actions, are then unified in a central hub to create our coherent, ongoing subjective experience. The research was published in the journal Nature Communications.

The scientists behind the new study proposed that our world model is fragmented into at least three core domains. The first is a “State” model, which represents the abstract context or situation we are in. The second is an “Agent” model, which handles our understanding of other people, their beliefs, their goals, and their perspectives. The third is an “Action” model, which predicts the flow of events and possible paths through a situation.

“There’s a long-held tradition, and with good evidence that the mind is composed of many, different modules specialized for distinct computations. This is obvious in perception with modules dedicated to faces and places. This is not obvious in higher-order, more abstract domains which drives our subjective experience. The problem with this is non-trivial. If it does have multiple modules, how can we have our experience seemingly unified?” explained study author Fahd Yazin, a medical doctor who’s currently a doctoral candidate at the University of Edinburgh.

“In learning theories, there are distinct computations needed to form what is called a world model. We need to infer from sensory observations what state we are in (context). For e.g. if you go to a coffee shop, the state is that you’re about to get a coffee. But if you find that the machine is out-of- order, then the current state is you’re not going to get it. Similarly, you need to have a frame of reference (frame) to put these states in. For instance, you want to go to the next shop but your friend had a bad experience there previously, you need to take their perspective (or frame) into account. You possibly had a plan of getting a coffee and chat, but now you’re willing to adapt a new plan (action transitions) of getting a matcha drink instead.”

“You’re able to do all these things in a deceptively simple way because various modules can coordinate their output, or predictions together. And switch between various predictions effortlessly. So, if we disrupt their ongoing predictions in a natural and targeted way, you can get two things. The brain regions dedicated to these predictions, and how they influence our subjective experience.”

To explore this, the research team conducted a series of experiments using functional magnetic resonance imaging, a technique that measures brain activity by detecting changes in blood flow. In the main experiment, a group of 111 young adults watched an eight-minute suspenseful excerpt from an Alfred Hitchcock film, “Bang! You’re Dead!” while inside a scanner. They were given no specific instructions other than to watch the movie, allowing the scientists to observe brain activity during a naturalistic experience.

To understand when participants’ predictions were being challenged and updated, the researchers collected data from separate groups of people who watched the same film online. These participants were asked to press a key whenever their understanding of the movie’s context (State), a character’s beliefs (Agent), or the likely course of events (Action) suddenly changed. By combining the responses from many individuals, the scientists created timelines showing the precise moments when each type of belief was most likely to be updated.

Analyzing the brain scans from the movie-watching group, the scientists found a clear division of labor in the midline prefrontal cortex, a brain area associated with higher-level thought. When the online raters indicated a change in the movie’s context, the ventromedial prefrontal cortex became more active in the scanned participants. When a character’s perspective or intentions became clearer, the anteromedial prefrontal cortex showed more activity. And when the plot took a turn that changed the likely sequence of future events, the dorsomedial prefrontal cortex was engaged.

The researchers also found that these moments of belief updating corresponded to significant shifts in the brain’s underlying neural patterns. Using a computational method called a Hidden Markov Model, they identified moments when the stable patterns of activity in each prefrontal region abruptly transitioned. These neural transitions in the ventromedial prefrontal cortex aligned closely with updates to “State” beliefs.

Similarly, transitions in the anteromedial prefrontal cortex coincided with “Agent” updates, and those in the dorsomedial prefrontal cortex matched “Action” updates. This provides evidence that when our predictions about the world are proven wrong, it triggers not just a momentary spike in activity, but a more sustained shift in the neural processing of that specific brain region.

Having established that predictions are handled by separate modules, the researchers next sought to identify where these fragmented predictions come together. They focused on the precuneus, a region located toward the back of the brain that is known to be a major hub within the default mode network, a large-scale brain network involved in internal thought.

By analyzing the functional connectivity, or the degree to which different brain regions activate in sync, they found that during belief updates, each specialized prefrontal region showed increased communication with the precuneus. This suggests the precuneus acts as an integration center, receiving the updated information from each predictive module.

To further investigate this integration, the team examined the similarity of multivoxel activity patterns between brain regions. They discovered a dynamic process they call “multithreaded integration.” When participants’ beliefs about the movie’s context were being updated, the activity patterns in the precuneus became more similar to the patterns in the “State” region of the prefrontal cortex.

When beliefs about characters were changing, the precuneus’s patterns aligned more with the “Agent” region. This indicates that the precuneus flexibly syncs up with whichever predictive module is most relevant at a given moment, effectively weaving the separate threads of prediction into a single, coherent representation.

The scientists then connected this integration process to subjective experience. Using separate ratings of emotional arousal, a measure of how engaged and immersed viewers were in the film, they found that the activity of the precuneus closely tracked the emotional ups and downs of the movie. The individual prefrontal regions did not show this strong relationship.

What’s more, individuals whose brains showed stronger integration between the prefrontal cortex and the precuneus also had more similar overall brain responses to the movie. This suggests that the way our brain integrates these fragmented predictions directly shapes our shared subjective reality.

“At any given time, multiple predictions may compete or coexist, and our experience can shift depending on which predictions are integrated that best align with reality,” Yazin told PsyPost. “People whose brains make and integrate predictions in similar ways are likely to have more similar experiences, while differences in prediction patterns may explain why individuals perceive the same reality differently. This approach provides new insight into how shared realities and personal differences arise, offering a framework for understanding human cognition.”

To confirm these findings were not specific to one movie or to visual information, the team replicated the key analyses using a different dataset where participants listened to a humorous spoken-word story. They found the same modular system in the prefrontal cortex and the same integrative role for the Precuneus, demonstrating that this is a general mechanism for how the brain models the world, regardless of the sensory input.

“We replicated the main findings across a different cohort, sensory modality and emotional content (stimuli), making these findings robust to idiosyncratic factors,” Yazin said. “These results were observed when people were experiencing stimuli (movie/story) in a completely uninterrupted and uninstructed manner, meaning our experience is continuously rebuilt and adapted into a coherent unified stream despite it originating in a fragmented manner.”

“Our experience is not just a simple passive product of our sensory reality. It is actively driven by our predictions. And these come in different flavors; about our contexts we find ourselves in, about other people and about our plans of the immediate future. Each of these gets updated as the sensory reality agrees (or disagrees) with our predictions. And integrates with that reality to form our ‘current’ experience.”

“We have multiple such predictions internally, and at any given time our experience can toggle between these depending on how the reality fits them,” Yazin explained. “In other words, our original experience is a product of fragmented and distributed predictions integrated into a unified whole. And people with similar way of predicting and integrating, would have similar experiences from the reality than people who are dissimilar.”

“More importantly, it brings the default mode network, a core network in the human brain into the table as a central network driving our core phenomenal experience. It’s widely implicated in learning, inference, imagination, memory recall and in dysfunctions to these. Our results offer a framework to fractionate this network by computations of its core components.”

But as with all research, the study has some limitations. The analysis is correlational, meaning it shows associations between brain activity and belief updates but cannot definitively prove causation. Also, because the researchers used naturalistic stories, the different types of updates were not always completely independent; a single plot twist could sometimes cause a viewer to update their understanding of the context, a character, and the future plot all at once.

Still, the consistency of the findings across two very different naturalistic experiences provides strong support for a new model of human cognition. “Watching a suspenseful movie and listening to a comedic story feels like two very different experience but the fact that they have similar underlying regions with similar specialized processes for generating predictions was counterintuitive,” Yazin told PsyPost. “And that we could observe it in this data was something unexpected.”

Future research will use more controlled, artificially generated stimuli to better isolate the computations happening within each module.

“We’re currently exploring the nature of these computations in more depth,” Yazin said. “In naturalistic stimuli as we’ve used now, it is impossible to fully separate domains (the contributions of people and contexts are intertwined in such settings). It brings richness but you lose experimental control. Similarly, the fact that these prefrontal regions were sensitive regardless of content and sensory information means there is possibly an invariant computation going on within them. We’re currently investigating these using controlled stimuli and probabilistic models to answer these questions.”

“For the last decade or so, there’s been two cultures in cognitive neuroscience,” he added. “One is using highly controlled stimuli, and leveraging stimulus properties to ascertain regional involvement to that function to various degrees. Second is using full-on naturalistic stimuli (movies, narratives, games) to understand how humans experience the world with more ecological accuracy. Each has brought unique and incomparable insights.”

“We feel studies on subjective experience/phenomenal consciousness has focused more on the former because it is easier to control (perceptual features/changes), but there’s a rich tradition and methods in the latter school that may help uncover more intractable problems in novel ways. Episodic ,emory and semantic processing are two great examples of this, where using naturalistic stimuli opened up connections and findings that were completely new to each of those fields.”

The study, “Fragmentation and multithreading of experience in the default-mode network,” was authored by Fahd Yazin, Gargi Majumdar, Neil Bramley, and Paul Hoffman.