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<td><span style="font-family:Helvetica, sans-serif; font-size:20px;font-weight:bold;">PsyPost – Psychology News</span></td>
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<td><a href="https://www.psypost.org/older-adults-consuming-more-spermidine-have-better-cognitive-performance/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">Older adults consuming more spermidine have better cognitive performance</a>
<div style="font-family:Helvetica, sans-serif; text-align:left;color:#999;font-size:11px;font-weight:bold;line-height:15px;">Jul 23rd 2025, 10:00</div>
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<p><p>New research suggests that a higher dietary intake of spermidine is associated with significantly better performance on cognitive tests among older adults. The potential protective effect was more pronounced in males, individuals who were somewhat overweight, those with hypertension or hyperlipidemia, and non-Hispanic Whites. The findings were published in the <a href="https://doi.org/10.1016/j.jad.2025.03.181"><em>Journal of Affective Disorders</em></a>.</p>
<p>Spermidine is a naturally occurring polyamine compound found in all living cells. It supports cellular growth, maintenance, and the removal of damaged components through a process called autophagy. It plays a key role in maintaining cellular health and has been linked in experimental studies to anti-aging and heart-protective effects. However, spermidine levels decline with age, which may contribute to age-related cellular dysfunction.</p>
<p>Foods rich in spermidine include aged cheese, soy products (especially natto), mushrooms, whole grains, legumes, green peas, and certain fruits such as grapefruit. Wheat germ and some fermented foods are also high in spermidine. The compound is available as a dietary supplement as well. Previous research has suggested that higher spermidine intake may reduce the risk of cardiovascular disease and enhance cognitive function, although human clinical trials remain limited.</p>
<p>Study author Yifan Ma and her colleagues sought to examine the relationship between dietary spermidine intake and cognitive performance in older adults. They analyzed data from the U.S. National Health and Nutrition Examination Survey (NHANES) collected between 2011 and 2014.</p>
<p>NHANES is a program administered by the Centers for Disease Control and Prevention that uses a nationally representative sample to assess the health and nutritional status of the U.S. population. It combines interviews, physical exams, and dietary assessments to generate a rich dataset used in public health research and policymaking.</p>
<p>For this analysis, the researchers included participants aged 60 and older who had completed cognitive function tests during the 2011–2014 survey cycles. The final sample included 2,674 participants, of whom 1,361 were women. Participants completed two 24-hour dietary recall interviews, during which they reported everything they had eaten or drunk in the previous 24 hours. They also completed a questionnaire about dietary supplement use. These responses were used to estimate each participant’s spermidine intake. Cognitive function was assessed using four standardized tests.</p>
<p>The results showed that participants in the highest quartile of spermidine intake (the top 25%) performed better on cognitive tests than those with lower intake. Further analyses revealed that the positive association between spermidine and cognitive performance was stronger in males, non-Hispanic Whites, individuals with a body mass index between 25 and 30, and those with high blood pressure or high blood lipid levels.</p>
<p>“This study provides evidence supporting the association between higher dietary SPD [spermidine] intake and improved cognitive performance in older adults. The protective effect was more pronounced in certain subgroups, particularly in males, non-Hispanic whites, and individuals with specific chronic conditions. These findings suggest that SPD may be a valuable component in dietary strategies aimed at improving cognitive health in older adults and populations with chronic diseases,” the study authors concluded.</p>
<p>The study contributes to the scientific understanding of the health effects of spermidine intake. However, it should be noted that the design of the study does not allow any causal inferences to be derived from the results. While it is possible that spermidine has neuroprotective properties, it is also possible that older individuals with better cognitive functioning are better able to provide themselves with healthy diets.</p>
<p>The paper, “<a href="https://doi.org/10.1016/j.jad.2025.03.181">Association between dietary spermidine intake and cognitive performance in older adults: The U.S. National Health and Nutrition Examination Survey, 2011–2014</a>,” was authored by Yifan Ma, Leyao Qi, Fangyi Zhu, Mengjie Xiao, Mengyao Li, Xu Zhang, Xiaodi Yuan, Yuan Wang, Changhao Sun, and Huanyu Wu.</p></p>
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<td><a href="https://www.psypost.org/an-ancient-survival-instinct-may-explain-why-we-crave-junk-food-during-uncertain-times/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">An ancient survival instinct may explain why we crave junk food during uncertain times</a>
<div style="font-family:Helvetica, sans-serif; text-align:left;color:#999;font-size:11px;font-weight:bold;line-height:15px;">Jul 23rd 2025, 08:00</div>
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<p><p>New research published in <em><a href="https://www.sciencedirect.com/science/article/abs/pii/S0950329325002071" target="_blank">Food Quality and Preference</a></em> provides evidence that people are more visually drawn to high-calorie foods when they anticipate future scarcity, especially in contexts that feel unstable or resource-poor. Using eye-tracking technology, the study showed that participants were quicker to fixate on, looked longer at, and rated high-calorie foods as more desirable—particularly if they imagined living in a world marked by economic uncertainty.</p>
<p>Across evolutionary history, the threat of food shortages has shaped human behavior in powerful ways. When resources are uncertain, people tend to seek out energy-dense foods that offer more calories per bite. This tendency may have been adaptive in ancestral environments, where finding enough food was often a matter of survival. </p>
<p>Today, this ancient preference may still influence eating behavior—especially in environments that signal danger, poverty, or instability. Researchers led by Ray Garza wanted to explore how cues from the environment interact with individual concerns about future food access. </p>
<p>“Evolutionary perspectives on eating behavior suggest that humans have always faced harsh environments, and prioritizing energy dense foods is a solution to a recurring adaptive problem of food insecurity,” said study author Ray Garza, an assistant professor of psychology and head of the Evolutionary Visual Lab at Texas A&M International University.</p>
<p>“Previous research shows that ecological cues of harshness (i.e., resources scarcity/violence) and anticipated food scarcity prompt individuals to select high-caloric foods. We wanted to explore the underlying mechanisms involved, such as visual attention indexed by tracking eye-movements. Most studies have relied upon survey data, and we wanted to utilize an experimental approach using eye-tracking.”</p>
<p>To investigate this, the researchers designed an experiment that exposed people to imagined ecological conditions before measuring their attention to different foods. A total of 142 participants, primarily women attending a predominantly Hispanic-serving university in Texas, were randomly assigned to one of three priming scenarios. One scenario portrayed a stable, resource-rich environment (safe condition). Another highlighted economic instability through scenes of job loss and foreclosures (resource scarce condition). The third emphasized violent, dangerous environments using imagery related to crime (violent condition).</p>
<p>After reading or viewing their assigned scenario, participants were calibrated to an eye-tracking device and shown 80 paired images of food items—each pair featuring one high-calorie and one low-calorie option. The eye-tracking software measured how quickly participants looked at the foods, how long they looked at them, and how often they returned their gaze. Participants also completed a food desirability task where they rated the appeal of 30 food images and estimated the number of calories in each item.</p>
<p>The researchers also assessed a range of individual differences. Participants filled out questionnaires measuring their hunger level, socioeconomic background, and a specific scale designed to assess anticipated food scarcity—a person’s belief that food shortages will likely occur in the future. This allowed the team to examine how personal expectations about scarcity interacted with the priming scenarios to influence food attention and preferences.</p>
<p>Across all conditions, participants were faster to look at high-calorie foods and spent more time visually attending to them compared to low-calorie foods. They also rated high-calorie foods as more desirable overall. These effects were seen even when controlling for hunger and socioeconomic status, suggesting a generalized preference for energy-dense foods.</p>
<p>But the most important findings emerged when individual beliefs about food scarcity were taken into account. Among people who anticipated more food scarcity, the priming condition made a difference. In the resource scarce scenario, those with higher food scarcity beliefs were more likely to look at high-calorie foods for longer and fixate on them more frequently. They also rated those foods as more desirable. In contrast, those same individuals did not show a similar preference shift in the violent condition, and in the safe condition, they actually showed slightly more interest in low-calorie foods.</p>
<p>“We did find that when primed with cues of safety, anticipated food scarcity was associated with higher desirability ratings for low-caloric compared to high-caloric foods,” Garza told PsyPost. “Safety cues may prime individuals with availability of resources, which in turn, limits the need for energy-dense food.”</p>
<p>This pattern suggests that not all environmental threats affect eating behavior in the same way. Situations that signal economic deprivation or limited access to food may activate evolved psychological mechanisms that prioritize immediate caloric gains. Violent environments, on the other hand, may generate stress or fear, which can disrupt normal appetite patterns or result in more generalized responses.</p>
<p>The eye-tracking results offered a unique window into the underlying cognitive processes. High-calorie foods were not only more desirable—they were visually prioritized. People with high anticipated food scarcity scores who were primed with resource scarcity directed more visual attention to high-calorie foods, suggesting that these foods are automatically flagged as more important under threat. The findings align with the insurance hypothesis, which proposes that people gravitate toward calorie-dense options as a buffer against future uncertainty.</p>
<p>The researchers interpret these results through the lens of life history theory, an evolutionary framework that explains how organisms adjust their behaviors based on environmental conditions. In unpredictable or harsh environments, a “faster” strategy—focused on immediate rewards rather than long-term planning—may be more adaptive. In this case, a faster strategy may manifest as heightened interest in high-calorie foods, which could provide immediate energy to help survive uncertain times.</p>
<p>“Anticipated food scarcity and cues of resource scarcity affect the way individuals attend to food by viewing high-caloric foods longer,” Garza explained. “This may be to potentially buffer against times of uncertainty, as visual information may influence decision making in eating behaviors.”</p>
<p>There are some limitations to consider. The experiment was conducted in a lab using still images, which may not reflect how people engage with real food in natural settings. Future studies could use wearable eye-tracking glasses in grocery stores or restaurants to examine attention in everyday environments. The sample, drawn largely from female college students, also limits generalizability. It’s unclear whether the same effects would be observed in men or older adults.</p>
<p>“We are looking at investigating other cues of harshness, such as intrasexual competition (i.e., same-sex competition) cues and its role in eating behavior using an eye-tracking paradigm,” Garza said.</p>
<p>The study, “<a href="https://doi.org/10.1016/j.foodqual.2025.105632" target="_blank">Ecological harshness cues modulate food preferences and visual attention: An eye-tracking study</a>,” was authored by Ray Garza, Dariela Galindo, Karla P. Garcia, and Tiffany Gutierrez.</p></p>
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<td><a href="https://www.psypost.org/trump-supporters-report-higher-levels-of-psychopathy-manipulativeness-callousness-and-narcissism/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">Trump supporters report higher levels of psychopathy, manipulativeness, callousness, and narcissism</a>
<div style="font-family:Helvetica, sans-serif; text-align:left;color:#999;font-size:11px;font-weight:bold;line-height:15px;">Jul 23rd 2025, 06:00</div>
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<p><p>A new psychological study has found that people who report favorable views of Donald Trump also tend to score higher on measures of callousness, manipulation, and other malevolent traits—and lower on empathy and compassion. The findings, based on two large surveys of U.S. adults, shed light on how personality traits relate to political beliefs, including support for Trump and conservative ideology. The research was recently published in the <em><a href="https://doi.org/10.1016/j.jrp.2025.104638" target="_blank">Journal of Research in Personality</a></em>.</p>
<p>Malevolent personality traits—sometimes called “dark” traits—include tendencies such as manipulativeness, callousness, narcissism, and a lack of empathy. These traits are often captured by concepts like psychopathy, Machiavellianism, and narcissism, which together reflect a general disposition toward exploiting or disregarding others for personal gain.</p>
<p>People with stronger malevolent traits may be more comfortable with aggression, dominance, or cruelty and less likely to value fairness or kindness. These tendencies are associated with lower levels of affective empathy (concern for others’ suffering) and, in some cases, higher levels of dissonant empathy (enjoyment of others’ pain). In contrast, benevolent traits reflect the opposite—a disposition marked by compassion, humanism, and a belief in treating others with dignity and respect.</p>
<p>The researchers conducted the study to better understand the psychological traits that underlie political ideology, particularly support for Donald Trump and conservative beliefs. Prior work had already linked conservative ideology with right-wing authoritarianism and social dominance, but the researchers hypothesized that malevolent personality traits might also play a role—especially given Trump’s rhetoric and behavior, which often display dominance, callousness, and disregard for social norms.</p>
<p>They were especially interested in whether support for Trump was associated with higher malevolent traits and lower empathy, and whether benevolent traits might predict a more liberal or non-authoritarian outlook. The study aimed to clarify how these personality dispositions relate to political beliefs and what this might reveal about the deeper psychological dimensions of ideology.</p>
<p>“This paper was several years in the making, starting as a result of the 2016 election, and was designed to address why some people might view favorably a political figure with a history of business failures, bankruptcies, misogynistic statements caught on video, use of charity money for a self-portrait, etc,” explained study author <a href="https://craigsneumann.weebly.com/" target="_blank" rel="noopener">Craig Neumann</a>, a Regents Professor of Psychology at the University of North Texas.</p>
<p>“Also, there is a large literature on personality and ideology (e.g., low honesty-humility associated with conservative ideology), but only recently have there been studies on malevolent personality (e.g., callousness, narcissism, Machiavellianism) and ideology. More critically, few studies have examined the associations between benevolent (affiliative) personality and political ideology. Finally, many studies in this area tend to statistically control demographic factors, but we sought to examine how the associations between personality and ideology might be moderated by gender or minority status.”</p>
<p>To investigate these links, the researchers conducted two large surveys with a total of over 9,000 participants from the United States. The first sample consisted of 1,000 men recruited online, about one-third of whom were racial or ethnic minorities. The second sample included 8,047 men and women who completed personality questionnaires on a public psychology website.</p>
<p>Participants in both samples completed a range of validated questionnaires measuring political attitudes, personality traits, and empathy. Political ideology was assessed through questions about general political orientation, preferences for military versus social spending, support for gun control, and evaluations of Trump’s first term as president. The researchers used structural equation modeling, a statistical technique that allows for the testing of relationships between multiple variables at once, while accounting for measurement errors.</p>
<p>In Sample 1, the researchers measured social dominance orientation (the belief that some groups should dominate others), right-wing authoritarianism (support for conformity, obedience, and traditional norms), and psychopathic traits. In Sample 2, they added measures of broader malevolent traits (psychopathy, Machiavellianism, narcissism) and benevolent traits (humanism, faith in humanity, Kantian respect for others). Empathy was also assessed in the first sample, distinguishing between its emotional, cognitive, and dissonant forms.</p>
<p>The findings consistently showed that people who identified as politically conservative—and especially those who rated Trump’s presidency highly—were more likely to score higher on measures of authoritarianism, social dominance, and malevolent personality traits.</p>
<p>In the first sample of men, all three predictors — social dominance, authoritarianism, and psychopathic tendencies — predicted conservative ideology and favorable views of Trump, but only for white participants. Among men of minority status, psychopathic traits were not significantly related to political ideology. This suggests that the psychological pathways to conservatism may differ based on racial or ethnic identity, possibly due to different experiences with social power and marginalization.</p>
<p>Support for Trump was also associated with distinct patterns in empathy. Compared to those who did not support Trump, Trump supporters reported lower affective empathy (less emotional concern for others) and higher dissonant empathy (greater enjoyment of others’ suffering). These differences held even after controlling for age, education, and racial background.</p>
<p>In the second, larger sample that included both men and women, the researchers focused on how broad personality dispositions—benevolent versus malevolent—related to political beliefs. They found that people who reported stronger benevolent traits, such as valuing the dignity and worth of others, were more likely to hold liberal views and reject Trump. In contrast, people who reported more malevolent traits—such as manipulation, selfishness, and emotional coldness—were more likely to support Trump and identify as conservative.</p>
<p>While both men and women showed this pattern, the associations were stronger for men. In other words, malevolent traits were more predictive of conservative ideology among men than among women. Women in the sample tended to score higher on benevolent traits overall and lower on malevolent ones.</p>
<p>Those who viewed Trump favorably reported higher levels of malevolent traits and lower levels of benevolent ones. In other words, Trump supporters scored higher on traits such as Machiavellianism, narcissism, and psychopathy—which reflect manipulativeness, entitlement, emotional callousness, impulsivity, and antisocial behavior—and lower on traits such as humanism, faith in humanity, and Kantianism, which reflect compassion, belief in others’ basic goodness, and a commitment to treating people as ends rather than means.</p>
<p>These differences were not explained by other factors such as age, income, education level, or minority status. The authors concluded that personality traits linked to callousness and self-centeredness may shape how people engage with politics—and in particular, how they relate to the Trumpist strain of conservatism.</p>
<p>One of the study’s most striking findings was the consistent link between empathy and political orientation. While people across the political spectrum are capable of empathy, the results suggest that those on the political right—especially those aligned with Trump—may experience and express empathy differently.</p>
<p>Supporters of Trump were less likely to feel concern for others’ suffering (lower affective empathy) and more likely to enjoy or be indifferent to others’ distress (higher dissonant empathy). Importantly, these differences were not found in cognitive empathy. Trump supporters were just as able as others to recognize emotions in others—they simply appeared to care less, on average.</p>
<p>The new findings align with earlier research showing that Donald Trump’s political appeal has been especially strong among individuals who endorse authoritarian aggression and group-based dominance. In the 2016 Republican primaries, Trump supporters stood out from supporters of other Republican candidates not because they were more submissive to authority or resistant to social change, but because they were <a href="https://www.psypost.org/authoritarian-aggression-and-group-based-dominance-distinguished-trump-supporters-from-other-republicans-in-2016/" target="_blank" rel="noopener">more likely to endorse the use of aggressive tactics</a> and hierarchical worldviews that place some groups above others.</p>
<p>The current study builds on this by suggesting that these ideological patterns are not just political opinions—they are rooted in deeper psychological dispositions, including lower empathy and stronger malevolent traits like callousness, narcissism, and enjoyment of others’ suffering.</p>
<p>“Consistent with emerging research, our findings suggest a link between malevolent (aversive) personality and conservative political ideology, which in our study included positive view of Trump, and that persons with malevolent personality dispositions view political figures with malevolent traits favorably,” Neumann told PsyPost. “Further, people who view malevolent political figures favorably also report less empathy for others and enjoy the suffering of others.”</p>
<p>“We also found that benevolent (affiliative) dispositions were associated with a liberal political ideology. All of these findings are bolstered by the use of a strong measurement invariance approach, indicating that measurement error or bias cannot account for the results. Finally, we found the same pattern of results across two samples which were from two different historical time periods when views of Trump may have changed (pre- and during COVID-19).”</p>
<p>But the study, like all research, has limitations. Although the study is based on large and diverse samples, the research was cross-sectional, meaning that it cannot determine cause and effect. It is also focused specifically on Trump’s first term in office, and attitudes may have shifted since then. Additionally, the study relied on self-report measures, which can be influenced by social desirability or personal biases, though the authors used statistical methods to reduce such effects.</p>
<p>It is also important to note that research compares average personality trait scores between two groups of people (those who viewed Trump favorably and those who did not). While the researchers found statistically significant differences—such as higher average scores on traits like psychopathy and lower scores on empathy among Trump supporters—these are group-level trends, not absolute labels. The findings do not mean that all Trump supporters are manipulative or lack compassion, nor that all non-supporters are empathetic or benevolent. Individuals within each group vary widely, and the results reflect differences in average tendencies, not universal characteristics.</p>
<p>“Next papers in the pipeline employ mega-samples from across the globe to further study of the connections between malevolent/benevolent personality and ideology, as well as modeling the core domains involved in Professor John Jost’s theory of motivated social cognition (epistemic, existential, relational) and their connection to ideology in different cultures,” Neumann said.</p>
<p>“Political ideology (left vs. right leaning; liberal vs. conservative) is not necessarily a good or bad thing, if it involves ideas about how to productively arrange our world. However, if a given ideology is fundamentally about one group’s malevolent domination of other individuals, then we should ask ourselves if this is the type of (uncivil) society we want to live in. For instance, does taking Medicaid away from vulnerable people while also giving money to the wealthy involve political malevolence or benevolence?”</p>
<p>The study, “<a href="https://doi.org/10.1016/j.jrp.2025.104638" target="_blank">Malevolent vs. benevolent dispositions and conservative political ideology in the Trump era</a>,” was authored by Craig S. Neumann and Darlene A. Ngo.</p></p>
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<td><a href="https://www.psypost.org/neuroscientists-target-glud1-receptor-to-repair-not-just-mask-chronic-pain/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">Neuroscientists target GluD1 receptor to repair, not just mask, chronic pain</a>
<div style="font-family:Helvetica, sans-serif; text-align:left;color:#999;font-size:11px;font-weight:bold;line-height:15px;">Jul 22nd 2025, 16:00</div>
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<p><p>Pain is easy to understand until it isn’t. A stubbed toe or sprained ankle hurts, but it makes sense because the cause is clear and the pain fades as you heal.</p>
<p>But what if the pain didn’t go away? What if even a breeze felt like fire, or your leg burned for no reason at all? When pain lingers without a clear cause, that’s <a href="https://my.clevelandclinic.org/health/diseases/15833-neuropathic-pain">neuropathic pain</a>.</p>
<p><a href="https://scholar.google.com/citations?user=5BGlpHIAAAAJ&hl=en">We are</a> <a href="https://scholar.google.com/citations?user=0fphogMAAAAJ&hl=en">neuroscientists who</a> study how pain circuits in the brain and spinal cord change over time. Our work focuses on the molecules that quietly reshape how pain is felt and remembered.</p>
<p>We didn’t fully grasp how different neuropathic pain was from injury-related pain until we began working in a <a href="https://medicine.tamu.edu/psychiatry/research/affective-neuroscience/dravid-lab%20.html">lab studying it</a>. Patients spoke of a <a href="https://my.clevelandclinic.org/health/diseases/12092-phantom-limb-pain">phantom pain</a> that haunted them daily – unseen, unexplained and life-altering.</p>
<p>These conversations shifted our focus from symptoms to mechanisms. What causes this ghost pain to persist, and how can we intervene at the molecular level to change it?</p>
<h2>More than just physical pain</h2>
<p><a href="https://doi.org/10.1152/physrev.00045.2019">Neuropathic pain</a> stems from damage to or dysfunction in the nervous system itself. The system that was meant to detect pain becomes the source of it, like a fire alarm going off without a fire. Even a soft touch or breeze can feel unbearable.</p>
<p>Neuropathic pain doesn’t just affect the body – it also <a href="https://doi.org/10.1016/j.neubiorev.2024.105673">alters the brain</a>. Chronic pain of this nature often leads to depression, anxiety, social isolation and a deep sense of helplessness. It can make even the most routine tasks feel unbearable.</p>
<p>About <a href="https://doi.org/10.2147/jpr.s127014">10% of the U.S. population</a> – tens of millions of people – experience neuropathic pain, and cases are rising as the population ages. Complications from diabetes, cancer treatments or spinal cord injuries can lead to this condition. Despite its prevalence, doctors often overlook neuropathic pain because its underlying biology is poorly understood.</p>
<p>There’s also an economic cost to neuropathic pain. This condition contributes to <a href="https://www.biospace.com/press-releases/neuropathic-pain-market-worth-11-53-billion-by-2030-coherent-market-insights">billions of dollars</a> in health care spending, missed workdays and lost productivity. In the search for relief, <a href="https://doi.org/10.1002/ejp.1494">many turn to opioids</a>, a path that, as seen from the opioid epidemic, can carry its own devastating consequences through addiction.</p>
<h2>GluD1: A quiet but crucial player</h2>
<p>Finding treatments for neuropathic pain requires answering several questions. Why does the nervous system misfire in this way? What exactly causes it to rewire in ways that increase pain sensitivity or create phantom sensations? And most urgently: Is there a way to reset the system?</p>
<p>This is where our lab’s work and the story of a receptor called GluD1 comes in. Short for <a href="https://pmc.ncbi.nlm.nih.gov/articles/PMC5553105/">glutamate delta-1 receptor</a>, this protein doesn’t usually make headlines. Scientists have long considered GluD1 a biochemical curiosity, part of the <a href="https://doi.org/10.1124/pr.109.002451">glutamate receptor family</a>, but not known to function like its relatives that typically transmit electrical signals in the brain.</p>
<p>Instead, GluD1 plays a different role. It helps <a href="https://doi.org/10.2217/fnl.13.35">organize synapses</a>, the junctions where neurons connect. Think of it as a construction foreman: It doesn’t send messages itself, but directs where connections form and how strong they become.</p>
<p>This organizing role is critical in shaping the way neural circuits develop and adapt, especially in regions involved in pain and emotion. Our lab’s research suggests that GluD1 acts as a <a href="https://doi.org/10.3390/cells10102644">molecular architect of pain circuits</a>, particularly in conditions like neuropathic pain where those circuits misfire or rewire abnormally. In parts of the nervous system crucial for pain processing like the <a href="https://doi.org/10.1111/bph.16296">spinal cord and amygdala</a>, GluD1 may shape how people experience pain physically and emotionally.</p>
<h2>Fixing the misfire</h2>
<p>Across our work, we found that disruptions to GluD1 activity is linked to persistent pain. Restoring GluD1 activity can reduce pain. The question is, how exactly does GluD1 reshape the pain experience?</p>
<p>In our first study, we discovered that <a href="https://doi.org/10.3390/cells10102644">GluD1 doesn’t operate solo</a>. It teams up with a protein called cerebellin-1 to form a structure that maintains constant communication between brain cells. This structure, called a <a href="https://doi.org/10.1016/j.neuron.2019.09.027">trans-synaptic bridge</a>, can be compared to a strong handshake between two neurons. It makes sure that pain signals are appropriately processed and filtered.</p>
<p>But in chronic pain, the bridge between these proteins <a href="https://doi.org/10.3390/cells10102644">becomes unstable and starts to fall apart</a>. The result is chaotic. Like a group chat where everyone is talking at once and nobody can be heard clearly, neurons start to misfire and overreact. This synaptic noise turns up the brain’s pain sensitivity, both physically and emotionally. It suggests that GluD1 isn’t just managing pain signals, but also may be shaping how those signals feel.</p>
<p>What if we could restore that broken connection?</p>
<p>In our second study, we injected mice with cerebellin-1 and saw that it <a href="https://doi.org/10.1111/bph.16296">reactivated GluD1 activity</a>, easing their chronic pain without producing any side effects. It helped the pain processing system work again without the sedative effects or disruptions to other nerve signals that are common with opioids. Rather than just numbing the body, reactivating GluD1 activity recalibrated how the brain processes pain.</p>
<p>Of course, this research is still in the early stages, far from clinical trials. But the implications are exciting: GluD1 may offer a way to repair the pain processing network itself, with fewer side effects and less risk of addiction than current treatments.</p>
<p>For millions living with chronic pain, this small, peculiar receptor may open the door to a new kind of relief: one that heals the system, not just masks its symptoms.<!-- Below is The Conversation's page counter tag. Please DO NOT REMOVE. --><img decoding="async" src="https://counter.theconversation.com/content/256982/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1"><!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: https://theconversation.com/republishing-guidelines --></p>
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<p><em>This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/neuropathic-pain-has-no-immediate-cause-research-on-a-brain-receptor-may-help-stop-this-hard-to-treat-condition-256982">original article</a>.</em></p></p>
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<td><a href="https://www.psypost.org/higher-income-may-boost-the-odds-of-finding-a-romantic-partner/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">Higher income may boost the odds of finding a romantic partner</a>
<div style="font-family:Helvetica, sans-serif; text-align:left;color:#999;font-size:11px;font-weight:bold;line-height:15px;">Jul 22nd 2025, 14:00</div>
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<p><p>While money may not buy happiness in singlehood, it could increase the desire—and likelihood—of entering a relationship. A new study published in the <a href="https://doi.org/10.1111/jomf.70000"><em>Journal of Marriage and Family</em></a> found that single adults with higher incomes were more likely to say they wanted a partner, felt more ready to date, and were more likely to begin a relationship within the next year. However, income was not associated with greater satisfaction in being single.</p>
<p>Singlehood has become more common in recent years, with nearly half of U.S. adults identifying as single and one-person households now the most common household type in Canada. Despite this trend, much of the research on finances and relationships has focused on couples—particularly how income relates to marriage, conflict, and divorce. But less is known about how money shapes the lives and attitudes of people who are not currently in a relationship.</p>
<p>Researchers from the University of Toronto and Carleton University wanted to understand whether single people with more financial resources are more satisfied with single life—or more interested in moving toward a romantic relationship. They were especially interested in whether higher income might signal a kind of readiness for partnership. Past studies suggest that people often want to achieve some financial stability before committing to a long-term relationship, but it’s unclear how this plays out among those who are currently single.</p>
<p>The research included two large studies—one based in the United States and the other in Germany—each designed to explore the link between income and relationship attitudes in single people. The studies were longitudinal, meaning they followed participants over time to see how their relationship status changed.</p>
<p>Study 1 included 638 U.S.-based single adults aged 25 to 35. Participants were recruited online and reported their annual income, satisfaction with being single, desire for a romantic partner, and how ready they felt to begin a relationship. They also indicated whether they intended to find a partner in the next six months. About 60% of participants completed a follow-up survey six months later, reporting whether they had entered into a romantic relationship during that period.</p>
<p>Study 2 drew on over a decade of data from the German Family Panel, which included 2,774 unique single individuals who reported their income, relationship attitudes, and status over multiple years. This study allowed researchers to examine how both current income and recent changes in income related to relationship outcomes one year later. It also provided an opportunity to test whether these links differed for men and women.</p>
<p>In both studies, higher income was not linked to greater satisfaction with singlehood. People with more money did not report enjoying their single lives more than those with less income. However, income was strongly associated with a greater desire for a romantic relationship, stronger feelings of readiness to date, and increased intent to start a relationship in the near future.</p>
<p>In the U.S. sample, single adults with higher income were more likely to say they wanted a partner and felt the time was right for a relationship. They also showed a greater intention to begin dating in the following six months. When surveyed again six months later, those with higher income were significantly more likely to have entered into a relationship.</p>
<p>The German sample echoed these findings. Participants with higher income were more likely to express a desire for a partner, and income predicted the odds of being in a relationship one year later. This effect was stronger for men than for women, though the gender difference was modest overall.</p>
<p>“I think that young people are making rational calculations in unstable economic conditions,” said <a href="https://www.macdonaldlab.ca/" target="_blank" rel="noopener">Geoff MacDonald</a>, a professor of psychology at the University of Toronto. “I think people get that they are not going to be able to enjoy a relationship if they are working 80 hours a week, or if they’re not sure where they’re going to live next year.”</p>
<p>Interestingly, recent changes in income—whether a participant earned more or less than the year before—had little effect on whether they wanted a relationship or actually found one. What mattered more was their current income level. This suggests that financial stability, rather than short-term financial improvement or decline, plays a larger role in shaping relationship intentions and outcomes.</p>
<p>Satisfaction with singlehood was generally unrelated to income in both studies. This held true even after accounting for subjective financial stress, feelings of deprivation, or worries about money. People with higher income may have had more resources and options, but this did not appear to translate into greater happiness with being single.</p>
<p>While the study provides evidence for a connection between income and relationship intentions, it does not prove that money <em>causes</em> people to want or begin relationships. Other factors—such as personality traits, life goals, or cultural values—may also play a role. The researchers focused on objective income, which is only one part of socioeconomic status. Future work could examine how other aspects, such as education level, perceived social class, or job stability, influence relationship readiness.</p>
<p>Another limitation is that both studies were conducted in Western countries with relatively individualistic cultures. In cultures where marriage is more closely tied to family expectations or economic arrangements, the link between income and partnering might be stronger—or take on different forms entirely. Gender norms and roles also vary across societies, and further research could explore how income affects men and women differently in contexts with less gender equality.</p>
<p>There are also unanswered questions about what kinds of material resources signal relationship readiness. Is it a stable income? Having one’s own apartment? Owning a car? Future studies could look more closely at these “relationship infrastructure” factors. Researchers could also explore whether higher income leads to greater confidence or a stronger sense of agency in romantic pursuit.</p>
<p>The study, “<a href="https://doi.org/10.1111/jomf.70000">Making (Enough for) Love: The Association of Income and Relationship Readiness</a>,” was authored by Johanna Peetz and Geoff MacDonald.</p></p>
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<td><a href="https://www.psypost.org/scientists-challenge-theory-that-human-eye-evolution-was-driven-by-cooperation/" style="font-family:Helvetica, sans-serif; letter-spacing:-1px;margin:0;padding:0 0 2px;font-weight: bold;font-size: 19px;line-height: 20px;color:#222;">Scientists challenge theory that human eye evolution was driven by cooperation</a>
<div style="font-family:Helvetica, sans-serif; text-align:left;color:#999;font-size:11px;font-weight:bold;line-height:15px;">Jul 22nd 2025, 12:00</div>
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<p><p>A widely popular idea in psychology and evolutionary science suggests that the distinctive look of the human eye—particularly the white area surrounding the iris—evolved to help us communicate cooperatively. But a new scientific paper published in <em><a href="https://doi.org/10.1111/brv.70033" target="_blank">Biological Reviews</a></em> challenges that theory, arguing that the idea lacks strong evidence and may have misrepresented both human and non-human primate eye variation. The authors propose that other evolutionary pressures, like light protection and sexual selection, may better explain the diversity in primate eye pigmentation, including our own.</p>
<p>The idea under scrutiny is known as the Cooperative Eye Hypothesis. This hypothesis suggests that humans evolved conspicuously white eyes to make it easier for others to follow our gaze. According to the theory, this trait supports uniquely human social behaviors such as collaboration, joint attention, and non-verbal communication. In contrast, other primates are thought to have darker, less visible eyes that obscure their gaze to avoid giving away intentions in competitive situations.</p>
<p>This idea has gained considerable popularity both in academia and in popular science. It’s been cited in thousands of scholarly works and widely shared in books and online media. But according to the authors of the new review, the hypothesis rests on flawed assumptions and has not held up under closer empirical scrutiny. They argue that the supposed uniqueness and uniformity of the human eye appearance is exaggerated and that the available evidence does not convincingly show that our bright eyes significantly improve communication compared to other primates.</p>
<p>“We have been trying to understand what drives variation in the appearance of eyes in primates for a few years,” said the lead author of the new paper, Juan Olvido Perea-García of Nicolaus Copernicus University and Universidad Las Palmas de Gran Canaria.</p>
<p>“A key idea when we started working on the topic was that human eyes were unique because they were the only ones with ‘white’ of the eyes. Supposedly, this evolved uniquely in humans to support also supposedly uniquely human communicative behaviors. But more and more evidence has emerged that other primates do actually have white of the eyes, it’s just that it hadn’t been looked into in enough detail.”</p>
<p>“In response to this, other teams tried to ‘save’ the uniqueness of the human eye by proposing that what really distinguished human eyes from those of other primates was the degree and how homogeneously depigmented human eyes were. But this is simply and visibly not true if we look at more pigmented individuals. We wanted to bring attention to the existing variation in human external eye appearance to set the record straight.”</p>
<p>First proposed in the late 1990s and popularized by researchers like Michael Tomasello, the Cooperative Eye Hypothesis suggests that human eyes evolved their distinctive appearance under pressures for improved social cooperation. The key feature is the bright white area around the iris, created by the sclera and conjunctiva, which is thought to make it easier to detect eye direction. This, the theory goes, allowed humans to communicate silently and efficiently through subtle shifts in gaze, laying the groundwork for complex group behaviors and even language development.</p>
<p>Early support for this idea came from studies comparing eye morphology across primate species. These studies claimed that only humans show such strong contrast between the iris and surrounding eye tissue, making our gaze uniquely visible. Based on these findings, it was proposed that our ancestors experienced evolutionary pressure to evolve highly visible eyes that promote cooperative behavior, while other primates retained darker, less expressive eyes to hide their intentions.</p>
<p>Despite its influence, the Cooperative Eye Hypothesis has several major weaknesses, according to the new review. The authors argue that the four central claims of the hypothesis—uniqueness, uniformity, communicative advantage, and empirical support—are either false or unproven.</p>
<p>First, human eyes are not as unique as previously claimed. Many non-human primates, such as golden langurs and pig-tailed macaques, have similarly bright peri-iridal regions, the area surrounding the iris. In fact, some species show comparable levels of pigmentation brightness, suggesting that bright eyes have evolved multiple times across the primate family tree. Even chimpanzees, often cited as having dark, “hidden” eyes, can exhibit scleral brightness similar to humans.</p>
<p>Second, the idea that human eye appearance is uniform across the species is incorrect. In reality, there is substantial variation in the brightness of the sclera among different human populations. Many people, especially those with darker skin tones, show visibly pigmented conjunctiva, contradicting the idea that all humans have fully white eyes. This variation has been observed for decades in medical literature but has largely been ignored in psychological studies supporting the Cooperative Eye Hypothesis.</p>
<p>Third, there is little evidence that bright eyes offer a substantial communicative advantage. Experiments suggest that even with darker eyes, humans and other primates can still follow gaze accurately, especially in familiar or well-lit contexts. Some researchers have shown that the time it takes for humans to interpret gaze direction is only slightly longer when the sclera is darkened artificially—and the accuracy remains unchanged. Studies also show that chimpanzees, under the right conditions, can follow gaze just as effectively.</p>
<p>Finally, the experimental foundation of the hypothesis is shaky. A key study by Tomasello and colleagues in 2007 claimed that human infants follow gaze more reliably than great apes, supposedly due to our distinct eye morphology. But the new review highlights serious methodological concerns with that study, including differences in testing environments and unfamiliarity of subjects with the experimental setup. The authors argue that these differences could explain the observed results, not inherent cognitive or anatomical differences.</p>
<p>“Human eyes are varied in their coloration and shape, and we do not know why this is the case yet,” Perea-García told PsyPost. “We know they are used in communication, but we do not know whether we got ‘eye whites’ for that. This is counter-intuitive, because we know we follow gaze. But just because we do something with a part of our bodies, it doesn’t mean it evolved for that function. For example, we use fingers to type on the keyboard, but our fingers obviously did not evolve for that purpose.” </p>
<p>“Science is always moving and we should remain skeptical of what appears obvious. We don’t doubt that the scientists who say all humans have homogeneously depigmented ‘whites’ of the eye believe this to be the case. But, due to their origins in Northern Europe or Northeast Asia, they probably have not been exposed to deeply pigmented individuals. Scientists are humans, and humans are not omniscient.”</p>
<p>Given the limitations of the Cooperative Eye Hypothesis, the authors propose that researchers explore alternative explanations for the evolution of eye appearance in humans and other primates. Three promising ideas are photoregulation, sexual selection, and non-referential communication.</p>
<p>The photoregulation hypothesis suggests that darker eye pigmentation protects the eye from harmful ultraviolet light, which may explain why some primates in equatorial regions have more heavily pigmented eyes. In this view, humans may have reduced eye pigmentation in part due to lower UV exposure in some ancestral environments—or due to other anatomical adaptations that made dark eyes less necessary.</p>
<p>Another possibility is that depigmented sclera evolved under sexual selection. In humans, bright eyes are often associated with youth and health, traits that are commonly preferred in mate selection. This could have led to a preference for lighter sclera over time, especially if they signaled good health or reproductive potential. Interestingly, human faces also display other juvenile features compared to other apes, possibly supporting this idea.</p>
<p>A third option is that visible eyes may enhance facial expressions or social signals more generally, without necessarily improving gaze detection. In many primates, the eye region is marked with bright skin or fur, drawing attention to the eyes as a part of emotional or affiliative communication. In this context, bright sclera might help amplify social cues like eye contact or expressions of emotion, rather than helping others follow gaze direction specifically.</p>
<p>Other explanations have also been considered, including random genetic drift, self-domestication, and even species recognition. While some of these ideas remain speculative, they illustrate that there are many ways to think about how eye appearance might have evolved—beyond cooperation alone.</p>
<p>Despite the progress made in understanding eye evolution, much remains unknown. One major limitation is the lack of detailed measurements of conjunctival and scleral pigmentation in both humans and other primates. Surprisingly, there is still no comprehensive dataset that maps how pigmentation varies across human populations or across different primate species.</p>
<p>“We are still lacking detailed measurements of pigmentation in the human eye, believe it or not,” Perea-García said. “Until then, it is all educated guesses.”</p>
<p>The authors suggest that new technologies and genetic methods could help answer key questions—such as when in evolutionary history humans developed lighter sclera and whether these changes happened gradually or suddenly. Investigating the genetics of pigmentation in the eye, and comparing it to other traits like skin or hair color, could offer deeper insights into the evolutionary forces at play.</p>
<p>They also encourage researchers to consider ecological and behavioral factors, such as habitat type, social structures, and mating preferences, when studying ocular traits. Better data across cultures and species will be needed to test whether any single hypothesis—or combination of factors—can account for the wide variety of eye appearances found in primates today.</p>
<p>“If anyone has the time and energy, I really recommend them to watch EDGE Science’s Youtube video on the topic. It does a fairly good job at explaining how this topic has progressed over the years, and how new data keeps forcing us to draw new conclusions: <a href="https://www.youtube.com/watch?v=_Fuo7axCWJ4" target="_blank">https://www.youtube.com/watch?v=_Fuo7axCWJ4</a>.”</p>
<p>The paper, “<a href="https://doi.org/10.1111/brv.70033" target="_blank">Look past the cooperative eye hypothesis: reconsidering the evolution of human eye appearance</a>,” was authored by Juan Olvido Perea-García, Aurora Teuben, and <a href="https://www.kai-caspar.de/" target="_blank">Kai R. Caspar</a>.</p></p>
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<p><strong>Forwarded by:<br />
Michael Reeder LCPC<br />
Baltimore, MD</strong></p>
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