Associations Between Gut Microbes and Social Behavior in Healthy 2-Year-Old Children.

OBJECTIVE: Emerging research has connected abundances of specific bacteria to differences in psychosocial behaviors in animals and adult humans. However, research assessing mind-microbiome associations in children is sparse with extant work primarily focused on populations with autism, making it unclear whether links are also present in typically developing children. The current study fills this gap by examining associations between prosocial-self-regulating temperaments (effortful control; EC) and the gut microbiome in typically developing children. METHODS: Maternal ratings of temperament were assessed in 77 toddlers 18 to 27 months of age (46.7% female, mean age = 23.14 months). Next-generation pyrosequencing of the V1-V3 region of the 16S rRNA gene was used to classify children's gut microbial composition from fecal samples. EC included the following subcategories: cuddliness, attentional focusing, attentional shifting, inhibitory control, and low-intensity pleasure. RESULTS: After adjusting for covariates, EC was positively associated with relative abundances of Akkermansia (Δ R2 = 0.117, b = 0.022, SE = 0.007, p = .002), with cuddliness (i.e., joy and ease of being held) driving the relation. Furthermore, attentional focusing was negatively associated with Alistipes (Δ R2 = 0.062, b = -0.011, SE = 0.005, p = .028). Permutational analysis of variance revealed no significant differences in community structure between high and low EC groups on the phylum level ( R2 = 0.00372, p = .745) or the genus level ( R2 = 0.01559, p = .276). CONCLUSIONS: Findings suggest that certain microbes may be linked to prosocial behaviors used to regulate emotion in typically developing children. Further research is needed to test whether these observations replicate in larger samples.

Do Positive Psychological Factors Equally Predict Resistance to Upper Respiratory Infections in African and European Americans?

Research has consistently shown that positive psychological constructs are linked to better physical health, but few studies have examined the role that race plays in this connection. We explored whether positive self-evaluations were equally protective against upper respiratory infection for 271 African American adults and 700 European American adults in a series of virus-exposure studies. Participants were assessed at baseline for psychological functioning and physical health, quarantined and exposed experimentally to a respiratory virus, and then monitored for infection and symptoms. Regression analyses revealed significant interactions between race and multiple positive psychological factors; several factors that were helpful to European Americans were unhelpful or even harmful to African Americans. Building on past work showing cross-cultural variation in the health correlates of affect, this study provides evidence that the health benefits of positive psychological constructs may not be universal and points to the need to explore factors that underpin these observed differential patterns.

Oxytocin, cortisol, and cognitive control during acute and naturalistic stress.

Although stress is a strong risk factor for poor health, especially for women, it remains unclear how stress affects the key neurohormones cortisol and oxytocin, which influence stress-related risk and resilience. Whereas cortisol mediates energy mobilization during stress, oxytocin has anti-inflammatory, anxiolytic, and analgesic effects that support social connection and survival across the lifespan. However, how these neurohormones interrelate and are associated with cognitive control of emotional information during stress remains unclear. To address these issues, we recruited 37 college-aged women (Mage = 19.19, SD = 1.58) and randomly assigned each to a one-hour experimental session consisting of either an acute stress (emotionally stressful video) or control (non-stressful video) condition in a cross-sectional manner across the semester. Salivary cortisol and oxytocin samples were collected at baseline and after the video, at which point participants also completed measures assessing affect and an emotional Stroop task. As hypothesized, the emotional stressor induced negative emotions that were associated with significant elevations in cortisol and faster Stroop reaction times. Moreover, higher baseline oxytocin predicted greater positive affect after the stressor and also better cognitive accuracy on the Stroop. Analyses examining the naturalistic stress effects revealed that basal oxytocin levels rose steeply three weeks before the semester's end, followed by rising cortisol levels one week later, with both neurohormones remaining elevated through the very stressful final exam period. Considered together, these data suggest that women's collective experiences of stress may be potentially buffered by a synchronous oxytocin surge that enhances cognitive accuracy and reduces stress "when the going gets tough".

Temporal Links Between Self-Reported Sleep and Antibody Responses to the Influenza Vaccine.

BACKGROUND: Growing evidence suggests that sleep plays an important role in immunological memory, including antibody responses to vaccination. However, much of the prior research has been carried out in the laboratory limiting the generalizability of the findings. Furthermore, no study has sought to identify sensitive periods prior to or after vaccination where sleep may have a stronger influence on antibody responses. METHODS: Eighty-three healthy young adults completed 13 days of sleep diaries and received the trivalent influenza vaccine on day 3 of the study. Measures of self-reported sleep duration, sleep efficiency, and subjective sleep quality were assessed on each day. Antibody levels to the influenza viral strains were quantified at baseline and 1 and 4 months following influenza vaccination. RESULTS: Shorter sleep duration, averaged over the collection period, was associated with fewer antibodies to the A/New Caledonia viral strain 1 and 4 months later, independent of baseline antibodies, age, sex, and cohort year. Analyses focused on nightly sleep on the days preceding and after the vaccination revealed that shorter sleep duration on the two nights before the vaccination predicted fewer antibodies 1 and 4 months later. Measures of self-reported sleep efficiency and subjective quality were unrelated to antibody responses to the influenza vaccination. CONCLUSION: These findings provide further support for an association between sleep duration and antibody responses to the influenza vaccine and suggest that perhaps sleep on nights prior to vaccination are critical. If replicated, these findings may support sleep as a target for enhancing vaccination efficacy.

Maternal expressions of positive emotion for children predicts children's respiratory sinus arrhythmia surrounding stress.

The aim of this study is to assess whether positive emotional exchanges (i.e., emotion coregulation) within the mother-child dyad play a protective role in children's physiological response to a distressing task. Specifically, we test whether positive emotion coregulation among mothers and their preschool-aged children is associated with children's respiratory sinus arrhythmia (RSA) at baseline, during, and following a frustration task. One hundred Singaporean mother-child dyads (Mchildage  = 3.5 years) participated in a standardized "Laughing Task" in which positive emotional constructs were measured. Children also participated in a frustration task while RSA was continuously monitored. Hierarchical linear regressions revealed that greater maternal positive emotional responses to children were associated with child RSA at baseline and in recovery from frustration, but not during frustration. These findings have implications for the important role that positive emotion responsivity from mothers may play in children's developing autonomic response systems, and underscore the need for longitudinal work on this topic.

Real Men Don't Cry: Skill Expressing Discrete Emotions Differentially Predicts Cardiovascular Disease Risk in Men and Women.

BACKGROUND: Expressing emotions effectively is central to social functioning and has links to health and cardiovascular disease (CVD) risk. Previous work has linked the ability to smile to lower CVD risk in men but has not studied other expressions or considered the context of these skills. PURPOSE: To test whether the ability to express fear, anger, sadness, happiness, and disgust cross-sectionally predict CVD risk in both genders and whether links are moderated by the ability to decode others' emotional signals. METHODS: A community sample of 125 men and women (30-75 years) provided trait emotion data before a laboratory visit where blood was drawn and performance-based assessments of the ability to signal and decode emotions were administered. Expressive accuracy was scored using FaceReader software. Projected CVD risk was calculated using Framingham, a New Zealand (NZ) specific, and Atherosclerosis CVD (ASCVD) risk algorithms. RESULTS: Accuracy expressing happiness predicted lower projected risk, whereas greater accuracy expressing fear and sadness predicted higher risk. Gender frequently moderated these links; greater accuracy expressing happiness predicted lower risk in men but not women. Conversely, greater accuracy expressing fear predicted higher risk in men, whereas greater accuracy expressing sadness predicted lower risk in women but, again, higher risk in men. The ability to accurately decode others' emotions moderated some links. CONCLUSIONS: The ability to signal emotion has complex links to health parameters. The ability to flexibly regulate expressions in accordance with gender norms may be one useful way of thinking about adaptive expressive regulation.

Positive Affect and Health: What Do We Know and Where Next Should We Go?

Positive affect (PA) is associated with better health across a wide range of physical health outcomes. This review reflects on why the study of PA is an essential component of our understanding of physical health and expands on pathways that connect these two variables. To encourage forward movement in this burgeoning research area, measurement and design issues in the study of PA and health are discussed, as are the connections between PA and a range of different health outcomes. Plausible biological, social, and behavioral pathways that allow for positive feelings to get under the skin and influence physical wellness are detailed and framed in the context of several theoretical models. Finally, new directions for the field and important methodological and interpretative considerations that are essential to moving this important research area forward are explored.

Misremembering pain: A memory blindness approach to adding a better end.

How people remember feeling in the past informs future decisions; however, memory for past emotion is subject to a number of biases. Previous research on choice blindness has shown that people often fail to notice when they are exposed to misinformation about their own decisions, preferences, and memories. This type of misinformation can influence how they later remember past events. In the present study, we examined the memory blindness effect in a new domain: memory for pain. Participants (N = 269) underwent a cold-pressor task and rated how much pain, distress, and positive and negative affect they had experienced. Later, participants were shown their pain ratings and asked to explain them. Some of the participants were shown lower pain ratings than they had actually made. In a second session, participants recalled how painful the task had been and how much distress and positive and negative affect they remembered experiencing. The results indicated that the majority of participants who were exposed to misinformation failed to detect the manipulation, and subsequently remembered the task as being less painful. The participants in the misinformation condition were not overall more willing to repeat the study tasks, but the participants who recalled less distress, less negative affect, and more positive affect were more willing to repeat the study tasks again in a future experiment. These results demonstrate the malleability of memory for painful experiences and that willingness to repeat aversive experiences may depend more on memory for affective reactions to the original experience than on memory for the physical pain itself.

The Use of Smartphones as a Digital Security Blanket: The Influence of Phone Use and Availability on Psychological and Physiological Responses to Social Exclusion.

OBJECTIVE: Mobile phones are increasingly becoming a part of the social environment, and when individuals feels excluded during a socially stressful situation, they often retreat to the comfort of their phone to ameliorate the negativity. This study tests whether smartphone presence does, in fact, alter psychological and physiological responses to social stress. METHODS: Participants (N = 148, 84% female, mean age = 20.4) were subjected to a peer, social-exclusion stressor. Before exclusion, participants were randomized to one of the following three conditions: (1) phone-present with use encouraged, (2) phone-present with use restricted, or (3) no phone access. Saliva samples and self-report data were collected throughout the study to assess salivary alpha amylase (sAA), cortisol, and feelings of exclusion. RESULTS: Participants in both phone-present conditions reported lower feelings of exclusion compared with individuals who had no access to their phone (F(2,143) = 5.49, p = .005). Multilevel modeling of sAA responses revealed that the individuals in the restricted-phone condition had a significantly different quadratic trajectory after the stressor compared with the phone use (υ = -0.12, z = -2.15, p = .032), and no-phone conditions (υ = -0.14, z = -2.64, p = .008). Specifically, those in the restricted-phone condition showed a decrease in sAA after exclusion, those in the no-phone condition showed a gradual increase, and phone users exhibited little change. Cortisol responses to the stressor did not vary by condition. CONCLUSIONS: Taken together, these results suggest that the mere presence of a phone (and not necessarily phone use) can buffer against the negative experience and effects of social exclusion.

Which Aspects of Positive Affect Are Related to Mortality? Results From a General Population Longitudinal Study.

Background: Previous research has shown a link between low positive affect and mortality, but questions remain about how positive affect is related to mortality and how this differs by gender and age. Purpose: To investigate the relationships between positive affect, negative affect, and mortality in a general population sample, and to examine whether these relationships were related to age, sex, or cause-specific mortality. Methods: We used data from 5,554 Norwegian participants aged 47-49 and 71-74 years who completed the Positive and Negative Affect Schedule (PANAS) and also provided data on demographics, health behaviors, and physical health as part of the Hordaland Health Study. The primary outcome was mortality after an average follow-up period of 16.5 years. Results: Participants in the lowest positive affect tertile had a near twofold increased mortality risk, compared to those in the highest positive affect tertile. This association was driven primarily by the PANAS "active" item and persisted, even after controlling for activity-related confounds and other positive affect items. No significant associations were found between negative affect and mortality. The relationship between positive affect and mortality was not significantly attenuated by age or sex. Although low positive affect was associated with an increased risk of mortality, it was not related to a specific cause of death. Conclusions: Low positive affect was significantly associated with mortality risk. The relationship was driven by the PANAS active item and not associated with cause-specific mortality. Findings suggest future research should examine the association between feeling inactive, sedentary behavior, and subsequent mortality.

Sleep quality buffers the effects of negative social interactions on maternal mood in the 3-6 month postpartum period: a daily diary study.

Sleep and social relationships are two key determinants of psychosocial health that undergo considerable change across the transition to motherhood. The current study investigated the bidirectional relationship between daytime Positive and Negative Social Interactions (PSIs & NSIs) and nighttime sleep quality on maternal mood across 1 week in the 3-6 month postpartum period. Sixty healthy, non-depressed first-time mothers completed 7-consecutive days of daily social interaction and sleep diaries. Results indicated that higher than average sleep quality buffered the effect of higher than average NSIs on maternal mood (i.e., buffered mood reactivity) and appeared to promote mood recovery following a particularly "bad day" (i.e., higher than average NSIs). In addition, although PSIs were more common than NSIs overall, the most frequent and positively rated PSIs were with baby as were the most frequent and negatively rated NSIs. To our knowledge, our results are the first to characterize the impact of PSIs on postpartum maternal mood, assess maternal-infant social interactions in daily diary study of postpartum social relationships, and demonstrate the role that maternal sleep quality plays in social discord-related mood reactivity and mood recovery processes in the 3-6 month postpartum period.

The Association of Daytime Maternal Napping and Exercise With Nighttime Sleep in First-Time Mothers Between 3 and 6 Months Postpartum.

OBJECTIVE: This study investigated the relationship of daytime maternal napping, exercise, caffeine, and alcohol intake to objective and subjective sleep indices. PARTICIPANTS: Sixty healthy, nondepressed, first-time mothers between 3 and 6 months postpartum. METHODS: Seven consecutive days of online behavior diaries, sleep diaries, and wrist actigraphy, collecting Total Sleep Time (TST), Sleep Onset Latency (SOL), and Wake After Sleep Onset (WASO). RESULTS: After controlling for infant age, employment status, infant feeding method, and infant sleeping location, mixed linear models showed that longer average exercise durations were associated with longer average TST, and longer average nap durations were associated with longer average WASO durations. Significant within-person differences in TST and SOL were also observed, such that, on days when participants exercised and napped longer than average, their respective TST and SOL durations that night were longer. CONCLUSION: Shorter nap durations and longer exercise durations were associated with longer TST, shorter SOL, and reduced WASO. Even small changes in daily exercise and napping behaviors could lead to reliable improvements in postpartum maternal sleep.

Greater ability to express positive emotion is associated with lower projected cardiovascular disease risk.

Positive emotion is associated with lower cardiovascular disease (CVD) risk, yet some mechanisms remain unclear. One potential pathway is via emotional competencies/skills. The present study tests whether the ability to facially express positive emotion is associated with CVD risk scores, while controlling for potential confounds and testing for sex moderation. Eighty-two men and women underwent blood draws before completing self-report assessments and a performance test of expressive skill. Positive expressions were scored for degree of 'happiness' using expression coding software. CVD risk scores were calculated using established algorithms based on biological, demographic, and behavioral risk factors. Linear regressions revealed a main effect for skill, with skill in expressing positive emotion associated with lower CVD risk scores. Analyses also revealed a sex-by-skill interaction whereby links between expressive skill and CVD risk scores were stronger among men. Objective tests of expressive skill have methodological advantages, appear to have links to physical health, and offer a novel avenue for research and intervention.

Better cognitive control of emotional information is associated with reduced pro-inflammatory cytokine reactivity to emotional stress.

Stress is strongly associated with several mental and physical health problems that involve inflammation, including asthma, cardiovascular disease, certain types of cancer, and depression. It has been hypothesized that better cognitive control of emotional information may lead to reduced inflammatory reactivity to stress and thus better health, but to date no studies have examined whether differences in cognitive control predict pro-inflammatory cytokine responses to stress. To address this issue, we conducted a laboratory-based experimental study in which we randomly assigned healthy young-adult females to either an acute emotional stress (emotionally evocative video) or no-stress (control video) condition. Salivary levels of the key pro-inflammatory cytokines IL-1ß, IL-6, and IL-8 were measured before and after the experimental manipulation, and following the last cytokine sample, we assessed participants' cognitive control of emotional information using an emotional Stroop task. We also assessed participants' cortisol levels before and after the manipulation to verify that documented effects were specific to cytokines and not simply due to increased nonwater salivary output. As hypothesized, the emotional stressor triggered significant increases in IL-1ß, IL-6, and IL-8. Moreover, even in fully adjusted models, better cognitive control following the emotional (but not control) video predicted less pronounced cytokine responses to that stressor. In contrast, no effects were observed for cortisol. These data thus indicate that better cognitive control specifically following an emotional stressor is uniquely associated with less pronounced pro-inflammatory cytokine reactivity to such stress. These findings may therefore help explain why superior cognitive control portends better health over the lifespan.

Affect variability and cortisol in context: The moderating roles of mean affect and stress.

Positive and negative affect have been shown to have implications for hormones like cortisol but how moment to moment changes in affect (i.e., affect variability) influence cortisol secretion is less well understood. Additionally, context characteristics such as mean affect and stress may influence the association between affect variability and cortisol output. In the current study, we examined affect, stress, and cortisol data from 113 participants (age range = 25-63, M = 35.63, SD = 11.34; 29% male; 42% White/Caucasian, 37% Asian or Pacific Islander, 13% Hispanic/Latino, 4% Black/African American, 1% Native American, Eskimo, or Aleut, 4% selected "other" for their race/ethnicity). Participants completed ecological momentary assessments assessing positive and negative affect and stress four times per day for five days and provided saliva samples at each time point. Saliva was assayed for cortisol, and area under the curve with respect to ground was computed. In a three-way interaction, both positive affect mean level and stress moderated the association between positive affect variability and cortisol (b = -1.55, t(100) = -3.29, SE = 0.47, p <.01, ß = -4.05). When breaking down this three-way interaction, in the context of low stress and high mean positive affect, variability was positively related to total cortisol output. In contrast, in the context of high stress and high mean positive affect, variability was negatively related to total cortisol output. While greater positive affect variability is generally worse for health-relevant outcomes (as prior research has shown and as we show here at low levels of stress), at high levels of stress, fluctuation in affect may be adaptive. For someone experiencing a high stress week, having fluctuations in positive affect may mean that they are adaptively changing to meet their environmental needs especially when they typically report high mean positive affect levels. There were no associations between negative affect variability and cortisol secretion nor did mean negative affect or stress play a moderating role for negative affect variability. This study provides evidence that positive affect variability's association with cortisol secretion throughout the day may vary based on stress and mean positive affect levels.

Is the emotion-health connection a "first-world problem"?

Emotions have been shown to play a critical role in health outcomes, but research on this topic has been limited to studies in industrialized countries, which prevents broad generalizations. This study assessed whether emotion-health connections persist across various regions, including less-developed countries, where the degree to which people's fundamental needs are met might be a better predictor of physical well-being. Individuals from 142 countries (N = 150,048) were surveyed about their emotions, health, hunger, shelter, and threats to safety. Both positive and negative emotions exhibited unique, moderate effects on self-reported health, and together, they accounted for 46.1% of the variance. These associations were stronger than the relative impact of hunger, homelessness, and threats to safety and were not simply attributable to countries' gross domestic products (GDPs). Furthermore, connections between positive emotion and health were stronger in low-GDP countries than in high-GDP countries. Our findings suggest that emotion matters for health around the globe and may in fact be more critical in less-developed areas.

Optimism is universal: exploring the presence and benefits of optimism in a representative sample of the world.

Current theories of optimism suggest that the tendency to maintain positive expectations for the future is an adaptive psychological resource associated with improved well-being and physical health, but the majority of previous optimism research has been conducted in industrialized nations. The present study examined (a) whether optimism is universal, (b) what demographic factors predict optimism, and (c) whether optimism is consistently associated with improved subjective well-being and perceived health worldwide. The present study used representative samples of 142 countries that together represent 95% of the world's population. The total sample of 150,048 individuals had a mean age of 38.28 (SD = 16.85) and approximately equal sex distribution (51.2% female). The relationships between optimism, subjective well-being, and perceived health were examined using hierarchical linear modeling. Results indicated that most individuals and most countries worldwide are optimistic and that higher levels of optimism are associated with improved subjective well-being and perceived health worldwide. The present study provides compelling evidence that optimism is a universal phenomenon and that the associations between optimism and improved psychological functioning are not limited to industrialized nations.

The influence of a motivational climate intervention on participants' salivary cortisol and psychological responses.

Research in achievement goal perspective theory suggests that the creation of a caring/task-involving (C/TI) climate results in more advantageous psychological and behavioral responses relative to an ego-involving (EI) climate; however, research has not yet examined the physiological consequences associated with psychological stress in relation to climate. Given the possible health and fitness implications of certain physiological stress responses, it is critical to understand this association. Thus, the purpose of this study was to examine whether an EI climate procures increases in the stress-responsive hormone cortisol, as well as negative psychological changes, following the learning of a new skill, compared with a C/TI climate. Participants (n = 107) were randomized to a C/TI or an EI climate in which they learned how to juggle for 30 min over the course of 2 hr. Seven salivary cortisol samples were collected during this period. Results indicated that EI participants experienced greater cortisol responses after the juggling session and significantly greater anxiety, stress, shame, and self-consciousness relative to C/TI participants. In contrast, the C/TI participants reported greater enjoyment, effort, self-confidence, and interest and excitement regarding future juggling than the EI participants. These findings indicate that motivational climates may have a significant impact on both the physiological and psychological responses of participants.

How and why could smiling influence physical health? A conceptual review.

ABSTRACTSmiling has been a topic of interest to psychologists for decades, with a myriad of studies tying this behavior to well-being. Despite this, we know surprisingly little about the nature of the connections between smiling and physical health. We review the literature connecting both naturally occurring smiles and experimentally manipulated smiles to physical health and health-relevant outcomes. This work is discussed in the context of existing affect and health-relevant theoretical models that help explain the connection between smiling and physical health including the facial feedback hypothesis, the undoing hypothesis, the generalized unsafety theory of stress, and polyvagal theory. We also describe a number of plausible pathways, some new and relatively untested, through which smiling may influence physical health such as trait or state positive affect, social relationships, stress buffering, and the oculocardiac reflex. Finally, we provide a discussion of possible future directions, including the importance of cultural variation and replication. Although this field is still in its infancy, the findings from both naturally occurring smile studies and experimentally manipulated smile studies consistently suggest that smiling may have a number of health-relevant benefits including beneficially impacting our physiology during acute stress, improved stress recovery, and reduced illness over time.

Does an Online Positive Psychological Intervention Improve Positive Affect in Young Adults During the COVID-19 Pandemic?

Meta-analyses indicate that positive psychological interventions are effective at increasing positive affect, as well as reducing anxiety and depression; however, it is unclear how well these effects generalize during periods of high stress. Therefore, the current study tested whether a 2-week online positive psychological intervention delivered during the COVID-19 pandemic, a naturalistic stressor, (1) increased positive affect; (2) improved psychological well-being, optimism, life satisfaction, perceived social support, and loneliness; (3) and reduced negative affect in college students, a group known to have high pandemic distress. Participants (N = 250; 76.9% female) ages 18-45 were recruited from the University of Pittsburgh undergraduate subject pool between September and November of 2020. Participants were randomized to the online positive psychological intervention or active control condition and stratified by trait positive affect, sex, and year in college. Participants in both conditions completed one writing activity every other day for two consecutive weeks. Control participants documented their activities for that day (e.g., meals, going to gym). Intervention participants chose from six positive psychology activities. All outcome variables were assessed pre- and post-intervention by validated questionnaires. Across both conditions, positive and negative affect decreased from pre- to post-intervention. No other psychological factor differed by condition, time, or their interaction. The current null findings are in line with a more recent meta-analysis indicating that positive psychological interventions may have smaller effects on psychological well-being and depressive symptoms than was reported pre-pandemic. Study findings may suggest reduced efficacy of virtual positive psychological interventions under highly stressful circumstances. Supplementary Information: The online version contains supplementary material available at 10.1007/s42761-022-00148-z.