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Winter is characterized by stressful conditions which compromise health and render animals more vulnerable to infection and illness than during other times of the year. Organisms are hypothesized to adapt to these seasonal stressors by increasing investment in immune function in response to diminished photoperiod duration. Here, we examined this hypothesis in a sample of healthy human participants. Using several functional immune assays in vitro, as well as by utilizing measures of in vivo proinflammatory cytokine levels, we predicted that shorter day length would be associated with greater investment in immunological function. Results revealed that shorter days predicted significant upregulation of several facets of immune function, including natural killer cell cytotoxicity, peripheral blood mononuclear cell proliferation (in response to, and in the absence of stimulation), and plasma levels of interleukin-6, as well as lower rates of Staphylococcus aureus growth in serum ex vivo. Further, consistent with the hypothesis that these trade-offs would be offset by decreased investment in mating effort, shorter day length also predicted lower levels of total testosterone in men. These results suggest that ambient photoperiod may be a powerful regulator of human immunological activity, providing some of the first evidence of seasonal changes in multiple facets of human immune function.

Early life stress increases one’s risk for health problems later in life, and many studies find that these effects are sex-differentiated. Here, we examined relationships between multiple sources of early life stress and adult immune function in humans across several functional assays. Adult participants provided retrospective information about their childhood (a) socioeconomic status, (b) household unpredictability, and (c) exposure to adverse experiences. Participants’ peripheral blood mononuclear cells (PBMCs) were then isolated for use in functional assays of immune performance: (a) tumor cell lysis by natural killer cells, (b) phagocytosis of Escherichia coli bioparticles, and (c) mitogen-induced leukocyte proliferation and cytokine release. In men, lower childhood socioeconomic status predicted decrements in immunological performance across functional assays, along with greater spontaneous cytokine release from PBMCs. These changes co-occurred with elevations in plasma testosterone levels. Similar effects were not observed for other sources of stress, nor were they found in women (with the exception of spontaneous cytokine release). These findings provide evidence that low childhood socioeconomic status has a lasting negative impact on multiple aspects of immune function, particularly in men.

Across three studies, we explore the relationship between cosmetic surgery, which functions as a costly appearance-enhancement tactic, and women's short-term mating effort. Study 1 demonstrates that women who exert increased short-term mating effort are more accepting of costly appearance-enhancement techniques (i.e., cosmetic surgery), but not relatively low-cost appearance-enhancement techniques (i.e., facial cosmetics). Study 2 and 3 further show that both men and women use information regarding a female targets' cosmetic surgery usage to infer increased short-term mating effort. Moreover, Study 3 demonstrates that inferences of short-term mating effort do not differ as a function of whether the target received facial or body cosmetic surgery. The findings of the current research demonstrate that women's engagement in extreme beautification procedures can influence others' perceptions of their short-term mating effort.

Previous research demonstrates reliable associations between low paternal investment and daughters' precocious and risky sexual behavior. However, little is known about the psychological changes that occur in response to paternal disengagement that encourage these patterns. Here, we aim to redress this empirical gap by testing the effects of paternal disengagement on women's perceptions of male mating intent. In 4 experiments, women who described their fathers' absence (vs. a comparison state) perceived greater: mating intent in the described actions of a hypothetical dating partner (Study 1), sexual arousal in male target faces (Studies 2 and 3), and mating interest from a male confederate (Study 4). In a mixed-methods study (Study 5), women with greater developmental exposure to harsh-deviant paternal behavior perceived greater sexual intent in men's actions than women with lesser exposure. Moreover, these perceptual differences predicted unrestricted sociosexuality among women in this sample. An internal meta-analysis (N = 408) across studies provided support for a relationship between paternal disengagement and women's perceptions of male sexual intent. Together, this research suggests that low paternal investment (including primed paternal disengagement and harsh-deviant fathering) causes changes in daughters' perceptions of men that may influence their subsequent mating behavior. (PsycINFO Database Record

Here, we propose a novel theoretical model linking present-focused decision-making to the activities of the immune system. We tested our model by examining the relationship between inflammatory activity – in vivo and in vitro – and decision-making characterized by impulsivity, present focus, and an inability to delay gratification. Results support our model, revealing that inflammation predicts these outcomes even after controlling for factors that may contribute to a spurious linkage between them. Moreover, subsequent analyses revealed that our model was a better fit for the data than alternative models using present-focused decision-making and its health-harming behavioural sequelae (e.g., smoking, risky sexual behaviour) to predict inflammation, lending support for the proposed directionality of this relationship. Together, these results suggest that inflammation may contribute to decision-making patterns that can result in undesirable personal and societal outcomes.

A growing body of research indicates that one's early life experiences may play an important role in regulating patterns of energy intake in adulthood. In particular, adults who grew up under conditions characterized by low socioeconomic status (SES) tend to eat in the absence of hunger (EAH), a pattern that is not generally observed among higher-SES individuals. In the current study, we sought to examine (a) the environmental correlates of low SES that drive the association between low childhood SES and EAH and (b) whether the relationship between these variables is already manifest in children ages 3-14. Results of our study revealed that growing up in low-SES environments predicted less food security, diminished ability to meet financial needs, and less environmental predictability/safety. Further, the results indicated that reduced environmental predictability/safety in the children's environment interacted with children's current energy need to predict eating behavior. Consistent with patterns observed in adults, children from more predictable/safe environments ate food commensurate with their energy need, whereas those from less predictable/safe environments ate comparably high amounts of food across levels of energy need. These results offer needed insights into the development of environmentally-contingent energy-regulation strategies.

Objective The current research examined whether cognitive schemas that emerge in the context of early life stress predict psychological and behavioral outcomes that increase obesity risk. Three studies tested this hypothesis, predicting that having an unpredictability schema-which is a mindset characterized by the belief that the world and the people in it are unpredictable and unreliable-would predict low body awareness and eating in the absence of hunger. Method Self-report measures of early life environment, unpredictability schema, body awareness, and eating habits were used in Studies 1-3. Blood glucose and an eating task were used as objective measures of energy need and energy intake in Study 3. Results In Study 1, low childhood socioeconomic status (SES), parenting inconsistency, and poor childhood neighborhood quality predicted having an unpredictability schema, which predicted lower body awareness. In Study 2, participants with an unpredictability schema were found to have lower body awareness, less mindful eating, and more self-reported eating in the absence of hunger. In Study 3, the pattern of results from Studies 1 and 2 were conceptually replicated using a laboratory eating task. Participants with an unpredictability schema had lower body awareness, which predicted eating in the absence of hunger. Conclusions These results suggest that having an unpredictability schema may be an important predictor of low body awareness and eating in the absence of hunger. Although eating in the absence of hunger may have historically promoted survival in circumstances marked by unpredictability, they may contribute to obesity risk in contemporary food-rich environments. (PsycINFO Database Record

Here, we present a mechanistically grounded theory detailing a novel function of the behavioral immune system (BIS), the psychological system that prompts pathogen avoidance behaviors. We propose that BIS activity allows the body to downregulate basal inflammation, preventing resultant oxidative damage to DNA and promoting longevity. Study 1 investigated the relationship between a trait measure of pathogen avoidance motivation and in vitro and in vivo proinflammatory cytokine production. Study 2 examined the relationship between this same predictor and DNA damage often associated with prolonged inflammation. Results revealed that greater trait pathogen avoidance motivation predicts a) lower levels of spontaneous (but not stimulated) proinflammatory cytokine release by peripheral blood mononuclear cells (PBMCs), b) lower plasma levels of the proinflammatory cytokine interleukin-6 (IL-6), and c) lower levels of oxidative DNA damage. Thus, the BIS may promote health by protecting the body from the deleterious effects of inflammation and oxidative stress.

Pepper & Nettle's theory of the behavioral constellation of deprivation (BCD) would benefit from teasing apart the conceptually distinct – although related – constructs of predictability and control. Our commentary draws from prior research conducted in the learning domain to demonstrate that predictability moderates the effects of control and independently exerts a powerful influence on outcomes relevant to the BCD.

The target article explores the role of food insecurity as a contemporary risk factor for human overweight and obesity. The authors provide conditional support for the insurance hypothesis among adult women from high-income countries. We consider the potential contribution of additional factors in producing variation in adiposity patterns between species and across human contexts.