Psychoactive drugs are widely used, it is thought, because they hijack reward-related neural circuitry. If so, drugs should be equally appealing to children and to adults of both sexes. Many drugs, however, are plant defensive chemicals. Hence, children, and to a lesser extent adult women, should have evolved to avoid consuming them to protect their, or their fetuses' and nursing infants', developing nervous systems, respectively. Analyses of national and cross-national data find virtually no substance use among children, a switch-like transition to substance use in adolescence, and a nearly universal male bias in substance use. They also find that various reproductive indices, such as total fertility rate and age of the youngest child, are negatively associated with women's substance use, even after controlling for indices of women’s social, economic, and educational status. These results suggest that fetal protection helps explain female drug use decisions. The onset of substance use in adolescents of both sexes might be explained by the diminishing developmental costs of toxin exposure vs. its increasing benefits in ancestral environments, such as self-medication against macroparasites.
Major depression is considered to be a pathological response to stress that elicits aversive responses towards depressed individuals. Alternatively, depression might involve honest signals of need in response to stress and help to bargain for increased support from reluctant others. To test this hypothesis, we examined responses to a wide range of emotional signals in a vignette study in which we also manipulated information about the signaler’s need and her levels of conflict with the social partner (participant) in a between-subjects factorial design. Specifically, a fictional sister asked the participant to help pay for medical treatment. The sister’s true need for money was either clear or questionable, and her level of conflict with the participant was either high or low. The sister’s signals were either verbal request, crying, depression, or, as a control, schizophrenic symptoms.
In our sample of 1,447 participants recruited from Amazon Mechanical Turk, depression increased belief in need and elicited more help than all the other proposed signals of need on our four outcome measures across all conditions. Simple crying and verbal requests were generally less effective. We also found evidence for the predicted interaction between signal type and conflict on relationship outcomes. Because signals comprising symptoms of schizophrenia caused a dramatic reduction in support, we can discount the hypothesis that help was provided due to symptoms of mental illness. Our results suggest that depression, an apparent human universal, is a relatively successful way of signaling honest need and eliciting support, consistent with costly signaling explanations.
Depression is bad and therefore a disorder
Immigrants have faced high burdens of stress since long before the current administration’s anti-immigrant policies. This study is an investigation of how immigration-related stress may impact the biology and health of Latinx immigrant mothers and children, considering recent increases in divisive rhetoric and anti-immigrant policies in the U.S. We compared hair cortisol and DNA methylation at stress-related candidate genes in mothers and children with interview data in Nashville, TN from two time points spanning the recent presidential election. Structured interviews were conducted with 82 immigrant mothers and their children (aged 5-13) between 2015 and 2016 and again in 2018. Using mixed-methods, we analyze perceived stressors, mental health, and buffering factors from mothers and children in relation to hair cortisol and bisulfite pyrosequencing at two stress-related genes. Mothers report high levels of depressive symptoms (24.3%), anxiety symptoms (35.1%), and moderate perceived stress (86.5%) as well as significantly decreased levels of optimism over time (mean difference = -3.4; p-value<0.001). Before the 2016 election, we find (log) children’s hair cortisol negatively associated with mother’s year’s in US (β = -0.07; p-value=0.04), and children’s worry over parent’s deportation (β = -0.31; p-value=0.069), suggesting a blunting effect on stress response. We see similar results following the election. We also see longitudinal epigenetic changes in FKBP5 (ρ = 0.42; p-value=0.05) in the mothers but no changes in the children. Increased stress over time can lead to biological and health consequences across the lifespan, especially for these already vulnerable families.
Funds provided by the Chancellors Research in Excellence Scholars at UCSD (Application # 4-G021) and Foundation for Child Development (VU-14).
Currently, cross-country variation in gender equality is thought to be the primary factor producing global tobacco use sex differences, with gender inequality, especially in low-to-middle-income countries, preventing women from obtaining and using tobacco. Our alternative hypothesis draws on the “fetal protection” theory from evolutionary anthropology which emphasizes that reproductively-aged women protect their fetuses and nursing infants via an evolved a network of toxin defenses, characterized by upregulated detoxification of- and/or strong aversions to- teratogenic substances (e.g. tobacco)—individual-level defenses that are furthermore reinforced by culture-level proscriptions aimed at safeguarding fetal/offspring health. Although support for the fetal protection model has been found (Hagen et al. 2016), prior research has used data aggregated at the nation-level and has neither examined individual-level variation nor considered that cultural norms may also influence tobacco use. Using individual-level data from a high fertility, tobacco-growing, ethnically and socioeconomically diverse province in the South Central Andes (Jujuy, Argentina), we explore the relationship various fertility indices and sociocultural tobacco norms have on nulliparous and multiparous women’s tobacco use outcomes (N=108), while controlling for demographic features and considering ethnic differences as main effects. Smoker status was determined via salivary cotinine and cross-validated with questionnaire data. Our analyses reveal ethnic differences in tobacco use attitudes and behaviors and suggest fertility characteristics are important factors in female smoking decisions. Consistent with fetal protection model predictions, these findings suggest smoking vulnerabilities intersect with sex and socio-cultural variables in an additive manner and open the door to future areas of research.
The presence of a sexual division of labor has been the focus of bioarchaeological research in a broad range of prehistoric contexts. Nonetheless, few data are available about the presence and type of gendered activities among Celtic populations. This gap hampers the analysis of the social nuances characterizing these populations and a broader understanding of the socioeconomic patterns featuring Iron Age communities of Western Europe. Here, we address these issues by testing the presence of gendered activities in a Celtic population (Cenomani Gauls) from Seminario Vescovile (Verona, NE Italy, 3rd-1st c. BC).
Entheseal changes at 9 postcranial attachment sites, as well as humeral and femoral shape and robusticity indices calculated from external long bone measurements are compared between sexes in a sample of 56 adult individuals (N females=22; N males =34). The effect of sex, age, and side on the considered variables are tested by means of generalized linear models, generalized estimating equations, and Mann-Whitney tests.
Analyses show a lack of difference between sexes in long bone shape, a higher incidence of upper and, especially, lower limb entheseal changes in males, and higher long bone robusticity in females.
These results suggest the presence at SV of sex-specific activities mostly related to farming and differently influencing the considered variables. At the same time, this study underlines the need to consider non-functional factors (e.g. nutritional and developmental) when trying to infer patterns of physical activity from osteological variables.