Human brain anatomy reflects separable genetic and environmental components of socioeconomic status

Socioeconomic status (SES) correlates with brain structure, a relation of interest given the long-observed relations of SES to cognitive abilities and health. Yet, major questions remain open, in particular, the pattern of causality that underlies this relation. In an unprecedently large study, here, we assess genetic and environmental contributions to SES differences in neuroanatomy. We first establish robust SES–gray matter relations across a number of brain regions, cortical and subcortical. These regional correlates are parsed into predominantly genetic factors and those potentially due to the environment. We show that genetic effects are stronger in some areas (prefrontal cortex, insula) than others. In areas showing less genetic effect (cerebellum, lateral temporal), environmental factors are likely to be influential. Our results imply a complex interplay of genetic and environmental factors that influence the SES-brain relation and may eventually provide insights relevant to policy

A neural fingerprint of adaptive mentalization

Mentalization – inferring other’s emotions and intentions – is crucial for human social interactions and is impaired in various brain disorders. While previous neuroscience research has focussed on static mentalization strategies, we know little about how the brain decides adaptively which strategies to employ at any moment of time. Here we investigate this core aspect of mentalization with computational modeling and fMRI during interactive strategic games. We find that most participants can adapt their strategy to the changing sophistication of their opponents, but with considerable individual differences. Model-based fMRI analyses identify a distributed brain network where activity tracks this mentalization-belief adaptation. Notably, the extent to which people update their belief about the other’s sophistication can be predicted out-of-sample from neural activity, providing a neural fingerprint of adaptive mentalization. Our approach illuminates the neural basis of mentalization ability and provides a new approach to assess these capabilities in healthy and clinical populations

Acute stress reduces effortful prosocial behaviour

Acute stress can change our cognition and emotions, but what specific consequences this has for human prosocial behaviour is unclear. Previous studies have mainly investigated prosociality with financial transfers in economic games and produced conflicting results. Yet a core feature of many types of prosocial behaviour is that they are effortful. We therefore examined how acute stress changes our willingness to exert effort that benefits others. Healthy male participants – half of whom were put under acute stress – made decisions whether to exert physical effort to gain money for themselves or another person. With this design, we could independently assess the effects of acute stress on prosocial, compared to self-benefitting, effortful behaviour. Compared to controls (n = 45), participants in the stress group (n = 46) chose to exert effort more often for self- than for other-benefitting rewards at a low level of effort. Additionally, the adverse effects of stress on prosocial effort were particularly pronounced in more selfish participants. Neuroimaging combined with computational modelling revealed a putative neural mechanism underlying these effects: more stressed participants showed increased activation to subjective value in the dorsal anterior cingulate cortex and anterior insula when they themselves could benefit from their exerted effort relative to when someone else could. By using an effort-based task that better approximates real-life prosocial behaviour and incorporating trait differences in prosocial tendencies, our study provides important insights into how acute stress affects prosociality and its associated neural mechanisms

Oxytocin promotes altruistic punishment

The role of neuromodulators in the enforcement of cooperation is still not well understood. Here, we provide evidence that intranasal applied oxytocin, an important hormone formodulating social behavior, enhances the inclination to sanction freeriders in a social dilemma situation. Contrary to the notion of oxytocin being a pro-social hormone, we found that participants treated with oxytocin exhibited an amplification of self-reported negative social emotions such as anger towards free-riders, ultimately resulting in highermagnitude and frequency of punishment of free-riders compared to placebo. Furthermore, we found initial evidence that oxytocin contributes to the positive effects of a punishment institution by rendering cooperation preferable in the oxytocin condition for even themost selfish players when punishment was available. Together, these findings imply that the neural circuits underlying altruistic punishment are partly targeted by the oxytonergic systemand highlight the importance of neuromodulators in group cohesion and normenforcement within social groups