Summary: The stress hormone cortisol reduces altruistic behaviors and alters brain activity in the dorsolateral prefrontal cortex in people with higher levels of empathy.
The stress hormone cortisol reduces altruistic behavior and alters activity in brain regions linked to social decision making—but only in people who are better at imagining others’ mental states, according to new research published in The Journal of Neuroscience.
In a study from Universität Hamburg, participants decided how much money to donate to a selection of charities before and after completing a stressful public-speaking task while researchers monitored their brain activity with fMRI.
To simulate the personal cost of making an altruistic decision, the participants received a portion of the money they did not donate. Before the stressful task, people with higher mentalizing ability, or the ability to imagine others’ mental states, donated more money than people with low mentalizing ability.
In people with high mentalizing ability, increased levels of the stress hormone cortisol decreased donations; cortisol had no effect on people with low mentalizing ability.
The researchers could predict how high mentalizers would choose to donate based on activity in the dorsolateral prefrontal cortex (DLPFC), a brain region involved in social decision making. Yet higher levels of cortisol infringed on this pattern, indicating stress reduced the neural representation of donations in the DLPFC.
These results reveal cortisol might alter the activity of the DLPFC, which has a more pronounced effect on people who rely on mentalizing to make social decisions.
About this neuroscience and altruism research news
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Altruism under stress: cortisol negatively predicts charitable giving and neural value representations depending on mentalizing capacity
Altruism, defined as costly other-regarding behavior, varies considerably across people and contexts. One prominent context in which people frequently must decide on how to socially act is under stress. How does stress affect altruistic decision-making and through which neurocognitive mechanisms?
To address these questions, we assessed neural activity associated with charitable giving under stress. Human participants (males and females) completed a charitable donation task before and after they underwent either a psychosocial stressor or a control manipulation, while their brain activity was measured using functional magnetic resonance imaging (fMRI). As the ability to infer other people’s mental states (i.e., mentalizing) predicts prosocial giving and may be susceptible to stress, we examined whether stress effects on altruism depend on participants’ general capacity to mentalize, as assessed in an independent task.
Although our stress manipulation per se had no influence on charitable giving, increases in the stress hormone cortisol were associated with reductions in donations in participants with high mentalizing capacity, but not in low mentalizers.
Multivariate neural response patterns in the right dorsolateral prefrontal cortex (rDLPFC) were less predictive of post-manipulation donations in high mentalizers with increased cortisol, indicating decreased value coding, and this effect mediated the (moderated) association between cortisol increases and reduced donations.
Our findings provide novel insights into the modulation of altruistic decision-making by suggesting an impact of the stress hormone cortisol on mentalizing-related neurocognitive processes, which in turn results in decreased altruism. The DLPFC appears to play a key role in mediating this cortisol-related shift in altruism.
Altruism is a fundamental building block of our society. Emerging evidence indicates a major role of acute stress and stress-related neuromodulators in social behavior and decision-making. How and through which mechanisms stress may impact altruism remains elusive.
We observed that the stress hormone cortisol was linked to diminished altruistic behavior. This effect was mediated by reduced value representations in the right dorsolateral prefrontal cortex (rDLPFC) and critically depended on the individual capacity to infer mental states of others.
Our findings provide novel insights into the modulation of human altruism linked to stress-hormone dynamics and into the involved socio-cognitive and neural mechanisms, with important implications for future developments of more targeted interventions for stress-related decrements in social behavior and social cognition.