Impulsive Choice and Altruistic Punishment Are Correlated and Increase in Tandem With Serotonin Depletion

Human cooperation may partly depend on the presence of individuals willing to incur personal costs to punish noncooperators. The psychological factors that motivate such 'altruistic punishment' are not fully understood; some have argued that altruistic punishment is a deliberate act of norm enforcement that requires self-control, while others claim that it is an impulsive act driven primarily by emotion. In the current study, we addressed this question by examining the relationship between impulsive choice and altruistic punishment in the ultimatum game. As the neurotransmitter serotonin has been implicated in both impulsive choice and altruistic punishment, we investigated the effects of manipulating serotonin on both measures. Across individuals, impulsive choice and altruistic punishment were correlated and increased following serotonin depletion. These findings imply that altruistic punishment reflects the absence rather than the presence of self control, and suggest that impulsive choice and altruistic punishment share common neural mechanisms

The influence of social preferences and reputational concerns on intergroup prosocial behaviour in gains and losses contexts

To what extent do people help ingroup members based on a social preference to improve ingroup members’ outcomes, versus strategic concerns about preserving their reputation within their group? And do these motives manifest differently when a prosocial behaviour occurs in the context of helping another gain a positive outcome (study 1), versus helping another to avoid losing a positive outcome (study 2)? In both contexts, we find that participants are more prosocial towards ingroup (versus outgroup members) and more prosocial when decisions are public (versus private) but find no interaction between group membership and either anonymity of the decision or expected economic value of helping. Therefore, consistent with a preference-based account of ingroup favouritism, people appear to prefer to help ingroup members more than outgroup members, regardless of whether helping can improve their reputation within their group. Moreover, this preference to help ingroup members appears to take the form of an intuitive social heuristic to help ingroup members, regardless of the economic incentives or possibility of reputation management. Theoretical and practical implications for the study of intergroup prosocial behaviour are discussed

Neural and Cognitive Signatures of Guilt Predict Hypocritical Blame

A common form of moral hypocrisy occurs when people blame others for moral violations that they themselves commit. It is assumed that hypocritical blamers act in this manner to falsely signal that they hold moral standards that they do not really accept. We tested this assumption by investigating the neurocognitive processes of hypocritical blamers during moral decision-making. Participants (62 adult UK residents; 27 males) underwent functional MRI scanning while deciding whether to profit by inflicting pain on others and then judged the blameworthiness of others’ identical decisions. Observers (188 adult U.S. residents; 125 males) judged participants who blamed others for making the same harmful choice to be hypocritical, immoral, and untrustworthy. However, analyzing hypocritical blamers’ behaviors and neural responses shows that hypocritical blame was positively correlated with conflicted feelings, neural responses to moral standards, and guilt-related neural responses. These findings demonstrate that hypocritical blamers may hold the moral standards that they apply to others.<br/

Vaccine Nationalism Counterintuitively Erodes Public Trust in Leaders

Global access to resources like vaccines is key for containing the spread of infectious diseases. However, wealthy countries often pursue nationalistic policies, stockpiling doses rather than redistributing them globally. One possible motivation behind vaccine nationalism is a belief among policymakers that citizens will mistrust leaders who prioritize global needs over domestic protection. In seven experiments (total N=4215), we demonstrate that such concerns are misplaced: nationally representative samples across multiple countries with large vaccine surpluses (Australia, Canada, U.K., and U.S.) trusted redistributive leaders more than nationalistic leaders — even the more nationalistic participants. This preference generalized across different diseases, and manifested in both self-reported and behavioral measures of trust. Professional civil servants however had the opposite intuition and predicted higher trust in nationalistic leaders, and a non-expert sample also failed to predict higher trust in redistributive leaders. We discuss how policymakers’ inaccurate intuitions might originate from overestimating others’ self-interest

Neural mechanisms for learning self and other ownership

The sense of ownership – of which objects belong to us and which to others - is an important part of our lives, but how the brain keeps track of ownership is poorly understood. Here, the authors show that specific brain areas are involved in ownership acquisition for the self, friends, and strangers

Dreading the pain of others? Altruistic responses to others' pain underestimate dread

A dislike of waiting for pain, aptly termed ‘dread’, is so great that people will increase pain to avoid delaying it. However, despite many accounts of altruistic responses to pain in others, no previous studies have tested whether people take delay into account when attempting to ameliorate others' pain. We examined the impact of delay in 2 experiments where participants (total N = 130) specified the intensity and delay of pain either for themselves or another person. Participants were willing to increase the experimental pain of another participant to avoid delaying it, indicative of dread, though did so to a lesser extent than was the case for their own pain. We observed a similar attenuation in dread when participants chose the timing of a hypothetical painful medical treatment for a close friend or relative, but no such attenuation when participants chose for a more distant acquaintance. A model in which altruism is biased to privilege pain intensity over the dread of pain parsimoniously accounts for these findings. We refer to this underestimation of others' dread as a ‘Dread Empathy Gap’

Serotonin depletion impairs both Pavlovian and instrumental reversal learning in healthy humans.

Funder: Gates Cambridge Trust; doi: https://doi.org/10.13039/501100005370Funder: DH | National Institute for Health Research (NIHR); doi: https://doi.org/10.13039/501100000272Serotonin is involved in updating responses to changing environmental circumstances. Optimising behaviour to maximise reward and minimise punishment may require shifting strategies upon encountering new situations. Likewise, autonomic responses to threats are critical for survival yet must be modified as danger shifts from one source to another. Whilst numerous psychiatric disorders are characterised by behavioural and autonomic inflexibility, few studies have examined the contribution of serotonin in humans. We modelled both processes, respectively, in two independent experiments (N = 97). Experiment 1 assessed instrumental (stimulus-response-outcome) reversal learning whereby individuals learned through trial and error which action was most optimal for obtaining reward or avoiding punishment initially, and the contingencies subsequently reversed serially. Experiment 2 examined Pavlovian (stimulus-outcome) reversal learning assessed by the skin conductance response: one innately threatening stimulus predicted receipt of an uncomfortable electric shock and another did not; these contingencies swapped in a reversal phase. Upon depleting the serotonin precursor tryptophan-in a double-blind randomised placebo-controlled design-healthy volunteers showed impairments in updating both actions and autonomic responses to reflect changing contingencies. Reversal deficits in each domain, furthermore, were correlated with the extent of tryptophan depletion. Initial Pavlovian conditioning, moreover, which involved innately threatening stimuli, was potentiated by depletion. These results translate findings in experimental animals to humans and have implications for the neurochemical basis of cognitive inflexibility.NIH