An adaptive role of collective decisions: shared responsibility in the human brain (360G-Wellcome-204702_Z_16_Z)

Decades of research in collective decision-making show that the reliability of joint decisions is far from guaranteed raising the obvious question: why is collective decision making so popular in human interactions? I suggest an alternative to the quest for collective accuracy. I hypothesise that collective decisions are adaptive because (1) joint (vs. individual) decisions decrease the sense of responsibility for mistakes both at behavioural and neuronal level ; (2) individuals seek to diminish the chances of punishments through engaging in collective decisions; and (3) individuals are assigned more responsibility and punished more severely than groups. I predict that shared responsibility and punishment avoidance in group decisions modulate the same cognitive/neuronal mechanisms that underlie the sense of agency and norm- enforcement in individual behaviour. By empirically testing these predictions behaviourally and neurally (using Magnetoencephalography and Transcranial Magnetic Stimulation), I will characterize the function of collective decisions, and help clarify the utility of cooperation.