Psychological constraints on aggressive predation in economic contests.

When humans compete, they invest energy and effort to injure others and to protect against injury and exploitation. The psychology behind exploiting others and protecting against exploitation is still poorly understood and is addressed here in an incentivized economic contest game in which individuals invested in predatory attack and prey defense. Consistent with standard economic theory on production and predation, we find that individuals compete less intensely when they attack rather than defend and that attacks disproportionally often fail.

Pupil mimicry promotes trust through the theory-of-mind network.

The human eye can provide powerful insights into the emotions and intentions of others; however, how pupillary changes influence observers' behavior remains largely unknown. The present fMRI-pupillometry study revealed that when the pupils of interacting partners synchronously dilate, trust is promoted, which suggests that pupil mimicry affiliates people. Here we provide evidence that pupil mimicry modulates trust decisions through the activation of the theory-of-mind network (precuneus, temporo-parietal junction, superior temporal sulcus, and medial prefrontal cortex).