A role for the medial temporal lobe subsystem in guiding prosociality: the effect of episodic processes on willingness to help others

Why are we willing to help others? Recent behavioral work on episodic processes (i.e. the ability to represent an event that is specific in time and place) suggests that imagining and remembering scenes of helping a person in need increases intentions to help. Here, we provide insight into the cognitive and neural mechanisms that enhance prosocial intentions via episodic simulation and memory. In Experiment 1, we scanned participants using functional neuroimaging as they imagined and remembered helping episodes, and completed non-episodic control conditions accounting for exposure to the story of need and conceptual priming of helping. Analyses revealed that activity in the medial temporal lobe (MTL) subsystem, as well as the right temporoparietal junction (RTPJ) predicted the effect of conditions on the strength of prosocial intentions. In Experiment 2, we used transcranial magnetic stimulation to disrupt activity in the RTPJ, and better isolate the contribution of MTL subsystem to prosocial intentions. The effect of conditions on willingness to help remained even when activity in the RTPJ was disrupted, suggesting that activity in the MTL subsystem may primarily support this prosocial effect. It seems our willingness to help may be guided, in part, by how easily we can construct imagined and remembered helping episodes.