Nadège Bault from the GATE will give a talk on Tuesday 14th January at the ISC amphitheater - 67 bd Pinel in Bron
"Neural dynamics of social tie formation in economic decision-making".
Cooperation arising during social interaction has been explained by a natural disposition of humans for prosocial behavior. However, the degree by which we are inclined to cooperate may depend on social ties. Social ties refer to a care about the interests of others, based on interaction history with a specific interaction partner. In models of other-regarding preferences, formalized through interdependent utility functions, weights are attached to other individuals’ welfare. These models generally assume the weights to be stable, regardless of previous interactions. We formulate instead a dynamic computational model that accurately predicted how tie formation influences decisions to contribute in a public good game. We used model-driven functional Magnetic Resonance Imaging (fMRI) to test the hypothesis that brain regions key to social interaction keep track of dynamics in tie strength. Activation in the medial prefrontal cortex (mPFC) tracked the individual’s public good contributions. Activation in the bilateral posterior temporal sulcus (pSTS), and temporo-parietal junction (TPJ) was modulated parametrically by the dynamically developing social tie – as estimated by our model – supporting a role of these regions in social tie formation. Activity in these two regions further reflected inter-individual differences in tie persistence and sensitivity to behavior of the interacting partner. Functional connectivity between mPFC and pSTS activations indicated that the representation of social ties is integrated in the decision process. These data reveal the brain mechanisms underlying the integration of interaction dynamics into a social tie representation which in turn influenced the individual’s prosocial decisions.