Neural Evidence of Social Ties: On the Role of Empathy and Sympathy in Sharing Frans van Winden

Neural Evidence of Social Ties: On the Role of Empathy and Sympathy in Sharing

Frans van Winden

, Johannes Fahrenfort

, Benjamin Pelloux

and Richard Ridderinkhof

1

University of Amsterdam,

University of Amsterdam and University of Lyon

†

Correspondance at: [email protected]

Objective: Recent theoretical and behavioral studies (van Dijk and van Winden 1997, van Dijk et al. 2002, Sonnemans et al. 2006) have provided some support for the existence of a social ties mechanism inducing sympathy (or antipathy) between people interacting in an economic environment. In this study, we use fMRI to see whether a neural basis for this mechanism can be found.

Methods: We had 29 pairs of subjects participating in this experiment. Each subject n the scanner was matched with an anonymous other participant who was in another room.

Participants’ brain activity was measured using fMRI while they were involved in a novel Neural Distributional Preferences Test, with real monetary incentives, both before and after a spell of economic interaction. Using these neural data, we are able to search for empathic neural responses triggered by a situation in which, as opposed to previous neural studies of empathy (e.g. Singer et al. 2006), outcomes benefiting the other are involved.

Results: We find that empathic neural responses in several brain regions related to reward are conditioned on the mere presence of the economic interaction (that is, independent of its quality). More particularly, we find that more empathic players showed greater activity in the striatum (a region associated with value and reward) when the other subject is receiving money during the post-interaction test. Moreover, we observe an impact of the cooperativeness of the other player on the activation of the posterior Superior Temporal Sulcus (pSTS) and the Posterior Cingulate Cortex (PCC), which may be interpreted as a representation of a social tie between the two players. Further supporting this interpretation is the finding that subsequent behavior in the economic interaction is predicted by the difference in activation of the pSTS and the PCC between the pre- and the post-tests. In contrast, the empathy related activity in the striatum is not predictive in this respect.

Conclusions: The results of this study suggest that empathic neural responses may only emerge if preceded by an interaction. Moreover, cooperative interaction fosters social ties (sympathy). Brain activity further suggests that the pSTS and the PCC play an important role in the formation of social ties and consequently in social economic decision making.

Acknowledgment: This study was funded by NWO.