Page 74 - Like me, or else... - Michelle Achterberg

Chapter 3
conjunction analyses with the separate contrasts of negative and positive versus neutral feedback showed that positive feedback resulted in increased activity in the striatum and the ventral mPFC, whereas negative feedback activation merely overlapped with dorsal mPFC and insula activation observed following both positive and negative feedback. Finally, we found that increased lateral PFC activity after negative social feedback was associated with relative shorter noise blast durations after negative feedback, indicative of more aggression regulation.
Results of prior studies left undecided whether there is a unique neural coding for negative social feedback compared to positive social feedback. In this study we found that, consistent with prior studies (Guyer et al., 2009; Davey et al., 2010; Gunther Moor et al., 2010b) there was increased activity in the ventral mPFC and the striatum after positive feedback. Numerous studies have shown that the striatum is involved in reward processing (for a review, see Sescousse et al. (2013)) and this fits well with theories suggesting that positive evaluations and social acceptance activates brain regions overlapping with those that are activated by the primary feelings of reward (Lieberman and Eisenberger, 2009). Notably, there was no neural activation that was specific for negative social feedback. In Cyberball paradigms, a number of studies observed specific heightened activity in insula and ACC in response to social rejection, which was interpreted as the feeling of social pain (Eisenberger and Lieberman, 2004; Lieberman and Eisenberger, 2009). There are several differences in the experimental paradigms, however, that may explain the divergent results. That is to say, in Cyberball paradigms social rejection is unexpected (for example, exclusion after a period of inclusion) and is therefore likely to violate social expectations. In contrast, in social evaluation paradigms such as used in the current study, equal proportions of negative, positive, and neutral feedback are presented, which may result in more equal saliency of negative and positive feedback. The current findings, which show enhanced insula and mPFC activity following both positive and negative feedback (relative to neutral feedback), suggest that the insula and mPFC in social evaluation paradigms might work as a salience network, and signal events that are socially relevant (Guroglu et al., 2010; van den Bos et al., 2011). Resting-state fMRI studies confirm that these regions are often active in concert, and have referred to this network as a salience network (Damoiseaux et al., 2006; Jolles et al., 2011; van Duijvenvoorde et al., 2016a). Future research may disentangle the role of expectation violation in more detail by asking participants to make predictions about whether they expect to be liked (Somerville et al., 2006; Gunther Moor et al. 2010), in combination with positive, negative, and neutral feedback.
An additional goal of this study was to examine the association between brain activation and behavioral responses to negative social feedback. A vast line of research has already shown that social rejection can result in retaliation (Twenge et al., 2001; Leary et al., 2006; DeWall and Bushman, 2011; Chester et al., 2014; Riva et al., 2015). Our study shows that receiving negative social
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