Page 75 - Like me, or else... - Michelle Achterberg

The neural basis of aggression regulation
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feedback is also followed by more aggressive behavior (i.e., by a longer noise blast towards the peer). In addition, we show that more activity in the right dlPFC is related to less aggression after negative social feedback (compared to neutral feedback), indicating that the lateral PFC is an important neural regulator of social aggression. Several studies on structural brain development have shown that the quality of brain connectivity between the PFC and the striatum is related to impulse control (Peper et al., 2013; van den Bos et al., 2014). That is to say, a large study on structural brain connectivity in typically developing individuals (258 participants, aged 8-25) revealed that less white matter integrity between subcortical and prefrontal brain regions was associated with more trait aggression (Peper et al., 2015). Moreover, Chester and DeWall (2016) recently demonstrated that more functional connectivity between the nucleus accumbens and the lateral PFC during decisions about aggressive acts was related to less behavioral aggression. This study is the first study to investigate aggressive responses after positive, neutral, and negative feedback, and shows a role of the dlPFC in individual differences in the regulation of aggressive behavior.
Some limitations regarding this study need to be acknowledged. First, although the noise blast is often used as a measure of aggression (e.g., Bushman (2002); Chester et al. (2014); Riva et al. (2015)), our cover story stated that the peers would not hear the noise blast. That is to say, the aggression measure may reflect frustration and anger, and hypothetical aggression. Future research should further test the ecological validity of the noise blast as a measure of aggression by including additional measures of aggression or information on participants’ histories of aggressive behavior. Secondly, our paradigm did not include an ‘opt out’ option, that is, we told participants to always push the noise blast button, even after positive feedback. This was done to keep task demands as similar as possible between the conditions. We explained that the noise would be very short and at very low intensity if the button was released as quickly as possible. However, participants may have wanted to refrain from any noise blast after positive feedback. Future research could take this into account by implementing options to respond either positive, neutral, or negative towards the peer, as can for example be implemented by using symbols (Jarcho et al., 2013).
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