Page 65 - Like me, or else... - Michelle Achterberg

The neural basis of aggression regulation
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directly retaliate to the peer who judged them, by sending a loud noise blast (Twenge et al., 2001; Chester et al., 2014). Noise blast duration was measured after each trial within the fMRI task and therefore we could examine how neural activity related to individual differences in noise blast duration. On a behavioral level, we hypothesized that negative social feedback would trigger reactive aggression, i.e. longer noise blasts (Twenge et al., 2001; Reijntjes et al., 2011; Riva et al., 2015). In addition, we hypothesized that less aggression (i.e., more aggression regulation, shorter noise blasts) would be related to increased activation in lateral PFC (Casey, 2015; Riva et al., 2015) particularly during negative feedback.
Methods
Participants
Thirty participants between the ages of 18 and 27 participated in this study (15 females, M=22.63 years, SD=2.62). They were either contacted from a participant database or they responded to an advert placed online. The institutional review board of the Leiden University Medical Center (LUMC) approved the study and its procedures. Written informed consent was obtained from all participants. All participants were fluent in Dutch, right-handed, and had normal or corrected-to- normal vision. Participants were screened for MRI contra indications and had no history of neurological or psychiatric disorders. All anatomical MRI scans were reviewed and cleared by a radiologist from the radiology department of the LUMC. No anomalous findings were reported.
Participants’ intelligence quotient (IQ) was estimated with the subsets ‘similarities’ and ‘block design’ of the Wechsler Intelligence Scale for Adults, third edition (WAIS-III; Wechsler (1997)). All estimated IQs were in the normal to high range (95 to 135; M=113.92, SD=9.23). IQ scores were not correlated to behavioral outcomes of the Social Network Aggression Task (noise blast duration after positive, neutral, negative feedback and noise blast difference scores, all p’s > .244)
Social Network Aggression Task
The Social Network Aggression Task (SNAT) was based on the social evaluation paradigm of Somerville et al. (2006) and Gunther Moor et al. (2010b). Prior to the fMRI session, participants filled in a profile page at home, which was handed in at least one week before the actual fMRI session. The profile page consisted of personal statements such as: “My favorite sport is...”, “This makes me happy:...”, “My biggest wish is...”. Participants were informed that their profiles were viewed by other individuals. During the SNAT participants were presented with pictures and feedback from same-aged peers in response to the participants’ personal profile. This feedback could either be positive (‘I like your profile’, visualized by
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