Neural Correlates of Aggression among Individuals from Low and High Socioeconomic Status: An ERP Study

Abstract

Event-related brain potentials were recorded to investigate electrophysiological correlates of aggression in high and low socioeconomic status (SES) participants who responded to violent and nonviolent images by using a choice reaction time paradigm. ERP data showed that violent images elicited a smaller N2 deflection than did nonviolent images in both high and low SES groups, but there was no difference in N2 amplitudes to aggressive and non-aggressive information as a function of SES. Notably, the latency of N2 in the low SES group was longer than that of the high SES group, suggesting slowness by the low SES group in deploying control responses. In addition, the low SES group exhibited significantly smaller P3 amplitudes to violent images, suggesting a reduction in brain activity known to reflect activation of the aversive motivational system, and this findings link this brain activity to aggressive behavior. As a whole the present findings show that participants low in SES seem to display similar psychophysiological responses to individuals high in aggression.

Do EEG and Startle Reflex Modulation Vary with Self-Reported Aggression in Response to Violent Images?

“…The vast majority of studies previously performed focused largely on the P300 component. They overwhelmingly show that highly aggressive individuals tend to show a more inhibited (smaller amplitude) P300 response than low aggressive individuals [31,50,51,52,53]. These studies posit the idea that the smaller P300 component may be due to cognitive deficits [51] or be associated with increases of aggression.…”

“…They overwhelmingly show that highly aggressive individuals tend to show a more inhibited (smaller amplitude) P300 response than low aggressive individuals [31,50,51,52,53]. These studies posit the idea that the smaller P300 component may be due to cognitive deficits [51] or be associated with increases of aggression. Wang et al [52] stated that this effect may imply a reduction in brain activity which has been known to reflect activation of the averse motivational system which can be linked to aggressive behaviour [54].…”

The Emerging (Social) Neuroscience of SES

“…Interestingly, research using an ERP paradigm in which participants viewed violent and non‐violent images revealed greater P3 amplitudes among high SES participants (versus low SES participants) in response to violent images Wang, Zhao, Qiu, Ybarra, Liu & Huang (). The authors suggest two possible interpretations for these results, including that low SES participants may have had greater exposure to violence and the reduced P3 amplitudes may reflect desensitization, or that the reduced P3 amplitudes suggest that it was less cognitively demanding for low SES participants to process these violent stimuli, consistent with the idea that neural systems of those from low SES contexts are better tuned to deal with potential threats.…”

“…However, because the authors did not use a typical paradigm for studying P3 (the number of violent stimuli and non‐violent stimuli trials were balanced, rather than a typical oddball paradigm in which one stimulus is far less common than the other), these results are somewhat difficult to interpret. Nor did Wang and colleagues () assess the LPP (an ERP marker of arousal linked to amygdala activation; Liu, Huang, McGinnis‐Deweese, Keil, & Ding, ), making it difficult to compare their results with the fMRI findings linking low SES to stronger amygdala responses to potential threats. It is also worth noting that this study was conducted with a Chinese sample, raising the possibility that SES may not always have the same neural consequences in all societies.…”

“…It is worth noting the vast majority of research on how SES affects neural responses has been conducted in the United States (but see Ma, Wang, & Han, 2011;Wang et al, 2012). Although some work suggests that SES has similar effects on constructs like self-construal and attentional biases in other countries including Russia and China (Grossmann & Varnum, 2011;Hamamura, Xu, & Du, 2013), it may be that in some cases culture and SES have interactive effects.…”