Incidental physical pain reduces brain activities associated with affective social feedback and increases aggression

Abstract

Physical pain may lead to aggressive behavior in a social context. However, it is unclear whether this is related to changes of social information processing. Thus, this study aimed to investigate the neural mechanisms underlying pain-induced aggression using functional magnetic resonance imaging. In the experiment, 59 healthy participants were recruited; 31 were treated with topical capsaicin cream (pain group), and 28 with hand cream (control group). Participants completed a social network aggression task, during which they underwent two phases: feedback processing; and attack exerting. Results revealed that participants in the pain group exhibited more aggression than those in the control group. During the feedback-processing phase, physical pain reduced brain activation in the right insula, left orbitofrontal cortex (OFC), and anterior cingulate cortex (ACC), which typically exhibited stronger activation in response to negative (and positive) versus neutral social feedback in the control group. However, during the attack-exerting phase, pain did not significantly alter activation of the dorsolateral prefrontal cortex (DLPFC). These findings suggest that pain increased aggression, while before that, it suppressed brain activities of the salience network involved in the process of salient social information and the value system associated with value representation of social events.

Effects of Positive and Negative Experiences on Cooperative Behavior: The Role of Sharedness

“…However, research should not be limited to physical experiences. Physical experiences (e.g., physical pain) implicitly play a similar role as social experiences (e.g., social pain) in affecting individuals' behavior [12]. Positive/negative experiences also include social experiences, such as success/failure and social acceptance/exclusion, which should be explored in future research.…”

“…Therefore, it is unclear whether the conclusion that negative experiences promote cooperation is drawn from "shared negative experience" or "negative experience". Although an increasing amount of evidence shows painful experiences (a kind of negative experience) promoted cooperation [16,17], studies also found pain could increase aggressive behavior [12]. These inconsistent results suggest the possibility that moderating variables exist in the relationship between positive/negative experiences and cooperative behavior.…”

“…This might be due to several reasons. First, prior studies might have solely examined the effect of positive [11] or negative experiences [12] and compared them with neutral experiences. Thus, there may be a lack of perspective in directly comparing the effects of positive and negative experiences.…”

“…Through these two studies, we aim to clarify how positive/negative experiences affect cooperation and improve the understanding of laws of cooperation. In previous studies on the effects of the positive experiences or negative experiences on cooperation, researchers usually invited university students as participants [12,16,17]. To be consistent with previous studies, university students were selected as participants in the present study.…”

Factors Associated with Aggression: A Nationwide Population- based Survey

“…Furthermore, according to the General Aggression Model (GAM), aggression is associated with various social, cognitive, developmental, and biological factors [11]. However, previous studies have focused on the relationship between aggression and only one or two factors, including age [12,13], sex [10], chronic pain [14], low levels of physical activity [14,15], depression, anxiety [16][17][18][19][20], and marital status [21].…”