Keele Research Repository

Research shows sibling relationships can influence cognitive development, specifically in terms of high-order processes involved in social functioning. These high-order processes take place in the human prefrontal cortex. While prefrontal connectivity can be influenced by factors experienced during developmental phases, it remains unclear how experiences of aggression towards a sibling in childhood can contribute to high-order processes in adulthood, specifically decision-making. Through two studies, we sought to establish a relationship between sibling aggression and decision-making styles reported in adulthood, as well as real-time risky decision-making. Study 1 examined the relationship between childhood experiences of sibling aggression and high-order function, specifically decision-making. Self-reports from 142 adult participants revealed that using sibling aggression to maintain dominance (ESAS; Harrison, Harrison, N. (2017). Sibling aggression: Associations with parenting styles, social dominance behaviour and co-occurring forms of family aggression (Doctoral thesis, University of Central Lancashire, UK). Retrieved from: https://clok.uclan.ac.uk/20917/) was linked to avoidant and spontaneous decision-making (GDMS; Scott & Bruce, Scott and Bruce, Educational and Psychological Measurement 55:818–831, 1995). The findings reported here indicate a possible role of sibling aggression in the development of avoidant and spontaneous decision-making styles. Study 2 investigated the relationship between childhood sibling aggression (ESAS; Harrison, Harrison, N. (2017). Sibling aggression: Associations with parenting styles, social dominance behaviour and co-occurring forms of family aggression (Doctoral thesis, University of Central Lancashire, UK). Retrieved from: https://clok.uclan.ac.uk/20917/) and performance in risky decision-making tasks (IOWA gambling task; Bechara et al., Bechara et al., Brain 123:2189–2202, 2000) among 75 adult participants. It revealed that experiences of sibling aggression did not predict risky decision-making. These findings indicate that the types of decisions made may be influenced by childhood sibling aggression, but not the level of risk involved in decisions made.