A systematic review and meta-analysis examining the relationship between everyday sadism and aggression: Can subclinical sadistic traits predict aggressive behaviour within the general population?

Abstract

Everyday sadism is unique among the dark personality traits that form the Dark Tetrad. Whilst it shares the Dark Core of Personality with psychopathy, narcissism, and Machiavellianism, it is theoretically distinct from the other members in that involves an appetite for cruelty. Given mounting evidence of everyday sadism being associated with socially aversive behaviour, and its potential utility in predicting harmful behaviour within the general population; the current review examined the relationship between sadism and aggressive behaviour. Seven well-established electronic bibliographic databases and two other sources were systematically searched. Supplementary searches were employed. The initial search identified 627 full-text articles. Following application of inclusion and exclusion criteria, 39 full-text articles inclusive of 52 studies were subject to quality assessment. Data was extracted from 52 studies, with 48 studies eligible for quantitative synthesis. Correlational analyses were the most common method of examining sadism and aggression. A multi-method approach was employed to standardize effect sizes into a common metric (correlation coefficient). A meta-analysis was conducted using 57 effect sizes from 48 studies with 22,179 participants, revealing a pooled correlation coefficient of 0.35 (95% CI = 0.29, 0.40). Significant heterogeneity was observed which warranted sensitivity and subgroup analyses. Overall, a moderate relationship was found between subclinical sadism and aggressive behaviour, as defined by acts ranging from verbal to physical, and sexual aggression and violence. A stronger, moderate relationship was found between sadism and perpetration of aggressive behaviour online, indicating that anonymity may unleash the darker side of personality within the general population. The implications of this finding are considered. • Systematic review and meta-analysis examining the relationship between everyday sadism and aggression. • Synthesized evidence suggests sadism is correlated with dispositional aggression and a range of aggressive behaviour. • Subgroup analysis included examining the relationship between sadism, sexual violence, and intimate partner violence. • Subgroup analysis examined the relationship between sadism and aggressive behaviour perpetrated online and offline. • Meta-regression analyses completed to examine potential moderator variables between sadism and aggression.