No sex differences in the origins of covariation between social and physical aggression.
Level 3 - non-randomized controlled study
Twin study using structural equation modeling in a non-clinical developmental cohort (graded by design analogy).
PubMed 30526706 · doi:10.1017/S0033291718003392
What was done
The authors examined maternal and teacher ratings of physical and social aggression in over 1,000 twin pairs aged 6–10 years (mean age 8.02 years) from the Michigan State University Twin Registry. A bivariate correlated factors model was used to decompose the covariance between social and physical aggression into genetic, shared environmental, and non-shared environmental components, testing for sex differences in these etiological contributions.
What was found
Covariation between social and physical aggression was driven by shared genetic and environmental influences across both mother and teacher reports. Specifically, 50% to 57% of genetic factors, 74% to 100% of shared environmental factors, and 28% to 40% of unique environmental factors influencing physical aggression also accounted for social aggression. The magnitude and pattern of these shared etiological factors did not significantly differ between boys and girls.
Why it matters
The results challenge the common assumption that social aggression is uniquely a female manifestation of aggression, indicating instead that social and physical aggression share underlying developmental and externalizing pathways in both sexes.
Limits
The abstract does not provide exact twin pair counts by zygosity or sex, exact correlation coefficients, or confidence intervals for the variance components. Findings rely on parent and teacher rating scales in children aged 6–10 and may not generalize to adolescent or adult populations or direct behavioral observations.
Cited by
- context Research shows that the same genes predisposing boys to physical aggression also predict relational aggression in girls.