Meta-analysis finds lower IQ linked to reactive violence, but effect is modest
Feb 22nd 2026
A systematic review published in Intelligence of 131 studies reports that people who commit impulsive violence tend to score lower on full, verbal and nonverbal IQ tests, with small but consistent correlations across more than 33,000 participants.
- Researchers reviewed 131 empirical studies and compared 1,860 violent individuals with 3,888 nonviolent controls while pooling correlations across 33,118 participants.
- Violent individuals scored significantly lower on full, verbal and nonverbal intelligence measures than nonviolent groups.
- The negative correlation between intelligence and aggression was modest, with coefficients ranging from -0.09 to -0.20.
- The association was strongest for reactive, impulsive violence rather than planned, proactive aggression.
- The intelligence gap remained after accounting for gender and socioeconomic factors and was larger when mental or personality disorders were present.
- Authors say lower IQ should be seen as a facilitator not a direct cause and recommend tailoring rehabilitation to cognitive needs, while noting limits such as varied IQ tests and an English and Spanish publication bias.