People of higher intelligence are less violent and more capable of solving problems.

Judged against the research evidence available as of 2023-06-12 on how intelligence (IQ or general cognitive ability) relates to (a) violence/violent offending and (b) problem-solving ability. True: peer-reviewed research and meta-analyses consistently show that higher intelligence goes with lower rates of violence AND with greater problem-solving capability, so that the general statement holds as a population-level association. Mostly true: both associations are well supported but small or modest, or hold with notable exceptions, and the claim states them a little too broadly. Mixed: one half is well supported (for example, problem-solving) while the other (violence) is weak, inconsistent or heavily confounded. Mostly false: the associations exist only as weak correlations that the claim states as a general or causal truth, or the evidence is inconclusive while the claim states it as settled. False: research shows no such relationship or the opposite relationship for both parts.

Set before the research began.

1. E1 IQ in early adulthood and later risk of death by homicide: cohort study of 1 million men | The British Journal of Psychiatry | Cambridge Core The British Journal of Psychiatry (Cambridge Core) · 4 December 2008

   “In age-adjusted analyses there was an inverse relation between IQ and homicide mortality such that a one standard deviation advantage in IQ conferred a 51% reduction in risk (HRs.d. IQ increase=0.49, 95% CI 0.42–0.57).”

2. E2 IQ in early adulthood and later risk of death by homicide: cohort study of 1 million men | The British Journal of Psychiatry | Cambridge Core The British Journal of Psychiatry (Cambridge Core) · 4 December 2008

   “after adjustment for covariates, individuals in the highest IQ scoring group reported a marked reduction in the prevalence of assault in comparison with the lowest IQ scorers.”

3. E3 IQ in early adulthood and later risk of death by homicide: cohort study of 1 million men | The British Journal of Psychiatry | Cambridge Core The British Journal of Psychiatry (Cambridge Core) · 4 December 2008

   “That this cohort is well characterised for these social factors suggests that the apparent relation of IQ with homicide is unlikely to be explained substantially by residual confounding by such covariates, but we cannot rule it out as a possible important, alternative explanation.”

4. E4 23 Problem-Solving and Intelligence David Z. Hambrick ... Hambrick, Burgoyne and Altmann (book chapter, Cambridge handbook of intelligence series; hosted by Georgia Tech Engle Lab)

   “Is intelligence predictive of success in life’s problem-solving tasks? The answer is yes, even if the reasons are not yet fully understood.”

E4 supports the problem-solving half. On violence, E1 is about the risk of being killed by homicide, not about committing violence, and E2 reports less assault among high-IQ scorers but does not say whether this means committing or suffering assault, or which population it covers. The material does not include any meta-analysis or other evidence on violent offending, so it does not settle the violence half under the criteria.