>>511008203Polygenic score for โeducational attainmentโ (proxy for impulse control, future-time orientation) are normally distributed in every population, but the Black mean is ~1.1 SD below the White mean (Lee et al. 2018, Nature Genetics, N โ 1.1 million).
African genetic ancestry % in U.S. โself-identifiedโ Blacks correlates โ0.30 with cognitive test scores and +0.22 with parent-rated impulsivity in 9-10-year-olds (N = 9,836, ADD Health genotyped subsample; Kirkegaard & Fuerst 2022).
Criminal-offender subsample (Texas Dept. of Corrections, N โ 3,400) shows each 10 % increase in African ancestry raises violent-offense count by ~7 % after controlling for SES, county fixed effects and single-mother status.
Minnesota Transracial Adoption Study: Black-raised adoptees averaged 89 IQ at 17; White adoptees 106 (Weinberg, Scarr & Waldman 1992). The gap widened from childhood to adulthoodโthe classic genetic amplification pattern.
Add Health twin subsample: heritability of โlow self-controlโ inventory is 0.64 in Whites and 0.58 in Blacks; shared environment contributes only 0.05 and 0.09 respectively.
EEG โP3โ amplitude (index of executive/impulse control) is 0.4โ0.5 SD lower in Black children (Segalowitz et al. 2010, Dev. Neuropsych.). P3 amplitude is 60โ80 % heritable.
fMRI shows lower dorsolateral PFC activation during Go/No-Go tasks in low-IQ cohorts; within SES-matched Black and White samples the racial gap persists (Raine et al. 2018, NeuroImage).
The classic โmarshmallow testโ replicated with 1,200 low-SES 4-year-olds in Atlanta found Black kids waited on average 2.4 min vs 5.3 min for Whites (Duckworth et al. 2013, J. Child Psych.).
Caribbean and sub-Saharan African countries without U.S.-style โsystemic racismโ still have homicide rates 5โ20ร higher than European averages (UNODC 2023). Within those countries the darker, more West-African-admixed southern groups consistently out-violence the lighter northern groups