Consequences of consanguinity on cognitive behavior

Abstract

In order to study the effects of consanguinity on IQ, a survey was conducted among the Ansari Muslims of Bhagalpur residing in suburban and rural areas. Both outbred (N=390 from suburban areas and N=358 from rural areas) and inbred (N's=300 and 266, respectively) children aged 9 to 12 years from socioeconomically middle-class families were administered the Weschler Intelligence Scale for Children-Revised [WISC(R)-74]. The coefficient of inbreeding, F, was .0625. The inbred children showed lower verbal (20 and 22%) and performance (30 and 20%) subtest scores and lower verbal (11 and 11%), performance (17 and 12%), and full-scale (15 and 12%) IQs. A three-factor analysis of variance performed on the full-scale IQ scores indicated that both consanguinity and locality affect IQ. The interaction between these two facors was also significant. Neither age nor sex affected these scores. Overall, subjects' performance scores were lower than verbal scores. © 1988 Plenum Publishing Corporation.