Intelligence, reading achievement, physical size, and social class. A study of St. Louis Caucasian boys aged 8-0 to 9-6 years, attending regular schools

A total of 334 nonreferred grade-school boys were examined for measures of physical growth, I.Q., and reading proficiency. SES was determined by the Hollingshead-Redlich index. Results of the study indicate: (1) for the total sample all physical measures significantly correlated with at least two of the three psychometric test scores; (2) SES alone accounted for 29 to 38% variance in psychometric scores; (3) mean scores of all psychometric and some physical variables significantly separated social classes: the higher the social class the greater the psychometric test scores (I.Q. and reading), HC, and height of the child; (4) holding constant SES decreased all correlations between intellectual performance and somatic growth; but (5) significant correlations remained between all physical measures and one or more psychometric scores; and (6) within individual social classes HC was the best physical predictor of WISC I.Q. and was significantly correlated with it in Classes I through IV.