Sources of continuity among nine measures of infant cognitive processing and later childhood intelligence quotient were examined through developmental structural equation models applied to a sample of 208 twin pairs measured from 7 to 36 months. Skills assessed appear related to general cognitive ability in a relatively unstable manner. (SLD)

Forty-eight male and 54 female left-handed junior college students in Stockholm were grouped according to familial sinistrality and strength of handedness. Performance on computerized reaction time (RT), maze, and verbal ability tests was assessed. Sex was the only factor differentiating left-handers on RT, and no factors affected verbal ability.…

Two studies (N=4,261 persons) illustrate an inverse relationship between ability level and correlations among IQ measures. Low IQ subjects showed higher correlations than did high IQ subjects. Intercorrelations of IQ subtests, intercorrelations of cognitive ability measures, and correlations of IQ with measures of cognitive ability displayed the…