A longitudinal study begun in 1956 on the effect of the child's temperament on his development included 141 children, 136 of whom remained throughout the study. Aged 4 to 10 years in 1966, the 69 boys and 67 girls had a mean IQ of 127 established at 3 and 6 years of age and were from 85 middle or upper middle class families. The Parental Attitude…