Family Size Tied to SAT, IQ Scores

Abstract

The findings of several studies which were presented at the 1985 meeting of the American Association for the Advancement of Science suggest that children from smaller families on the average score higher on achievement and intelligence tests and attain higher educational levels than children from larger families. Between 1963-80 the average national score on the Scholastic Aptitude Test (SAT) declined from 490-445 and since that time the scores began increasing gradually. Robert B. Zajonc and several other researchers maintain that the earlier decline and the recent increase are related to changes in the average size of the students families over time. The average family size of the students who took the examine between 1963-79 increased steadily through 1980. Since 1980 the family size of the students began to decline. This trend according to Zajonc will continue for the next 16-18 years. By the end of the century scores will again decline as a result of the decline in births which began in 1980. Zajonc presented findings in regard to a recent study of the Iowa Test scores of primary school students to support his confluence theory. The theory states that children from families with a large number of children and with small birth intervals are less intellectually mature than children from smaller families with longer birth intervals. Children from smaller families are more mature because they interact more with adults than children from large families do. Also children from families with long birth intervals are more intellectually mature because either they interact with siblings who are considerably older and more mature than they are or they serve as instructors to siblings who are much younger than they are. Children in families with small birth intervals interact with siblings who are their own peers. Zajonc found that variations in the Iowa test scores in recent years were associated with changes in family size. In 1962 the average newborn in the US was a 3rd child and in 1979 the average newborn was a 2nd child. Children born in the earlier time period had lower scores than those born in the more recent time period. A study conducted by Judith Blake examined the educational attainment of the children of 56000 white fathers in the US. The study revealed that children from smaller families compared with those from larger families tended to have higher grades and were more likely to finish high school and to attend college. Fathers educational level was the best predictor of educational attainment and family size was the 2nd best predictor of educational attainment. Family size was a better predictor of educational attainment than socioeconomic status. A study conducted by James V. Higgins revealed that children from small families had higher intelligence quotients (IQs) than children from large families and that parents of small families had higher IQs than parents of large families. Higgins suggested that the IQ levels were inherited.