The relation of primary mental abilities in five- and six-year-olds to sex of child and characteristics of his sibling.

Abstract

As part of a larger study of the effect upon the personality of children of such family constellation details as sex of child, sex of sibling, ordinal position of child in his sibship and difference in age between child and sibling, it was decided to determine whether intellectual skills would show a significant relationship to these same variables. The question of the effect of the ordinal position of a child upon his intelligence test performance has been much explored as has also the question of the relative performance of the two sexes on various tests. Our study we may expect to make a contribution to the field, however, because (a) the interaction of the variables, sex, sib's sex, ordinal position and the age difference between siblings has been investigated as well as the main effects; and (b) a different test has been used, namely the SRA Primary Mental Abilities Test, Primary Form (3I). Since the subtests of the Thurstone Test are alleged not to be highly correlated (test intercorrelations on the standardization population ranged from +.46 to +.67) and to measure rather abilities, it should be of interest to discover whether performance on the specific abilities subtests bears any relation to the independent variables mentioned above. The Primary Mental Abilities Test was given to our subjects by the