The relationship of ordinal position and sibling sex status to cognitive abilities

Abstract

The influence of the interaction of ordinal position and sibling sex status on cognitive activity was examined. Results generally confirm the superiority of the 1st born over the 2nd born on cognitive activity. Directional trends suggest that the presence of a male sibling enhances quantitative scores, the presence of a female enhances language scores, males having a greater effect on females than vice versa. (PsycINFO Database Record (c) 2016 APA, all rights reserved)