Sex‐related differences on a task of volume and density

A sex‐related difference, favoring boys, was found on initial performance of two samples (one British, one American) of 10‐ and 11‐year‐old children on a task of volume and density. After a period of classroom instruction that included opportunities for children to interact with appropriate materials and each other, both boys and girls performed at a higher level on the task, but the difference between them remained the same. There was no indication of a sex‐related difference other than a time lag, in pattern of development of the concept. The question of why there is a sex‐related difference, which persists in spite of experience and instruction, is discussed.