Dual-task procedures-elaborative strategy use and finger-tapping-were used to examine both recall and mental effort demands of elaboration strategy use with equal numbers of boys and girls at grades two and three. Knowledge-base access was examined by comparing different item types in the associative learning list:masculine, feminine,andmixed.Results showed that boys and girls did not differ in their recall of arbitrarily paired items (e.g.,mixedpairs). A Sex by Item Type (masculine vs feminine) interaction, however, revealed that for feminine pairs girls recalled more than boys, whereas for masculine pairs no sex difference was observed. Finger tapping interference scores indexed mental effort. Similar to the recall findings, results indicated that the elaboration of feminine pairs required less mental effort by girls in contrast to boys. Elaboration of masculine pairs was not associated with a sex difference. The results were discussed in terms of sex differences in knowledge-base access.