The present article focuses on the role of mental effort as an informa
tion processing link mediating the effects of motivational factors on
remembering task performance. A general model of strategy selection, i
ncorporating mental effort as a mediator of the effects of motivationa
l factors on strategy selection, is first discussed; this model provid
es a framework for the analysis of the loci of individual and developm
ental differences in memory task performance. Two experiments are then
described which were designed to test predictions of the model. Exper
iment 1 examined the effects of different levels of extrinsic motivati
on and general academic skill on third-grade children's spontaneous us
e of mnemonic strategies. Experiment 2 examined the effects of the eff
ort demands of strategy use during training on strategy transfer by ad
ults. The findings from the two experiments are discussed in the conte
xt of the presented model of motivational influences on strategy use.