ABSTRACT  An investigation of selected research projects which focus on intellectual development is presented. That treatment begins with a description of psychologically-oriented studies and illustrates the many ways in which studying a second language in school settings contributes to the cognitive development of the learner. The primary goal of the article is to describe completed research studies with a view toward synthesizing various authors' views. Foreign language educators might find the information useful as they establish various rationales for foreign language study in their particular situations.