This overview of recent research on individual differences especially concerns that research which relates to human learning and instruction. Several major areas of research are identified, and within each area various issues related to that area and representative studies are discussed. Whenever possible, references to more comprehensive reviews of the literature are provided. Major emphasis is placed on research investigating performance on psychometric tests in terms of cognitive tasks or processes underlying that performance and on research related to aptitude-treatment interactions. Research on intelligence is also discussed, and reference is made to some of the research on cognitive style, adaptive instruction, and the role of individual differences in learning and cognitive processes. Finally, several issues related to future research on individual differences are discussed. Forty-four bibliographic citations are appended. (Author/GDC)