This paper discusses the relationship between individual differences and educational practices by reviewing the historical models of teaching and past research on learner characteristics. The mental testing movement is reviewed in terms of the emergence of aptitude as a measurable concept. Learner motivation is also discussed along with the effectiveness of various teaching methods and educational practices that take individual differences into account. A number of recommendations relating to admissions policies and student counseling are listed as well as recommendations to provide needed diversity of teaching-learning situations. (JAC)