The author illustrates how "different factor analysts, using different batteries of tests, with different kinds of subjects . . . come up with different factors," and that "the only safe thing to do is to give credence only to the factors on which several factor analysts agree." Factors relating to higher mental processes, because they are relatively difficult to measure, are only just emerging. Six factors, which have been at least confirmed and reconfirmed once and which the author believes are important in thinking about higher mental processes, are discussed. These factors, which have been called by various names, are referred to here as deduction, induction, general reasoning, integration, maturation, and grades. Each is defined and different research in which each factor was found is described. Plots of some higher mental processes revealed by factor analysis are presented.