FIGURE 16.1 Intelligence and individual differences Intelligence is considered a crucial dimension of individual differences because IQ scores (1) correlate with other conceptually related dimensions such as general knowledge and grades at any one age (dotted arrows extending from IQ to other outcomes at age 7); (2) show considerable continuity over age (solid arrows); and (3) predict future outcomes, such as years of education and income in adulthood (dashed arrows connecting IQ score at age 7 to other later outcomes).