“…Rather, traditional tests focus much more on measuring past learning, which can be the result of differences in many factors, including motivation and available opportunities to learn. Some theories of intelligence extend this definition by suggesting that there is a general factor of intelligence, often labeled g, that underlies all adaptive behavior (Brand, 1996;Jensen, 1998; see essays in Sternberg & Grigorenko, 2002b). In many theories, including the theories most widely accepted today (e.g., Carroll, 1993;Gustafsson, 1994;Horn, 1994), other mental abilities are hierarchically nested under this general factor at successively greater levels of specificity.…”