Simple reaction time as a suppressor variable in the chronometric study of intelligence

Individual differences in reaction time (RT) to various elementary cognitive tasks (ECTs) reflect variance in both peripheral (sensorimotor) and central components of information processing. Minimizing the variance associated with peripheral processes by controlling simple RT in chronometric studies of more complex ECTs involving choice, discrimination, memory scanning, or other central processes, can increase the correlation between RTs and scores on complex psychometric tests of ability, thereby identifying more clearly the elementary processes involved in psychometric g and other abilities. Simple RT can be controlled by subtraction, partial correlation, and multiple correlation. The relative effectiveness of the different methods depends on various features of the chronometric data. The methods are explicated, with examples from a study of simple, choice, and discriminative RTs (the odd man out paradigm) in 213 male students from three colleges.