Predictors of individual differences in mail-coding skills and their variation with ability level

Personality and cognitive predictors of mail coding were investigated in 2 samples, 1 of high coding ability (N=56) and 1 of mixed ability (N=158). Two approaches to predicting correlates of skill within groups of differing ability were compared: Ackerman's (1988) ability theory, and Norman and Shallice's (1985) account of levels of action control. The predictors of mail-coding skill varied with ability: Personality variables were more predictive among higher ability subjects, and cognitive measures were more predictive among lower ability subjects. Implications of the findings for theories of individual differences in skill are discussed.