The retention of skills over extended periods of nonuse is important for individuals in many occupations, particularly those such as the military reserves and emergency response (Villado et al., this volume). It has generally been argued that individuals of higher ability will suffer less decay of learned skills over time (Farr, 1987). For the most part, however, individual differences characteristics other than general ability have not been considered with respect to skill decay and relationships more complex than the one between ability and eventual decay, although it has been acknowledged that more research on these issues is needed (Arthur, Bennett, Stanush, and McNelly, 1998). In addition, the literature on skill decay has been characterized by a focus on simple rather than complex tasks, which stands in stark contrast to the fact that occupations in which skill decay is often cited as being most important require skills that are highly complex and adaptive in nature. The purpose of the present chapter is to contribute to the literature on skill decay by making progress in both of these areas. This will be accomplished by exploring relationships between select cognitive and non-cognitive individual difference characteristics and error during training of a complex skill. Specifically, results are presented from a study involving 102 university students who com - pleted training on a computerized multitasking simulation. The multitasking simulation recorded error data for two types of errors: errors of omission and errors of commission. Data were also collected on working memory, perceptual

speed, conscientiousness, and anxiety during the multitasking simulation. Results of the study indicated that working memory was related to errors of commission, perceptual speed was related to errors of omission, and anxiety was related to both types of error.