Age, attention, expertise, and time-sharing performance.

Time-sharing efficiency and resource allocation from a group of pilots with expertise in time-sharing and a group of nonpilots (ages 20-79 years) were examined. Participants performed 5 dual tasks that represented different degrees of structural similarity as characterized by the structure-specific resource model. Age, expertise, and structural similarity were found to interactively affect time-sharing performance through attentional resources. Age-related deficits in time-sharing were evident under conditions of intense attentional demands and when precise control was required. Modest expertise modulation of the age effects is likely to increase with more domain-specific time-sharing. The structure-specific resource model provided a useful framework for interpreting the relationship between aging and time-sharing performance.