Two experiments investigated the effects of age and domain-specific experience on the speed and accuracy of visual inspection performance. In Experiment 1, young (it4 age = 26.5 years) and middle-aged (it4 age = 45.7 years) medical laboratory technologists (MTs) and matched novices were tested on a domain-specific version and on a domain-general version of a probe recognition task. Middle-aged subjects were slower than younger subjects on both versions, and MTs were more accurate but slower than controls on the domain-specific task. In Experiment 2, MTs and controls were tested on the same tasks under single-task and dual-task conditions. Middle-aged adults were slower and less accurate than young adults under dualtask conditions in the general version. For the domain-specific version, the response times and error data suggested that skilled performance is less demanding of age-limited general-purpose processing resources.
Many aspects of complex visual-cognitive performance, such as visual search and divided attention, show declines during the adult years (e.g., . Further, it is commonly reported that the magnitude of age-related deficit in visual-cognitive performance increases as a function of increased task complexity and number of processing operations (e.g., see Cerella and Hale, 1994;. Although there is a lack of consensus regarding the appropriate terminology for describing such age-performance relations, and a lack of understanding of the mechanisms that might account for this general pattern of results, investigators have attributed age-related deficits in visual-cognitive performance to reductions in the efficiency, speed, or availability of generalpurpose processing resources (e.