Age differences in dual-task interference are localized to response-generation processes

Dual-task differences in younger and older adults were explored by presenti ng 2 simple tasks, with the onset of the 2nd task relative to the Ist task carefully controlled. The possibility of an age-related reduction in the ab ility to generate and execute 2 similar motor programs was explored by requ iring either a manual response to both tasks or a manual response to the Is t and an oral response to the 2nd and was confirmed by the evidence. The ag e-related interference was greater than would be expected from a general sl owing of processing in older adults. The possibility of an age-related redu ction in the capacity to process 2 tasks in the same perceptual input modal ity was explored by presenting both tasks in the visual modality or the I s t task in the auditory modality and the 2nd task in the visual modality and was not supported by the evidence. There was greater interference when bot h tasks were in the same modality, but it was equivalent for older and youn ger adults. Age differences in dual-task interference appear quite localize d to response-generation processes.