Aging and input processing in dual-task situations.

The psychological refractory period (PRP) paradigm was used to test whether older participants suffer from input interference in dual-task situations. Young (24 years) and older (57 years) adults gave speeded responses to 2 successively presented stimuli. The results showed increased susceptibility of older participants to input interference. Further experiments revealed that this input interference is related to the salience of the 2nd stimulus and that it is specific to older participants. Our findings indicate that parallel processing at the input stages of dual-task performance requires cognitive control. An age-related decline in the control of input processes should be considered as one source of age effects in dual-task performance.