Adults of three age groups (18–27, 39–45, and 59–66 years) performed an auditory duration discrimination task with short (200 ms) or long (400 ms) sinusoidal tones. Performance was highly accurate and reaction times were on the same level in all groups, indicating no differences in auditory duration processing. Task irrelevant rare changes of the frequency of the stimuli were introduced to check whether the subjects, firstly, were distracted by changes in the environment while focusing on the task relevant information (indicated by prolonged responses), and, secondly, could re-focus on the relevant task after distraction. The results show that a distraction effect is present in all groups. Importantly, the 59–66 years group showed a behavioral distraction effect nearly twice as high as the other groups. The event-related brain potentials (ERPs) show mismatch negativity (MMN), P3a, and reorienting negativity (RON) elicited by deviants which are present in all groups. Aging effects on these ERP components were observable in all three components but a revealed a weak significant effect for the MMN only. Taken together, the behavioral and ERP results suggest that the function of balancing the processing of task irrelevant changes in the stimulation while focusing on task relevant information is effective during adulthood until the 7th decade of life. (Author/publisher)
Samenvatting