Flanker interference in young and older participants as reflected in event-related potentials.

The present study investigates behavioural and event-related potential (ERP) differences between young and older participants in two variants of a flanker task. Flankers preceded the target by 100 ms (Experiment 1) or were presented simultaneously with the target (Experiment 2). In both experiments the response times showed an age-related slowing and a compatibility effect, which did not differ significantly across age. The older participants committed only half as many errors as the young ones. The visual ERPs revealed that the speed of visual perception was similar between groups. In addition the processing of the targets, but not of the flankers, appeared to be enhanced in the older participants. Moreover the lateralized readiness potential (LRP) started later and was larger for old vs. young participants, which was most pronounced for the incorrect LRP activation due to the flankers. The LRP amplitude effect is due to an enhanced activation over contralateral motor areas, which appears to be a general finding unrelated to the error rate. In summary, in the present study we could not find evidence for enhanced flanker interference in the performance of older compared to young participants. The reduced error rates for older participants are likely due to enhanced processing of the targets and delayed transmission of flanker information from visual to motor areas.