Adult visual choice-reaction time, age, sex and preparedness: A test of Welford's problem in a large population sample

The relationship between age, sex and visual three-choice reaction time was investigated with a representative sample of adult subjects who participated in a large health survey in Finland (the Mini-Finland Survey). Subjects' age varied from 30 to 79 years. Reaction time increased reliably with increasing age. Men were faster than women across all age levels. The shortest of the irregularly presented inter-stimulus intervals (ISI) slowed down the performance of elderly subjects in particular. This suggests that they had more difficulty than younger subjects in getting prepared for an uncertain event. They also committed most errors at the longest ISI. This was interpreted as a result of their relative inability to maintain the optimum level of preparation. On the whole, men displayed a higher error rate than women, which suggests that the observed male superiority is at least in part due to response strategies. The importance for aging research of sampling the subjects and task types is briefly discussed.