Age and IQ effects on stimulus and response timing.

Normal older participants (aged 60-79 years), with known scores on the Culture Fair Intelligence Test, were tested on 4 timing tasks (i.e., temporal generalization, bisection, differential threshold, and interval production). The data were related to the theoretical framework of scalar timing theory and ideas about information processing and aging. In general, increasing age and decreasing IQ tended to be associated with increasing variability of judgments of duration, although in all groups events could be timed on average accurately. In some cases (e.g., bisection), performance differences between the older participants and students nearly 50 years younger used in other studies were negligible.