The Allocation of Attention in Multisource Monitoring Behaviour: Adult Age Differences

Two experiments are reported in which elderly subjects showed less attentional selectivity than young subjects. The observing response (OR) task used was an analogue of an industrial monitoring situation in which faults occurred with different probabilities on three machines. When subjects were allowed to observe at their own rates, the mean fault rate on the system influenced the selectivity of the young group, but the relationship did not hold for the older group. The age effect was less in a second experiment where observing rate was constrained. When coupled with conclusions from earlier work, subjective assessments indicate that selectivity differences cannot be traced to a failure on the part of the old subjects to comprehend the relative probabilities of signals on the different machines. A possible explanation of the attenuated selectivity in old subjects is suggested.