This research was designed to further our understanding of age differences in contingency judgements and to consider the role of working memory in such judgements. Experiment 1 examined age differences in contingency judgement accuracy when information processing requirements were manipulated. Young and older adults estimated the degree of contingency between two categorical variables. Contingencies, amount of information, and speed of execution were varied. Participants discriminated the contingencies well. Judgement accuracy declined with smaller numbers of trials and shorter intertrial intervals. The judgement deterioration was more severe for older adults. In Experiment 2, speed interfered again more with the judgements made by older adults. Modulations of this effect occurred as a function of stimulus duration and distribution of event frequencies. Overall, the judgement deterioration is consistent with Wagner's (1981) model of automatic memory processing.