The role of age and prior beliefs in contingency judgment.

This experiment investigated how prior beliefs affect young and older adults' ability to detect differences in objective contingency. Participants received new evidence that the objective contingency between two events was positive, negative, or zero when they believed that there was a positive or negative relationship between events, when they believed that the events were unrelated, and when they had no knowledge of the relationship between the events. They were then asked to estimate the objective contingency and recall the contingency evidence. Beliefs that events were or could be related improved young adults' contingency discrimination. Moreover, these beliefs did not produce biases in young adults' memory for the contingency evidence, but rather affected how they weighted this evidence at judgment. In contrast, these same beliefs did not improve older adults' contingency discrimination, but did produce biases in their memory for the evidence that were similar to those seen in their judgment. These findings are discussed in terms of age-related changes in working memory executive processes that impair older adults' ability to fully evaluate both belief-confirming and disconfirming contingency evidence and update their beliefs with this information.