Memory factors in age-related differences in simple reasoning.

Adults in their 50s were compared with adults in their late teens or 20s in the accuracy of relatively simple reasoning decisions involving varying amounts of information. Because the magnitude of the age differences in decision accuracy was independent of the amount of information relevant to the decision, it was suggested that adults in their 20s and 50s do not differ in the effectiveness of integrating information across multiple premises. However, the 2 groups differed in the accuracy of trials involving only a single relevant premise, and thus it was inferred that 1 factor contributing to reasoning differences within the age range from 20 to 60 may be a failure to encode, or retain, relevant information.