Five-Rule Effects in Young and Older Adults’ Arithmetic: Further Evidence for Age-Related Differences in Strategy Selection

Abstract

Young and elderly adults were asked to say whether a series of complex arithmetic problems were true or false so as to test five-rule effects. The five-rule effect in arithmetic problem verification tasks refers to faster and more accurate judgments for false equations when the proposed product matches the five rule (i.e., Nx5 = product with a unit digit equal to 0 or 5; e.g., 5x16=85) than when it mismatches the rule (e.g., 5x18=93). Results showed better performance on match than on mismatch problems in young adults but equal performance in older adults. Moreover, five-rule effects were larger when 75% of problems mismatched the five-rule and smaller when 25% of problems mismatched the five rule, in young adults. Only under high-mismatch condition did older adults show significant five-rule effects. Implications of these findings for further understanding age-related differences in arithmetic strategy selection and other high-level cognitive domains are discussed.