The Role of Working Memory and Sensorimotor Speed in Adult Age Differences in Mental Subtraction

This study, involving a total of 161 adults between 20 and 79 years of age, investigated age-related differences of cognitive processing in mental subtraction. Aggregated and individual data analyses were conducted to evaluate the relative importance of working memory and sensorimotor speed in adult age differences in mental subtraction. Overall, reaction time and errors increased with the advance of age and arithmetic task difficulty, but the magnitude of age differences in mental subtraction was significantly reduced by statistically controlling measures of working memory and sensorimotor speed. Moreover, there is a larger attenuation of the age-related effects on mental subtraction after control of sensorimotor speed than after control of working memory. However, age-related differences in mental subtraction were not fully mediated by working memory and sensorimotor speed.