Mental Exercise and Mental Aging: Evaluating the Validity of the "Use It or Lose It" Hypothesis.

It is widely believed that keeping mentally active will prevent age-related mental decline. The primary prediction of this mental-exercise hypothesis is that the rate of age-related decline in measures of cognitive functioning will be less pronounced for people who are more mentally active, or, equivalently, that the cognitive differences among people who vary in level of mental activity will be greater with increased age. Although many training studies, and comparisons involving experts, people in specific occupations, and people whose mental activity levels are determined by their self-reports, have found a positive relation between level of activity and level of cognitive functioning, very few studies have found an interactive effect of age and mental activity on measures of cognitive functioning. Despite the current lack of empirical evidence for the idea that the rate of mental aging is moderated by amount of mental activity, there may be personal benefits to assuming that the mental-exercise hypothesis is true.