ABSTRACT
There are two principal methods of studying aging, the longitudinal and the cross-sectional. The problem of practice effects is avoided if one uses a cross-sectional design in which different groups of people are sampled across the age range and their performance is measured on a single occasion. A solution to the problem is to combine longitudinal and cross-sectional approaches by adding a new cohort of participants at each test age. There is broad general agreement that working memory is susceptible to the effects of age, although it is not always clear exactly which aspects are most vulnerable. Digit span is relatively resistant whereas sentence span in which participants must process a sequence of sentences and then recall the final word does tend to be sensitive to aging, the degree of decrement is however less marked than one might expect.
