How does normal aging affect memory?

Comparisons of younger and older people's scores on memory, learning, and intelligence tests suggest that mental sharpness declines slightly with age. But whether such comparisons are valid is questionable because timed tests may favor the younger person. The older person's information processing is a little slower: in one study, elderly people took 20 to 40 milliseconds longer than younger people to detect gaps in circles. Thus, the lower scores of older persons may simply reflect a slowing of their responses, not a reduction in their mental sharpness.

People may require more time and effort to learn new information as they age, but once they've learned it, they retain it as well as younger people. In practical terms, slightly slower thinking is not necessarily a disadvantage. It may actually reflect more thorough reasoning and result in fewer mistakes.