Consistent with the frequent memory complaints among older adults, cross-sectional studies tend to show robust, age-related declines on a variety of memory tasks. In comparison with younger adults, older adults show deficits in working memory (e.g., keeping thoughts activated in the face of distraction, as would be involved in mentally multiplying 2 large numbers) and long-term memory (e.g., remembering a list of words). These observed memory deficits with age correspond with biological changes in the brain. Older brains tend to exhibit loss of volume, particularly in the frontal lobes; loss of myelination; reduced blood flow; sparser dendritic branching; and reduced levels of some neurotransmitters. All of these are thought to compromise basic memory functioning.

In the face of this clear evidence of behavioral and biological declines ...