Age-related change in visual information processing: Toward a unified theory of aging and visual memory

Memory for semantic information is relatively preserved through the normal aging process. Visuospatial memory remains less intact. In the present article a theory is proposed that links this processing difference to normal age-related generalized cognitive slowing, and to the appearance of specific age-related differences in memory performance. Evidence for these suggestions is presented from work in four areas: mental rotation, spatial memory, paired-associates learning, and free recall. Cognitive performance in young and older respondents is shown to vary predictably with systematic variation of visuospatial and semantic stimulus factors consistent with these hypotheses. A further test of these ideas derives from the development of a clinically useful mnemonic system for older adults that is based on these principles. Taken together, this research indicates that much of the deficit observed in the memory performance of older adults may derive not from memory problems per se, but rather from the action of generalized cognitive slowing, which contributes to diminished abilities to represent and process visual images. This series of findings may provide a framework for understanding a wide variety of the processes involved in aging and visual memory, and for the creation of applications to aid the memory of older adults.