When mental images are very detailed: image generation and memory performance as a function of age.

Older adults appear to have problems in mental imagery which seem to influence memory, such as in the recall of concrete words. However, the effects of imagery instruction on old participants' memory are quite inconsistent (Richardson, 1980; Salthouse, 1992). Two experiments explored the effects of aging on the nature of mental images generated from non-related nouns, and their memory. A sample of 234 participants, young (20-22 years) young-old (55-65 years), old (66-75 years) and old-old (>75 years), were recruited from universities and recreation centres. In Experiment 1 participants were required to generate mental images and describe them accurately in 40 s. Mental images were classified as general, specific-contextual and self-referred. Details were distinguished between relevant, information useful for describing a mental image and irrelevant, information which is not pertinent, or useful for describing a mental image. A final memory task was proposed. In Experiment 2 evocation and description time was manipulated in order to reduce the production of irrelevant detail: a shorter condition (evocation+description time=20 s) and a longer condition (evocation+description time=40 s). Results show that older adults produce a higher number of general and self-referred images but a lower number of specific images;report a greater quantity of irrelevant detail;recall a lower number of items. Decrease in evocation and description time reduced the irrelevant details and increased older adults' memory performance.