[Implications of mental image processing in the deficits of verbal information coding during normal aging]. / Implications des processus d'imagerie mentale dans le déficit du codage imagé des informations verbales au cours du vieillissement normal.

Our study specifies the contributions of image generation and image maintenance processes occurring at the time of imaginal coding of verbal information in memory during normal aging. The memory capacities of 19 young adults (average age of 24 years) and 19 older adults (average age of 75 years) were assessed using recall tasks according to the imagery value of the stimuli to learn. The mental visual imagery capacities are assessed using tasks of image generation and temporary storage of mental imagery. The variance analysis indicates a more important decrease with age of the concretness effect. The major contribution of our study rests on the fact that the decline with age of dual coding of verbal information in memory would result primarily from the decline of image maintenance capacities and from a slowdown in image generation.

Aging effect on visual and spatial components of working memory.

The aim of this study was to evaluate the effect of aging on the storage of visual and spatial working memory according to Logie's model of working memory (1995). In a first experiment young, elderly, and very old subjects carried out two tasks usually used to measure visual span (Visual Patterns Test) and spatial span (Corsi Block Tapping test). In the second experiment, we modified the encoding time of the Visual Patterns Test so that it was the same as in the Corsi Block Tapping test. Results indicate that the visual span decreases more with advanced age than the spatial span, even when the encoding time between the Visual Patterns Test and the Corsi Block Tapping test is controlled. These results support the fractionation of the visuo-spatial working memory and show that the more pronounced age-related effect on the visual span is robust and independent of the encoding time.

Aging and categorization: could relevant pieces of information reduce older persons' inhibitory deficit?

The goal of this study was to reduce the inhibitory deficit on the elderly by creating "optimizing conditions" in a categorization task. It was hypothesized that increasing the number of relevant pieces of information would reduce the difficulty associated with processing irrelevant information on a categorization task, since the number of relevant solutions to solve the problem would increase, while the total number of pieces of information to be processed would remain the same. This hypothesis was tested on 27 young adults and 30 elderly people using a task requiring the matching of a stimulus figure to one of the two response figures having one or more attributes in common with the stimulus. In line with previous findings, the results indicated an age-related inhibitory decline. However, consistent with the hypothesis, as the number of relevant attributes increased, the performance of elderly people improved and response times decreased, supporting the notion of latent cognitive resources.

[Differential effects of aging on processes involved in mental imagery generation]. / Effet différentiel du vieillissement sur les processus impliqués dans la génération d'images mentales.

The purpose of this study was to measure the degree to which the deterioration of mental image generation processes observed in elderly subjects by Dror and Kosslyn (1994) depends on the nature of the processing (referential vs. representational) involved in performing the task at hand. In keeping with the results of research showing that processing resources diminish as normal aging occurs (Craik & Bird, 1982; Rabinowitz, Craik & Ackerman, 1982), we suggest that generation ability based on referential processing is affected to a greater extent in older adults than is the generation ability involving representational processing. Fifteen young adults and 15 elderly persons performed a generation task modeled on that used by Dror and Kosslyn (1994). Observations were based on two contrasting conditions. In the first instance, subjects were required to generate an image representation of numbers when instructed to do so by a graphic stimulus, e.g., "31" (representational generation). In the second case, generation was produced on the basis of a verbal stimulus, e.g., "thirteen" (referential generation). Results (response time and number of accurate answers) show that, compared to young adults, elderly adults have a diminished ability to generate images based on words rather than numbers and do so at a slower pace. Our results suggest, therefore, that the performance of the first type of generation is cognitively more demanding for elderly subjects than that which is founded on figurative stimuli. The deterioration of mental image generation processes observed in elderly subjects by Dror and Kosslyn (1994) is therefore dependent on the nature of processing (referential vs. In conclusion we suggest two complementary assumptions to explain the observed dissociation. The differential effect of age may be the result of a deficienness cy linked to the nature of processing (control vs. automatic). Our second assumption is that, more specifically, referential generation involves more processing resources than does representational generation because it requires an additional transcoding operation. In this instance, the differential effect of aging that we observed would be closely linked to the number of cognitive operations involved in mental image generation.