Biomedical subjects

J C Scailquin

Publications and source records attributed to J C Scailquin.

4 recordsLinked to original sources

PubMed1998

The visuospatial sketchpad for mental images: testing the multicomponent model of working memory.

In the model of Baddeley (Working Memory, Oxford University Press, Oxford, 1986), one function of the visuospatial sketchpad (VSSP) component of working memory is to allow the processing of mental images. Properties of the VSSP were investigated by means of the usual dual-task paradigm (to search for interference from the other components of working memory, i.e., the articulatory loop and the central executive), applied to three distinct subprocesses of mental imagery (Kosslyn, 1994 Image and Brain. MIT Press, Cambridge, MA): image generation (Experiment 1), image maintenance (Experiment 2), and image rotation (Experiment 3). First, in the control condition (no interference task) of each experiment, we replicated the effects of stimulus or task complexity already reported. Second, no interference from the articulatory loop was observed. Third, maintenance of images appeared free from any interference. And fourth, generation and rotation tasks were interfered to a greater extent by the central executive than by the involvement of the VSSP in a secondary task. These observations (a) support the dissociation between the articulatory loop and the VSSP, (b) suggest an important use of central attentional resources in the generation and rotation of mental images, (c) would support the distinction between visual and spatial components in the structure of working memory, and (d) suggest the dissociation of the VSSP into two subcomponents: a passive visuospatial store and an active device for recapitulating visuospatial information.

Adolescent↗

PubMed1997

Dissociation between categorical and coordinate spatial computations: modulation by cerebral hemispheres, task properties, mode of response, and age.

Kosslyn suggested a dissociation of two kinds of spatial representations: categorical and coordinate, the former computed by the left hemisphere and the latter by the right hemisphere. In addition, with practice, a "categorization" of the coordinate computation would appear. These suggestions resulted largely from an experiment, replicated by others, in which the subjects had to estimate the relative position of a dot and a line by giving an oral response, and feedback was provided. The present series of five experiments was an attempt to test whether this finding could be generalized, under several methodological manipulations, some of which have already been used by researchers in separate studies. In the five experiments, accuracy was a more contributive dependent variable than correct latencies, and practice effects on the task X field interaction were not verified. Experiments 1-3 concerned the kind of response. When a manual instead of an oral response was required (Experiment 1; n = 32 Ss), the expected dissociation was observed (as well as when the latency of responses made by the right hand were studied). When the number of oral responses was increased from two (a binary choice) to eight, the dissociation was still observed for accuracy but disappeared when a more liberal criterion of accuracy was used to reduce the considerable task effect (Experiment 2; n = 32 Ss), or when response requirements were equated for both tasks (Experiment 3; n = 32 Ss). In Experiment 4 (n = 32 Ss), a manual response was called but the feedback was removed and the task dissociation disappeared. Finally, the task dissociation observed in Experiment 1 was not verified when a sample of elderly subjects was enrolled (Experiment 5; n = 32 Ss). However, age per se was the source of an interesting additional dissociation since only the coordinate computation was age sensitive. Our results suggest that the dissociation proposed by Kosslyn between the computation of categorical vs coordinate spatial relationships is highly unstable and sensitive to subtle methodological factors (vocal vs manual response, presence vs absence of feedback, binary vs "continuous" response, age) which could preclude its general application.

Adolescent↗

PubMedDate not supplied

The fate of global precedence with age.

The literature is virtually devoid of studies examining the effect of aging on the "global precedence" effect (Navon, D. [1977]. Cognitive Psychology, 9, 353-383). In this paradigm, global letters formed with local letters are shown, and the subject has to recognize either the local or the global letters. The relation between the global and the local letters is either congruent, neutral, or conflicting. Five experiments are reported, with five sets of 16 young and five sets of 16 elderly, healthy, adult subjects. The global precedence effect was observed in both age groups in the basic perceptual experiment as designed by Navon (Experiment 1). In addition, young and elderly subjects were able to process separately the global and the local shapes when attention was not directed towards a specific level (Experiment 1a). However, subpopulations emerged, especially in the elderly, depending on their ability to "resist" to the interference of the global shape upon the processing of the local form. This could support the few indirect published data suggesting that global precedence tends to diminish or to disappear with age. In experiments 2 and 2a, subjects were retained only if they did process the local level better than at random. Global precedence was confirmed in both young and elderly subjects. Again, elderly subjects manifested an increased sensitivity to interference. Moreover, a general effect of age remained, even in the control (neutral) conditions, suggesting difficulties of encoding in elderly. Therefore, in Experiment 3, encoding conditions of both age groups were equated by increasing exposure duration of the material for elderly. Subjects of Experiment 3 were also submitted to a Stroop test, to verify whether the increased sensitivity to interference in the elderly was specific to the "Navon task" or the expression of a general effect of aging on inhibition mechanisms. The global precedence phenomenon was observed in young and elderly subjects, with no sign of an effect of age under these conditions; in elderly, furthermore, the interference effect did not appear to result from a general aspecific deficit of inhibition mechanisms. It thus appears that the global precedence phenomenon resists well the effects of aging, but that subpopulations of elderly subjects should be considered in future studies.

Adolescent↗

PubMedDate not supplied

Effects of aging on the generation of mental images.

Image generation is one component of mental imagery, and consists in the activation of stored visual information in long-term memory to sequentially create a temporary pattern on a visuospatial short-term memory display. Little is known about the fate of image generation over the human life span. In the present study, 165 healthy participants aged 18 to 80 years were enrolled for an image generation task to image an uppercase letter in response to its lowercase version displayed as the cue, and to decide if a displayed probe would be near to or on the image. Uppercase letters were simple versus complex, and the probe appeared in a region of the uppercase letter that is generated early versus late. Comparative analyses (ANOVAs) on accuracy and correct latency confirmed the sequential nature of image generation, and showed a detrimental and linear effect of aging only on the activation subprocess. Structural analyses (LISREL) revealed, however, that these effects of age were entirely mediated by inhibition mechanisms, speed of processing, and working memory.

Adolescent↗