ABSTRACT
Five experiments using a visuospatial task were conducted to study memory accuracy and variability and to identify the origin of variations in steady states. This research was conducted from a dynamical perspective, that is, by analyzing the temporal course of discrepancies between the perceptual configuration and its memory (accuracy) and the temporal course of discrepancies between 2 successive memories (variability). In Experiment 1 the stimulus (12 black dots randomly disposed) was presented repeatedly to assess the general evolution of accuracy and variability. In Experiments 2 and 3 memory accuracy and memory variability were separated to identify their relationship. In Experiments 4 and 5 memory variability was studied to determinate the origin of steady state variations. Results show that memory accuracy and memory variability evolved independently and that memory variability reached a threshold that was subject-dependent. The dynamic properties of image construction and stability are discussed.
Subject(s)
Attention , Mental Recall , Orientation , Pattern Recognition, Visual , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Psychomotor PerformanceABSTRACT
Two experiments addressed the question of the spatial deficits of Parkinson disease (PD) patients, using a spatial location task which varied the characteristics of the task along an effortful continuum. In the more effortful task, 11 PD patients, 10 elderly control subjects, and 13 young control subjects were given 3 min to learn the layout of 12 places labeled on a map and then reproduce it. In the less effortful task, 9 new PD patients, 9 new elderly control subjects, and 10 new young control subjects were given 3 min to learn the layout of 12 black dots and then asked to reproduce it. In both cases the task was repeated twice. The results showed that PD patients were less accurate than young and elderly control subjects in the less effortful task. In contrast, the performance of PD patients and elderly control subjects were equivalent in the more effortful task. These results support the idea of a specific visuospatial deficit in Parkinson's disease. Moreover, the deficit in effortful tasks seems to be due to normal aging.
Subject(s)
Aged/psychology , Mental Recall , Orientation , Parkinson Disease/psychology , Psychomotor Performance , Adult , Aging/psychology , Anomia/diagnosis , Anomia/psychology , Attention , Female , Humans , Male , Middle Aged , Parkinson Disease/diagnosis , Pattern Recognition, Visual , Reference ValuesABSTRACT
Two experiments dealing with the learning of a space by map or by navigation approached the questions of equivalency of the cognitive processes involved in spatial information and of response fluctuation. In the first experiment, 11 subjects were asked to situate, six times, 18 locations on a blank map. In the second experiment, the subjects were first given 3 min to learn a map with 12 locations marked, and then asked to reproduce it. The task was repeated six times, using three different maps. This gave us several trials per subject, so that distortion could be distinguished from response fluctuation. In Experiment 1, the range of values was the same for response inaccuracy and response fluctuation; in Experiment 2, the range was greater for response inaccuracy than for response fluctuation. The results showed that space learning by navigation and space learning by map involve different cognitive processes.
