Dynamic instability of visuospatial images.

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.