Annie Vinter

The self-organizing consciousness

We propose that the isomorphism generally observed between the representations composing our momentary phenomenal experience and the structure of the world is the end-product of a progressive organization that emerges thanks to elementary associative processes that take our conscious representations themselves as the stuff on which they operate, a thesis that we summarize in the concept of Self-Organizing Consciousness (SOC).

Mentally represented motor actions in normal aging: I. Age effects on the temporal features of overt and covert execution of actions

The present study examines the temporal features of overt and covert actions as a function of normal aging. In the first experiment, we tested three motor tasks (walking, sit-stand-sit, arm pointing) that did not imply any particular spatiotemporal constraints, and we compared the duration of their overt and covert execution in three different groups of age (mean ages: 22.5, 66.2 and 73.4 years). We found that the ability of generating motor images did not differentiate elderly subjects from young subjects. Precisely, regarding overt and covert durations, subjects presented similarities for the walking and pointing tasks and dissimilarities for the stand-sit-stand task. Furthermore, the timing variability of imagined movements was always greater compared to actual movements and was of the same amount in the three groups of age. In the second experiment, we investigated the effect of age (three groups with mean ages: 22, 64.8 and 73.2 years) upon temporal characteristics of covert and overt movements involving strong spatiotemporal constraints (speed/accuracy trade-off paradigm). During overt execution young and elderly subjects respected Fittss law despite the fact that movement speed progressively decreased with age. Thus, while execution is deteriorated, the motor preparation process is still intact in old age, and follows well-known laws of biological motions. For covert execution, movement speed progressively decreased with age but elderly subjects did not respect Fittss law. This suggests that the generation and control of motor intentions that consciously do not come to execution, particularly those concerning complex motor actions are progressively perturbed in the aging brain.

Decline in motor prediction in elderly subjects: Right versus left arm differences in mentally simulated motor actions

This study investigates the effects of age upon the temporal features of executed and imagined movements performed with the dominant (D; right) and nondominant (ND; left) arms. Thirty right-handed subjects were divided into two groups: (i) the young group (n=15; mean age: 22.5+/-2.5 years) and (ii) the elderly group (n=15; mean age: 70.2+/-2.2 years). The motor task, involving arm pointing movements among four pairs of targets (.5cm, 1cm, 1.5cm and 2cm), imposed strong spatiotemporal constraints. During overt performance, young and elderly subjects modulated movement duration according to the size of targets, despite the fact that movement speed decreased with age as well as in the left arm compared with the right. This observation was also valid for the covert performance produced by the young group. However, such a strong relationship between covert movement durations and target size was not as obvious in the elderly group. Young, compared to elderly subjects, showed stronger correlations and smaller absolute differences between executed and imagined movements for both arms. Additionally, the absolute difference between executed and imagined arm movement durations was more pronounced for the left than the right arm in aged subjects. This result suggests a selective decline with age of mental prediction of motor actions, which is more prominent when the ND arm is involved.

Implicit motor learning through observational training in adults and children

Although evidence of implicit motor learning on the basis of observation alone has been reported, there is some data to suggest that the phenomenon could be contaminated by the intentional exploitation of explicit knowledge. In the present experiment, a special procedure was adapted to study observational learning in a situation involving the acquisition of a new drawing behavior. The participants consisted of adults and children 6–10 years of age. The results provide support for the view that overt motor practice is not strictly necessary for implicit motor learning. They demonstrate that children display capacities similar to those of adults in this form of learning. Some suggestions are made to account for the contradictory results present in this area of research.

Mentally Simulated Motor Actions in Children

The present study investigated the effects of age and arm preference on motor imagery ability. Children (groups: 6.5, 8.3, and 10.1 years) and young adults (22.4 years) physically or mentally performed a drawing motor task with the right or the left arm. Imagery ability, accessed by the timing correspondence between executed and imagined movements, was poor at 6 and 8 years but improved at age 10, and was robust in adults. The arm condition had no influence on imagery ability. We suggest that maturation of parietal and prefrontal cortices during development may contribute to improvement of action representation.

The representation of gravitational force during drawing movements of the arm

Abstract The purpose of the present experiment was to study the way in which the central nervous system (CNS) represents gravitational force (GF) during vertical drawing movements of the arm. Movements in four different directions: (a) upward vertical (0°), (b) upward oblique (45°), (c) downward vertical (180°) and (d) downward oblique (135°), and at two different speeds, normal and fast, were executed by nine subjects. Data analysis focused upon arm movement kinematics in the frontal plane and gravitational torques (GTs) exerted around the shoulder joint. Regardless of movement direction, subjects showed straight-line paths for both speed conditions. In addition, movement time and peak velocity were not affected by movement direction and consequently changes in GT, for both speeds tested. Movement timing (evaluated through the ratio of acceleration time to total time) changed significantly, however, as a function of movement direction and speed. Upward movements showed shorter acceleration times when compared with downward movements. Concerning the four directions, movements made at 0° and 45° differed significantly from those made at 135° and 180°. Drawing movements executed at rapid speed presented similar acceleration and deceleration times compared with movements executed at normal speed, which showed greater acceleration than deceleration times. In addition, the form of velocity profiles (assessed through the ratio of maximum to mean velocities), was significantly modified only with movement speed. Results from the present study suggest that GF is efficiently incorporated into internal dynamic models that the brain builds up for the execution of arm movements. Furthermore, it seems that GF not only is a mechanical parameter to be overcome by the motor system but also constitutes a reference (vertical direction), both of which are represented by the CNS during inverse kinematic and dynamic processes.

The formation of structurally relevant units in artificial grammar learning.

A total of 78 adult participants were asked to read a sample of strings generated by a finite state grammar and, immediately after reading each string, to mark the natural segmentation positions with a slash bar. They repeated the same task after a phase of familiarization with the material, which consisted, depending on the group involved, of learning items by rote, performing a short term matching task, or searching for the rules of the grammar. Participants formed the same number of cognitive units before and after the training phase, thus indicating that they did not tend to form increasingly large units. However, the number of different units reliably decreased, whatever the task that participants had performed during familiarization. This result indicates that segmentation was increasingly consistent with the structure of the grammar. A theoretical account of this phenomenon, based on ubiquitous principles of associative memory and learning, is proposed. This account is supported by the ability of a computer model implementing those principles, PARSER, to reproduce the observed pattern of results. The implications of this study for developmental theories aimed at accounting for how children become able to parse sensory input into physically and linguistically relevant units are discussed.

Implicit Learning in Children and Adolescents with Mental Retardation.

The literature on implicit learning in persons with mental retardation is scarce and contradictory with respect to the relationship between degree of intellectual disability and impact of implicit-learning processes on performance. We examined children and adolescents with mild or moderate mental retardation and typically developing children matched on MA with regard to their implicit learning. Individuals with mental retardation modified their behavior after an implicit training procedure in a way similar to MA- or CA-matched controls. The impact of implicit learning did not vary as a function of IQ or age. However, some differences appeared between groups in their explicit remembering of the training conditions. The theoretical implications of these results are discussed.

Representational flexibility in children's drawings: Effects of age and verbal instructions

This study aims to investigate representational and syntactical flexibility in childrens drawing behaviour, and the extent to which changes introduced at both representational and syntactical levels are related to age or can be induced by contextual manipulations. A Deletion task required three age groups of 5-, 7- and 9-year-old children to draw objects that had been rendered partially invisible, thanks to magic transformations. Two different verbal instructions about what was to remain visible in the objects, and two different objects, one regularly and one non-regularly drawn, were designed to investigate contextual sensitivity in childrens representational and syntactical behaviour respectively. The results provided evidence for sequential-like developments with regard to both representational and syntactical flexibility in children. The extent to which the procedural constraints of drawing prevented representational flexibility to be expressed was investigated in a second experiment, in which the deletions were performed by means of an eraser on pre-printed 2D line drawings. The results showed that the expression of representational flexibility across ages did not fundamentally change as a function of the load imposed by the procedural constraints.

Isolating unconscious influences: the neutral parameter procedure.

Earlier demonstrations of unconscious learning have been regularly challenged. In this paper, we suggest that earlier demonstrations were not compelling due to certain properties of the experimental situations, and notably that conscious exploitation of explicit knowledge, if present, would coincide or conflict with the results of unconscious processing. We designed a method consisting of inducing a neutral behavioural change in the way subjects drew geometric figures. Two experiments showed that important and long-lasting modifications of drawing behaviour were obtained following specially devised practice, although these modifications could not be expected from deliberate adaptive strategies. In addition, we showed that subjects were unaware of the manipulation to which they had been exposed. The study provides striking evidence for unconscious learning and offers insights for the design of suitable new tools to investigate unconscious cognition.