Visual‐motor localizations in normal and subnormal development

Abstract

Subnormal and normal children, of like mental age, were compared on a visual target localization task. Severely subnormal children were found to be less accurate than normal children, in conditions where they visually directed or visually guided their hand to the target and received visual knowledge of results. On visually directed localizations without knowledge of results or with proprioceptive knowledge of results (same hand) no significant difference was found between normal and severely subnormal children. Another experiment with moderately subnormal children revealed that developmental changes on visually directed and visually guided localizations are a function of mental age rather than chronological age.

The role of sensory modality for the reproduction of shape by the severely retarded

“…The present experiments show that whereas visual and motor movements can share a common representation, nevertheless the efficiency of storage of information from these two sensory modalities is differential and to some extent sensory specific. agreement with results obtained from target pointing experiments (Anwar, 1981~). In these experiments on visual-motor localization, visual knowledge of results could not be effectively used by severely subnormal children.…”

“…However, we have some evidence to suggest that a motor deficit alone cannot be regarded as the crucial factor responsible for poor performance on perceptual-motor tasks (Anwar & Hermelin, 1979;Anwar, 1981u, b). For example, in three-dimensional space, Down's syndrome and non-Down's syndrome adolescents were able to improve their visual-motor target localizations when they could manually feel the extent of their error (Anwar, 1981~). Such visual-target localizations did not improve when the error information was only visually available to the child.…”

Kinaesthetic Movement After‐effects in Children With Down's Syndrome*

“…In recent experiments on visual-motor target localisations (Anwar, 1979a) evidence was obtained which tended to support a hypothesis of proprioceptive over visual dominance in Down's syndrome subjects. It was found that under conditions of visual direction (where a target can be seen but the pointing hand cannot) Down's syndrome children were able to improve accuracy significantly when given proprioceptive feedback but not when given visual error information.…”

Εκτίμηση Λεπτών Αντιληπτικο-Κινητικών Δεξιοτήτων Παιδιών Με Ελαφρά Νοητική Καθυστέρηση

“…Σύµφωνα µε την Anwar (1981), τα παιδιά µε σοβαρή καθυστέρηση γενικά έχουν φτωχές οπτικο-κινητικές ικανότητες. Μια υποθετική εξήγηση, η οποία δόθηκε απ' τον Abercrombie (1970), είναι ότι ίσως τα σοβαρά νοητικά καθυστερηµένα παιδιά δίνουν αντικρουόµενη προσοχή σε οπτικές και ιδιοδεκτικές εισόδους.…”

“…Στη µελέτη της Anwar (1981) συγκρίθηκαν µέτρια και σοβαρά νοητικά καθυστερηµένα παιδιά µε τυπικώς αναπτυσσόµενα παιδιά ίδιας νοητικής ηλικίας σ' ένα βασικό οπτικο-κινητικό έργο εντοπισµού του οπτικού στόχου. Τα αποτελέσµατα των πειραµάτων της δείχνουν ότι τα παιδιά µε σοβαρή νοητική καθυστέρηση ήταν λιγότερο ακριβή απ' τα τυπικώς αναπτυσσόµενα παιδιά, σε συνθήκες όπου καθοδηγούσαν οπτικά το χέρι τους στο στόχο και λάµβαναν οπτική γνώση των αποτελεσµάτων.…”