Gibson's Hypothesis Research Articles

Strategy planning in dogs (Canis familiaris) in a progressive elimination task

Domestic dogs (Canis familiaris) were administered a progressive elimination task in which they had to visit and deplete three baited sites. Dogs were brought back to the starting point after each visit to any site whether they had made a correct or an incorrect choice. In Experiment 1 (n=10) the results revealed that the dogs randomly selected among the sites when they were equidistant from the starting point whereas they relied on the least distance rule when one of sites was closer to the starting point than were the other sites. In Experiment 2 (n=12), the dogs first chose the left target when angular deviation between adjacent targets varied whether the least angular deviation was on the right of the left. Results are interpreted in terms of Gibson's hypothesis about cooperative hunters. The discussion also emphasizes comparisons with cats (i.e., solitary hunters).

Motor and Cognitive Functions of the Hand in Infancy and Childhood

This paper reviews recent work on the development of the perceptual information-seeking function of the hand in relation to its motor-executive function. The general argument is that from five to six months of age, i.e. when the movements of the hand begin to be systematically controlled by vision, manual haptic competences are consistently under-used and are obscured by a strong visual dominance. Although intramodal haptic discrimination and visual-tactual cross modal transfer take place very early in infancy, infants and children make poor use of their manual perceptual abilities. Consequently, their observed performance on bimodal visual-haptic tasks and in cross modal tasks do not fully support Gibson's hypothesis of amodal processing of perceptual information.

Normal hair zinc levels of children

From literature data, a negative correlation was derived between the normal average hair zinc levels of 5-yr-old children and the calcium levels in their drinking water (hair zinc level in mg/kg=-(0.158±0.003) calcium level in mg/L+134;r=0.993,n=6,p=0.0006). Exposure of hair samples of a 5-yr-old child to water with different levels of calcium and zinc did not provide evidence for an exogenous effect of calcium in drinking water on hair zinc levels. Thus, these results support Gibson's hypothesis that calcium in hard drinking water interferes with Zn absorption.

Infants' Sensitivity to Accretion and Deletion of Texture as Information for Depth at an Edge

Based on Gibson's hypothesis that accretion and deletion of texture in the optic array provides unambiguous information for the spatial layout of surfaces, we sought evidence of early responsiveness to this information with infant subjects. 5- and 7-month-olds viewed computer-generated random-dot displays in which accretion and deletion of texture provided the only information for contours, specifying either a foreground surface moving in front of and occluding a moving background surface or 2 partially overlapping surfaces. The infants in both age groups showed significant preferences to reach for the apparently nearer regions in the displays. Since previous research has shown that infants reach more frequently for the nearer of 2 surfaces, these results indicate that 5- and 7-month-olds are sensitive to accretion and deletion of texture as information for the spatial layout of surfaces.

HETEROGENEITY OF HUMAN ERYTHROCYTE TRANSKETOLASE: A PRELIMINARY REPORT

A modified procedure for the preparation of transketolase from erythrocytes by dialysis and column ion-exchange resin chromatography is described. Changes have been made in the resin used, the column dimensions and the elution procedure so as to separate the enzyme with improved resolution, prepare the apoenzyme free of thiamine pyrophosphate and study the kinetics of its activation or reactivation by the coenzyme. On the basis of the elution profile of the enzyme activity from the chromatographic column, two different samples of the transketolase have been isolated, which differ not only in their isoelectric properties, but also in the proportion of the transketolase present in the apoenzyme form. Not only do the apoenzymes isolated from each of the two fractions differ in the way in which they recombine with thiamine pyrophosphate but kinetic analysis of the results shows that each fraction contains at least two variants of transketolase differing in their affinity for thiamine pyrophosphate. Three, probably four, separate variants have been identified which differ in their affinities for thiamine pyrophosphate over a range greater than 10(4). It is concluded that these two fractions of the enzyme must contain different subsets of the eight isoenzymes of transketolase of differing isoelectric points and that some of these isoenzymes must differ also in their affinity for the coenzyme. The implications of these findings for the Blass and Gibson hypothesis about the pathogenesis of the Wernicke-Korsakoff syndrome are considered.

Further Reflections on J. J. Gibson's Hypothesis of Picture Perception

more detail his 'ecological' hypothesis of pictorial perception. In a previous article [2] I commented upon some possible flaws in Gibson's hypothesis. Although I believe that, in general, Gibson's hypothesis is one of the more fruitful contemporary analyses of art, his latest formulation still contains, I believe, some problems. 1. Gibson's hypothesis contains at its core the following assumption: the analysis of picture perception should be separated from the analysis of the perception of the environment, what may be called 'world perception'. This separation of picture perception from world perception casts serious doubts upon most contemporary psychological analyses of perception since, as Gibson remarks, most psychologists rely upon the use of 2dimensional diagrams in their perceptual experiments. If

Practice Effects for Auditory Localization: A Test of a Differentiation Theory of Perceptual Learning and Development

Practice and transfer of practice in an auditory localization task were observed for three different information conditions (normal, transformed and reduced) to examine four aspects of Gibson's (1969) differentiation theory of perceptual learning and development. Support was found for the propositions that: (i) dimensions of difference, rather than prototypes, are learned; (ii) specificity is a more appropriate response measure than number of correct responses; (iii) perceptual learning will occur regardless of whether feedback is given or not; (iv) transfer of practice will be greater if dimensions of difference (as opposed to prototypes) are learned. It was also found that feedback during practice did not affect transfer. In an apparent contradiction though, specificity increased in the absence of dimensions of difference. This increase was interpreted as being associated with the detection of non-task-related information and was seen as lending support to Gibson's hypothesis that, perceptual learning is motivated by intrinsic cognitive drive and is terminated by a reduction in subjective uncertainty.

Practice effects for auditory localization: a test of a differentiation theory of perceptual learning and development.

Practice and transfer of practice in an auditory localization task were observed for three different information conditions (normal, transformed and reduced) to examine four aspects of Gibson's (1969) differentiation theory of perceptual learning and development. Support was found for the propositions that: (i) dimensions of difference, rather than prototypes, are learned; (ii) specificity is a more appropriate response measure than number of correct responses; (iii) perceptual learning will occur regardless of whether feedback is given or not; (iv) transfer of practice will be greater if dimensions of difference (as opposed to prototypes) are learned. It was also found that feedback during practice did not affect transfer. In an apparent contradiction though, specificity increased in the absence of dimension of difference. This increase was interpreted as being associated with the detection of non-task-related information and was seen as lending support to Gibson's hypothesis that, perceptual learning is motivated by intrinsic cognitive drive and is terminated by a reduction in subjective uncertainty.

The Role of Optical Expansion Patterns in Locomotor Control

Patterns of optical expansion during approach to a surface were simulated, and 20 men were asked to locate the focus of that expansion under different conditions. Errors were less when the pattern was framed and when the visual field was small. Further, the subjects located the focus with any real confidence and accuracy only at the fastest expansion rate (i.e., .5 sec before theoretical surface impact), which casts doubt on J. J. Gibson's hypothesis of the importance of the focus of expansion in locomotor control.