Joint attention in term and preterm infants at 12 months corrected age: the significance of gender and intervention based on a randomized controlled trial

This study tested the effects of optimized neonatal mother–infant transactions on joint attention performance at 12 months. Surviving infants <2000 g from a geographically defined area were randomly assigned to a preterm intervention (n = 71) or preterm control group (n = 69). Comparisons were made between preterm groups, secondary with a term group (n = 75). Joint attention was measured using the Early Social Communication Scales. Preterm intervention infants scored significantly higher than preterm control infants on elements Initiating Joint Attention (p < 0.05), Initiating Object Requests (p < 0.05), and Responding to Social Interaction (p < 0.0005). Intervention was not associated with performance on elements Responding to Joint Attention, or on Responding to Requests. ELBW infants scored significantly lower than VLBW and LBW infants on imperative functions. Girls outperformed boys on all communication elements. An intervention implemented during the neonatal period can be of advantage for certain aspects of joint attention performance in preterm infants.     

Stimulus overselectiv1ty of autistic children in a two stimulus situation

Autistic and normal children were trained to respond to a complex stimulus involving an auditory component (white noise) and a visual component (red floodlight). After the Ss had acquired this discrimination, the individual components were presented singly to assess their control over the Ss' behavior. The autistic Ss' unlike the normals, demonstrated stimulus overselectivity in that seven out of nine Ss responded to only one of the components. These results were consistent with those of a previous study where autistics showed stimulus overselectivity in an experiment involving three modalities. In both experiments, the previously non-functional stimulus was made functional when trained separately.     

ACHROMATIC COLOUR CONSTANCY

The traditional conception of achromatic colour constancy, defined in terms of a psychophysical colour-albedo relation, is found to be unfruitful from a functional as well as a theoretical point of view. An alternative definition of colour constancy in terms of the validity of perception of illumination is suggested.     

TRAINING OF PERIPHERAL VISUAL ACUITY

An experiment was performed to investigate whether the duration of exposure and the size of the test objects are factors critical for obtaining a training effect in peripheral visual acuity. Contrary to previous results it is shown that considerable improvement may be obtained even under conditions of flash stimulation, provided that the test object used for training is sufficiently small to be just discriminable. The results are interpreted in terms of shifts in the maximum momentary level of attention from the central to the peripheral area of the visual field.     

EFFECT OF REWARD AND PUNISHMENT ON VISUAL PERCEPTION OF FIGURE–GROUND

Eight experiments, based on the original design of Schafer & Murphy (1943) for study of the development of the figure—ground relationship, are examined and the results found to be contradictory. The definition given of the perception of the figure–ground relationship is judged to be inadequate and ascribed to an unwillingness of behavioristically oriented psychologists to analyze the term perception with reference to perceptual experience.     

Driving skills after whiplash

Previous studies have shown that some persons with longlasting problems after whiplash have changed eye movements. These changes have been related to disturbance of the posture control system. The question raised in the present study is whether such disturbances can influence daily life functions connected with balance, position and external movements, such as car driving. A group of 23 persons with disturbed eye movements due to whiplash injury, was tested in a driving simulator, together with a closely matched control group. The results revealed significant differences between the two groups with respect to response times to the traffic signs presented, identification of type of sign, as well as steering precision while the subjects’ attention was directed to the process of identifying the signs. Alternative explanations such as driving experience, pain, medication or malingering are at least partly controlled for, but cannot completely be ruled out. A distorted posture control system leading to disturbance of eye movements seems to be the most likely primary causative factor, but these disturbances are most certainly complexly determined. Reduced attention capacity is considered to be a mediating secondary factor. Registration of eye movements may be a useful diagnostic tool to evaluate driving skill after whiplash.     

Sex differences in tactual-kinaesthetic and visual perception of vertically

Previous studies on visual and tactual-kinaesthetic perception with head tilted sidewise have shown that the greater deviations are to the left, i.e. the adjustments of a luminous line or a pivoting rod tend to fall counter-clockwise to the perpendicular. This paper shows significant sex difference in tactual-kinaesthetic perception only. Men and women show similar and small deviations to the right with head tilted to the left but, with head tilted to the right, women show clearly greater deviations to the left. The discussion of the visual perception of verticality (the so-called Aubert phenomenon) has been confusing. Our results in the visual experiments show small deviations, and they support Aubert's statement.     

VALUE AND SIZE PERCEPTION

A detailed review is presented of studies related to the accentuation hypothesis of Bruner & Goodman (1947). It is found that the results from (1) coin studies, (2) symbol studies, and (3) other studies are conflicting and do not substantiate the hypothesis. Through an analysis of this hypothesis and a specification of the concept of perception, the various designs are found to be inadequate for demonstrating perceptual accentuation of size. The hypothesis is forwarded that value asserts an influence upon imaginary processes related to the experience of size.     

CONVERGENCE AS A CUE T O PERCEIVED SIZE AND DISTANCE

A wire mesh was used as stimulus object in the old 'wall-paper experiment'. Fixating a small object on the near side of the wire mesh, the mesh appears of course double. By adjusting the fixation object back and forth a position can be reached at which fusion of the double image is obtained. At this moment the wire mesh appears to shift location. A nearly perfect one-to-one correspondence obtained between the perceived distance of the 'fused.' wire mesh and the actual convergence distance. It is concluded that the convergence mechanism may provide perfectly specific information to the visual system concerning the spatial location of objects.     

THE FACTOR OF PROXIMITY: An attempt to specify its critical conditions

Two experiments were undertaken for the purpose of investigating whether the Factor of Proximity, operative in perceptual organization according to Gestalt theory, should be specified with reference to the perceived or to the objective spacing of the elements of a stimulus field. The results indicate that a series of dots arranged in horizontal and vertical rows is more readily grouped in vertical than in horizontal lines. This finding implies that the Factor of Proximity cannot be exactly specified either in terms of the perceived or the objective spacing of the elements to be grouped.