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PubMed1975

Effects of auditory and visual modalities in recall of words.

Ten experimental conditions were used to study the effects of auditory and visual (printed words, uncolored and colored pictures) modalities and their various combinations with college students. A recall paradigm was employed in which subjects responded in a written test. Analysis of data showed the auditory modality was superior to visual (pictures) ones but was not significantly different from visual (printed words) modality. In visual modalities, printed words were superior to colored pictures. Generally, conditions with multiple modes of representation of stimuli were significantly higher than for conditions with single modes. Multiple modalities, consisting of two or three modes, did not differ significantly from each other. It was concluded that any two modalities of the stimuli presented simultaneously were just as effective as three in recall of stimulus words.

Auditory Perception↗
PubMed1975

Duration of experienced expansion and contraction of a circle.

The stimulus was a white outline circle which for 60 msec. was projected onto a screen 2 m. from S. The diameter of the circle was 10 cm. and the circle line was approximately 1.5 mm. wide. Fixating the center of the circle Ss reported experiencing the circle as expanding from the point of fixation to full size and then contracting to the point of fixation. Ss' experiences fell in two classes. The durations of Ss' experience of expansion-contraction were measured in msec. Ss also participated in experiments in which they fixated the nethermost point of a 17-cm. vertical straight line which was 2 mm. wide. Ss experienced the line as lengthening from the point of fixation to full length and then shortening to the point of fixation. For a given S the duration of the experienced expansion-contraction of the circle and the experienced lengthening shortening of the straight line were the same.

Color Perception↗
PubMed1976

Picture memory (pseudomatching) in rhesus monkeys.

Pseudomatching, the selection of the correct comparison stimulus without dependence on presentation of a sample stimulus, was demonstrated in monkeys being trained ostensibly on a matching-to-sample, shock-avoidance tast. Pseudomatiching occurred whenever the problem sets were not fully counterbalanced for key position and correct symbol and seemed to represent memorization of specific stimulus configurations. Some animals showed the capacity to memorize hundreds of different 4-choice problems as indicated by test trials on which the samples were omitted. To prevent pseudomatching contamination of matching-to-sample behavior one must arrange full counterbalancing and randomization of stimuli and reinforcements. Pseudomatiching test trials are also recommended.

Animals↗
PubMed1980

Effect of a changing stimulus on the performance of learning disabled and normal children.

The effect of stimulus complexity on the performance of 30 learning disabled and 30 normal Caucasian children (age range 10- to 11.6-year-olds) was compared. Reaction time and response patterns were analyzed separately using a three-factor analysis of variance design, with repeated measures over the last factor. The dependent variables were analyzed over both changing and constant conditions. Under the changing condition, colored squares of the 3 by 4 stimulus matrix were assigned at random on every trial. Under the constant condition the colored squares remained in the same position on every trial. The results support the notion that stimulus complexity affects reaction time for both learning disabled and normal children. No response patterns were shown.

Child↗
PubMed1980

Comparative study of factor structure of Raven's Coloured Progressive Matrices.

The Raven Coloured Progressive Matrices were administered on group or individual bases to children ranging in age from 4 yr. 9 mo. to 11 yr. 0 mo. (N = 728). Factor analysis yielded three factors: 1. Perceptual closure involving complex figures and patterns with heterogeneous inner structures, 2. Concrete and abstract reasoning, 3. Completion of homogeneous patterns and recognition of given elements. Factor matrix comparisons across age groups resulted in a mean similarity coefficient of .75. Comparisons of data with earlier analyses also resulted in high similarity. This supports the hypothesis of a three-factor structure rather than a four-factor solution or a simple dual classification into items which can be solved by perceptual processes and those which require conceptual solutions.

Child↗
PubMed1985

Perception of orientation of motion as affected by change in divergence of texture, change in size, and in velocity.

When there is relative motion between an observer and a textured surface such as the ground, motion-related visual information is available about the orientation of the surface through vergence of the paths of the elements of the texture, change in their sizes and in their velocities. This experiment determined the perceptual effectiveness of each variable in foveal and peripheral viewing for producing perceptions of three-dimensional motion. The three variables were electronically separated and displayed singly, in all possible pairs, and all together. Subjects communicated their perceptions of degree of perceived surface tilt at the top, bottom, and middle of the display for the eight different combinations of variables because, during pilot work perceived surface bendings were frequently noted where top, bottom, and middle appeared tilted to different extents. All three variables can lead to relatively reliable perceptions of perceived orientation of the plane of motion, with change in velocity being the most powerful determiner. Change in size was the weakest. Certain combinations can lead to perceptions of extreme warping and should be avoided in motion displays. Subjects consistently underestimate the amount of simulated tilt. Foveal viewing was more accurate than peripheral viewing but peripheral performance was adequately consistent as an input channel for some orientation tasks.

Depth Perception↗
PubMed1987

Reflex modification by the human auditory startle blink by antecedent interruption of a visual stimulus.

The effect of a preceding brief interruption in the illumination of a small numeral eight on the auditory startle blink was investigated in human subjects. In Exp. 1 (n = 9) trials were given in which a 20-msec. interruption of the visual stimulus preceded elicitation of the startle blink by a loud tone at intervals from 80 to 200 msec. Compared to trials on which the digit was continuously lit but the reflex was elicited, the blink was augmented at 80 msec. and depressed at longer intervals. Exp. 2 (n = 24) showed that the depressive effect peaked at about 200 msec. and did not depend upon requiring subjects to make judgements concerning the stimuli. In Exp. 3 (n = 17) dark intervals ranged from 1.25 msec. to 40 msec. and preceded the loud tone by 200 msec. Reflex effects paralleled subjects' reports: dark intervals of 10 msec. or greater reliably inhibited the reflex and subjects reported seeing the dark interval at least 50% of the time at intervals of 8 msec. or greater, suggesting that the reflex method may be useful as an alternative objective technique for measuring visual temporal resolution.

Adolescent↗
PubMed1987

Depth on a flat screen.

The hypothesis was tested that the coupling of parallax shifts between objects depicted on a monitor screen around a fixation point with the head movements of an observer viewing this screen monocularly around a point coinciding with the fixation point is sufficient to create a convincing depth impression and to enable the observer to make reliable estimations of depth. The estimates were based on monocular vision and involved the aligning of wedges. The investigation consisted of two analogous experiments carried out simultaneously, one on depth estimations virtually in the screen and one on depth estimations virtually in front of the screen. In each experiment three conditions were compared: an active condition in which the coupling of parallax shifts and observer's head movements operated, a passive condition in which it did not, and a real-life set-up to measure the maximum reliability in depth estimation. The hypothesis is confirmed: in the active condition the variances in the alignments are significantly smaller than in the passive condition and approach those in the real-life set-up. This holds not only for estimates in the screen but also for estimates in front of the screen, that is, we can make a thing apparently leap out of the screen towards the observer. Results are interpreted against the background of the debate between the direct and the indirect theories of perception.

Cues↗
PubMed1988

Phenomenal thickness of a transparent surface.

Two basic phenomenal properties of an achromatic transparent surface have so far been reported in the literature, namely, density and lightness. This paper provides experimental support for a new phenomenal variable, the visual thickness of a transparent surface. The more transparent is a surface, the less thick it appears.

Depth Perception↗
PubMed1989

A method of stereoptically simulating manifolds of three-dimensional objects using only a single display pattern: a shape-depth-texture invariance.

A means of conceptualizing and generating visual displays that are "self-stereoptic manifolds" is described. First, single patterns that can replace pairs of stereograms to produce illusions of depth are defined and an example is shown. Patterns such as these produce illusory three-dimensional objects hanging in space before or behind the display surface. It is further demonstrated geometrically that such a display actually has three-dimensional information embedded in it peculiar to each of a family, or manifold, of objects that can be experienced one at a time. Each object of the family appears when the viewer looks in space where it "exists." The others remain invisible unless their locations are fixated. If any member of a specific manifold of three-dimensional illusory objects is physically duplicated as a real object and textured in the same way that the illusory object appeared to be, then this new real object will, in turn, generate an illusion of each of the other objects of the manifold when the observer fixates in space where each "exist." Also, if then the viewer looks where the original display previously was, the newly constructed object will disappear and the display will reappear. The geometry and the advantages and disadvantages in relation to a stereoptic pair are discussed.

Depth Perception↗