Influence of ball and background patterns on perception of visual direction of a moving object.
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Raven's Coloured Progressive Matrices was administered to 150 subjects (75 males, 75 females) ranging in age from 20 to 86 yr. Subjects were placed into one of three age groups: adult (M age = 27.04 yr.), middle-age (M age = 53.36 yr.), old (M age = 73.78 yr.), with 25 males and 25 females in each age group. Significant differences between age groups on the matrices were obtained after partialing out the effects of educational level, while sex of subject was not significant.
12 subjects judged the magnitude of the corridor illusion as two independent variables were manipulated, complexity of context and orientation of the target figures. The contexts included a complete corridor, one with vertical elements deleted, and one having but two converging lines. Figures embedded within these contexts were thin black lines oriented either vertically or horizontally. Although the context had a significant effect upon the magnitude of the illusion, orientation of the judged lines did not. These results suggest that it is legitimate to use the corridor illusion to illustrate size-distance relationships.
This study examined simultaneously the effects of distance of projection (4-, 6-, and 8-horizontal ft.) and object size (6-, 8.5-in., and 10-in. diameter balls) on object reception by children in the first grade. 6 boys and 6 girls were randomly assigned to each of the 3 distances (36 subjects total). Each subject was administered 36 trials, 12 attempted catches with each ball size at their assigned distance. All balls were projected by a device designed to control accuracy as well as the angle of projection for projections to each distance. Each attempted each was evaluated by a 5-point scale (r = .96). Trials, sex, distance of projection, ball size, and related interactions were examined using a conventional analysis of variance. Ball size was the only significant main effect, but the interaction between ball size and sex was also significant. Post hoc analysis indicated that the 10-in. ball gave significantly more catching success than the 8.5- or the 6-in. ball. Although more success in catching was achieved with the larger ball sizes, no difference in catching was attributable to the varying distances. The sequences for catching success according to ball size at each distance were not significantly different.
The present study investigated Gestalt principles of proximity, similarity and closure. 32 subjects reproduced distances between dots and lines. Two stimulus exposure times were used. Time was significant for proximity, similarity, and closure. Type of distance estimated was significant for proximity and closure and the interaction of time and type of distance was significant for similarity. Most accurate estimations were consistently found for fast exposure times, and internal distances were estimated more accurately than external distances.
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24 subjects were tested to check the hypothesis proposed by Kleitman about a "basic rest-activity cycle". Reaction time tasks were delivered at 10-min. intervals for 320 min. Spectral density function analyses showed no significant periods within the limits of the cycle. Discussion concerns fulfilling assumptions of spectral analysis and Fisher's test.
The effects of the constancy phenomena in vision seem to be to provide information about the environment which is not solely dependent upon the characteristics of shape or size of the retinal image but which is modified by the brain to appear closer to the idealized characteristics of the real object. There is a regression away from the retinal image towards the actual object's characteristics. A plate viewed from an angle tends to look more like a disc than would be predicted from the geometry of perspective. This ability of the brain to impose conditions on perception is a high-level process which may be adversely affected by the depressive action of alcohol on the nervous system. In this case, objects such as road signs, etc. would tend to look smaller and so more distant than when sober if regression is inhibited. Drivers' reactions may be delayed if hazards are seen smaller and further away, thereby increasing the possibility of accident. This research indicates a reduction in phenomenal regression after ingestion of alcohol. There are implications for accident-rates in driving or in industry.
Of 24 students from a psychology class in high school 12 were randomly assigned to a Massed Practice group (4 boys, 8 girls each) and 12 to a Distributed Practice group. They viewed a Necker cube for a 3-min. trial on three occasions separated by a week. The Massed Practice group had no rests while the Distributed Practice group rested 1 min. after each 1 min. of viewing. There were no significant differences for total reversals between Massed and Distributed groups on any trial. There were no significant differences between boys and girls on Trials 1 and 2, but on Trial 3 boys reported significantly more reversals than girls. Within each group there was a significant increase in the number of reversals from Trial 1 to Trial 3, indicating learning effects. Rigidity scores did not correlate significantly with the total Necker cube reversals for Trials 1, 2, or 3. The massed and distributed practice effects were not present although learning was noted. Longer rests may be needed for practice effects within trials; long rests of 7 days between trials may account for lack of differences.
Suppose that there is a circle in front of a cross, the central part of which is occluded by the circle. One usually perceives these figures, as such, although the objective description of the stimulus pattern might be that there is a circle with four limbs attached to it. Here the occluded contours of the cross might be 'inferred.' Until now it has not been demonstrated clearly whether this 'inference' is based on higher cognitive processes or on perceptual processes. However, by manipulating binocular disparity so that the four limbs are seen in front of the circle, the occluded contours become visible, the color of the limbs spreads into the inside of the contours, and the color spreading surface appears transparent, suggesting that the 'inference' is on a perceptual basis. Interestingly, cornered subjective contours of the cross are observed.
Although speech and vocal music are consistently shown to impair serial recall for visually presented items, instrumental music does not always produce a significant disruption. This study investigated the features of instrumental music that would modulate the disruption in serial recall. 24 students were presented sequences of nine digits and required to recall the digits in order of presentation. Instrumental music as played either forward or backward during the task. Forward music caused significantly more disruption than did silence, whereas the reversed music did not. Some higher-order factor may be at work in the effect of background music on serial recall.
A technique is reported in which an oral description of empty squares had to be visualized. A tone signaled completion, and a response was made whether the last square had touched a previous square. The chain lengths varied from 10 to 19 squares at closure. Local closure sizes consisted of 4 to 10 squares. Closures up to 6 squares produced the least errors. There were biases in response as a function of response type and chain length. The technique could be useful for monitoring continuous spatial visualization.
47 subjects adjusted the extended vertical lines of 20 inverted-T figures to make them appear equal to a horizontal line and rated the confidence in their accuracy after each trial. One group viewed figures of varying sizes, a second group viewed figures of standard size, and a third group viewed figures of standard size but received feedback on their accuracy immediately after completing Trial 5. Except for a significant increase in accuracy on Trial 6 for the Feedback Group, there were no differences in performance among groups. Subjects made the vertical line significantly shorter than the horizontal line on initial trials but their accuracy improved over trials. In contrast, there was no consistent increase in confidence, and several analyses indicated that confidence ratings were unrelated to accuracy. These results suggest that the subjects were unaware of the decrement in illusion that occurred over trials.
Size estimation may be influenced by characteristics recalled about the object viewed. This study evaluated the influence of object familiarity on estimation of size. We compared size estimates of several familiar objects with size estimates of undefined objects matched for dimensions of pattern and color. Those estimating the size of the familiar objects made significantly larger errors than those estimating the size of the undefined objects. In a second study size estimation errors from memory were larger than when objects were directly viewed. Experience with the objects appears to decrease accuracy of estimates of size but errors may be reduced by directly observing the object.
Human computational vision models that attempt to account for the dynamic perception of egomotion and relative depth typically assume a common three-stage process: first, compute the optical flow field based on the dynamically changing image; second, estimate the egomotion states based on the flow; and third, estimate the relative depth/shape based on the egomotion states and possibly on a model of the viewed surface. We propose a model more in line with recent work in human vision, employing multistage integration. Here the dynamic image is first processed to generate spatial and temporal image gradients that drive a mutually interconnected state estimator and depth/shape estimator. The state estimator uses the image gradient information in combination with a depth/shape estimate of the viewed surface and an assumed model of the viewer's dynamics to generate current state estimates; in tandem, the depth/shape estimator uses the image gradient information in combination with the viewer's state estimate and assumed shape model to generate current depth/shape estimates. In this paper, we describe the model and compare model predictions with empirical data.
The visual system processes object properties (such as shape and color) and spatial properties (such as location and spatial relations) in distinct systems, and neuropsychological evidence reveals that mental imagery respects this distinction. The findings reported in this article demonstrate that verbalizers typically perform at an intermediate level on imagery tasks, whereas visualizers can be divided into two groups. Specifically, scores on spatial and object imagery tasks, along with a visualizer-verbalizer cognitive style questionnaire, identified a group of visualizers who scored poorly on spatial imagery tasks but excelled on object imagery tasks. In contrast, a second group of visualizers scored high on spatial imagery tasks but poorly on object imagery tasks. The results also indicate that object visualizers encode and process images holistically, as a single perceptual unit, whereas spatial visualizers generate and process images analytically, part by part. In addition, we found that scientists and engineers excel in spatial imagery and prefer spatial strategies, whereas visual artists excel in object imagery and prefer object-based strategies.
Recent studies have suggested a theoretical distinction between active elaboration and passive storage in visuospatial working memory, but research with older adults has failed to demonstrate a differential preservation of these two abilities. The results are controversial, and the investigation of the active component has been inhibited by the absence of any appropriate experimental procedures. A new task was developed involving the mental reconstruction of pictures of objects from fragmented pieces, and this provides a useful procedure for exploring active visuospatial processing. Significant differences in terms of both correctness and response latency were obtained between young and older adults and between younger old and older old adults. Performance also varied with visual complexity, mental rotation, and processing load. It is concluded that this ecologically relevant procedure constitutes a very powerful, sensitive, and reliable tool for identifying individual differences in visuospatial working memory.