The effects on the predictive variance of a new subject’s score for a new test

Abstract: It is often required to predict the scores or their variations under interest. Ishii and Watanabe (2001) investigated, in the context of psychological measurement, the Bayesian predictive distribution of a new subject’s scores for tests and subjects’ scores for a new test. In this paper, the Bayesian posterior predictive distribution of a new subject’s scores for a new parallel test were considered. And the effects of the number of subjects, the number of the tests, and the test reliability were investigated. Then, it was found that, under assumptions that (co)variance parameters are known, the predictive variance of a new subject’s score for a new test was equal to the predictive variances of the new subject’s scores for the existent tests. It was also found that the effect of the number of subjects was relatively large and the effect of the number of tests was relatively small, when a new subject’s scores for existent tests were not observed.     

Occlusion as a depth cue in the Wheatstone-Panum limiting case

We examined the hypothesis (Ono & Wade, 1985) that occlusion of far stimuli by a near one on the same visual line can operate as a depth cue in stereograms containing different numbers of targets in the two eyes. By controlling eye positions, we created conditions in which the visual system could interpret the retinal images as originating from stimuli on the visual axis of one eye and also created other conditions in which the origin of the retinal images was ambiguous. In Experiment 1, we presented two lines to one eye and a single line to the other eye. When the image of the line on the temporal side of the line pair on one retina fused with the image of the single line on the other retina, the nonfused line appeared farther away more often than it did when the image on the nasal side fused. In Experiment 2, we used two differently shaped stimuli. In the condition in which the nonfused stimulus represented an object being occluded, it appeared farther away more often than in the four conditions in which it did not. In Experiment 3, we extended the idea to three different objects. When the middle of the three images fused with the single image, the nonfused stimulus appeared farther when it could be interpreted as being occluded than when it could not. In the condition in which the most temporal image fused with the single image, the nonfused stimuli appeared farther than in the condition in which the most nasal one fused. The results supported the hypothesis that occlusion plays a role in depth perception in the Wheatstone-Panum limiting case.     

General Learned Irrelevance and Its Prevention

Random presentation of a tone and an electric shock to rats interfered with subsequent acquisition of a light–shock association. This interference, or “general learned irrelevance” phenomenon, however, could be prevented by prior learning of a positive relationship between the tone and the shock or that between a noise and the shock. These results strongly support the ideas that animals learn irrelevant stimulus relationships and that prior experience of stimulus relevance prevents learning irrelevance. The similarity of this observed prevention effect to an immunization effect on learned helplessness phenomena is discussed.     

Starting position of movement and perception of angle of trunk flexion while standing with eyes closed.

The present study attempted to investigate the effect of position on the perception of angle of trunk flexion while standing. For this purpose, the range effect was factored out by setting the constant target angle at 10 degrees, with varied starting positions of trunk flexion. We found that subjects underestimated angle of trunk flexion when the starting position was close to a quiet standing posture, overestimated when close to maximum trunk flexion, and correctly perceived it when at the middle position. Less perceptual distortion was observed at the positions close to maximum trunk flexion in the present study than in our previous one, in which various target angles of trunk flexion were reproduced from a quiet standing posture. The reduced distortion in the present study was believed to have resulted from factoring out the range effect. The flexion angle of the hip joint changed in tandem with that of the trunk, while very little movement was observed in the ankle, knee, and neck joints. Judging from the changing pattern of hip-joint angle, the muscle activity of the erector spinae and biceps femoris increased gradually to 90 degrees trunk flexion. In contrast, the actual increment of muscle activity reached zero or a minimum value at the middle angles as the angle of trunk flexion increased. It was assumed that the abrupt change in kinesthetic information associated with muscle activity exerted a great influence on the perception of trunk flexion.     

Size-distance paradox with accommodative micropsia

Two experiments tested the hypothesis that the paradoxical relative distance judgment associated with the size-distance paradox is due to the visual system’s assuming equal linear size and perceiving a smaller angular size for the closer stimulus equal in visual angle. In Experiment I, two different sized coins were presented successively, and 16 Ss were asked to give ordinal judgments of apparent distance and apparent size. When the two coins depicted the same figures, the closer stimulus was judged to be farther and smaller, more frequently, than when two coins depicted different figures. In Experiment II, 48 Ss were asked to give ratio judgments of apparent distance, apparent linear size, and apparent angular size for two stimuli which were presented successively. When the stimuli were of equal shape, the mean ratios of the far stimulus to the near stimulus were smaller for the apparent distance but larger for the apparent linear size and angular size than when the stimuli were of different shape. The obtained distance judgments were consistent with the hypothesis but the obtained judgments of linear size and angular size were not.     

Apparent movement and change in perceived location of a simulus produced by a change in accommodative vergence

Using a psychophysical method of adjustment, 175 Ss, ranging in age from 3 to 20 years, made four adjustments each of a luminous line to subjective vertical, horizontal, and 45-deg tilts in the dark. There were no significant differences in mean errors of adjustment to the vertical and horizontal over the ages tested. There were significant differences in intra-S variability of adjustment to the horizontal and vertical, with the greatest improvement occurring before age 10. Older children and adults produced significantly larger mean errors of adjustment to the 45-deg tilt than did the younger children; but the variability of settings by younger children was very high, indicating that they did not discriminate the 45-deg tilt more accurately than the older groups. The intra-S variability at all ages showed that adjustment was more accurate to the horizontal and vertical than to the 45-deg tilt.     

Extraction of linguistically relevant pragmatic contrast through language learning

This study explores whether pragmatic contrast that is not expressed as relevant in the subjects' native language is extracted through language learning. Miniature artificial languages were used. In Experiment 1, a contrast was created such that four persons appeared together in each situation, with three persons performing the same activities and the fourth one performing a different target activity. Under this presentation condition pragmatic contrast was shown to be rather easily extracted. In Experiments 2 and 3, a single person appeared in each situation and contrast was created serially by changing the position in which the person performing the target activity was placed. Under these presentation conditions sufficient evidence for the extraction of pragmatic contrast was not found. Experiment 2 also examined the effect of different experience of instances on the extraction of pragmatic contrast. Results showed that although different experience did not produce a differential effect as expected, a definite conclusion was not drawn for a low level of performance. It was formulated that the two presentation conditions differed in the degree of transparency for a mapping relation between the linguistic structure and the pragmatic contrast. Implications of the findings were suggested in relation to a natural learning situation.Deep gratitude is due to Professor D. D. Steinberg for his reading of an earlier version of this paper.     

The interaction of perceived distance with the perceived direction of visual motion during movements of the eyes and the head

A horizontally moving target was followed by rotation of the eyes alone or by a lateral movement of the head. These movements resulted in the retinal displacement of a vertically moving target from its perceived path, the amplitude of which was determined by the phase and amplitude of the object motion and of the eye or head movements. In two experiments, we tested the prediction from our model of spatial motion (Swanston, Wade, & Day, 1987) that perceived distance interacts with compensation for head movements, but not with compensation-for eye movements with respect to a stationary head. In both experiments, when the vertically moving target was seen at a distance different from its physical distance, its perceived path was displaced relative to that seen when there was no error in pereived distance, or when it was pursued by eye movements alone. In a third experiment, simultaneous measurements of eye and head position during lateral head movements showed that errors in fixation were not sufficient to require modification of the retinal paths determined by the geometry of the observation conditions in Experiments 1 and 2.     

Unimmediate construction of syntactic structure for garden path sentences in Japanese

While self-paced reading and eye-fixation have been used as on-line measures of sentence processing, they provide only indirect evidence as to the exact syntactic state during sentence processing. Two experiments were designed to fill this gap, where garden path sentences in Japanese were used and the marker demanding reanalysis of a previously established syntactic structure appeared at the end of these sentences. Forty-eight students were given a probe verb from an embedded clause and required to quickly identify the subject whose syntactic role could be confirmed only when they later encountered the marker. Findings showed that correct identification was below 50% immediately after the marker (0-sec delay) and increased gradually, reaching 82% at the delay of 4 sec. However, perfect identification was not obtained even for the latter delay condition. The findings indicate that parsers cannot immediately reconstruct the previous syntactic structure but need a certain period of time to reach a final decision. They also suggest that a distinction should be clarified between the moment-to-moment syntactic computation being made and the syntatic structure being constructed during sentence processing.Deep gratitude is due to Professor D. D. Steinberg for his reading of an earlier version of the paper.