Leonardo's constraint: two opaque objects cannot be seen in the same direction

Given Leonardo's constraint that 2 opaque objects cannot be seen in the same direction, how are the regions of objects occluded to 1 eye included in perception? To answer this question, the authors presented 3-dimensional stimuli, similar to the ones that concerned Leonardo, and measured the visual directions of their monocular and binocular regions. When the distance between near and far objects was large, the nonfixated object was seen as double and blurry. Leonardo's constraint was met by seeing the near object as double and transparent or the distant object as double and superimposed. When the distance between near and far objects was small, the constraint was met by a perceptual displacement and compression of parts of the nonfixated object.     

Judgments of grammaticality of sentences with a differing number of arguments: a comparison of English and Japanese speakers

This study explored native speakers' linguistic intuition as revealed in judging the grammaticality of sentences. Speakers of English (n = 36) and Japanese (n = 57) judged the relative grammaticality of sentences involving a verb which occurred together with one, two or three arguments. Findings showed that English speakers were more affected by the number of arguments in sentences. They judged sentences having three arguments as grammatical most often and ones having one or two arguments as grammatical less often. However, Japanese speakers gave rather similar and more grammatical judgments regardless of the number of arguments in sentences. The findings indicate a difference in tightness of argument structure in the two languages even when the sentences judged are simple sentences and they are given without any sentential context.     

The relativity of linguistic intuition: The effect of repetition on grammaticality judgments

Three experiments were performed to show the relativity of linguistic intuition in grammaticality judgments. In Experiment 1, 12 students judged the relative grammaticality of isolated sentences twice, receiving a repetition treatment between the two judgments. During the repetition phase, they were exposed to a repeated presentation of sentences. The findings show that the repetition treatment makes a judgment criterion more stringent for both grammatical and ungrammatical sentences. In Experiment 2, a release-from-the-proactive-inhibition paradigm was used. Twelve students first judged the grammaticality of the isolated sentences, then received the repetition treatment, and finally, made a second judgment for the sentences embedded in context. No change in judgment criterion was found for the second judgment. Judgments of the ungrammatical sentences, when embedded in context, were found to be more lenient. In Experiment 3, 12 students judged sentences embedded in context. No change in judgment criterion was found. These findings are interpreted as suggesting that linguistic intuitions as revealed in grammaticality judgments are not absolute but relative in that they are easily influenced by repetition and other variables, such as embedded context.     

Effect of repetition on grammaticality judgments under objective and subjective self-awareness conditions

Three experiments were performed to investigate the differential effect of repeated presentation of sentences on judgments of grammaticality under the two mental states of objective and subjective self-awareness. In Experiment 1, 22 students judged the relative grammaticality of sentences twice, receiving a repetition treatment between the two judgments. During the repetition phase, they were exposed to a repeated presentation of sentences. The findings showed that repetition makes a judgment criterion more stringent on judgments after repetition than on those before repetition for the subjectively self-aware subjects, while it does not influence the judgments for the objectively self-aware subjects. Experiment 2 was run using a revised procedure with 26 students. The findings showed the expected, interaction, such that the repetition makes a criterion stringent for the subjectively self-aware subjects while it makes the criterion lenient for the objectively self-aware subjects. Experiment 3 examined with 12 students whether the finding for the latter subjects could be explained, by divided attention theory in a concurrent task condition. The findings showed no change of judgment criterion. These findings indicate that repeated exposure to the sentences exerts differential effects on grammaticality judgments dependent on whether the subjects are objectively or subjectively self-aware.     

Is Trait Rumination Associated with the Ability to Generate Effective Problem Solving Strategies? Utilizing Two Versions of the Means-Ends Problem-Solving Test

This study examined the relationship between trait rumination and the effectiveness of problem solving strategies as assessed by the Means-Ends Problem-Solving Test (MEPS) in a nonclinical population. The present study extended previous studies in terms of using two instructions in the MEPS: the second-person, actual strategy instructions, which has been utilized in previous studies on rumination, and the third-person, ideal-strategy instructions, which is considered more suitable for assessing the effectiveness of problem solving strategies. We also replicated the association between rumination and each dimension of the Social Problem-Solving Inventory-Revised Short Version (SPSI-R:S). Japanese undergraduate students (N = 223) completed the Beck Depression Inventory-Second Edition, Ruminative Responses Scale (RRS), MEPS, and SPSI-R:S. One half of the sample completed the MEPS with the second-person, actual strategy instructions. The other participants completed the MEPS with the third-person, ideal-strategy instructions. The results showed that neither total RRS score, nor its subscale scores were significantly correlated with MEPS scores under either of the two instructions. These findings taken together with previous findings indicate that in nonclinical populations, trait rumination is not related to the effectiveness of problem solving strategies, but that state rumination while responding to the MEPS deteriorates the quality of strategies. The correlations between RRS and SPSI-R:S scores indicated that trait rumination in general, and its brooding subcomponent in particular are parts of cognitive and behavioral responses that attempt to avoid negative environmental and negative private events. Results also showed that reflection is a part of active problem solving.     

Visual Evoked Potentials to Geometric Forms: Effects of Spatial Orientation

Five outlined geometric figures of equal contour length were presented monocularly below the fixation point (FP); an upright equilateral triangle (upright triangle), an inverted equilateral triangle (inverted triangle), an upright square (square), a 45°-tilted square (diamond) and a circle. The angular separation between FP and the top of the figures was held constant. Transient visual evoked potentials (VEPs) were recorded monopolarly from inion, 4, 7, 10 cm above it (l, l4, l7, l10) and Cz for ten subjects. The grand-averaged subtracted waves were obtained between the figure and blank (control) conditions. N1 (mean peak latency: 155 ms) and P2 (240 ms) waves were identified. ANOVAs were conducted for the latency and amplitude values. Main results were as follows: On the N1 amplitude at l4 and l, the upright triangle, inverted triangle and diamond figures evoked significantly larger responses than did the square and the circle. However, no significant difference was found among the former three figures. These findings on the N1 amplitude suggest that the effect of a triangle is orientation-free and that of a square is orientation-bound.     

Using motor tasks to quantitatively judge 3-D surface curvatures

The primary objective of this study was to quantitatively investigate the human perception of surface curvature by using virtual surfaces and motor tasks along with data analysis methods to estimate surface curvature from drawing movements. Three psychophysical experiments were conducted. In Experiment 1, we looked at subjects’ sensitivity to the curvature of a curve lying on a surface and changes in the curvature as defined byEuler’s formula, which relates maximum and minimum principal curvatures and their directions. Regardless of direction and surface shape (elliptic and hyperbolic), subjects could report the curvature of a curve lying on a surface through a drawing task. In addition, multiple curves drawn by subjects were used to reconstruct the surface. These reconstructed surfaces could be better accounted for by analysis that treated the drawing data as a set of curvatures rather than as a set of depths. A pointing task was utilized in Experiment 2, and subjects could report principal curvature directions of a surface rather precisely and consistently when the difference between principal curvatures was sufficiently large, but performance was poor for the direction of zero curvature (asymptotic direction) on a hyperbolic surface. In Experiment 3, it was discovered that sensitivity to the sign of curvature was different for perceptual judgments and motor responses, and there was also a difference for that of a curve itself and the same curve embedded in a surface. These findings suggest that humans are sensitive to relative changes in curvature and are able to comprehend quantitative surface curvature for some motor tasks.     

Binocular single vision achieved by fusion and suppression

The occurrences of fusion and suppression were determined from stereograms which produced two retinal images located at equal distances but in opposite directions from the fovea. Subjects reported whether the dichoptic stimulus appeared single or not, and if single whether it appeared in the center of the visual field. The report of centrality is predicted by the fusion theory of single vision and that of noncentrality by the suppression theory. Experiment 1, with eight subjects, showed that for small disparities perceived singleness was the percept predicted by the fusion theory; for larger disparities, the percepts could sometimes be predicted by the fusion theory and other times by the suppression theory. Experiment 2, with 16 subjects, showed that with larger stimuli the percept predicted by the fusion theory is more likely to occur. Experiment 3, with four subjects, showed that the centrality was reported when the stimuli were presented for 100 msec. This result provided support for our interpretation that the centrality reports in Experiments 1 and 2 were not due to fixation error and suppression.     

The cyclopean eye vs. the sighting-dominant eye as the center of visual direction

In three experiments, competing hypotheses concerning the center of visual direction were examined with the stimuli used in the Card test which requires a subject to position the card with a hole so that a target can be seen. Each experiment used six right- and six left-sighting-eye subjects. In Experiment 1, the aperture and the target were collinear with the sighting eye. The mean apparent locations of the aperture when the target was fixated, and of the target when the aperture was fixated, were consistent with only the cyclopean-eye hypothesis; that is, the 95% confidence intervals of these means contained the predicted values from the cyclopean-eye hypothesis but not those from the sighting-eye hypothesis. In Experiment 2, subjects moved the card from the side of the nonsighting eye, and in 88% of the trials it was stopped when the nonsighting eye viewed the target. In Experiment 3, the target was viewed through the aperture with both the sighting and nonsighting eye in six different stimulus arrangements. The 95% confidence intervals of all 12 mean apparent locations of the targets contained the predicted values from the cyclopean-eye hypothesis but none of those from the sighting-eye hypothesis. These results are compatible with the cyclopean-eye hypothesis, and we therefore conclude that the sighting eye is not the center of visual direction.     

Oculomotor adjustments and size-distance perception

The relationship between perceived size and distance and oculomotor adjustments were assessed in two experiments. In both experiments, Ss were required to make scalar linear size, angular size, and distance judgments of stimuli subtending a constant retinal image size at different levels of convergence. The results of the first experiment indicate that the perceived linear size, angular size, and distance of the stimulus decreased with increased convergence, the decrease in perceived linear size being greater than that of perceived angular size. While again showing a decrease in perceived linear and angular size, the results of the second experiment also show that there was a smaller decrease in perceived distance with increased convergence when Ss continued to view the stimulus as convergence was changed than when they did not view the stimulus as convergence was changed. The implications these results have for size and distance perception are discussed.