Non-verbal IQ is correlated with visual field advantages for short duration coherent motion detection in deaf signers with varied ASL exposure and etiologies of deafness

Studies have reported a right visual field (RVF) advantage for coherent motion detection by deaf and hearing signers but not non-signers. Yet two studies [Bosworth R. G., & Dobkins, K. R. (2002). Visual field asymmetries for motion processing in deaf and hearing signers. Brain and Cognition, 49, 170-181; Samar, V. J., & Parasnis, I. (2005). Dorsal stream deficits suggest hidden dyslexia among deaf poor readers: Correlated evidence from reduced perceptual speed and elevated coherent motion detection thresholds. Brain and Cognition, 58, 300-311.] reported a small, non-significant RVF advantage for deaf signers when short duration motion stimuli were used (200-250 ms). Samar and Parasnis (2005) reported that this small RVF advantage became significant when non-verbal IQ was statistically controlled. This paper presents extended analyses of the correlation between non-verbal IQ and visual field asymmetries in the data set of Samar and Parasnis (2005). We speculate that this correlation might plausibly be driven by individual differences either in age of acquisition of American Sign Language (ASL) or in the degree of neurodevelopmental insult associated with various etiologies of deafness. Limited additional analyses are presented that indicate a need for further research on the cause of this apparent IQ-laterality relationship. Some potential implications of this relationship for lateralization studies of deaf signers are discussed. Controlling non-verbal IQ may improve the reliability of short duration coherent motion tasks to detect adaptive dorsal stream lateralization due to exposure to ASL in deaf research participants.     

运动觉、布局无关运动与路径整合

路径整合是空间导航的一个重要子领域。本研究采用了一种三角形完成任务的新变式来研究路径整合问题，发现在剥夺被试的视觉输入的前提下，去除被试部分运动觉后，其绩效有不同水平的下降；同时还发现在编码过程中与路径布局无关的不同方向旋转间并无显著性差异。此外，由于本研究是在室外空间中所做的现场研究，故得到的结果优于室内所做的经典研究，进而验证了前人的一个猜测。     

The perception of biological and mechanical motion in female fragile X premutation carriers

Previous studies reported impaired visual information processing in patients with fragile X syndrome and in premutation carriers. In this study, we assessed the perception of biological motion (a walking point-light character) and mechanical motion (a rotating shape) in 25 female fragile X premutation carriers and in 20 healthy non-carrier controls. Stimuli were moving stimulus dots embedded among a cloud of noise dots. Sensitivity (d′) for motion detection was determined. Emotional symptoms were assessed by Hamilton’s depression and anxiety rating scales. Results revealed that the premutation carriers displayed lower sensitivities for biological and mechanical motion relative to the non-carriers. This deficit was more pronounced in the case of biological stimuli. The premutation carriers displayed higher depression and anxiety scores relative to the non-carriers. Higher depression, but not anxiety, scores were associated with decreased sensitivity for biological, but not mechanical, motion in the carrier group. These results suggest that motion perception deficits are detectable in fragile X premutation carriers, and that the impairment of biological motion perception is associated with depressive symptoms.     

手的拦截运动的速度伴随效应及影响因素

对手的拦截运动的理论假设、速度伴随效应及其影响因素进行了总结和分析。指出:(1)“速度伴随效应”的机制可能在于补偿反应延迟、维持必需的注视时间、对即时运动信息的利用或时间-准确性权衡;(2)手的拦截运动指标受目标运动方向、先前任务、练习、目标大小、运动表征和策略以及双眼线索等因素的影响;(3)对拦截运动的进一步研究可在统一理论解释的基础上进行,克服研究方法和范围的局限。     

视觉运动知觉脑机制的研究现状

视觉运动是探索脑功能的一个重要研究途径,该对视觉运动通路与色彩的关系、视觉运动知觉的产生,对于视觉信息的不同阶段的处理以及立体视觉等若干问题进行了回顾与讨论,并概述了其中若干理论及其争论,提出了未来视觉研究可能存在的问题与研究方向。     

Body movements of male and female speakers and their influence on perceptions of personality

Men and women score differently on some personality traits and people’s behavior reflects who they are. Therefore, males and females could be expected to express themselves differently on a behavioral level. To test this idea we turned the public performances of speakers (20 female and 20 male) into stick figure movies. Students of the University of Vienna (n = 150) rated these movies on scales measuring the Big Five personality traits. The participants experienced difficulties in ascribing the correct sex to the stick figures. Nevertheless, stick figures representing male speakers received higher ratings for extraversion and emotional stability than stick figure animations of female speakers. In addition, gender stereotypes seemed to influence the participants’ ratings. Agreeableness, for instance, was preferably classified as female trait. In conclusion, our results suggest that body motion conveys social information, that men and women present themselves differently, and that people’s judgments are influenced by gender stereotypes.     

An application of the optic sphere theory in discrimination of slant with minimal information

In Johansson and Börjesson (1989), a new theory of visual space perception—the optic sphere theory—was presented in which the hemispheric shape of the retina is utilized for determination of slant of plane surfaces in wide-angle perception. The process of the optic sphere mechanism can be described as the projection of a translating distal line on the optic sphere, and an extrapolation of this projection to a great circle. The determination of the 3-D slant of the distal line is made by identification of points of no change on the great circle during its rotation. The main objective of the present study was to investigate this process as applied to central stimulation of the retina with reduced and minimal information of slant or horizontal orientation. Each stimulus pattern consisted of either two continuous lines or two pairs of dots in motion presented on a computer screen. The pairwise lines and the pairs of dots defined simulated 3-D slants (or horizontal orientations) of different magnitude within each pair, and the subjects' task was to discriminate between these simulated slants. It was shown that the simulations evoke percepts of 3-D slants, and of horizontal orientations, and that it is possible to discriminate between them even from minimal information (pairs of dots). Further, the empirical findings of Börjesson (1994) indicated that longer extrapolations of the projected arc to a point of no change yield less accurate discriminations of slant. We failed to replicate this in Experiment 4, in which case stimulus variables that covaried with extrapolation length were eliminated or minimized. It is suggested that this raises some doubt about discrimination accuracy as dependent on extrapolation length per se. The overall conclusion, however, is that the optic sphere theory represents a possible explanation of, or analogy to, the process utilized by the visual system for determination of the simulated 3-D slants and horizontal orientations in the present study.     

The relationship between apparent motion and object files

Object files (OFs) play an important role in theories of mid-level vision. On some influential views, OFs operate and persist only via spatiotemporal continuity. One open question concerns what occurs when direct spatiotemporal continuity is absent: Do OFs move in accordance with any motion correspondence ultimately resolved? Specifically, do OFs accord with apparent motion (AM) correspondences, which arise despite a lack of continuous spatiotemporal stimulation? In Experiment 1, subjects were presented with an AM display consisting of two circles that, across two frames, were seen as moving between two noncontiguous locations. The two objects were primed with two symbols and were then moved in a single step; a third symbol appeared, and could either match the symbol from the closer or the further object. We found a robust object specific preview benefit (OSPB) for the shorter path, in other words, the path along which AM was perceived. In order to control for the possibility that priming occurs at any nearby object, in Experiment 2, the original two objects never disappeared, but two new objects appeared in the would-be AM locations. No AM was perceived, and no OSPB obtained. In the third experiment the OSPB effect persisted even when motion along the shorter path included an unlikely featural transformation (circles turning into squares). In Experiment 4, which was nearly identical to Experiment 2, no OSPB obtained despite unique featural matches between the initial and new objects, seemingly because no AM was perceived. In Experiment 5, we failed to find an effect of featural priming, even when distance between the objects was equated. Finally, we extended the OSPB effect to two additional kinds of AM—line motion (Experiment 6) and phi motion (Experiment 7), supplying strong evidence that AM correspondences and OF correspondences are controlled by the same basic rules.     

Temporal perception is enhanced for goal-directed biological actions

ABSTRACT

Research into the visual perception of goal-directed human action indicates that human action perception makes use of specialized processing systems, similar to those that operate in visual expertise. Against this background, the current research investigated whether perception of temporal information in goal-directed human action is enhanced relative to similar motion stimuli. Experiment 1 compared observers’ sensitivity to speed changes in upright human action to a kinematic control (an animation yoked to the motion of the human hand), and also to inverted human action. Experiment 2 compared human action to a non-human motion control (a tool moved the object). In both experiments observers’ sensitivity to detecting the speed changes was higher for the human stimuli relative to the control stimuli, and inversion in Experiment 1 did not alter observers’ sensitivity. Experiment 3 compared observers’ sensitivity to speed changes in goal-directed human and dog actions, in order to determine if enhanced temporal perception is unique to human actions. Results revealed no difference between human and dog stimuli, indicating that enhanced speed perception may exist for any biological motion. Results are discussed with reference to theories of biological motion perception and perception in visual expertise.     

Differential activation of a central inhibition system by motion and colour distractors

ABSTRACT

The selection of relevant stimuli is partially achieved through inhibition of irrelevant distractors. Using the distractor induced blindness (DIB) paradigm, we investigated whether these inhibitory processes depend on the feature dimension that is used to define distractors. Following a pilot study that found motion and colour targets to be comparably salient, we analysed distractor effects of those two feature dimensions. In both feature dimensions, an inhibition effect depended on the number of distractors. Colour, however, was more sensitive to distractor episodes as compared to motion: The level of inhibition was more pronounced, and its activation required less distractors. The results of a control experiment provided further evidence that, in fact, the feature dimension -instead of design differences between tasks- is responsible for this observation. The dimension-sensitive bias in the activation of a central inhibition system may be attributed to a differential processing of visual signals, depending on their behavioural relevance.