The acquisition of observing.

Pigeons were exposed to stimuli correlated with the presence or absence of a variable-interval 60-second schedule of reinforcement only while they depressed a crossbar or "perch." In the first experiment, the stimuli were different tilts of a line displayed on the key. When the difference in brightness between the line and the background (salience) was maximal, seven of eight birds acquired the discrimination, but when the difference was reduced by 50%, only one succeeded. In the second experiment, wavelength of chamber illumination served as the relevant dimension. Neither experiment showed a large effect attributable to the magnitude of the difference (disparity) between the positive and the negative stimulus. Individual differences in time spent observing were positively correlated with level of discrimination in the presence of the stimuli. All birds produced the positive stimulus for a greater proportion of the available time than they did the negative stimulus. This may be the mechanism that provides selective reinforcement of observing. Finally, the formation of a discrimination was analyzed in terms of changes in the proportion of time spent in contact with the discriminative stimuli.     

双眼视差的神经机制与知觉学习效应

双眼瞳距使得空间某物体在左右眼视网膜的成像存在微小位置差异, 这种差异被称为双眼视差(binocular disparity), 是立体视知觉的重要信息来源。对双眼视差的心理物理学研究始于18世纪初, 迄今已有接近两百年的历史。近年来, 双眼视差研究主要集中在两方面。其一是用电生理、脑成像技术考察双眼视差在视觉背、腹侧通路的模块化表征, 其脑区表征反映出视觉系统的层级式、平行式加工规律。其二是应用知觉学习范式研究双眼视差的可塑性。未来研究应综合脑成像和神经调控技术考察双眼视差的神经机制及其学习效应, 包括双眼视差与多种深度线索间的信息整合和交互作用。应用方向上, 可结合虚拟现实等技术优化训练范式, 实现立体视力的康复和增强。     

Stimulus disparity and punisher control of human signal-detection performance

The present experiment examined the effects of varying stimulus disparity and relative punisher frequencies on signal detection by humans. Participants were placed into one of two groups. Group 3 participants were presented with 1:3 and 3:1 punisher frequency ratios, while Group 11 participants were presented with 1:11 and 11:1 punisher frequency ratios. For both groups, stimulus disparity was varied across three levels (low, medium, high) for each punisher ratio. In all conditions, correct responses were intermittently reinforced (1:1 reinforcer frequency ratio). Participants were mostly biased away from the more punished alternative, with more extreme response biases found for Group 11 participants compared to Group 3. For both groups, estimates of discriminability increased systematically across the three disparity levels and were unaffected by the punisher ratios. Likewise, estimates of response bias and sensitivity to the punisher ratios were unaffected by changes in discriminability, supporting the assumption of parameter invariance in the Davison and Tustin (1978) model of signal detection. Overall, the present experiment found no relation between stimulus control and punisher control, and provided further evidence for similar but opposite effects of punishers to reinforcers in signal-detection procedures.     

Chapter 2: Sex and the Elderly: No Laughing Matter in Religion

SUMMARY

This article provides a brief background for the study of sex and older persons. It examines the prevailing attitudes among older persons and society in general. A number of critical issues regarding sexuality in the latter years of life is addressed.     

Perception of relative depth interval: Systematic biases in perceived depth

Given an estimate of the binocular disparity between a pair of points and an estimate of the viewing distance, or knowledge of eye position, it should be possible to obtain an estimate of their depth separation. Here we show that, when points are arranged in different vertical geometric configurations across two intervals, many observers find this task difficult. Those who can do the task tend to perceive the depth interval in one configuration as very different from depth in the other configuration. We explore two plausible explanations for this effect. The first is the tilt of the empirical vertical horopter: Points perceived along an apparently vertical line correspond to a physical line of points tilted backwards in space. Second, the eyes can rotate in response to a particular stimulus. Without compensation for this rotation, biases in depth perception would result. We measured cyclovergence indirectly, using a standard psychophysical task, while observers viewed our depth configuration. Biases predicted from error due either to cyclovergence or to the tilted vertical horopter were not consistent with the depth configuration results. Our data suggest that, even for the simplest scenes, we do not have ready access to metric depth from binocular disparity.     

Stereo disparity facilitates view generalization during shape recognition for solid multipart objects

Current theories of object recognition in human vision make different predictions about whether the recognition of complex, multipart objects should be influenced by shape information about surface depth orientation and curvature derived from stereo disparity. We examined this issue in five experiments using a recognition memory paradigm in which observers (N = 134) memorized and then discriminated sets of 3D novel objects at trained and untrained viewpoints under either mono or stereo viewing conditions. In order to explore the conditions under which stereo-defined shape information contributes to object recognition we systematically varied the difficulty of view generalization by increasing the angular disparity between trained and untrained views. In one series of experiments, objects were presented from either previously trained views or untrained views rotated (15°, 30°, or 60°) along the same plane. In separate experiments we examined whether view generalization effects interacted with the vertical or horizontal plane of object rotation across 40° viewpoint changes. The results showed robust viewpoint-dependent performance costs: Observers were more efficient in recognizing learned objects from trained than from untrained views, and recognition was worse for extrapolated than for interpolated untrained views. We also found that performance was enhanced by stereo viewing but only at larger angular disparities between trained and untrained views. These findings show that object recognition is not based solely on 2D image information but that it can be facilitated by shape information derived from stereo disparity.     

Integration of motion parallax with binocular disparity specifying different surface shapes

We investigated the interaction between motion parallax and binocular disparity cues in the perception of surface shape and depth magnitude by the use of the random dot stimuli in which these cues specified sinusoidal depth surfaces undulating with different spatial frequencies. When ambiguous motion parallax is inconsistent with unambiguous disparity cue, the reasonable solution for the visual system is to convert the motion signal to the flow on the surface specified by disparity. Two experiments, however, found that the visual system did not always use this reasonable solution; observers often perceived the surface specified by a composite of the two cues, or the surface specified by parallax alone. In the perception of this composite of the two cues, the apparent depth magnitude increased with the increase of the depth magnitude specified by both cues. This indicates that the visual system can combine the depth magnitude information from parallax and disparity in an additive fashion. The interference with parallax by disparity implies that the parallax processing is not independent of the disparity processing.     

复杂图形的双眼视差敏感性

该研究用心理物理学实验方法,以能正确分辨图形在深度上起伏周期数的多少作为判据,检测了七名被试的体视性能。实验结果表明,被试者观看复杂图形的视差敏感性是和图形在深度上变化的复杂程度有关。如果以视差作纵坐标,以图形在深度起伏频率为横坐标,则其深度感知的范围是一个区域,该区域的频率变化范围是从０．１周／度到４周／度,当深度变化频率大于４周／度,则无深度感知。七名被试的双眼深度敏感区有个体差异,但其区域的形状是相似的。     

团队权力分布差异对团队冲突的影响：程序公平和合法性的作用

近年来团队权力分布差异与团队冲突间关系受到了学界较大关注, 但相关研究结果仍存在分歧。通过对70个工作团队的调查, 探讨了团队权力分布差异对团队冲突(任务冲突、关系冲突)作用的边界条件。结果发现, 程序公平调节了两者间关系：当程序公平较高时, 团队权力分布差异与任务冲突、关系冲突负相关; 当程序公平较低时, 团队权力分布差异与任务冲突、关系冲突正相关。此外, 被中介的调节模型分析显示, 团队合法性感知中介了程序公平的上述调节作用。     

对恶性肿瘤性别差异的再认识

恶性肿瘤性别差异表现在发病率、预后、治疗等多方面。生理结构、生活方式、工作、性格等流行病学因素是造成恶性肿瘤性别差异的外因,性激素及其受体研究在一定程度上解释了性别差异的本质,且为恶性肿瘤的内分泌治疗提供了理论依据。随着分子生物学技术发展,基因多态、分子突变等深入研究成果揭示更深层次的原因。