Within-session Analysis Of Visual Discrimination

Within-session changes in responding by pigeons during a maintained successive discrimination procedure were examined in four experiments. In the first two experiments, which involved discrimination of visual flicker rate, within-session changes in responding were minimal or absent. A third experiment, which examined discrimination of rectangular forms, demonstrated that the absence of within-session changes in responding was not limited to flicker-rate stimuli. A fourth experiment showed that the absence of within-session changes in responding was not due to high task difficulty in the previous experiments. For the group of subjects in each experiment, within-session changes in responding did not influence discrimination performance. Therefore, measures of overall response rate accurately represented responding both within and across sessions. The occasional appearance of within-session decreases in responding for a few birds may be attributable to satiation.     

Change mechanisms in cognitive therapy of a simple phobia: Logical analysis and empirical hypothesis testing

The effectiveness of two hypothesized change mechanisms in cognitive therapy was investigated: logical analysis and empirical hypothesis testing. Thirty-eight spider phobics, as determined by performance on a behavioral avoidance test, were randomly assigned to either one of these two conditions or to a no-treatment control condition. Subjects participated in three group sessions. Outcome phobia questionnaire data suggested that both mechanisms produced desirable changes in a short period of time, with stronger evidence that logical analysis was superior to the control. Outcome from the behavior avoidance test and self-efficacy ratings failed to reach statistical significance but the trends were in the direction of positive change. Results are discussed in terms of the tripartite response dessynchrony hypothesis. Suggestions for future process research in cognitive therapy are provided.William O'Donohue, Ph.D., is an assistant professor of psychology at Northern Illinois University.Jeff Szymanski is a graduate student in clinical psychology at Northern Illinois University.The authors would like to thank Christine Casselles, Melissa McKelvie, Thomas M. Brown, Jill C. Rudman, Bonnie Schrieber, Amy Ray, Anne Valle, Lisa Herold, Jacqueline Ryan, Heather Barta, and Angela Leek for their assistance in this project. Moreover, the authors are grateful to Sol Feldman and Jane Fisher for their comments on an earlier version of this paper.     

Effects of reinforcing preselected approximations on the topography of the rat's bar press

The effects of different shaping approximations on the topography of the rat's bar press were investigated in two experiments. Behavior was classified into discrete components, and changes in components and their sequential organization were analyzed. Experiment 1 examined response form early in training and found that specific components reinforced during shaping were incorporated into press sequences. Experiment 2 investigated how response form changed when a shaping contingency was relaxed later in training. Two topographies were selected for reinforcement, and both appeared in the press sequences of all subjects by the end of shaping. Subsequently, all variations of bar pressing were reinforced, and neither topography was necessary to satisfy the contingency. Although the frequency of the topographies reinforced during shaping declined for 3 of 4 subjects during this phase, the most frequent press sequence for 2 rats at the end of training included both unnecessary topographies. Variability in press topographies declined when all emitted variants were reinforced. However, all subjects emitted novel response forms throughout training. The results demonstrate that specific response-reinforcer contingencies influence response form by modulating component availability and organization.     

Rod suppression of cone-mediated information about colour and form during dark adaptation

Following substantial bleaches, the specific form and hue thresholds were measured during dark adaptation with a test stimulus of 1 x 2 degrees at 40 degrees extrafoveally. The wavelength of the test field was varied between runs. The results show that both thresholds started to rise at about the cone-rod break of the dark-adaptation curve, irrespective of wavelength used in the test. Furthermore, the specific threshold for form was found to rise when a scotopic stimulus was superimposed on a photopic test flash. On the other hand, both thresholds remained at the cone-plateau level when the test flash was confined within the rod-free fovea. In order to explain the rise in the specific thresholds, it is suggested that signals from rods generated directly in response to the test stimulus may suppress both cone-mediated form and colour. It is also suggested that this type of rod-cone interaction represents a general characteristic involved in several kinds of visual information processing.     

Does the Traditional Treatment of Enthymemes Rest on a Mistake?

In many actual arguments, the conclusion seems intuitively to follow from the premisses, even though we cannot show that it follows logically. The traditional approach to evaluating such arguments is to suppose that they have an unstated premiss whose explicit addition will produce an argument where the conclusion does follow logically. But there are good reasons for doubting that people so frequently leave the premisses of their arguments unstated. The inclination to suppose that they do stems from the belief that the only way in which an argument's conclusion can follow definitely from its premisses is to follow logically. I argue that this belief is mistaken. I propose a revision of the current generic conception of logical consequence, and its variant specifications, to avoid the paradoxes of strict implication. The revised conception can then be naturally extended to include also what we might call 'enthymematic consequence'. This concept is a kind of consequence, whose properties merit investigation.     

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.     

汉语语句句式表征及命题表征能力的年龄比较

通过三个年龄段的被试对同命题不同句式汉语语句再认的比较,以再认比率和再认反应时为指标,探讨了句子在记忆中的表征问题。研究结果表明：（１）命题表征是一种原始倾向,既不同于记忆准确性的年龄发展,它在性质上又区别于记忆误差。把句式表征与命题表征分化开是后天发展的结果;（２）命题表征的建立和巩固需要时间,但一经建立,巩固性较强。相反,句式表征的巩固性较差。     

V.A. Smirnov’s Results in the Field of Modern Formal Logic

This paper is a survey of V.A. Smirnovs main results in modern logic.     

奏鸣曲式中调性结构对紧张感的影响——以莫扎特与贝多芬钢琴奏鸣曲为例

音乐紧张感是音乐聆听的基础与重要环节。本研究选取莫扎特与贝多芬的音乐作品, 运用紧张感模型计算与行为实验两种方法, 探讨奏鸣曲式中的调性结构对紧张感的影响。研究发现, 奏鸣曲中呈示部、展开部与再现部三部分的紧张感变化具有差异, 展开部的紧张感高于呈示部与再现部, 再现部的紧张感高于呈示部, 这源于转调距离与转调频率的差异。本研究探讨了在大尺度的真实音乐作品中调性结构对紧张感的影响, 为音乐学领域的研究提供佐证和新的视角。     

镜像等效或守恒及其打破：从行为到认知神经机制的研究证据

镜像等效或守恒是动物与人类个体对两侧对称自然物体的一种进化自适应加工。但是, 这种知觉特性会妨碍包含镜像字符的文字阅读学习。阅读者有必要学会利用镜像泛化抑制的“去学习”机制, 打破镜像等效或守恒, 以获得识别镜像字符的能力。这一过程中, 左侧梭状回皮层通过与早期视觉皮层、顶叶皮层和口语脑网络的交互作用, 逐渐发展出一个可以识别镜像字符的视觉词形区(visual word form area, VWFA)。今后的研究需要关注两半球及其连合纤维在镜像等效或守恒加工中的作用、镜像泛化与抑制的详尽加工机制及其对镜像书写的影响、正常汉语儿童的汉字镜像泛化加工等问题。