两种参照作用下的视觉定位

本实验采用多点视觉定位作业,研究视觉定位中的两种参照对定位成绩的影响。实验采用一些附加线条与三个刺激形成有特征的刺激图和无特征的刺激图,并与没有附加线条的情况进行了比较。有特征的刺激图是指这些附加的线条与刺激点构成一定的特征,如一个字母或图形等;无特征的刺激图指刺激点不能与附加线条构成有规律的特征。结果发现,当有附加线条的图形呈现时,被试的定位误差大于控制组,表现出一级参照对视觉定位的干扰作用,而且在呈现时间为100ms、200ms、300ms时,都是如此。在有特征组内,不同的特征对定位精确性的影响依赖于时间因素。     

风险决策中的参照点效应研究

本研究以展望理论和社会决策范式模型为基础,着重探讨三种参照点对个体和群体风险决策产生的影响。３００名被试经实验者设置参照点后分别在个体和群体条件下对不同风险度的博弈方案进行选择。结果表明：（１）个体决策中,损失参照点的被试和无得失经验者比得益者更冒险;（２）得益被试的决策受到社会比较的影响;（３）损失参照点的被试并未对群体决策有更大影响,决定群体决策结果的主要是多数原则。     

汉字内隐记忆的实验研究（Ⅱ）：任务分离和反应倾向

在实验Ｉ的基础上,操纵学习时的呈现时间（２５０ｍｓ,５００ｍｓ,７５０ｍｓ）和注意变量（目标和非目标字）,运用任务分离方法及间接证明逻辑,比较了再认测验和整字偏好测验在不同条件下的辨别力（Ａ′）和反应倾向（Ｂ″）。结果：（１）双向功能分离的出现表明再认测验和偏好测验存在本质差异。根据“过程纯净”假设,可以推证内隐记忆存在于偏好测验中。此时,匹配比较法的标准未满足。（２）偏好测验中,５００ｍｓ呈现目标字时,有显著正向启动效应：７５０ｍｓ呈现非目标字时,有显著负向启动效应。（３）内隐记忆和外显记忆发生时,都具有稳定的心理状态。但是前者的报告标准较松宽,而后者的较严格。     

多点触觉定位

在左手食指第一节腹侧分别进行1个点、2个点和3个点的定位实验,探讨了多点定位的特点。实验发现,按单个点的定位误差来计算．1个点和3个点的定位误差无显著差异,且二者均显著地低于2个点的定位误差;在2个点的定位中,一个点的定位误差是此2个点的空间距离的函数．定位误差有随距离加大而增加的趋势;在3个点的定位中．同一个点在不同的3点组台中的定位误差无显著差异。结果指示,多点触觉定位除以受刺激的躯体部位框架为参照（基本参照）外,还受到诸刺激点构成的刺激模式（次级参照）的影响。     

人格特质对选择性加工偏向的影响

采用词性辨别和注意探测任务,考察了神经质和外倾性对选择性加工偏向的影响。结果表明：（1）放试在选择信息时存在特质一致性倾向;（2）在单一刺激条件下,当刺激词呈现时间为0．5s时,高神经质对所有效价词的RT均快于低神经质;而当呈现时间为1．0s时,外倾者比内倾者的反应潜伏期更短4（3）双重刺激条件下的选择性加工偏向比单一刺激条件更明显;（4）在词性辨别任务中．刺激词呈现时间只影响了神经质被试对情绪词的RT;在注意探测任务中,呈现时间对内外倾被试的加工偏向影响不显著。     

与立体视觉相关的视诱发电位研究

在微机上编制能产生动态随机点立体图（ＤＲＤＳ）,亮暗类棋盘格和随机点背景三种图形刺激的软件．记录了３４例正常人在这三种刺激下的ＶＢＰ．其结果为：（１）ＤＲＤＳ刺激下的ＶＥＰＮ１波潜伏期为２６５±２５ｍｓ,基波能量占总交流能量的６３．２±１８．９％．（２）亮暗类棋盘格刺激下的ＶＥＰＮ１波的潜伏期为１９０±２２ｍｓ,基波能量占总交流能量的３９．２±１９．６％．（３）随机点背景刺激下的ＶＥＰ波则为一些杂乱的小波．结果提示：动态ＲＤＳ刺激下的ＶＥＰ除在潜伏期方面具有特异性外,并在谐波的能量分布上也具有特异性,且客观性更强．根据这些特征有助于对立体视觉功能进行客观性评价．     

短时距知觉中的面积效应

初步探讨了短时距（１─５ｓ）下时距刺激的面积大小和立体框架大小对时距知觉的影响及其成因。结果表明：刺激的面积大小对短时距知觉的影响极其显著;存在两种不同反应类型的被试─－大小依存者与非大小依存者,在不同反应类型的被试中刺激的立体框架大小对短时距知觉的影响不同,刺激的立体框架大小对大小依存者的短时距知觉的影响极其显著,但对非大小依存者的影响不显著。     

重复启动作业中词的语义透明度的作用

用词素重复启动的方法考察合成词的心理表征。目标刺激为２４个语义透明度词、２４个不透明词以及４８个非词（都是两个字）。启动刺激有５种：（１）目标词本身,（２）目标词的第一词素,（３）目标词的第二词素,（４）由目标词的两个词素颠倒后形成的非词,（５）包含目标词的一个词素的非词。启动刺激的呈现时间是１００毫秒,随后是目标刺激４００毫秒。被试的任务是尽快准确地按键判断目标刺激是否是一个词。研究发现,（２）、（３）、（５）条件下的重复启动中,透明度表现出显著的效应：透明词的启动量显著大于不透明词。结果支持合成词的表征受语义透明度的影响,透明词和不透明词的词素和整词在心理表征中的关系可能不同：前者是一种兴奋性的连接,后者是一种抑制性的连接。     

多参照系条件下信息获取方式对绝对方位判断的影响

把参照系整合基础上的绝对方位判断分解成路径获取过程（目标位置信息）、自身定向过程（前行方向信息）和物体定位过程（目标物体相对于参照物体的方位信息）,系统地考察了多参照系条件下信息获取方式对该任务的影响。研究以视觉形式呈现空间信息,实验1a和1b的任务中均包括上述三个过程,前者以地图的形式呈现前行方向信息、后者以语词的形式直接呈现前行方向信息;实验2有两个任务,分别独立于路径描述（定位后判断）和自身定位（定向后判断）。所有任务均为目标位置（R0o－前、R45o－左前/右前、R90o－左/右、R135o－左后/右后, R180o－后）×前行方向（北、东南西、斜方向）的组内设计、因变量为正确率和判断时间为主,共有64名大学生被试（男女各半）参与实验。发现：0o和180o位置优势效应、朝北优势效应在所有任务中都很明显;实验1和定向后判断任务中存在正方向R90o位置优势效实;定位后判断时间短于定向后判断时间,但总体所用时间上没有差异。结合信息获取的方式和可能使用到的判断策略,从绝对方位判断的认知结构上展开了讨论。     

自我参照框架决定了自我面孔优势效应的出现

研究使用外显面孔再认实验(实验一)和内隐面孔感知实验(实验二)检验自我参照框架是否是自我面孔加工优势出现的决定性因素这一假设。具有不同朝向(左或右)的被试自己面孔和朋友面孔呈现在视野中央, 实验一中, 被试的任务为参照自我框架(观察者角度)或他人框架(被观察的像的角度)判断自我面孔的朝向(忽视朋友面孔), 或者判断朋友面孔的朝向(忽视自我面孔); 实验二中, 被试的任务为参照自我框架或他人框架判断所有面孔的朝向。结果表明：自我参照框架促进自我面孔加工优势的出现, 而他人参照框架消减自我面孔优势, 这种效应稳定地存在于外显和内隐两项任务中。并且, 自我参照框架对自我优势效应的促进作用不依赖于面孔刺激背景。     

Selecting spatial frames of reference for visual target localization

This study examined the selection of spatial frames of reference for target localization in visual search. Participants searched for local target characters in global character configurations. The local targets could be localized relative to the character configuration in which they were embedded or relative to the presentation screen on which the configurations were displayed. We investigated under which conditions the configurations, or the screen served as frame of reference for target localization. Three experiments revealed an increasing impact of screen-related target localization with decreasing spatial uncertainty of targets in screen-related coordinates. The results indicate the capability of the visual system to localize relevant visual stimuli with respect to those frames of reference that yield the most redundant spatial distribution of these stimuli.     

刺激结构对视觉定位的影响

本实验采用多点定位作业,结合部分报告法,研究视觉刺激的整体结构对定位成绩的影响。所呈现的刺激为1、2、3或4个颜色点。其中2、3、4点刺激分别是直线、正三角形和正方形。结果发现,当呈现时间较长时,1点和2、3、4点的定位误差无显著差异。但是1点的定位反应时却显著少于2、3、4点。这提示出现视觉定位的结构效应。而当呈现时间较短时,却没有这种结构效应。实验还发现,这种结构效应并不因刺激结构的不同而有区别。     

听障和听力正常人群空间主导性和空间参照框架的交互作用

通过要求被试分别在近处空间和远处空间完成空间参照框架的判断任务, 考察了听障和听力正常人群空间主导性和空间参照框架的交互作用。结果表明：(1)相对于听力正常人群, 听障人群完成自我参照框架判断任务的反应时更长, 而在完成环境参照框架判断任务无显著差异; (2)听障人群和听力正常人群空间主导性和空间参照框架交互作用呈现出相反模式。研究表明, 听障人群在听力功能受损后, 其空间主导性和空间参照框架的交互作用也产生了变化。     

Benefits of interhemispheric collaboration can be eliminated by mixing stimulus formats that involve different cortical access routes

Previous studies indicate that the benefits of dividing an information processing load across both cerebral hemispheres outweigh the costs of interhemispheric transfer as tasks become more difficult or cognitively complex. This is demonstrated as better performance when two stimuli to be compared are presented one to each visual field and hemisphere than when both stimuli are presented to the same single hemisphere (an across-hemisphere advantage). Two experiments indicate that this finding does not generalize to complex tasks that require matching numeric quantities represented by two very different visual formats whose processing involves somewhat different cortical areas: digits and dice-like dot patterns. In fact, mixing these stimulus formats consistently produces a within-hemisphere advantage. We propose that, when two simultaneously presented stimuli are presented in sufficiently different visual formats, identification of the two stimuli may take place in parallel, via different cortical access routes and with little or no interference, even when they are presented to the same cerebral hemisphere.     

The relationship between allocentric and egocentric frames of reference and categorical and coordinate spatial information processing

We report two experiments on the relationship between allocentric/egocentric frames of reference and categorical/coordinate spatial relations. Jager and Postma (2003) suggest two theoretical possibilities about their relationship: categorical judgements are better when combined with an allocentric reference frame and coordinate judgements with an egocentric reference frame (interaction hypothesis); allocentric/egocentric and categorical/coordinate form independent dimensions (independence hypothesis). Participants saw stimuli comprising two vertical bars (targets), one above and the other below a horizontal bar. They had to judge whether the targets appeared on the same side (categorical) or at the same distance (coordinate) with respect either to their body-midline (egocentric) or to the centre of the horizontal bar (allocentric). The results from Experiment 1 showed a facilitation in the allocentric and categorical conditions. In line with the independence hypothesis, no interaction effect emerged. To see whether the results were affected by the visual salience of the stimuli, in Experiment 2 the luminance of the horizontal bar was reduced. As a consequence, a significant interaction effect emerged indicating that categorical judgements were more accurate than coordinate ones, and especially so in the allocentric condition. Furthermore, egocentric judgements were as accurate as allocentric ones with a specific improvement when combined with coordinate spatial relations. The data from Experiment 2 showed that the visual salience of stimuli affected the relationship between allocentric/egocentric and categorical/coordinate dimensions. This suggests that the emergence of a selective interaction between the two dimensions may be modulated by the characteristics of the task.     

An oblique effect in aesthetics: homage to Mondrian (1872-1944)

The effect of the orientation of Mondrian's paintings on their aesthetic appeal was examined. Eight paintings, four with horizontal/vertical frames in the original and four with oblique frames, were presented in eight different orientations and rated for aesthetic appeal on a 7-point scale. There was a stronger preference for pictures presented so that their component lines were horizontal and vertical than for pictures presented with their component lines in an oblique orientation. In addition, subjects showed a preference for the original orientation, perhaps because rotation changes the lateral balance of the paintings as well as the orientation of the component lines. There was no overall preference for one frame orientation over another, but there was an interaction between frame orientation and component orientation, resulting in a preference for paintings where the components were parallel to the surrounding frame. It is suggested that the aesthetic oblique effect reported here is related to the oblique effect in orientation perception and the privileged access which horizontal and vertical lines have to the visual system. This offers a possible mechanism for aesthetic judgments of abstract patterns: we find pleasing those stimuli which are closely tuned to the properties of the human visual system.     

Matching cue size and task properties in exogenous attention

Exogenous attention is an involuntary, reflexive orienting response that results in enhanced processing at the attended location. The standard view is that this enhancement generalizes across visual properties of a stimulus. We test whether the size of an exogenous cue sets the attentional field and whether this leads to different effects on stimuli with different visual properties. In a dual task with a random-dot kinematogram (RDK) in each quadrant of the screen, participants discriminated the direction of moving dots in one RDK and localized one red dot. Precues were uninformative and consisted of either a large or a small luminance-change frame. The motion discrimination task showed attentional effects following both large and small exogenous cues. The red dot probe localization task showed attentional effects following a small cue, but not a large cue. Two additional experiments showed that the different effects on localization were not due to reduced spatial uncertainty or suppression of RDK dots in the surround. These results indicate that the effects of exogenous attention depend on the size of the cue and the properties of the task, suggesting the involvement of receptive fields with different sizes in different tasks. These attentional effects are likely to be driven by bottom-up mechanisms in early visual areas.     

The relationship between space and time in the perception of stimuli moving behind a slit

When a shape defined by a set of dots plotted along its contour is presented in a sequence of frames within the boundaries of a slit, and in each frame only one dot (featureless frame) or two dots (feature frame) are displayed, a whole moving dotted shape is perceived. Masking techniques and psychophysical measures have been used to show that a dynamic random-dot mask interferes with shape identification, provided the interframe interval is greater than about 15 ms, and there are no stimulus features for recognition in individual frames. A similar pattern of results was obtained when the observer had only to detect the movement of a single dot or a pair of dots against a dynamic-noise background. It is concluded that the visual system can resolve the correspondence problem in both apparent movement (one moving dot) and aperture viewing (featureless-frame condition) by extracting motion before the extraction of features in each frame. However, the results also show that where feature identification in each frame is possible, it can also be used to identify the moving targets.     

How chimpanzees (<Emphasis Type="Italic">Pan troglodytes</Emphasis>) perform in a modified emotional Stroop task

The emotional Stroop task is an experimental paradigm developed to study the relationship between emotion and cognition. Human participants required to identify the color of words typically respond more slowly to negative than to neutral words (emotional Stroop effect). Here we investigated whether chimpanzees (Pan troglodytes) would show a comparable effect. Using a touch screen, eight chimpanzees were trained to choose between two simultaneously presented stimuli based on color (two identical images with differently colored frames). In Experiment 1, the images within the color frames were shapes that were either of the same color as the surrounding frame or of the alternative color. Subjects made fewer errors and responded faster when shapes were of the same color as the frame surrounding them than when they were not, evidencing that embedded images affected target selection. Experiment 2, a modified version of the emotional Stroop task, presented subjects with four different categories of novel images: three categories of pictures of humans (veterinarian, caretaker, and stranger), and control stimuli showing a white square. Because visits by the veterinarian that include anaesthetization can be stressful for subjects, we expected impaired performance in trials presenting images of the veterinarian. For the first session, we found correct responses to be indeed slower in trials of this category. This effect was more pronounced for subjects whose last anaesthetization experience was more recent, indicating that emotional valence caused the slowdown. We propose our modified emotional Stroop task as a simple method to explore which emotional stimuli affect cognitive performance in nonhuman primates.     

The influence of the acoustic context on vertical sound localization in the median plane

The influence of background sounds (frames) on vertical localization of single sound sources (targets) was examined in four experiments. Loudspeakers (five targets and four frames) were positioned in the median plane, ranging from +30 degrees to -30 degrees above and below the subject's ear level. The subjects determined the vertical position of the targets by either verbal judgments or manual pointing. Frame and target sounds were presented concurrently or successively with a 1-sec interval; both consisted of (1) 300-Hz square waves, (2) noise, or (3) targets of noise and frames of 300-Hz square waves. Particularly in the second condition, the subjects consistently shifted the apparent target positions away from the frame locations. This contrast effect persisted even 1 sec after the offset of the frames. No effect was found with different waveforms for the frame and the target. Results are related to recent findings indicating a similar effect in the azimuthal dimension. Possibly the effect is based on a mechanism in which the auditory system adapts to recently heard sound source positions.