EFFECTS OF EQUAL AND UNEQUAL REINFORCER DURATION DURING FUNCTIONAL ANALYSIS

In the functional analysis described by Iwata, Dorsey, Slifer, Bauman, and Richman (1982/1994), reinforcer duration varied across conditions (e.g., brief attention vs. 30 s of escape); this may result in unequal exposure to the establishing operations for aberrant behavior. In this study, we compared the effects of unequal and equal reinforcer duration during a functional analysis. The results showed that reinforcer duration affects the rate of aberrant behavior and may potentially alter functional analysis interpretation.     

Separating The Effects Of Trial-specific And Average Sample-stimulus Duration In Delayed Matching To Sample In Pigeons

Pigeons were studied in two experiments employing delayed matching-to-sample (DMTS) tasks in which the reduction in delay to reinforcement signaled by the onset of the sample stimulus was manipulated by varying sample-stimulus duration. In Experiment 1, the duration of the sample stimulus was either 5 s or 10 s for one sample stimulus and 10 s or 20 s for the other. Subjects matched more frequently when the sample duration was 10 s following the sample associated with the shorter average duration. This finding is analogous to the memory distribution effect found by Honig (1987) in a successive DMTS task that varied retention interval. In Experiment 2, sample duration was either 5 s or 15 s. In Phases 1 and 3 each sample duration was correlated with a particular sample color, and in Phase 2 sample duration and color were uncorrelated. When sample duration was 5 s, subjects matched more frequently when sample duration and color were correlated than when they were uncorrelated. Overall, subjects matched more frequently when sample duration and color were correlated. The data from both experiments support Wixted's (1989) model, which states that one determinant of choice in a DMTS task is the delay-reduction value of the sample stimulus.     

Delayed matching-to-sample performance of hens: Effects of sample duration and response requirements during the sample

Six domestic hens were trained under a delayed matching-to-sample procedure with red and green keylights as sample and comparison stimuli and a 1.5-s delay interval. The hens were trained to stop pecking the sample stimuli when a tone sounded. Duration of the sample stimuli (2 to 10 s) and the number of pecks required on the key on which these stimuli were presented (0 to 10) were altered across conditions. Both the response requirement on the sample key and the duration of sample presentations affected accuracy. These findings are in agreement with those of earlier studies using other species and somewhat different procedures.     

Techniques for establishing schedules with wheel running as reinforcement in rats.

In three experiments, access to wheel running was contingent on lever pressing. In each experiment, the duration of access to running was reduced gradually to 4, 5, or 6 s, and the schedule parameters were expanded gradually. The sessions lasted 2 hr. In Experiment 1, a fixed-ratio 20 schedule controlled a typical break-and-run pattern of lever pressing that was maintained throughout the session for 3 rats. In Experiment 2, a fixed-interval schedule of 6 min maintained lever pressing throughout the session for 3 rats, and for 1 rat, the rate of lever pressing was positively accelerated between reinforcements. In Experiment 3, a variable-ratio schedule of 20 or 35 was in effect and maintained lever pressing at a very stable pace throughout the session for 2 of 3 rats; for 1 rat, lever pressing was maintained at an irregular rate. When the session duration was extended to successive 24-hr periods, with food and water accessible in Experiment 3, lever pressing settled into a periodic pattern occurring at a high rate at approximately the same time each day. In each experiment, the rats that developed the highest local rates of running during wheel access also maintained the most stable and highest rates of lever pressing.     

学前儿童对时距的估计及其策略

该研究旨在探查学前儿童对时距的认识过程及其认识策略。使用2秒、4秒、6秒、8秒四种不同的时间间隔作为刺激物,在每次呈现之后要求儿童按键再现时距。5岁和6岁的学前儿童参加这一实验。主要结果表明:5、6岁儿童已能区分只有几秒钟差异的单一时距;在无声音参照条件下,他们对4秒钟的估计较为准确,而在有声音参照条件下,5岁儿童则对6秒钟的估计更趋准确。研究材料还证实了,儿童从5岁起初步能够使用时间标尺,开始把时间看成是可以计数的维量。     

IRT中最小化χ2/EM参数估计方法

对IRT的双参数Logistic模型（2PLM）中未知参数估计问题,给出了一个新的估计方法――最小化χ2/EM估计。新方法在充分考虑项目反应理论(IRT)与经典测量理论(CTT)之间的差异的前提下,从统计计算的角度改进了Berkson的最小化χ2估计,取消了Berkson实施最小化χ2估计时需要已知能力参数的不合实际的前提,扩大了应用范围。实验结果表明新方法能力参数的估计结果与BILOG相比,精确度要高,且当样本容量超过2000时,项目参数的估计结果也优于BILOG。实验还表明新方法稳健性好     

时距的短时保持: 缩短还是变长

采用Wearden和Ferrara(1993)的经典方法, 分别考察了1s以下(350 ms~650 ms)和1s以上(1000 ms ~ 2000 ms)不同类型(空、实时距)和通道(视、听)时距的短时保持效应。实验1发现, 不同刺激通道条件下, 1s以下时距的短时保持都呈现出主观缩短, 其中视觉条件比听觉条件明显; 实验2表明, 1s以上时距在不同刺激通道条件下都呈现出主观变长, 其中听觉条件比视觉条件明显。分析表明, 主观缩短趋势可能是由主观缩短效应和正的顺序误差效应共同作用所致, 而主观变长趋势是由主观变长效应和负的顺序误差效应造成的。     

状态焦虑对回溯式时距判断的影响：认知评价和记忆偏向有调节的中介作用

探讨状态焦虑对回溯式时距判断的影响, 并检测记忆偏向与认知评价在其中的中介和调节作用。实验1招募大学生60人, 随机分为高、低状态焦虑组, 采用情绪诱导程序诱导高、低状态焦虑; 采用口头估计任务测量回溯式时距判断, 考察高、低状态焦虑诱导后的回溯式时距判断差异。实验2在实验1的基础上, 招募大学生60人, 增加自由回忆任务测量记忆偏向, 考察状态焦虑对回溯式时距判断的影响中记忆偏向的中介作用。实验3在实验1和实验2的基础上, 招募大学生90人, 增加视觉模拟心境量表测量认知评价, 考察状态焦虑对回溯式时距判断的影响, 并检测认知评价与记忆偏向在其中的作用。结果发现：(1)在回溯式时距判断中, 高状态焦虑比低状态焦虑更高估时距; (2)在状态焦虑对回溯式时距判断的影响中, 记忆偏向具有中介作用; (3)在状态焦虑对回溯式时距判断的影响中, 认知评价和记忆偏向存在有调节的中介作用：只有当认知评价得分较低时, 即对于认为焦虑对身体健康有害程度较低的个体而言, 在状态焦虑影响回溯式时距判断中, 记忆偏向具有完全中介作用, 即状态焦虑只通过记忆偏向影响回溯式时距判断。研究结果揭示了焦虑个体回溯式时距判断的内部过程, 验证了注意闸门模型中有关用于计时的记忆资源越多对于时距越高估的假设, 丰富了焦虑通过记忆偏向影响回溯式时距判断的解释视角, 为通过调整认知评价改善焦虑个体时距偏差提供了重要参考。     

Eye movement control during scene viewing: Immediate degradation and enhancement effects of spatial frequency filtering

What controls how long the eyes remain fixated during scene perception? We investigated whether fixation durations are under the immediate control of the quality of the current scene image. Subjects freely viewed photographs of scenes in preparation for a later memory test while their eye movements were recorded. Using the saccade-contingent display change method, scenes were degraded (Experiment 1) or enhanced (Experiment 2) via blurring (low-pass filtering) during predefined saccades. Results showed that fixation durations immediately after a display change were influenced by the degree of blur, with a monotonic relationship between degree of blur and fixation duration. The results also demonstrated that fixation durations can be both increased and decreased by changes in the degree of blur. The results suggest that fixation durations in scene viewing are influenced by the ease of processing of the image currently in view. The results are consistent with models of saccade generation in scenes in which moment-to-moment difficulty in visual and cognitive processing modulates fixation durations.     

Cognitive control of fixation duration in visual search: The role of extrafoveal processing

Participants' eye movements were monitored in two visual search experiments that manipulated target-distractor similarity (high vs. low) as well as the availability of distractors for extrafoveal processing (Free-Viewing vs. No-Preview). The influence of the target-distractor similarity by preview manipulation on the distributions of first fixation and second fixation duration was examined by using a survival analysis technique which provided precise estimates of the timing of the first discernible influence of target-distractor similarity on fixation duration. We found a significant influence of target-distractor similarity on first fixation duration in normal visual search (Free Viewing) as early as 26–28 ms from the start of fixation. In contrast, the influence of target-distractor similarity occurred much later (199–233 ms) in the No-Preview condition. The present study also documented robust and fast acting extrafoveal and foveal preview effects. Implications for models of eye-movement control and visual search are discussed.