Temporal reproduction

A signal appeared for a certain time period. After the period elapsed, pigeons had to begin and complete a sequence of 15 responses in a time window ranging from the signal duration to 50% longer. Sessions involved as many as 10 different signal durations occurring in a random sequence. The times produced by pigeons often were in the same ranges as those that have been found with adult human subjects. The average times were described equally well as linear or power functions of signal duration. However, instead of the overestimation of durations usually found when animals have timed the duration of antecedent stimuli, the linear functions suggested that the pigeons underestimated the durations of their own behavior. The birds showing the strongest control when the conditions involved eight or 10 different duration requirements revealed the constant coefficients of variation that support Weber's law and scalar timing theory. Scalar timing in temporal differentiation appears to depend on non-ambiguous information about the duration required for reinforcement and on a high degree of sensitivity to the duration requirement.     

儿童青少年大脑认知功能事件相关电位P_（300）的年龄特征

从发展心理学的角度．对幼儿到大学六个年龄组的儿童青少年进行了事件相关电位Ｐ_（３００）测定．结果发现：反映大脑认知功能的事件相关电位Ｐ_（３００）各成分随着年龄增长而发展的趋势十分明显,从而进一步说明了认知发展的特点与大脑高级神经系统活动功能发展特点的密切关系。     

The effects of varying the distribution of generalization stimuli within a constant range upon the bisection of a sound-intensity interval by rats

Two male, albino rats were trained on a two-valued, self-paced, discrete-trials auditory discrimination. In the presence of a high-intensity stimulus (90 decibels SPL, 4 kiloHertz), response A was reinforced; in the presence of a low-intensity stimulus (50 decibels SPL, 4 kiloHertz), response B was reinforced. When discrimination performance was asymptotic, stimuli intermediate in intensity were presented with the training stimuli in a maintained generalization paradigm. Generalization gradients were derived from the relative frequencies of response A in the presence of each stimulus. A relative frequency of 0.50 was then determined and used as the bisection point of the intensity interval defined by the 90- and 50-decibel stimuli. The bisection point varied with the distribution of the stimuli presented in generalization. This effect was similar to context effects seen in human psychophysics.     

Conditioning of within-trial patterns of key pecking in pigeons

The possibility of conditioning systematic patterns of responding during brief discrete trials was studied by requiring hungry pigeons to key peck and then pause or to pause and then key peck in order to gain access to food. These schedules were highly effective in promoting decelerated and accelerated rates of responding, respectively, within individual trials; indeed, performance was quite similar to that observed when explicit external stimuli were correlated with “peck” and “pause” portions of the daily trials. Finally, schedules of reinforcement that did not selectively reinforce peck-pause or pause-peck patterns neither generated these patterns nor maintained them at the previous high levels. The results, therefore, confirm Shimp's (1976) proposal that organized groupings of discrete responses may function as operants—even in the absence of strict response-reinforcer contiguity.     

Conditioning of two-response patterns of key pecking in pigeons

On discrete trials, two response keys were made available to hungry pigeons and food reinforcement depended on the order in which the required two key pecks occurred. In different phases, only one of the four possible two-peck sequences (left-left, left-right, right-left, and right-right) produced food reinforcement. In each case, the pigeons learned to perform the correct two-peck sequence more often than the incorrect sequences. Furthermore, the course of differentiation mastery indicated that both reinforcement history and response-reinforcer contiguity influenced performance. These results reveal that response patterns comprising two instances of the same response left-left and right-right) or instances of two different responses (left-right and right-left) may function as operants, thereby extending the generality of conditioning principles from discrete responses to structured sequences of behavior. These and other results are discussed in terms of contiguity-based and memory-based models of learning.     

Response acquisition under targeted percentile schedules: a continuing quandary for molar models of operant behavior.

The number of responses rats made in a "run" of consecutive left-lever presses, prior to a trial-ending right-lever press, was differentiated using a targeted percentile procedure. Under the nondifferential baseline, reinforcement was provided with a probability of .33 at the end of a trial, irrespective of the run on that trial. Most of the 30 subjects made short runs under these conditions, with the mean for the group around three. A targeted percentile schedule was next used to differentiate run length around the target value of 12. The current run was reinforced if it was nearer the target than 67% of those runs in the last 24 trials that were on the same side of the target as the current run. Programming reinforcement in this way held overall reinforcement probability per trial constant at .33 while providing reinforcement differentially with respect to runs more closely approximating the target of 12. The mean run for the group under this procedure increased to approximately 10. Runs approaching the target length were acquired even though differentiated responding produced the same probability of reinforcement per trial, decreased the probability of reinforcement per response, did not increase overall reinforcement rate, and generally substantially reduced it (i.e., in only a few instances did response rate increase sufficiently to compensate for the increase in the number of responses per trial). Models of behavior predicated solely on molar reinforcement contingencies all predict that runs should remain short throughout this experiment, because such runs promote both the most frequent reinforcement and the greatest reinforcement per press. To the contrary, 29 of 30 subjects emitted runs in the vicinity of the target, driving down reinforcement rate while greatly increasing the number of presses per pellet. These results illustrate the powerful effects of local reinforcement contingencies in changing behavior, and in doing so underscore a need for more dynamic quantitative formulations of operant behavior to supplement or supplant the currently prevalent static ones.     

视觉诱发电位与老年人智力和记忆力相关性研究的多因素逐步回归分析

以年龄在55—79岁的正常人(男40人,女34人,平均年龄64.34±5.67岁)为被试,做视觉诱发电位(VEP),并测试韦氏智力测验的11项分值及智力商数、临床记忆测验的5项分测验及记忆商数、测量血压和头颅CT的脑萎缩程度,根据眼底动脉硬化表现和神经体征确定脑动脉硬化的程度.将上述资料数字化输入计算机进行多因素逐步回归分析。结果表明,智力和记忆力分别与视觉诱发电位的某些指标变量有关,与脑动脉硬化程度有关,与收缩压相关性较大,与舒张压相关性不大,与生理性脑萎缩程度关系不大。还探讨了推测老年人智力和记忆力的计算公式。     

Control over response number by a targeted percentile schedule: reinforcement loss and the acute effects of d-amphetamine.

Two fixed-consecutive-number-like procedures were used to examine effects of acute d-amphetamine administration on control over response number. In both procedures, rats were required to press the left lever at least once and then press the right lever to complete a trial. The consecutive left-lever presses on each trial comprised a "run." Under the targeted percentile schedule, reinforcement was provided if the current run length was closer to the target length (16) than half of the most recent 24 runs. This differentially reinforced run length while holding reinforcement probability constant at .5. A second group acquired the differentiation under the targeted percentile schedule, but were then shifted to a procedure that yoked reinforcement probability by subject and run length to that obtained under the targeted percentile schedule. The two procedures generated practically identical control run lengths, response rates, reinforcement probabilities, and reinforcement rates. Administration of d-amphetamine disrupted percentile responding to a greater degree than yoked control responding. This disruption decreased reinforcement frequency less in the former than the latter procedure. The similar baseline responding under these two procedures suggests that this difference in sensitivity was due to behavioral adjustments to drug prompted by reduction of reinforcement density in the yoked control but not the percentile schedule. These adjustments attenuate the drug's effects under the former, but not the latter, procedure.     

心理性应激的时间加工进程:来自ERP的证据*

采用有时间压力的算术题目诱发被试的心理性应激体验,并用事件相关电位技术(ERP)探讨心理性应激发生时大脑神经活动的时程变化。行为数据结果发现有时间压力下被试的反应时更短;脑电数据结果发现有时间压力组的容易题目比无时间压力组的容易题目诱发出更大的N1峰值、更长的P2潜伏期和更大的P300波幅;有时间压力组的困难题目比无时间压力组的困难题目同样诱发出更大的N1峰值、更长的P2潜伏期和更大的P300波幅,但这种组别主效应仅表现在部分电极点上。该研究结果表明心理性应激增加了早期知觉加工的负载,导致知觉加工速度减慢,在信息加工后期阶段需要占用更多的认知资源。     

两种任务下情绪韵律的加工进程

采用ERP技术分别考察了情绪判断和性别判断任务下情绪韵律的加工进程。结果显示：在175-275ms时间段,情绪韵律的加工受实验任务的调节,情绪判断任务下存在效价主效应及负性偏向,愤怒比高兴和中性诱发了更正的P2成分,而性别判断任务则无效价效应。在后期评价加工及反应准备阶段（400-800ms）,两种任务下,愤怒都比高兴和中性诱发了更正的晚成分。上述结果说明,不同情绪韵律的识别存在不同的认知机制,并在一定程度上会受加工任务的调节。