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.     

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.     

言语的情绪韵律和情绪语义对听觉去信息掩蔽的作用

言语的情绪信息(情绪性韵律和情绪性语义)具有去听觉掩蔽的作用, 但其去掩蔽的具体机制还不清楚。本研究通过2个实验, 采用主观空间分离范式, 通过操纵掩蔽声类型的方式, 分别探究言语的情绪韵律和情绪语义去信息掩蔽的机制。结果发现, 情绪韵律在知觉信息掩蔽或者在知觉、认知双重信息掩蔽下, 均具有去掩蔽的作用。情绪语义在知觉信息掩蔽下不具有去掩蔽的作用, 但在知觉、认知双重信息掩蔽下具有去掩蔽的作用。这些结果表明, 言语的情绪韵律和情绪语义有着不同的去掩蔽机制。情绪韵律能够优先吸引听者更多的注意, 可以克服掩蔽声音在知觉上造成的干扰, 但对掩蔽声音在内容上的干扰作用很小。言语的情绪语义能够优先获取听者更多的认知加工资源, 具有去认知信息掩蔽的作用, 但不具有去知觉信息掩蔽的作用。     

Vulnerability of facial attractiveness perception to early and multi-year visual deprivation

Judgments of facial attractiveness invariably accompany our perception of faces. Even neonates appear to be capable of making such judgments in a manner consistent with adults. This suggests that the processes supporting facial attractiveness require little, if any, visual experience to manifest. Here we investigate the resilience of these processes to several years of early-onset visual deprivation. Specifically, we study whether congenitally blind children treated several years after birth possess the ability to rate facial attractiveness in a manner congruent to normally sighted individuals. The data reveal significant individual variability in the way each newly sighted child perceives attractiveness. This is in marked contrast to data from normally sighted controls who exhibit strong across-subject agreement in facial attractiveness ratings. This variability may be attributable, in part, to atypical facial encoding strategies used by the newly sighted children. Overall, our results suggest that the development of facial attractiveness perception is likely to be vulnerable to early visual deprivation, pointing to the existence of a possible sensitive period early in the developmental trajectory.     

知觉线索对元记忆监控的影响

近年来, 越来越多的证据表明知觉线索影响个体的高级认知--元记忆。元记忆指个体对自己学习和记忆活动的认知, 其核心成分是监测和控制。研究发现, 多种知觉线索(如字体大小、音量、文本清晰度、重量、亮度等)影响个体的元记忆监测(如学习判断和自信心评定)及控制(如学习时间分配)。这种影响可能是加工流畅性所致, 也可能基于人们的信念产生。未来研究有必要进一步探究知觉线索影响元记忆监控的条件, 并厘清加工流畅性和信念的具体作用。     

注意促进效应依赖于项目-背景的质心间距

近期研究者发现, 在某些条件下增加对第一任务的注意能够提高伴随发生的第二任务的成绩, 并将其命名为注意促进效应。研究者提出双任务交互模型对之进行解释, 认为该效应产生的必要条件是时间上的重叠, 而不受空间距离的影响。基于对这一观点的质疑, 本研究探究了检测项目与背景图片的质心间距对注意促进效应的影响。结果发现, 当目标项位于背景图片中央时(质心间距为0), 表现出注意促进效应; 而当二者分开一定的空间距离时, 出现了注意干扰/抑制效应。由此可见, 项目和背景的质心间距会对注意促进效应产生影响。     

听觉信息掩蔽的亚成分：基于行为和脑成像研究的证明

听觉掩蔽的机制是解决嘈杂声学环境下对特定目标声音进行加工, 即“鸡尾酒会”问题的关键。听觉掩蔽可以分为能量掩蔽和信息掩蔽两种类型。前者是因为目标和掩蔽声音在听觉外周在时间和频率上的重叠所造成的, 而后者被认为是掩蔽声音在听觉中枢和目标声音竞争加工资源所造成的。长久以来, 信息掩蔽一直被当作一种单一成分的现象, 这一概念框架已经成为制约对其机制进行深入研究的一个瓶颈。信息掩蔽中至少包含有知觉信息掩蔽和认知信息掩蔽两种亚成分, 它们源于不同的中枢机制。多个说话人声音掩蔽的条件下, 总体掩蔽量是能量掩蔽、知觉信息掩蔽和认知信息掩蔽等成分总和的结果。操纵掩蔽和目标声音的知觉空间分离、掩蔽声音的可懂度以及掩蔽和目标声音的知觉相似度, 可以实现对两种信息掩蔽亚成分的双重分离。应用功能性核磁共振成像技术可以发现两者有不同的神经机制。     

情绪面孔搜索不对称性：情绪观与知觉观的争议

情绪面孔搜索不对称性是指当负性情绪面孔作为目标, 正性情绪面孔作为分心物时, 其搜索速度比正性情绪面孔作为目标时(负性情绪面孔作为分心物)更快。对于这一现象的解释存在争议, 研究者主要从不同情绪面孔在情绪因素和知觉因素两个方面的差异进行解释。来自行为研究和认知神经科学的证据对情绪面孔搜索不对称性效应的解释主要有威胁性刺激捕获假设和情绪摆脱假设的情绪观, 以及嘴部差异说、闭合结构说、知觉组群说以及其他面部特征假设的知觉观。经过对比评价两类观点的理论异同和实验证据认为未来的研究可以整合情绪因素和知觉因素来解释该效应。     

大小字号的文本对中文读者眼动模式和阅读知觉广度的影响

摘 要 研究以眼动仪为工具,采用移动窗口范式考察不同字号文本对读者阅读知觉广度和眼动模式的影响。实验结果发现,被试阅读大、小字号文本时的阅读知觉广度都是四个字。字号大小不影响读者的阅读知觉广度,但是影响读者的眼动模式。具体表现为：被试阅读小号字文本的平均注视时间、总注视时间比大号字文本长,平均眼跳距离更短,相对眼跳距离（单位为字的个数）更长,注视次数更多。