Effect of varying the duration of grain presentation on automaintenance

In a series of three experiments the effects of variation in grain duration on automaintenance were evaluated. In the first experiment, key illumination was followed by grain only when pigeons did not peck the key. Each subject was exposed to 2-, 4-, and 8-second feeder durations in blocks of 10 sessions. Subjects pecked on a high percentage of trials at all feeder durations. The mean peck latency was shorter in the 8-second condition than in the two other conditions in five of six subjects. The conditional probability of pecking given successive keylight-grain pairings did not increase as the number of pairings increased. The second experiment was identical to the first, except that key pecking had no scheduled consequence. Under these conditions, all three subjects showed substantial responding. The recorded measures showed no systematic relationship to feeder duration in this study. In the third experiment, two different stimuli were followed by feeder presentations of either identical (2- or 8-second) or different (2- and 8-second) durations within each session. Subjects tended to respond sooner and with a higher overall rate in the presence of the stimulus associated with the longer feeder duration only when different feeder durations were presented within the same session. This result was confirmed by direct observation of the pigeons. The results of these experiments suggest that the effects of varying grain duration may be small, compared to the effects of varying other variables. The results also suggest that the location as well as the frequency of pecking may be an important measure in the analysis of factors controlling the pigeon's key peck.     

Effects Of Fixed-interval Schedule And Reinforcer Duration On Responding Reinforced By The Opportunity To Run

Two experiments investigated the effects of schedule value and reinforcer duration on responding for the opportunity to run on fixed-interval (FI) schedules in rats. In the first experiment, 8 male Wistar rats were exposed to FI 15-s, 30-s, and 60-s schedules of wheel-running reinforcement. The operant was lever pressing, and the consequence was the opportunity to run for 60 s. In the second experiment, 8 male Long-Evans rats were exposed to reinforcer durations of 15 s, 30 s, and 90 s. The schedule of reinforcement was an FI 60-s schedule. Results showed that postreinforcement pause and wheel-running rates varied systematically with reinforcer duration but not schedule value. Local lever-pressing rates decreased with reinforcer duration. Overall lever-pressing rates decreased with reinforcer duration but increased with schedule value. Although the reinforcer-duration effect is consistent with previous research, the lack a schedule effect appears to be the result of long post-reinforcement pauses following wheel-running reinforcement that render the manipulation of the interval requirement ineffective.     

海洛因成瘾者的脑灰质密度下降

本研究对海洛因成瘾者（n=34）和无毒品依赖的正常被试（n=34）进行磁共振脑结构扫描,用基于体素的形态学测量（VBM）方法分析被试间灰质密度的差异,并考察了海洛因成瘾者用药时间与灰质密度之间的关系。结果表明,同正常对照组相比,海洛因成瘾者其额叶和颞叶下部的灰质密度显著下降。进一步分析显示,用药时间短于5年的成瘾者其灰质密度下降不明显,而用药时间5年以上的患者其灰质密度下降非常显著。本文讨论了上述结果的潜在临床价值和理论意义。     

Differential levels of speech and manual dysfluency in adults who stutter during simultaneous drawing and speaking tasks

We examined the disruptive effects of stuttering on manual performance during simultaneous speaking and drawing tasks. Fifteen stuttering and fifteen non-stuttering participants drew continuous circles with a pen on a digitizer tablet under three conditions: silent (i.e., neither reading nor speaking), reading aloud, and choral reading (i.e., reading aloud in unison with another reader). We counted the frequency of stuttering events in the speaking tasks and measured pen stroke duration and pen stroke dysfluency (normalized jerk) in all three tasks. The control group was stutter-free and did not increase manual dysfluency in any condition. In the silent condition, the stuttering group performed pen movements without evidence of dysfluency, similar to the control group. However, in the reading aloud condition, the stuttering group stuttered on 12% of the syllables and showed increased manual dysfluency. In the choral reading condition stuttering was virtually eliminated (reduced by 97%), but manual dysfluency was reduced by only 47% relative to the reading aloud condition. Trials where more stuttered events were generally positively correlated with higher manual dysfluency. The results are consistent with a model in which episodes of stuttering and motor dysfluency are related to neural interconnectivity between manual and speech processes.     

事件持续时间对情景模型更新的影响

采用移动窗口技术,探讨文本阅读中事件持续时间对情景模型更新的影响。实验1探讨不同的事件持续时间对情景模型更新进程的影响。结果发现,情景模型的更新受到事件持续时间的影响;实验2探讨在不同的事件持续时间条件下,情景模型的更新符合动态观还是静态观,结果支持了情景模型更新的动态观。该研究表明,事件持续时间与时间转换大小之间的关系对情景模型的更新起着重要的作用。同时,情景模型的更新符合动态观。     

On the dissociation between reaction time and response duration as a function of lexical and sublexical reading: An examination of phonetic decoding and computational models

Neurobiological models of reading account for two ways in which orthography is converted to phonology: (1) familiar words, particularly those with exceptional spelling-sound mappings (e.g., shoe) access their whole-word lexical representations in the ventral visual stream, and (2) orthographically unfamiliar words, particularly those with regular spelling-sound mappings (i.e., pseudohomophones [PHs], which are orthographically novel but sound like real words; e.g., shue) are phonetically decoded via sublexical processing in the dorsal visual stream. The present study used a naming task in order to compare naming reaction time (RT) and response duration (RD) of exception and regular words to their PH counterparts. We replicated our earlier findings with words, and extended them to PH phonetic decoding by showing a similar effect on RT and RD of matched PHs. Given that the shorter RDs for exception words can be attributed to the benefit of whole-word processing in the orthographic word system, and the longer RTs for exception words to the conflict with phonetic decoding, our PH results demonstrate that phonetic decoding also involves top-down feedback from phonological lexical representations (e.g., activated by shue) to the orthographic representations of the corresponding correct word (e.g., shoe). Two computational models were tested for their ability to account for these effects: the DRC and the CDP+. The CDP+ fared best as it was capable of simulating both the regularity and stimulus type effect on RT for both word and PH identification, although not their over-additive interaction. Our results demonstrate that both lexical reading and phonetic decoding elicit a regularity dissociation between RT and RD that provides important constraints to all models of reading, and that phonetic decoding results in top-down feedback that bolsters the orthographic lexical reading process.     

It felt fluent but I did not like it: fluency effects in faces versus patterns

Whether you like a person or not is often appraised in a glance. However, under such short presentation durations stimuli are harder to perceive and, according to hedonic fluency theory-which holds that higher fluency is linked to higher liking-thus, are liked less. Given that liking considerably influences person perception, we tested how shorter and longer presentation durations affect liking for faces and compared this with abstract patterns. To capture facets of fluency of processing we assessed felt fluency, liking, and certainty ratings. Following predictions of fluency theory, longer presentation durations led to higher felt fluency, certainty, and positively affected liking judgments in the abstract patterns. In faces, felt fluency and certainty also increased with longer durations. However, with longer durations, faces were liked less, and liking was not related to felt fluency. In other words, in contrast to hedonic fluency theory, faces are more attractive when only seen for a short amount of time. Thus, fluency does not inevitably lead to more positive evaluations—it rather depends on the stimulus category. We discuss these findings in terms of the special status that faces have with regard to human perception and evaluation.     

数目和呈现方式对时距估计的影响

采用口头估计的方法,考察刺激的数目和呈现方式对时距估计的影响。以时距估计的平均值、准确性和变异性为指标,结果表明：（1）数目多少影响时距估计的平均值和准确性,数目少引起低估,数目多导致高估,数目多少与时距长度一致时,准确性高。（2）呈现方式影响时距估计的变异性,同时呈现时变异性最大;（3）数目和呈现方式的交互作用显著,固定频率和变化频率呈现时,数目影响时距估计。（4）随着时距的增加,时距估计的平均值由高估向低估,准确性由低向高发展。这表明时距和数目在心理表征上存在连接,数目和呈现方式在不同的时间范围内影响     

决策过程中的记忆可提取性效用

记忆的可提取性效用是人们在评估过往事件时所感受到的愉悦或满意程度, 这种评估建立在人们从记忆中提取出的信息基础上。研究发现, 人们对过往事件进行评估时会出现违反效用最大化原则的决策, 主要表现在三个实验现象上：峰终律、时长忽视和违背单调叠加性。研究者多从原型判断的角度去理解这些现象, 但可提取性效用是否还有其他内在机制仍然有待进一步研究。     

Words, hemispheres, and dissociable subsystems: the effects of exposure duration, case alternation, priming, and continuity of form on word recognition in the left and right visual fields

Three experiments explore aspects of the dissociable neural subsystems theory of hemispheric specialisation proposed by Marsolek and colleagues, and in particular a study by [Deason, R. G., & Marsolek, C. J. (2005). A critical boundary to the left-hemisphere advantage in word processing. Brain and Language, 92, 251–261]. Experiment 1A showed that shorter exposure durations for lower-case words (13 ms) are associated with reduced right visual field (RVF) advantages compared with longer exposure durations (144 ms). Experiment 1B compared report accuracy for lower case and mixed case words at the same exposure duration (144 ms). The RVF advantage was reduced for mixed case words due to case alternation having more of an adverse effect in the RVF than in the LVF. Experiment 2 tested a different prediction of dissociable neural subsystems theory. Four-letter words were presented in mixed case in the LVF or RVF for 100 ms. They were preceded at the same location by a prime which could be in the same word in the same alternation pattern (e.g., FlAg–FlAg), the same word in the opposite alternation pattern (e.g., fLaG–FlAg), or an unrelated letter string in the same or opposite case alternation pattern (WoPk–FlAg or wOpK–FlAg). Relative to performance in the letter string prime conditions, which did not differ significantly between the two visual fields, there was more of an effect of word primes in the RVF than in the LVF. Importantly, the benefit of a word prime was the same whether the prime was in the same alternation pattern or was in the opposition alternation pattern. We argue that these results run contrary to the predictions of dissociable neural subsystems theory and are more compatible with theories which propose that a left hemisphere word recognition system is responsible for identifying written words, whether they are presented in the LVF or the RVF, and that letters are processed to an abstract graphemic level of representation before being identified by that system.