The effects of reinforcer magnitude on timing in rats

The relation between reinforcer magnitude and timing behavior was studied using a peak procedure. Four rats received multiple consecutive sessions with both low and high levels of brain stimulation reward (BSR). Rats paused longer and had later start times during sessions when their responses were reinforced with low-magnitude BSR. When estimated by a symmetric Gaussian function, peak times also were earlier; when estimated by a better-fitting asymmetric Gaussian function or by analyzing individual trials, however, these peak-time changes were determined to reflect a mixture of large effects of BSR on start times and no effect on stop times. These results pose a significant dilemma for three major theories of timing (SET, MTS, and BeT), which all predict no effects for chronic manipulations of reinforcer magnitude. We conclude that increased reinforcer magnitude influences timing in two ways: through larger immediate after-effects that delay responding and through anticipatory effects that elicit earlier responding.     

儿童青少年返回抑制发展的实验研究

采用返回抑制线索——靶子模式,比较了单线索和双线索条件下儿童返回抑制的发展变化。选取了4组被试,6岁、9岁、12岁和17岁各20名。结果显示:(1)儿童返回抑制在单线索条件下出现的晚,而在双线索条件下出现的早;(2)返回抑制出现的时间进程随年龄的增长而逐渐显现,年龄对返回抑制有重要影响;(3)儿童返回抑制发展的关键期可能是在12岁左右。     

Infant touching behaviour during mother–infant face‐to‐face interactions

The study of infant communication during mother–infant interactions has largely focused on infants' distal behaviours, while neglecting their more proximal behaviours, such as touch. Yet, touch is an important modality through which infants and mothers communicate; it is also a vital means through which infants self‐regulate and explore their surroundings. The present study was designed to investigate the touching behaviours of 44, 51/2‐month‐old, healthy, full‐term infants during face‐to‐face mother–infant interactions. A still‐face (SF) procedure was used in order to examine differences in the types and locations of infant touch across normal and perturbed interaction periods, when mothers exhibit changes in their emotional availability. Results revealed that infant touch varied with changes in maternal availability. During the SF period, when mothers were unavailable, infants used more active, soothing, and reactive tactile behaviours (stroke, finger, pat, and pull), and they spent more time touching themselves. In contrast, infants used mostly passive touch (static) during the Normal periods, when their mothers were available. They also spent a significant portion of time touching their mothers. The variations in infant touch across periods suggest that infants communicate their affective states through touch. The findings also support the regulatory and exploratory roles of infant touch, especially during periods of maternal unavailability. Copyright © 2007 John Wiley & Sons, Ltd.     

MAU程序和自由讨论的群体决策质量比较

采用实验室研究方法,比较了在信启、不分享条件下多特征效用模型(MAU)决策程序和自由讨论对群体决策质量的影响,并对影响MAU决策质量的主要因素进行了初步探讨。结果发现：(1)MAU程序可以较好地克服群体动力学方面的一些消极影响,表现出挖掘信息(尤其是非分享信息)的充分性。但MAU程序在被试的态度和社会交互作用等心理效标上并未显示出优势;(2)在MAU条件下,群体规模的增大对分享和非分享信息的讨论量无显著影响。而任务难度效应要和群体规模一起才能起到作用。     

Reducing Parent Distress and Increasing Parent Coping-Promoting Behavior During Children's Medical Procedure

The study investigated whether involving parents in their child's cognitive-behavioral intervention would effectively reduce parent distress during their child's medical procedure. Parents participating with their 3- to 7-year-old children prior to a voiding cystourethrogram were randomly assigned to an intervention (N = 20) or a standard care (N = 20) condition. The intervention included provision of information, coping skills training, and parent coaching. Parents participating in the intervention had a significant reduction in anxiety following the intervention relative to parents in standard care. Trained parents displayed fewer distress-promoting and more coping-promoting behaviors during the procedure, even though parents in both conditions reported similar levels of anxiety during the procedure. Involving parents in children's interventions is crucial to reduce parent distress and prepare parents to assist their child during the medical procedure.     

Comparison of variance and covariance patterns in parallel and serial theories of timing.

Parallel and serial timing processes are analyzed for their account of the dynamics of intertrial responding in the peak procedure. A strictly serial model, such as the behavioral theory of timing (Killeen & Fetterman, 1988), does not fit the dynamic correlation pattern in the location and duration of the middle high-rate responding portion of peak trials. In contrast, the parallel scalar expectancy theory model, with a sample for memory and threshold, does fit this pattern. A modification of the serial model is presented that also accommodates the within-trial covariance pattern. The modification, which is formally equivalent to a model for human tapping (Wing & Kristofferson, 1973), entails the addition of concurrent processes operating in parallel with serial timing.     

选择性注意中意识与无意识过程分离的实验研究

以汉语单字词为材料,通过颜色来区分目标和分心物,采用过程分离程序,直接探讨了目标激活与分心物抑制和意识、无意识过程之间的关系。结果表明,（１）靶词充当分心物时,不仅意识过程存在的概率降低,无意识过程存在的概率也降低。这一结果说明,在选择性注意任务中,信息是有关还是无关,并不能分离意识和无意识过程;（２）靶词充当目标时,加工水平影响Ｐｃ,但不影响Ｐｕ,而靶词充当分心物时,加工水平既不影响Ｐｃ,也不影响Ｐｕ。因此,加工水平能否分离意识和无意识过程,依赖于靶词的作用或信息是否有关     

Choice and foraging: the effects of accessibility on acceptability.

Pigeons responded in a successive-encounters choice procedure in which accessibility of the less profitable of two outcomes varied either in terms of probability of encounter or search time to encounter (keeping search time to the more profitable outcome constant). When the less profitable outcome was made more probable its acceptance became more likely. However, when search time to encounter the less profitable outcome was shortened, its acceptance became less likely. Both results are consistent with the delay-reduction hypothesis and with an optimality model developed for application to the successive-encounters choice procedure.     

Some effects of response-correlated increases in reinforcer magnitude on human behavior

After training under short or long fixed-interval schedules, humans responded under a modified fixed-interval schedule in which magnitude of reinforcement (X or 2X) was minimally correlated with response frequency. Response frequencies that equaled or exceeded a minimum response criterion were followed by the larger reinforcer at the end of the interval; otherwise, the smaller reinforcer was delivered. The modified schedule alternated with the baseline schedule across conditions. In a control condition, the reinforcer magnitudes produced by control subjects were yoked to those of experimental subjects. Experimental subjects, but not control subjects, showed increased responding. In addition to the baseline and modified fixed-interval schedules used in Experiment 1, subjects in Experiment 2 also responded under a second modified fixed-interval contingency in which increases in reinforcer magnitude were more highly correlated with response frequency. Experimental subjects, but not control subjects, showed increased responding under both procedures. Direct comparison of these two procedures showed that the high-correlation procedure produced greater increases in responding than did the low-correlation procedure.     

Controlled and automatic uses of memory in depressed patients: effect of retention interval lengths

The present study examines controlled and automatic uses of memory in clinically depressed patients by applying the Process Dissociation Procedure developed by Jacoby (1991) to a stem completion memory task with short and long retention intervals. The results show that the contribution of controlled processes is lower in depressed patients than in controls, especially for the longest retention interval, whereas the contribution of automatic processes is equivalent in both groups and unaffected by the length of the retention interval. These findings are discussed in a cognitive control framework.