Human Signal-detection Performance: Effects Of Signal Presentation Probabilities And Reinforcer Distributions

University students participated in one of four standard two-choice signal-detection experiments in which signal presentation probability was varied and the reinforcement distribution was held constant and equal. In Experiments 1, 3 and 4, subjects' performance showed a systematic response bias for reporting the stimulus presented least often. Experiments 1 and 4 showed that this effect was reliable with extended training and monetary, rather than point, reinforcement. In Experiment 2, all correct responses were signaled in some way, and this produced the opposite relationship between signal presentation probability and response bias. Experiments 1 and 3 found that explicitly deducting money (intended as punishment) for equal numbers of incorrect responses on each alternative, or varying the obtained overall rate of reinforcement, produced no clear change in response bias. The bias, shown by humans, for reporting the stimulus presented least often remains a challenge for theories of stimulus detection.     

Appraisals of Child Behavior by Mothers of Problem and Nonproblem Toddlers

Mothers of problem and nonproblem toddlers rated videotapes of their own and unfamiliar children's behavior. They classified the behaviors as positive, negative, or neutral, and evaluated the intensity of the positive or negative behaviors. Ratings did not differ by problem status; however, all mothers classified their own children's behavior as less negative than did an independent observer. Mothers also evaluated all children's negative behavior as less aversive than did the observer. Finally, mothers mistakenly classified less of their own children's behavior as negative and more as positive when compared to their biases in classifying unfamiliar children's behavior.     

Attentiveness of mothers and fathers to their baby's cries

Thirty-two mother-father-infant triads participated in a study to examine whether parents' responsiveness to their own infant's distress was affected by the infant's birth order and gender. After separating from their 10- to 11-month-old baby, one parent from each family (16 mothers and 16 fathers) was selected to hear cries that were attributed to the child. Consistent with previous findings regarding physiological reactions to crying and observations of caretaking behavior, first-time parents gave quicker and more frequent attention to their infants than did multiporous parents. Speedy intervention was related to the amount of caretaking responsibilities that parents reported they assumed and to the age at which parents believed that their infant first recognized them. The results demonstrate the importance of caretaking for promoting parental sensitivity to infant signals.     

On the discriminability of stimulus duration.

The performance of pigeons trained to detect differences in the duration of stimuli was analysed using a matching model of signal detection. Two white stimuli, S1 and S2, differing in duration, were arranged with equal probability on the center key of a three-key chamber. S1 was systematically varied from 5 seconds to 25 seconds while S2 remained constant at 30 seconds. On completion of the center-key stimulus, a peck on the center key turned on the two red side keys. A left-key response was "correct" when S1 had been in effect on the center key and a right-key response was "correct" on S2 trials. A correct response produced a 3-second magazine light accompanied intermittently by food. Incorrect responses produced 3-second blackouts. Detection performance was measured under two procedures. In the first, the obtained reinforcement ratio was uncontrolled by allowing the number of food reinforcements obtained for correct left- and right-key responses to vary as the stimuli were changed. In the second procedure, the presentation of food reinforcement was controlled by holding the obtained reinforcement ratio constant. Discriminability changed as a function of stimulus differences under both procedures. No such trend was found in response bias.     

Concurrent fixed-interval variable-ratio schedules and the matching relation

Five rats responded under concurrent fixed-interval variable-ratio schedules of food reinforcement. Fixed-interval values ranged from 50-seconds to 300-seconds and variable-ratio values ranged from 30 to 360; a five-second changeover delay was in effect throughout the experiment. The relations between reinforcement ratios obtained from the two schedules and the ratios of responses and time spent on the schedules were described by Baum's (1974) generalized matching equation. All subjects undermatched both response and time ratios to reinforcement ratios, and all subjects displayed systematic bias in favor of the variable-ratio schedules. Response ratios undermatched reinforcement ratios less than did time ratios, but response ratios produced greater bias than did time ratios for every subject and for the group as a whole. Local rates of responding were generally higher on the variable-ratio than on the fixed-interval schedules. When responding was maintained by both schedules, a period of no responding on either schedule immediately after fixed-interval reinforcement typically was followed by high-rate responding on the variable-ratio schedule. At short fixed-interval values, when a changeover to the fixed-interval schedule was made, responding usually continued until fixed-interval reinforcement was obtained; at longer values, a changeover back to the variable-ratio schedule usually occurred when fixed-interval reinforcement was not forthcoming within a few seconds, and responding then alternated between the two schedules every few seconds until fixed-interval reinforcement finally was obtained.     

The interaction between stimulus and reinforcer control on remembering.

In a symbolic matching-to-sample task, 6 pigeons obtained food by pecking a red side key when the brighter of two white lights had been presented on the center key and by pecking a green side key when the dimmer of two white lights had been presented on the center key. Across Part 1 and Parts 6 to 10, the delay between sample-stimulus presentation and the availability of the choice keys was varied between 0 s and 25 s. Across Parts 1 to 5, the delay between the emission of a correct choice and the delivery of a reinforcer was varied between 0 s and 30 s. Although increasing both types of delay decreased stimulus discriminability, lengthening the stimulus-choice delay produced a greater decrement in choice accuracy than did lengthening the choice-reinforcer delay. Additionally, the relative reinforcer rate for correct choice was varied across both types of delay. The sensitivity of behavior to the distribution of reinforcers decreased as discriminability decreased under both procedures. These data are consistent with the view, based on the generalized matching law, that sample stimuli and reinforcers interact in their control over remembering.     

左侧眶额皮层在自动情绪调节下注意选择中的作用：来自经颅直流电刺激的证据

前人研究表明自动情绪调节能够自上而下地影响情绪及情绪性注意过程。近来有研究提示自动情绪调节与眶额皮层(orbitofrontal cortex, OFC)有关。也有研究表明左侧OFC的激活影响负性注意偏向。本研究采用经颅直流电刺激技术,考察阈下启动情绪控制目标条件下,抑制左侧眶额皮层兴奋性是否影响负性注意偏向。结果发现,使用阴极刺激抑制左侧OFC活动可以加快被试对与恐惧刺激位置一致的探测点的反应。该结果提示左侧眶额皮层是自动情绪调节下情绪性注意选择相关的重要脑区。     

不同康复时相戒除者对海洛因相关线索的注意偏向

以84名生理脱瘾后处于不同康复时相的海洛因戒除者为被试,采用情绪Stroop范式,以海洛因相关线索为自变量,考察了海洛因戒除者的注意偏向特性及其动态变化。结果发现:(1)海洛因戒除者对相关线索存在着显著的注意偏向;(2)海洛因戒除者对相关线索的注意偏向随康复期的延长无显著改善。该研究支持了Franken关于药物成瘾的注意偏向模型。     

视觉观点采择中自我中心性偏差的抑制和归因之争

自我中心性偏差是社交失败的重要原因,但其产生机制还存在争议。以往研究存在抑制性选择模型与流利性错误归因两种理论观点:前者认为对自身观点的抑制失败会导致自我中心性偏差;后者则认为错误地选择自身更为流畅的信息会导致自我中心性偏差。为整合上述争论,提出抑制-归因协同作用模型,认为抑制和归因两种加工或可共同导致自我中心性偏差。未来研究应借助精巧的研究范式和特殊被试群体,进一步验证该模型。     

Effects of rater conscientiousness on evaluations of task and contextual performance of older and younger co-workers

The possibility for age discrimination and stereotypes to affect performance evaluations is rising. Although careful evaluations might be expected from conscientious raters, little is known about whether they might show more or less bias towards certain age groups. Therefore, in our study using a time-lagged design, we investigated the effects of rater conscientiousness on the performance evaluations of younger and older actual co-worker (N = 242). We found that raters who were more conscientious provided higher ratings for older workers than for younger workers on task performance and organizational citizenship behaviours. Specifically, we tested the model of mediated moderation, in which the relation between rater conscientiousness and ratee age predicts ratee-perceived conscientiousness, which in turn predicts performance ratings. The model was significant for older ratees, but not for younger ratees. We discuss our results in terms of the “similar to me” effects and implications for organizational practices.