Concurrent-schedule performance: Effects of relative and overall reinforcer rate

Six pigeons were trained to respond on two keys, each of which provided reinforcers on an arithmetic variable-interval schedule. These concurrent schedules ran nonindependently with a 2-s changeover delay. Six sets of conditions were conducted. Within each set of conditions the ratio of reinforcers available on the two alternatives was varied, but the arranged overall reinforcer rate remained constant. Each set of conditions used a different overall reinforcer rate, ranging from 0.22 reinforcers per minute to 10 reinforcers per minute. The generalized matching law fit the data from each set of conditions, but sensitivity to reinforcer frequency (a) decreased as the overall reinforcer rate decreased for both time allocation and response allocation based analyses of the data. Overall response rates did not vary with changes in relative reinforcer rate, but decreased with decreases in overall reinforcer rate. Changeover rates varied as a function of both relative and overall reinforcer rates. However, as explanations based on changeover rate seem unable to deal with the changes in generalized matching sensitivity, discrimination accounts of choice may offer a more promising interpretation.     

Temporal proximity and reinforcement sensitivity in multiple schedules

Distributions of reinforcers between two components of multiple variable-interval schedules were varied over a number of conditions. Sensitivity to reinforcement, measured by the exponent of the power function relating ratios of responses in the two components to ratios of reinforcers obtained in the components, did not differ between conditions with 15-s or 60-s component durations. The failure to demonstrate the “short-component effect,” where sensitivity is high for short components, was consistent with reanalysis of previous data. With 60-s components, sensitivity to reinforcement decreased systematically with time since component alternation, and was higher in the first 15-s subinterval of the 60-s component than for the component whose total duration was 15 s. Varying component duration and sampling behavior at different times since component transition may not be equivalent ways of examining the effects of average temporal distance between components.     

The interaction of stimulus and reinforcer control in complex temporal discrimination.

Six pigeons were trained in a discrete-trials signal-detection procedure to discriminate between a fixed-duration stimulus (5 s or 20 s) and a set of variable durations ranging from 2.5 s to 57.5 s in steps of 5 s. For each fixed-duration stimulus, the ratio of reinforcer frequencies contingent upon reporting the fixed versus the variable stimulus was systematically manipulated. Detection performance was well controlled by both the stimulus value and the reinforcer ratio. Both the discriminability between the fixed duration and the set of variable durations, and the discriminability between the fixed duration and each of the variable durations, were independent of the reinforcer-frequency ratio when discriminability was measured as log d. The sensitivity of response bias to reinforcement-ratio changes was independent of the value of the fixed duration, but was not independent of the discriminability of the variable durations from the fixed durations. Under current models, discriminability measures in complex temporal discrimination may be independent of biasing manipulations, but bias measures are not independent of stimulus values.     

Choice between reliable and unreliable outcomes: mixed percentage-reinforcement in concurrent chains.

Pigeons' choices between alternatives that provided different percentages of reinforcement in mixed schedules were studied using the concurrent-chains procedure. In Experiment 1, the alternatives were terminal-link schedules that were equal in delay and magnitude of reinforcement, but that provided different percentages of reinforcement, with one schedule providing, reinforcement twice as reliably as the other. All pigeons preferred the more reliable schedule, and their level of preference was not systematically affected by variation in the absolute percentage values, or in the magnitude of reinforcement. In Experiment 2, preference for a schedule providing 100% reinforcement over one providing 33% reinforcement increased systematically with increases in the duration of the terminal links. In contrast, preference decreased systematically with increases in the duration of the initial links. Experiment 3 examined choice with equal percentages of reinforcement but unequal delays to reinforcement. Preference for the shorter delay to reinforcement was not systematically affected by variation in the absolute percentage of reinforcement. The overall pattern of results supported predictions based on an extension of the delay-reduction hypothesis to choice procedures involving mixed schedules of percentage reinforcement.     

亲子依恋与儿童抑郁症状的关系：儿童对环境的生物敏感性的作用及父母差异

不良的亲子依恋是导致儿童抑郁症状的风险因素,但其对儿童的影响会因儿童对环境的生物敏感性不同而存在差异。为探究家庭中母子、父子依恋对儿童抑郁症状的影响及儿童生物敏感性(本文中采用迷走神经抑制作为指标)在其中的作用,本研究结合行为任务、问卷报告、生理测量等多种研究手段,招募150名学龄儿童(平均年龄8.64岁,63名女孩)参与研究。结果表明：(1)学龄儿童的母子依恋水平高于父子依恋水平。(2)高水平的母子依恋与父子依恋会同等程度地降低儿童的抑郁症状。(3)儿童对环境的生物敏感性对母子依恋影响儿童抑郁症状路径的调节作用显著,生理上对环境更敏感(高迷走神经抑制)的儿童更易得益于高母子依恋,表现出较低的抑郁水平;但同时,这类儿童在母子依恋较低时也更易表现出较高的抑郁水平。(4)儿童的生物敏感性对父子依恋影响儿童抑郁症状路径的调节作用不显著,高父子依恋对生物敏感性水平不同的儿童均存在有利影响。(5)在不同情境中测量的迷走神经抑制对亲子依恋影响儿童抑郁症状的调节作用模式相似,表现出跨情境一致的特点。本研究率先揭示儿童迷走神经抑制与亲子依恋对儿童抑郁症状的联合作用机制及父母角色差异。     

Behavioral consequences of intergroup sensitivity

Communication of criticism between groups is important to productive societal discourse, but may serve to inflame conflict. The defensive rejection of intergroup, relative to intragroup, criticism (intergroup sensitivity effect [ISE]) may contribute to such divides. The ISE has been observed in self-report measures, but such measures are weak and biased predictors of actual (divisive) behavior. We review recent research demonstrating that the ISE does have costly behavioral consequences. We next consider the debate concerning whether the ISE reflects defense of a valued social identity or enforcement of a conversational norm. We therefore review recent evidence for an ISE among individuals lacking identification with the target of the criticism. Third, we examine how the ISE may affect a variety of behaviors relevant to societal divisions, including political reconciliation, environmental sustainability, and vaccination. Lastly, we outline future research that can clarify the underlying mechanisms of the ISE and promote conciliatory intergroup behavior.     

Dark adaptation of foveal cones during the cone-plateau period

Following substantial bleaching by "white" light, absolute threshold, relative spectral sensitivity and sensation of hue of monochromatic lights were measured at the central fovea during the cone-plateau period. The absolute-threshold level was found to increase and then decrease markedly, the relative spectral sensitivity remained invariant, while the sensation of hues of monochromatic lights from the long- and middle-wave regions of the spectrum changed toward hues of shorter wavelengths.     

追踪作业中几种心理负荷评估指标敏感性的研究

本研究在模拟追踪作业情境下 ,对主任务绩效测定、主观评定和若干生理测量在心理负荷评估中的敏感性进行了实验。实验采用重复测量的被试者内设计 ,2 0名被试 (男女各半 )在六档负荷下分别从事五分钟追踪作业。所选用的指标有追踪作业平均误差距离、追踪警告次数、主观负荷评定、心率、心率变异和血压。结果发现 :1主任务绩效在评估追踪作业心理负荷中具有最高的敏感性 ,主观评定次之 ,心率变化率和心率变异变化率也随负荷变化 ,血压指标随负荷变化的趋势不明显 ;2除血压指标外 ,其余各指标之间均存在明显的相关 ,这提示它们在评估追踪作业心理负荷中具有较大的可靠性。     

Toward culturally sensitive intervention with arab families in Israel

Over the past three decades, Arab society in Israel has been undergoing processes of transition. These processes are manifested by changes in the economy, education, the status of women, family structure, and by socio-cultural changes and transformations in patterns of coping with social problems. There is a serious lack of empirical research on the implications of this process for the value systems of Arab society and families in Israel and a dearth of relevant intervention-oriented literature. This article outlines the basic cultural values in the Arab society in Israel in an attempt to illuminate the relevance of these values for family structure and for direct interventions with Arab families in Israel.