Extended pausing by humans on multiple fixed-ratio schedules with varied reinforcer magnitude and response requirements

We conducted three experiments to reproduce and extend Perone and Courtney's (1992) study of pausing at the beginning of fixed-ratio schedules. In a multiple schedule with unequal amounts of food across two components, they found that pigeons paused longest in the component associated with the smaller amount of food (the lean component), but only when it was preceded by the rich component. In our studies, adults with mild intellectual disabilities responded on a touch-sensitive computer monitor to produce money. In Experiment 1, the multiple-schedule components differed in both response requirement and reinforcer magnitude (i.e., the rich component required fewer responses and produced more money than the lean component). Effects shown with pigeons were reproduced in all 7 participants. In Experiment 2, we removed the stimuli that signaled the two schedule components, and participants' extended pausing was eliminated. In Experiment 3, to assess sensitivity to reinforcer magnitude versus fixed-ratio size, we presented conditions with equal ratio sizes but disparate magnitudes and conditions with equal magnitudes but disparate ratio sizes. Sensitivity to these manipulations was idiosyncratic. The present experiments obtained schedule control in verbally competent human participants and, despite procedural differences, we reproduced findings with animal participants. We showed that pausing is jointly determined by past conditions of reinforcement and stimuli correlated with upcoming conditions.     

Fairness Between Competing Claims

Fairness is a central, but under-theorized, notion in moral and political philosophy. This paper makes two contributions. Firstly, it criticizes Broome’s seminal account of fairness in (1990–1991) Proc Aristotelian Soc 91:87–101, showing that there are problems with restricting fairness to a matter of relative satisfaction and holding that it does not itself require the satisfaction of the claims in question. Secondly, it considers the justification of lotteries to resolve cases of ties between competing claims, which Broome claims as support for his theory, and contrasts random procedures to contests of skill, which may also be considered lotteries in a broader sense. I offer no alternative account of fairness of my own, but hope to point the way for future research on the nature of fairness.     

Evidence for expectancy as a mediator of avoidance and anxiety in a laboratory model of human avoidance learning

A laboratory model was developed to study human avoidance learning. Participants could avoid an electric shock signalled by a 5-s conditioned stimulus (CS) by pressing one of a set of response buttons. Self-reported shock expectancy and skin conductance were recorded during a subsequent 10-s interval before shock. Shock expectancy declined when the correct avoidance response was learned and returned when the response was unavailable. Learning transferred to another shock CS. Parallel effects were observed on skin conductance once performance anxiety was controlled by requiring responding on all trials. Learning was faster when the Pavlovian contingencies were trained before introduction of the instrumental response. The results support a cognitive model of anxiety in which performance of an avoidance response reduces expectancy of an aversive outcome and thereby reduces anxiety.     

Retrieval Inhibition and Memory Distortion: Negative Consequences of an Adaptive Process

ABSTRACT— Despite the fact that misinformation effects have long been studied by both applied researchers and modelers of human memory, there is little consensus as to the value of such endeavors. We argue that this may be due to a failure to identify the underlying mechanism responsible for such memory distortions. We consider novel evidence for a relationship between retrieval-induced forgetting and the reporting of misinformation. We also explore the extent to which retrieval inhibition underpins this relationship and the implications this has for the modeling of memory and finding potential solutions to real-world problems.     

环境基因组计划(EGP)对预防医学发展的影响

1998年美国正式启动环境基因组计划,该计划旨在探讨环境－基因的交互作用,寻找对环境因素损伤的易感基因及环境反应基因的多态性在疾病病因和发病过程中的作用,因而该计划的实施将对预防医学的发展产生重要的影响。     

Predicting Positive Academic Intention Among African American Males and Females1

Significant attention has been given to the educational shortcomings of African American students. This study examined predictors of educational success among African American high school sophomores. It explored factors that predict differences in students’ academic intention to complete the school year, and how these factors differ by gender. The study was guided conceptually by the theory of planned behavior (TPB). We also assessed perceptions of self. Results indicated that most students had positive predispositions toward school‐year completion, with females being more positively oriented toward academic success than males. The TPB's attitude component was the only predictor tested to operate differentially across gender. Having a positive attitude toward school was a significantly greater predictor of intention to complete the school year for males than for females.     

DECREASING ERRORS IN READING‐RELATED MATCHING TO SAMPLE USING A DELAYED‐SAMPLE PROCEDURE

Two men with intellectual disabilities initially demonstrated intermediate accuracy in two‐choice matching‐to‐sample (MTS) procedures. A printed‐letter identity MTS procedure was used with 1 participant, and a spoken‐to‐printed‐word MTS procedure was used with the other participant. Errors decreased substantially under a delayed‐sample procedure, in which the choice stimuli were presented first and the sample was presented only after 5 s without a response to the choice stimuli.