Discrimination training, partial reinforcement, and increases in intertrial interval all reduce response speed in a continuously reinforced key-pecking task

Pigeons were trained in a discrete-trial task in which a response to the center key obtained illumination of a side key and a single response to the side key terminated a trial with either reinforcement or nonreinforcement. Center-key speeds (i.e., reciprocals of latencies) declined with increases in intertrial interval, and it is argued that this effect is related to a decreased likelihood as intertrial interval increases that birds will be near the key at trial onset. Side-key speeds on trials with reinforcement decreased both with increases in intertrial interval and with shifts from continuous reinforcement to either a discrimination or a partial-reinforcement condition. The effects on side-key speeds are compared with effects observed in alley-running tasks using rats, and an interpretation in terms of frustration theory is offered for the results obtained in both types of task.     

The relationship between pronunciation and listening discrimination when Japanese natives are learning English

Two Japanese students were taught to pronounce and discriminate English words that contain unfamiliar phonemic contrasts (e.g., rock and lock). Teaching pronunciation was found to be easier than teaching listening discrimination. Teaching listening discrimination resulted in collateral improvement in pronunciation and, to a lesser extent, vice versa.     

In Defense of Affirmative Action

Affirmative action refers to positive steps taken to hire persons from groups previously and presently discriminated against. Considerable evidence indicates that this discrimination is intractable and cannot be eliminated by the enforcement of laws. Numerical goals and quotas are justified if and only if they are necessary to overcome the discriminatory effects that could not otherwise be eliminated with reasonable efficiency. Many past as well as present policies are justified in this way.     

Categorization of natural movements by pigeons: visual concept discrimination and biological motion

In three experiments, pigeons were exposed to a discriminated autoshaping procedure in which categories of moving stimuli, presented on videotape, were differentially associated with reinforcement. All stimuli depicted pigeons making defined responses. In Experiment 1, one category consisted of several different scenes of pecking and the other consisted of scenes of walking, flying, head movements, or standing still. Four of the 4 birds for which pecking scenes were positive stimuli discriminated successfully, whereas only 1 of the 4 for which pecking was the negative category did so. In the pecking-positive group, there were differences between the pecking rates in the presence of the four negative actions, and these differences were consistent across subjects. In Experiment 2, only the categories of walking and pecking were used; some but not all birds learned this discrimination, whichever category was positive, and these birds showed some transfer to new stimuli in which the same movements were represented only by a small number of point lights (Johansson's “biological motion” displays). In Experiment 3, discriminations between pecking and walking movement categories using point-light displays were trained. Four of the 8 birds discriminated successfully, but transfer to fully detailed displays could not be demonstrated. Pseudoconcept control groups, in which scenes from the same categories of motion were used in both the positive and negative stimulus sets, were used in Experiments 1 and 3. None of the 8 pigeons trained under these conditions showed discriminative responding. The results suggest that pigeons can respond differentially to moving stimuli on the basis of movement cues alone.     

Limited matching on concurrent-schedule reinforcement of academic behavior

Three adolescent students with special educational needs were given a choice between completing one of two available sets of math problems. Reinforcers (nickels) across these alternatives were arranged systematically in separate experimental phases according to three different concurrent variable-interval schedules (reinforcement ratios of 2:1, 6:1, and 12:1). Time allocated to the two stacks of math problems stood in linear relationship to the reinforcement rate obtained from each stack, although substantial undermatching and bias were observed for all subjects. However, changes in the schedules were not followed by changes in allocation patterns until adjunct procedures (e.g., changeover delays, limited holds, timers, and demonstrations) were introduced. The necessity of adjunct procedures in establishing matching in applied situations is discussed as a limitation to quantitative applications of the matching law in applied behavior analysis.     

A procedure for studying the within-session onset of human drug discrimination.

The purpose of the present study was to develop a procedure for measuring the within-session onset of human drug discrimination. During daily sessions, under double-blind conditions, caffeine-abstinent adults ingested a letter-coded capsule containing 178 mg caffeine or placebo. Trials were presented at 30-s intervals, beginning immediately after drug ingestion and continuing for 60 min. On each trial, subjects could guess which of their two letter-coded drugs they had received by pressing a left button (for one drug) or right button (for the other drug); subjects could also press a center "no guess" button instead of guessing. Each trial ended after one button press. After each session, subjects were told which drug they had received. Subjects earned one point (worth $0.10 per point) for each correct guess. Subjects lost either 0, 1, or 10 points for each incorrect guess; the point-loss contingencies were varied in random order across sessions. Discrimination earnings accumulated across all sessions. The point-loss contingencies decreased random responding and delayed the discrimination time course. Overall, this procedure provided an orderly and relatively continuous measure of the within-session onset of drug discrimination and should have a range of applications in understanding the human behavioral pharmacology of drugs.     

When do errors in reinforcer delivery affect learning? A parametric analysis of treatment integrity

Treatment integrity is the extent to which components of an intervention are implemented as intended (Gresham, 1989). Recent behavior-analytic literature has begun to evaluate the effects of reduced-treatment integrity on the efficacy and efficiency of skill-acquisition interventions. This study extended the current literature on the effects of errors of omission and commission of reinforcer delivery by replicating and extending Hirst and DiGennaro Reed (2015). Using a randomized-control group design, we compared undergraduate student participants' acquisition of conditional discriminations in a parametric analysis of different error values. A computer program erred in reinforcer delivery on 0%, 5%, 10%, 15%, 20%, 25% and 50% of trials. The purpose of the current study was to identify which levels of reduced integrity slowed or prevented acquisition. Our data replicated the findings of Hirst and DiGennaro Reed, and extended parametric analyses by identifying that errors in reinforcer delivery occurring on 15% or fewer trials (i.e., 85% integrity) were unlikely to prevent participants' responding from meeting the mastery criterion. These results could inform future research on how treatment-integrity errors change behavior-analytic procedures and the effects on skill acquisition for consumers of applied behavior analysis.     

自闭症儿童父母歧视知觉对群际关系的影响:一个有调节的中介作用模型

采用问卷法对474名自闭症儿童父母进行调查研究,考察歧视知觉对自闭症儿童父母群际关系的影响,同时考察群际焦虑的中介作用以及自尊对该中介过程的调节。结果表明：（1）歧视知觉对自闭症儿童父母的群际关系具有显著负向预测作用;（2）群际焦虑在自闭症儿童父母的歧视知觉和群际关系中起部分中介作用;（3）自尊调节了群际焦虑在歧视知觉和群际关系间中介作用的直接路径和后半路径。具体而言,在高自尊情况下,自闭症儿童父母的歧视知觉对群际关系的影响作用加强;在低自尊情况下,自闭症儿童父母的群际焦虑对自闭症儿童父母群际关系影响作用加强。     

The Influence of Family and Community Factors on Ethnic Identity

Ethnic identity (EI) is influenced by many factors, but few studies have examined the relative contribution of parenting style and other factors to EI. We addressed this gap by examining the effects of family and community factors on the EI of ethnic minority students enrolled in graduate psychology programs in the United States. The results suggest that family, peers, and experiences of discrimination significantly influence EI. Familial cultural socialization was the strongest contributor to EI. La identidad étnica (EI, por sus siglas en inglés) recibe influencia de muchos factores, pero pocos estudios han examinado la contribución relativa del estilo parental y otros factores a la EI. Abordamos este vacío examinando los efectos de los factores de familia y comunidad en la EI de estudiantes de minorías étnicas matriculados en programas de psicología de posgrado en los Estados Unidos. Los resultados sugieren que la familia, los compañeros y las experiencias de discriminación influyen en la EI de forma significativa. La socialización cultural familiar fue el factor que ejerció la mayor influencia sobre la EI.