Concurrent schedules: Effects of time- and response-allocation constraints

Five pigeons were trained on concurrent variable-interval schedules arranged on two keys. In Part 1 of the experiment, the subjects responded under no constraints, and the ratios of reinforcers obtainable were varied over five levels. In Part 2, the conditions of the experiment were changed such that the time spent responding on the left key before a subsequent changeover to the right key determined the minimum time that must be spent responding on the right key before a changeover to the left key could occur. When the left key provided a higher reinforcer rate than the right key, this procedure ensured that the time allocated to the two keys was approximately equal. The data showed that such a time-allocation constraint only marginally constrained response allocation. In Part 3, the numbers of responses emitted on the left key before a changeover to the right key determined the minimum number of responses that had to be emitted on the right key before a changeover to the left key could occur. This response constraint completely constrained time allocation. These data are consistent with the view that response allocation is a fundamental process (and time allocation a derivative process), or that response and time allocation are independently controlled, in concurrent-schedule performance.     

Sensory superstition on multiple interval schedules.

Pigeons were exposed to multiple schedules in which an irregular repeating sequence of five stimulus components was correlated with the same reinforcement schedule throughout. Stable, idiosyncratic, response-rate differences developed across components. Components were rank-ordered by response rate; an approximately linear relation was found between rank order and the deviation of mean response rate from the overall mean rate. Nonzero slopes of this line were found for multiple fixed-interval and variable-time schedules and for multiple variable-interval schedules both when number of reinforcements was the same in all components and when it varied. The steepest function slopes were found in the variable schedules with relatively long interfood intervals and relatively short component durations. When just one stimulus was correlated with all components of a multiple variable-interval schedule, the slope of the line was close to zero. The results suggest that food-rate differences may be induced initially by different reactions to the stimuli and subsequently maintained by food.     

Structural models for the mediation of salience effects on attribution

Previous research has demonstrated that salient information is overrepresented in causal attributions. Two experiments were conducted to investigate potential mediators for this effect and to make a case for the use of structural models in explanations of process. Two mediators were considered: enhanced visual recall of salient stimuli and exaggerated schema-relevant recall of salient stimuli. Although analyses of variance supported the visual recall model, structural analyses demonstrated its implausibility. Analyses of variance and structural models revealed that schema-relevant recall, that is, information seen as representative of causal influence, is a plausible mediator; this was particularly true of relevant visual information. Results suggest that salience effects (S. E. Taylor & S. T. Fiske in L. Berkowitz (Ed.), Advances in experimental social psychology (Vol. 11). New York: Academic Press, 1978) are due to: (a) the attentional advantage of inherently salient visual events and (b) the influence of stored visual and nonvisual schema-relevant information on causal judgments.     

The self-serving attributional bias: Beyond self-presentation

An experiment was conducted to provide empirical support for the notion that asymmetrical causal attributions for favorable and unfavorable outcomes result from a self-serving attributional bias that occurs independently of self-presentational concerns. Subjects did either well or poorly on an ego-involving test for which their performance, attributions, and evaluations of the test were either public or private. A pattern of self-serving responses for subjects' attributions and evaluations of the test was found in the private conditions, thus providing evidence of the influence of outcome favorability on individuals' perceptions of causality. Theoretical and practical implications of these finding are discussed and suggestions for future research are offered.     

Counting eliminates the repetition effect in judgments of temporal duration.

College student subjects estimated the duration of time intervals (8–54 sec) by counting or not (N=35 per group). Counting eliminated the repetition effect (a decline in the magnitude of estimations across trials), and resulted in a truncation of the psychophysical function. The former result was interpreted as contrary to Treisman's (1963) model. The latter result was attributed to the effortfulness of counting, which was established in a subsequent experiment.     

Semantic focus and sentence comprehension.

Reaction time to detect a phoneme target in a sentence was found to be faster when the word in which the target occurred formed part of the semantic focus of the sentence. Focus was determined by asking a question before the sentence; that part of the sentence which comprised the answer to the sentence was assumed to be focussed. This procedure made it possible to vary position of focus within the sentence while holding all acoustic aspects of the sentence itself constant. It is argued that sentence understanding is facilitated by rapid identification of focussed information. Since focussed words are usually accented, it is further argued that the active search for accented words demonstrated in previous research should be interpreted as a search for semantic focus.     

Reward and number of choices in children's probability learning: An attempt to reconcile conflicting findings

Five event schedules (75:0, 75:25, 75:0:0, 72:25:0, 75:12.5:12.5) were examined in a size discrimination task with penny rewards and plastic token markers. The subjects were 100 fourth graders (mean age = 9.4 years) and 100 undergraduates of both sexes. Whether or not the event probabilities summed to unity proved to be a more important determiner of terminal performance than the number of response alternatives in the task (p < .01). Females maximized more than males (p < .001) and college students more than fourth graders (p < .001). Greater maximization was exhibited by fourth graders in the reward condition (p < .01). These reward effects appeared to be more consistent with a detrimental-effects-of-reward interpretation than either utility or expectancy interpretations.     

Imaging,empathy, and causal attribution

Three studies were conducted to test whether imagery accounts for the effects of empathy on attributions, that is, whether attributers construct and scan a mental image of social scenarios the same way that actual participants scan a real environment. According to this interpretation, attributers “see” the world as the participant does and make vicarious attributions. An alternative interpretation holds that subjects base vicarious attributions on recreating the motivations and affect of the actor, so that imaging is irrelevant to empathy and attributions. In the first study, subjects who imagined a story from the perspective of a particular character later showed differential recall of story details as a function of role, but not differential attributions. In Experiment 2, role-taking subjects showed clear effects of imaged perspective on recall for story details, but no effects on attributions of causality for an accident. Further, recall and attribution were uncorrelated. In the last study, empathy and imagery role-taking instructions produced independent effects: imagers showed pronounced perspective-relevant recall and empathizers did not. Neither showed unambiguous vicarious attributions. Recall and attribution were again uncorrelated. These studies suggest that the imagery explanation of empathy effects is untenable, and imply that the recall of perspective-relevant details is unlikely to mediate attributions of causality in imaginary scenarios.     

A multi-element analysis of the effect of teacher aides in an "open"-style classroom

Open classrooms with few rules, individualized instruction, and informal class organization present new problems for the application of behavior principles. The effects of three types of teacher aides on student achievement and on-task behavior were studied. Each was compared with a standard no-aide condition. Subjects were 54 third graders in two "open"-style classrooms. The three types of aide, helping adult, disciplinary adult, and helping fifth-grade aide, were compared in a multi-element design with a no-aide control. The helping-adult aide significantly affected the academic output of the class, when compared with the no-aide condition. All aide conditions produced more academic work and on-task behavior than did the standard no-aide condition.