The free-operant partial reinforcement effect: A discrimination analysis

Twelve continuously reinforced rats were extinguished in a modified operant chamber, with an S^D for goal-approach after each bar-press. Three groups of twelve rats each trained under FR 10 were extinguished with the S^D for goal-approach after every 6, 10, or 14-bar-presses, respectively. Results showed: (1) number of bar-presses to extinction was a direct function of the bar-press to S^D ratio during extinction, (2) number of food or goal-approaches was independent of both training and extinction conditions, and (3) prior to the breakdown in discrimination a revised response-unit hypothesis, based on a discrimination analysis of the effect of intermittent reinforcement, accurately predicted the number of bar-presses for each FR group.     

A test of expectancy theory in a field setting using female clerical employees

Female clerical workers were rated on seven dimensions of job performance using behaviorally based rating scales, these 266 subjects responded to questionnaire items concerned with their expectations dealing with (1) whether their job effort resulted in effective performance (Expectancy I), and (2) whether job performance leads to reward outcomes (Expectancy II). These Expectancies were found not to be highly related to the measures of job performance in contrast to expectancy theory predictions. Satisfaction with reward outcomes was found to be differentially related to individuals' expectations that performance results in the attainment of particular outcomes.     

A note on a paper by Rumelhart and Greeno

The parameters of the models described by Rumelhart and Greeno in this journal (1971) are constrained in certain ways. Neglect of this fact in their paper leads them to an inadmissible set of parameter values, and an invalid argument and statement concerning the equivalence of two models. However, their conclusion that the Restle model fits their data better than the Luce model remains unchanged.     

On-line monitoring of eye-position signals in contingent and noncontingent paradigms

This paper presents a research methodology for the study of human attentional and perceptual processes by means of on-line monitoring of eye-position signals. The first part of the presentation considers techniques by which commercially available apparatus may be interfaced to a minicomputer for purposes of monitoring eye-position signals during psychological experiments. Hardware and software techniques related to automating the calibration, recording, and analysis of eye-position data are discussed. The second part of the paper discusses a more advanced research methodology, one in which visual stimuli are contingent upon momentary eye-position signals. The methodology is appropriate to a variety of studies in which eye movements are considered to be part of an attentional control system. Several experimental applications are described. The implementation of eye-position-stimulus contingencies on a small computer poses additional technical problems, several of which are discussed.     

Modeling strategy shifts in a problem-solving task

A computer simulation model was fitted to human laboratory data for the Missionaries and Cannibals task to explain (1) the effects upon problem performance of giving a hint, and (2) the effects of solving the problem a second time after one successful solution had been achieved. Most of the variance in the relative frequencies of different moves can be explained by positing that the effect of the hint, or of previous experience in solving the problem, is to cause subjects to switch more promptly from a strategy of balancing the numbers of missionaries and cannibals on both sides of the river, to a means-ends strategy.     

REDUCING TIME LIMITS: A MEANS TO INCREASE BEHAVIOR OF RETARDATES1

A common assumption in special education is that temporal limits for a task should be expanded so that ample time is provided for completing the work. This study describes the opposite strategy of restricting temporal limits to augment academic performance. Three educable retarded children received token reinforcement contingent on the number of correct math problems answered during daily sessions. A reversal design was used to assess the effects of an abrupt reduction in time limits (20-5-20 min) and a graduated sequence of reductions (20-15-10-5-20 min). The graduated sequence resulted in rate increases of correct responding ranging from 125% to 266% and these gains endured when temporal limits were again expanded. In contrast, the abrupt shift produced interfering emotional behaviors and rate decreases in academic performance of 25% to 80%. The findings indicate that systematically restricting temporal limits for an academic task can further enhance the performance of slow learners already maintained by a token system.     

Projective and inductive generation of abstract logics

An abstract logic A, C consists of a finitary algebraA and a closure systemC onA. C induces two other closure systems onA, C _P andC _I, by projective and inductive generation respectively. The various relations amongC, C _P andC _I are determined. The special case thatC is the standard equational closure system on monadic terms is studied in detail. The behavior of Boolean logics with respect to projective and inductive generation is determined.Allatum est die 17 Junii 1975     

Sex-related patient and therapist effects on clinical judgment

The purpose of this investigation was to submit the claim of sex-related bias in clinical judgment to more thorough empirical testing than had been the case in previous research. Patient sex and stereotypic sex-role were factorially varied in a clinical protocol that was sent with related materials to 640 sex-stratified, randomly selected Members and Fellows of APA Division 29 (Psychotherapy). Approximately 30% (N=182) of those contacted returned usable data, including information about their own sex-role traditionalism and evaluation of the hypothetical patients' psychological well-being. Results confirmed the effectiveness of the stereotypic sex-role manipulation. However, no consistent effects were found for any of the four variables of interest considered in isolation or in combination, thereby refuting allegations of covert sex-related discrimination perpetrated under the aegis of psychological appraisal. Favorableness of clinical impressions was not mediated by therapists' self-reported attitudes toward the patients. The study's generally unexpected outcome was tentatively attributed to enhanced professional sensitization to the sociocultural barriers to full psychological functioning in women.This report is based on a master's thesis written by the first author under the sponsorship of the second and submitted in partial fulfillment of the requirements for the MA degree at Vanderbilt University, 1974. The research was supported in part by the Vanderbilt University Research Council. The contributions of Stephen Amira and Joseph M. Schwartz are gratefully acknowledged.