Stimulus control of free-operant avoidance: The contribution of response rate and incentive relations between multiple-schedule components

The associations formed in the components of a multiple schedule can be classified as (1) stimulus-response (S-R) associations and (2) stimulus-reinforcer (S-S^R) associations. The present experiments sought to determine the individual contribution of these S-R and S-S^R associations to stimulus control by manipulating them independently. Responses postponed shocks by 25 sec in the presence of a tone alone and a light alone in all experiments. The contingencies programmed in the absence of both tone and light established a reference for the S-R and S-S^R associations in tone and in light. All four possible combinations of signalling response increase or decrease together with incentive increase or decrease were studied. Although the influence of the contingencies operating in the absence of tone and light was difficult to detect from response rates in tone or light, presenting tone and light together revealed clear effects. Response rates in tone and light together relative to those in either alone depended upon the contingency operating in the absence of tone and light. Stimulus-response and stimulus-reinforcer associations appeared to counteract each other when in opposition and combine together to enhance each other when in agreement. This suggested that the associations of a stimulus to response and to incentive combine algebraically in determining stimulus control. An algebraic analysis in terms of the S-R and S-S^R associations conditioned to the stimulus elements comprising the training and test stimuli accounted for the observed patterns of data.     

Effect of sample presentation time on long-delay matching in the pigeon

The effect of sample stimulus presentation time on long-delay matching in highly practiced pigeons was investigated. The birds were found capable of above chance matching performance at a delay of 60 sec provided the sample stimulus was presented for 4 sec or longer. Matching accuracy increased as a negatively accelerated function of sample stimulus presentation time and decreased as a negatively accelerated function of time since the termination of the sample. The rate of forgetting was found to be independent of sample stimulus presentation time. The data were inconsistent with a temporal discrimination interpretation of the effect of presentation time on delayed matching. The data were interpreted as supporting a simple trace strength and decay model of pigeon delayed matching.     

Rapid educational rehabilitation for prison inmates

One of the major goals of prisons has been the educational rehabilitation of inmates. Studies have shown that predelinquents as well as delinquents could be motivated to achieve in academic areas through the use of an incentive system. The present study attempted to extend the behavioral yield of such a system with prison inmates. The academic performance of two inmates in math and English were compared when two levels of incentives were made contingent on that performance. The results showed that the two inmates passed academic tests as much as nine times faster under an enriched schedule of incentives than under a standard one. This increase in rate of performance was translated into actual academic achievement as one of the inmates passed 9th through 12th grade algebra in only 14 days. A standardized test confirmed this academic advancement for both inmates. These high rates of performance and academic achievement are even more dramatic in view of the fact that five months prior to this procedure, both inmates had been tested as being below average in intelligence.     

Individual differences in self-reinforcement style and performance in self-and therapist-controlled weight reduction programs

Thirty-seven overweight subjects were recruited from the staff of a V. A. Hospital for a weight reduction program. A self-reinforcement (SR) test was administered prior to treatment and subjects were classified as high or low self-reinforcers. Subjects were then exposed to one of two behavioral weight-reduction programs or a minimal treatment control condition. One treatment program emphasized self-control (SC) and the other incorporated a therapist controlled financial contingency for weight loss (EC). A significant interaction was found between SR group and treatment condition. High SR subjects lost weight at the rate of 1.49 pounds per week in the SC condition and only 0.37 pounds per week in EC. Low SR subjects lost at the rate of 1.06 and 1.01 pounds per week respectively in SC and EC. Implications for treatment and future research were discussed. The financial contingency had either neutral or negative effects. Caution was advised for any future use of that procedure.     

Texture gradient effectiveness in the perception of surface slant

To assess the development of monocular slant perception as well as the relative effectiveness of different sources of information, children in first, third, and fifth grades and college adults were asked to make judgments of surface slant on the basis of monocular texture gradient information. Accuracy of judgment increased with increasing age. In addition, differences in gradient effectiveness were found. Compression gradients were relatively ineffective sources of information, whereas perspective and multiple gradients resulted in greater accuracy. The results suggest limitations on the specificity of certain forms of gradients.     

Blocking of incidental information in young children

Methods of increasing learning efficiency through a blocking technique were examined in young children. An experimental group of children was trained on an initial task with one relevant dimension, followed by redundancy training in which an incidental dimension also became relevant. A control group given only redundancy training was compared to this group to test how much the experimental subjects blocked or screened out the incidental dimension. In order to increase blocking, three methods were used: a preset transfer problem, an overtraining on the initial task, and a delay following training. The most important finding was increased blocking through the Preset Condition. Overtraining and Delay Conditions had no effect. In addition, more slow learners on the initial task learned about the incidental dimension than fast or intermediate learners. Also, fewer subjects given form on the initial task learned about the incidental dimension than those given color. The Combined Blocking, Delay, and Overtraining group showed partial blocking, while the Preset group demonstrated complete blocking. No developmental differences occurred. The results were interpreted using a modification of Trabasso and Bower's attention model (Attention in learning: Theory and research. New York: Wiley, 1968).     

A probe trial procedure for the study of children's discrimination learning and transfer

A discrimination reversal problem was presented to 192 children varying in age from 3 to 5 years. At the end of both the initial learning and transfer trials, probe trials were introduced to ascertain the response rule describing children's choices. Results were analyzed in terms of a binary division of the children according to their responses to the probe stimuli; children who responded errorlessly (concept responders) were contrasted with children who made errors on the probes (instance responders). Using this criterion, it was found that many children transferred in a way different from the way they learned the initial problem. There was no difference in the proportion of younger and older children responding conceptually to the original problem, but older children were more likely to transfer conceptually when standard geometric blocks were used as stimuli. Future studies must consider the possiblity that learning and transfer may be accomplished by different processes whose application differs with age, the nature of the stimuli, and the stage of training.     

Handling negative inputs: On the plausible equity formulae

Equity research has been based on defining formulae that do not necessarily imply the hypotheses thought to have been derived from them and that are not consistent with empirical data cited as supporting equity theory. Neither Adams' (1965) ratio definition nor Walster et al.'s (1970, 1972, 1973) formula satisfy the fundamental criterion that, when equity holds, outcome should be an increasing function of input. Six formulae that do satisfy this fundamental criterion (including Adams' ratio definition restricted to positive ratios, Walster et al.'s revision of their formula, three formulae generated by a simple constructive procedure, and an exponential definition) are compared with respect to 11 other criteria and with respect to their predictions of the results of two thought experiments.