Algorithmic shaping and misbehavior in the acquisition of token deposit by rats

In two experiments, rats were trained to deposit ball bearings down a hole in the floor, using an algorithmic version of shaping. The experimenter coded responses expected to be precursors of the target response, ball bearing deposit; a computer program reinforced these responses, or not, according to an algorithm that mimicked the processes thought to occur in conventional shaping. In the first experiment, 8 of 10 rats were successfully shaped; in the second, 5 of 5 were successfully shaped, and the median number of sessions required was the same as for a control group trained using conventional shaping. In both experiments, “misbehavior,” that is, excessive handling and chewing of the ball bearings, was observed, and when the algorithmic shaping procedure was used, misbehavior could be shown to occur in spite of reduced reinforcement for the responses involved.     

The nature and treatment of stuttering as revealed by fMRI A within- and between-group comparison

This article reviews some of our recent functional magnetic resonance imaging (fMRI) studies of stuttering. Using event-related fMRI experiments, we investigated brain activation during speech production. Results of three studies comparing persons who stutter (PWS) and persons who do not stutter (PWNS) are outlined. Their findings point to a region in the right frontal operculum (RFO) that was consistently implicated in stuttering. During overt reading and before fluency shaping therapy, PWS showed higher and more distributed neuronal activation than PWNS. Immediately after therapy differential activations were even more distributed and left sided. They extended to frontal, temporal, and parietal regions, anterior cingulate, insula, and putamen. These over-activations were slightly reduced and again more right sided two years after therapy. Left frontal deactivations remained stable over two years of observation, and therefore possibly indicate a dysfunction. After therapy, we noted higher activations in persons who stutter moderately than in those who stutter severely. These activations might reflect patterns of compensation. We discuss why these findings suggest that fluency-inducing techniques might synchronize a disturbed signal transmission between auditory, speech motor planning, and motor areas.

Educational objectives: The reader will learn about and be able to: (1) identify regions of brain activations and deactivations specific for PWS; (2) describe brain activation changes induced by fluency shaping therapy; and (3) discuss the correlation between stuttering severity and brain activation.     

Reinforcement of compliance with respiratory treatment in a child with cystic fibrosis.

An 8-year-old boy with cystic fibrosis (CF), mental retardation, and autism exhibited noncompliance with respiratory treatments that were essential for the management of his CF. A treatment involving shaping cooperation while still allowing escape for aggression and avoidance behavior resulted in increases compliance with respiratory treatments and decreases in problem behavior. Treatment gains were maintained over 3 months.     

Reinforcing saccadic amplitude variability

Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we reinforced the least frequent saccadic amplitudes to increase variability, and then reinforced the central part of the amplitude distributions to reduce variability. The target was placed at a constant distance from the fovea after the saccade to maintain the postsaccadic visual signal constant and an auditory reinforcement was delivered depending on saccadic amplitude. The second experiment tested the effects of the contingency. We reinforced high levels of variability in 4 participants, whereas 4 other participants were assigned to a yoked control group. On average, saccadic amplitude standard deviations were doubled while the medians remained mostly unchanged in the experimental participants in both experiments, and variability returned to baseline level when low variability was reinforced. In the control group no consistent changes in amplitude distributions were observed. These results, showing that variability can be reinforced, challenge the idea of a stochastic neural noise. We instead propose that selection processes constrain saccadic amplitude distributions.     

A response to "On token reinforcement and stuttering therapy: Another view on findings reported by Howie and Woods (1982)"

Ingham's (1983) critique of our research is based on the unwarranted assumption that it claimed to be a replication of Ingham and Andrews' (1973a) study. Our report did not claim to be a replication. Procedural differences between treatments do not preclude the possibility of drawing general conclusions that may apply to related treatments, or suggesting possible confounding variables that might be operating in another study. We have nevertheless dealt with each of Ingham's methodological objections. In general, we believe that we struck an acceptable compromise between the needs of clients and theoretical and research demands. We stand by our original conclusions, and note with satisfaction that Ingham concurs with our emphasis on systematic structure rather than the presence or absence of rewards as the crucial component of this type of stuttering treatment.     

Conditional discrimination after errorless and trial-and-error training.

Children were trained on a visual discrimination by stimulus shaping, stimulus fading, or trial-and-error. Those who did not acquire the conditional discrimination received a second, different training. More children initially trained by stimulus shaping acquired the conditional discrimination than did those initially trained with stimulus fading or trial-and-error. After a history of fading or trial-and-error training, children were less likely to acquire the conditional discrimination even after the more successful procedure of shaping was later used.     

Transient effects of acquisition history on generalization in a matching-to-sample task

This study examined the role of learning history on the acquisition of a matching-to-sample task. Twelve preschool children learned four stimulus classes through instructions, shaping, or imitation. After reaching criterion, the subjects were exposed to changed discrimination contingencies to determine how each learning history affected the acquisition of responses appropriate to the new contingencies. All subjects reached criterion on the new relations, although the subjects with a shaping history adapted slightly more quickly than those subjects with a history of instructions or imitation. Given sufficient exposure to changed contingencies, rule-driven insensitivity to contingencies was overcome by experience with consequences. This result may be specific to younger subjects, but it suggests that instructions can be used in education without creating insensitivity to contingencies.     

USING PERCENTILE SCHEDULES TO INCREASE EYE CONTACT IN CHILDREN WITH FRAGILE X SYNDROME

Aversion to eye contact is a common behavior of individuals diagnosed with Fragile X syndrome (FXS); however, no studies to date have attempted to increase eye‐contact duration in these individuals. In this study, we employed a percentile reinforcement schedule with and without overcorrection to shape eye‐contact duration of 6 boys with FXS. Results showed that although aversion to eye contact is often thought to be unamenable to change in FXS, it can be shaped in some individuals using percentile schedules either alone or in combination with overcorrection.