Positive contrast, negative induction, and inhibitory stimulus control in the rat

In Experiment I, 24 rats were trained on a multiple variable-interval variable-interval schedule with a doorlight and white noise serving as component cues. Two groups were then shifted to a multiple extinction variable-interval schedule, and a third group was maintained on the multiple variable-interval variable-interval schedule. The multiple extinction variable-interval condition produced positive contrast when either the light or noise signalled extinction, and both of these cues acquired inhibitory stimulus control as measured by a combined cue test. In Experiment II, the multiple variable-interval variable-interval condition was shifted to multiple extinction variable-interval for one group, to multiple variable-time variable-interval for a second group, and was unchanged for the third group. The two experimental conditions produced identical patterns of response-rate reduction in the altered component, but the multiple extinction variable-interval condition produced positive contrast, whereas the multiple variable-time variable-interval condition did not. Subsequent combined cue and resistance to reinforcement tests revealed that the cue signalling extinction acquired stronger inhibitory stimulus control than the cue signalling variable time.     

Signalled free-operant avoidance of shock by pigeons pecking a key

Two pigeons were trained to peck a key under a free-operant avoidance schedule. Then, changes in key color signalled the beginning (safe period) and the end (warning period) of the response-shock interval, with a response required to change the key color. Finally, a change in key color signalled the warning period and either a response or a shock reinstated the safe stimulus. During signalled avoidance, response rate was higher during the warning stimulus than during the safe stimulus. More responding tended to occur in the warning stimulus when it was terminated by either a response or a shock than by only a response. In either procedure, response latency during the warning stimulus was a function of the duration of the warning stimulus. In general, response and shock rate were higher during unsignalled than during signalled avoidance. When the warning stimulus was brief, the results were similar to those of unsignalled avoidance. These results confirm previous findings with pigeons, are in general agreement with data provided by other species in studies of signalled avoidance, and thereby indicate the transituationality of the key-pecking operant.     

The nature of control by spoken words over visual stimulus selection.

Eight retarded adolescents were trained to select one (a trained S+) of two visual stimuli in response to a spoken word (a trained word). Two different visual stimuli alternated randomly as the S-. To determine if the spoken work was merely a temporal discriminative stimulus for when to respond, or if it also specified which visual stimulus to select, the subjects were given intermittent presentations of untrained (novel) spoken words. All subjects consistently selected the trained S+ in response to the trained spoken word and selected the previous S- in response to the untrained spoken words. It was hypothesized that the subjects were responding away from the trained S+ in response to untrained spoken words, and control by untrained spoken words would not be observed when the trained S+ was not present. The two visual S- stimuli selected on trials of untrained spoken words were presented simultaneously. The untrained spoken words presented on these trials no longer controlled stimulus selections for seven subjects. The results supported the hypothesis that previous control by spoken words was due to responding away from the trained S+ in response to untrained spoken words.     

BEHAVIOR ANALYSIS APPLIED TO ENVIRONMENTAL/ECOLOGICAL PROBLEMS; A REVIEW1

Recent applications of operant technology, including the manipulation of environmental conditions and response consequences, have been directed toward the improvement of man-environment relations. This document summarizes the research designs, procedures, results, and conclusions of these recent behavioral interventions for ecological rebalance. Each of the 32 studies reviewed was undertaken since 1970; all studies were relatively successful in changing the probability of an ecology-related response; all studies incorporated basic methodologies applicable for large-scale, community programs; most of the investigations were conducted in field settings (e.g., college campuses, grocery stores, mobile-trailer parks, homes, movie theaters, public campgrounds, and a football stadium). Several of the studies are as yet unpublished. Sources for receiving documentation of the unpublished research are provided in this document. About 50% of the investigations reviewed were designed to influence behaviors related to environmental litter; the others were of behavior-modification programs that substantially increased bus-ridership, decreased lawn-trampling, promoted the purchase of drinks in returnable rather than throwaway containers, initiated a recycling process, or reduced energy consumption. Essentially, the interventions were either preventive in nature (i.e., designed to discourage environment-destructive behaviors before they occur), or remedial (i.e., designed to encourage behaviors that correct an existing environmental problem). Usually, the preventive measures emphasized responses priming (or prompting), while the corrective measures applied some form of positive reinforcement. Response priming was accomplished with modelling techniques, or with written and/or verbal prompts presented either publicly or on a personal, one-to-one basis. Among the positive reinforcement procedures were field applications of token economies, lottery systems, feedback programming, and intergroup contests, as well as individual contingency contracting. Some experimental designs provided for comparisons between the behavioral effects of response priming and positive reinforcement.     

Dimensional stimulus control following brief wavelength training

Pigeons with extensive training pecking a key illuminated by a white line then had brief training with the key illuminated by 555 nanometers. This was immediately followed by a wavelength generalization test in extinction. Dimensional stimulus control about the training wavelength increased with the duration and number of reinforcements given on variable-interval 30-sec and variable-interval 10-sec schedules in Experiment I. In Experiment II, dimensional stimulus control was obtained after only 4 min of wavelength training from birds with prior and independent discrimination training. Experiment III provided groups equated in number of reinforcers with groups in Experiment I and two 8-min duration groups. Analyses, which included results from both Experiments I and III, showed that dimensional stimulus control increased: (a) more rapidly as a function of the duration of variable-interval 10-sec than variable-interval 30-sec reinforcement; (b) at the same rate across variable-interval reinforcement schedules, as a function of the number of reinforcers available during brief wavelength training.     

Food deliveries during the pause on fixed-interval schedules

Pigeons were trained on fixed-interval schedules of food delivery. In Experiments I and II, the fixed interval was initiated by the previous fixed-interval reinforcer; in Experiment III, the fixed interval was initiated by the first key peck following the preceding fixed-interval reinforcer (a chain fixed-ratio one, fixed-interval schedule). During the postreinforcement pause, variable-time schedules delivered food independent of any specific response. Rate of food delivery during the pause had only small effects on pause duration in Experiments I and II. In Experiment III, however, pause duration increased systematically with the rate of food delivery during the pause. These data suggest that the momentary proximity to reinforcement delivered via the fixed-interval schedule exerts potent control over pause termination. Additional analysis revealed that pause termination was unaffected by the intermittent delivery of food during the pause. Such data suggest that the temporal control by fixed-interval schedules is highly resistant to interference.     

Stimulus control of differential-reinforcement-of-low-rate responding

Five pigeons were given single-stimulus training on an 8-sec differential-reinforcement-of-low-rate schedule followed by steady-state generalization training using 12 wavelength stimuli. Three birds had a high percentage of reinforced responses on the training schedule and flat generalization gradients of total responses. The birds with fewer reinforced responses had much steeper generalization gradients. Generalization gradients plotted as a function of both stimulus wavelength and interresponse time showed that for most birds, stimulus control was restricted to responses with long interresponse times. Responses with very short interresponse times were not under stimulus control and there was some evidence of inhibitory control of short interresponse times. Interresponse-times-per-opportunity functions, plotted as a function of stimulus wavelength, showed that stimulus wavelength controlled the temporal distribution of responses, rather than the overall rate of response. The data indicate that the differential-reinforcement-of-low-rate schedule generates several response categories that are controlled in different ways by wavelength and time-correlated stimuli, and that averaging responses regardless of interresponse-time length obscures this control.     

Changes in Anxiety Control Beliefs Following a Brief CBT Treatment and Their Association With Anxiety Symptom Reduction

Anxiety control beliefs (i.e., beliefs regarding one’s ability to cope with external, fear-inducing threats and internal reactions to those perceived threats) have been found to negatively predict anxiety symptoms in children and adults and to be modifiable by cognitive-behavioral therapy for anxiety disorders. The current study examines whether changes in anxiety control beliefs were seen following a brief, intensive treatment for specific phobias, and whether those changes were associated with improvements in the targeted phobia and comorbid anxiety disorder symptoms. Participants were 135 children and adolescents (M age = 9.01 years, 49% male) who received one-session treatment (OST) with or without parental involvement for their primary specific phobia. Results indicated that self-reported anxiety control beliefs significantly increased following treatment and that these increases significantly predicted reductions in specific phobia severity and symptoms of comorbid anxiety disorders 6 months and 1 year following treatment. Findings illustrate that involvement in a single 3-hour OST was associated with changes in anxiety control beliefs and demonstrate the potential importance of targeting control beliefs in pediatric anxiety treatment.     

Childhood Maltreatment,Emotional Response Inhibition,and Suicide in Psychiatric Inpatients

Childhood abuse and/or neglect adversely influences development of neurocognitive systems that regulate affect and behavior. Poor inhibitory control over emotional reactions is thus one potential pathway from maltreatment to suicide. Adult psychiatric inpatients completed the Childhood Trauma Questionnaire and an emotional stop-signal task indexing negative emotional action termination (NEAT): the ability to inhibit ongoing motor reactions to aversive stimuli triggered by negative affect. Clinical interviews assessed suicidal thoughts and behaviors during hospitalization (n = 131) and at follow-up assessments 6 months later (n = 87). Our primary aim was to examine whether maltreatment history and NEAT explain overlapping variance in suicidal behaviors (1) retrospectively and (2) 6 months following hospital discharge. Contrary to prediction, childhood maltreatment was unrelated to history of suicidal behaviors. However, NEAT was consistently associated with prior suicidal acts, even controlling for suicidal ideation and demographic covariates. NEAT similarly contributed to the prediction of post-discharge suicidal behaviors, whereas we found no effect of maltreatment history. The present study suggests that NEAT captures suicide risk independently of childhood maltreatment. Results implicated NEAT impairment specifically, rather than broader response inhibition deficits (e.g., to positive stimuli), in past and future suicidal behaviors. These findings provide preliminary support for NEAT as a behavioral vulnerability marker for suicide, with implications for understanding links between maltreatment history and suicidal acts.