An experimental analysis of the effects of d-amphetamine and cocaine on the acquisition and performance of response chains in monkeys.

In one component of a multiple schedule of food presentation, monkeys acquired a different four-response chain each session by responding sequentially on three keys in the presence of four geometric forms (learning). In the other component, the four-response chain was the same each session (performance). Both d-amphetamine and cocaine, at the higher doses, disrupted the behavior in the learning component; the overall response rate decreased, the overall accuracy was impaired (i.e., percent errors increased), and there was less within-session error reduction. The performance component was generally less sensitive than the learning component to the disruptive effects of both drugs on rate and accuracy. After pre-feeding or during an extended session, the response rate decreased in both components, but accuracy was generally unaffected. When the four discriminative stimuli in both components were removed, the behavior was disrupted to a greater extent in the performance component. The disruptive effects of both drugs on behavior in the learning component were attenuated when the drugs were administered during the session after the response chain had been acquired. It was concluded that the greater sensitivity of the learning component to disruptive drug effects is related to the relatively weak stimulus control and/or the lower rate of reinforcement associated with that component.     

Control of responding during stimuli that precede transitions in reinforcement frequency

Pigeons' responses were reinforced on a variant of a mixed variable-interval extinction schedule of reinforcement in which the transition to the higher reinforcement rate was signaled by a trace stimulus projected on the response key prior to the onset of the component correlated with food delivery. In the first of two experiments, the duration of the trace stimulus preceding the component correlated with food delivery was varied from 1.5 to 50.0 s and in the second experiment, the reinforcement frequency in the same component was varied from 10 to 60 reinforcers per hour. Pigeons pecked at the trace stimulus preceding the onset of the component correlated with food delivery even though responding was not reinforced in its presence and only one of the changes in reinforcement rate (i.e., from extinction to reinforcement) was signaled. The rate of pecking during the trace stimulus was a function of its duration but not of the reinforcement frequency in the following component. Higher rates generally occurred at the shorter trace-stimulus durations. Component responding following the offset of the trace stimulus was under discriminative control of the trace stimulus whether or not responding occurred in the presence of the trace stimulus.     

Saying and doing: A contingency-space analysis

Correspondences between verbal responding (saying) and nonverbal responding (doing) may be organized in terms of the classes of verbal/nonverbal relations into which particular instances of verbal/nonverbal response sequences can enter. Contingency spaces, which display relations among events in terms of the probability of one event given or not given another, have been useful in analyses of nonverbal behavior. We derive a taxonomy of verbal/nonverbal behavior relations from a contingency space that takes into account two conditional probabilities: the probability of a nonverbal response given a verbal response and that probability given the absence of the verbal response. For example, positive correspondence may be said to exist as a response class when the probability of doing is high given saying but is otherwise low. Criteria for other generalized classes, including negative correspondence, follow from this analysis.     

Effects of relative reinforcer frequency on complex color detection

Pigeons were trained under a discrete-trials detection procedure in which one of a set of color stimuli was presented on the center key and a single response turned off the stimulus and illuminated two side keys. Single responses to one or the other side key produced occasional reinforcers depending on the value of the color stimulus. In Experiment 1, one color-stimulus set comprised 559, 564, 569, and 574 nm, and right-key pecks were occasionally reinforced following presentations of members of this set. The other stimulus set comprised 579, 584, 589, and 594 nm, and left-key pecks were occasionally reinforced following presentations of members of this set. Across seven experimental conditions, the left/(left + right) relative reinforcer frequency was varied from .1 to .9. In Experiment 2, one stimulus set contained only one member, 574 nm, and right-key responses were occasionally reinforced following its presentation. Over 12 experimental conditions, two manipulations were carried out. First, the number of stimuli comprising the other stimulus set was increased from one (579 nm) to two (579 and 584 nm) to three (579, 584, and 589 nm) and to four (579, 584, 589, and 594 nm), and left-key responses were reinforced occasionally following center-key presentations of members of this set. Second, for each stimulus combination, the left/(left + right) relative reinforcer frequency was varied from .1 to .5 to .9 across three experimental conditions. The principal finding of Experiments 1 and 2 was that reinforcers and stimuli interacted in their effects on behavior. In Experiment 3, pairs of adjacent stimuli (5 nm apart) in the range 559 to 594 nm were presented in each experimental condition, and the left/(left + right) relative reinforcer frequency was held constant at .5. The data from all three experiments were analyzed according to a detection model describing performance in multiple-stimulus two-response procedures. This model provided independent measures of stimulus discriminability, contingency discriminability, and bias. The analysis showed that (a) consistent with the color-naming function, pigeons were better able to discriminate between higher nanometer values than lower nanometer values; (b) their ability to discriminate between the stimuli was independent of the number of wavelengths comprising each stimulus set; (c) they allocated delivered reinforcers very accurately to the previously emitted response; and (d) no consistent biases emerged.     

Visually guided catching and tracking skills in pigeons: A preliminary analysis

Research on reaching, tracking, and catching in the pigeon has been hampered by limitations of technology. A new system was developed in which the target was a small rectangle presented on a video display terminal and the pecking response was detected with touch technology. The target moved up and down vertically with sinusoidal velocity. A coincidence between the location of the pigeon's beak and the cursor produced reinforcement. The pigeon pecked ahead and behind the target, but most pecks occurred behind the target so the dominant tracking strategy was lagging. The pigeon was adept at “catching” the target at many locations throughout the trajectory. Transfer of motor learning was tested on probe trials during which the trajectory changed from vertical to horizontal. On transfer trials the pigeons' dominant pattern of pecking immediately shifted from vertical to horizontal. The motor skill displayed by the pigeons was flexible and adaptive, suggesting that the pigeons had learned to track the cursor.     

Generalization and maintenance of the reduction of self-injurious behavior maintained by two types of reinforcement

The self-injurious forehead-gouging behavior that had resulted in blindness for a profoundly retarded 27-yr-old male was successfully treated using a combination of differential reinforcement of incompatible behavior during unstructured situations and prevention of escape during compliance situations. After self-injurious behavior was reduced to a low frequency, a reduction of his daily dose of chloral hydrate was accompanied by a large increase in self-injury, but the behavior gradually returned to its previous low level. A large increase in self-injury also occurred following transfer to another living unit, but the behavior again decreased to a low frequency. Treatment gains were maintained following transfer to another residential facility with follow-up observations occurring at 1, 2, 8, 15, 22, 27 and 35 months. The multiple determination of self-injurious behavior in this one S highlights the behavioral complexity of some of these behaviors.     

On the relationship of hardiness to the Type A behavior pattern: Perception of life events versus coping with life events

A correlational study examined the relationship between perceptions of life events and psychological distress with regard to the moderating effects of personality. Subjects assessed for both hardiness (S. C. Kobasa, 1979, Journal of Personality and Social Psychology, 37, 1–11) and Type A behavior (M. Friedman & R. Rosenman, 1974, Type A Behavior and Your Heart, New York: Knopf) completed the Langner psychiatric symptom inventory, reported life events for the previous year, and rated each event for its desirability, controllability, and foreseeability. Results indicated that an accumulation of events perceived as undesirable was associated with distress for subjects low in hardiness. In contrast, events perceived as moderately controllable or uncontrollable, regardless of their desirability, were associated with increased distress for Type A's. The likelihood of experiencing any given event was not related to any personality type. However, hardy individuals differed from their low hardy counterparts in that, on average, they were more likely to perceive an event as desirable and controllable. No such perceptual biases were observed between Type A and B subjects. The discussion focuses on the combination of personality variables and the moderating effects of perceiving events versus coping with events in the stress-health relationship.     

Message therapy: Language approach to stuttering therapy with children

Message therapy is a clinical procedure designed to be used as a carry-over technique with school-age stutterers or as a sole technique with the preschooler. The focus of therapy is on a unit of communication rather than on the moment or place of stuttering. One of the basic assumptions of the procedure is that the child is beginning to monitor how he/she is speaking rather than what is being communicated (i.e., the “message”)—each task requiring a different cognitive process. The emphasis of the therapy is to redirect the child's attention to “what he/she is saying.” The clinical procedures are discussed as they relate to the specific population.     

Intelligence and age as predictors of motor performance

The Yule-Oseretsky test of motor performance was administered to 10 ‘undifferentiated’ mentally-retarded adults, 10 normal children and 10 normal adults. In accordance with Denny's (1964) 3-group design, the children were matched on mental age with the retardates, the normal adults were matched on chronological age with the retardates, and the children and normal adults were matched on intelligence quotient. The results showed that mental age predicted performance on both fine and gross motor tasks, with the children and retarded adults both obtaining similar relatively-low scores.