Choice as a function of local versus molar reinforcement contingencies.

Rats were trained on a discrete-trial probability learning task. In Experiment 1, the molar reinforcement probabilities for the two response alternatives were equal, and the local contingencies of reinforcement differentially reinforced a win-stay, lose-shift response pattern. The win-stay portion was learned substantially more easily and appeared from the outset of training, suggesting that its occurrence did not depend upon discrimination of the local contingencies but rather only upon simple strengthening effects of individual reinforcements. Control by both types of local contingencies decreased with increases in the intertrial interval, although some control remained with intertrial intervals as long as 30 s. In Experiment 2, the local contingencies always favored win-shift and lose-shift response patterns but were asymmetrical for the two responses, causing the molar reinforcement rates for the two responses to differ. Some learning of the alternation pattern occurred with short intertrial intervals, although win-stay behavior occurred for some subjects. The local reinforcement contingencies were discriminated poorly with longer intertrial intervals. In the absence of control by the local contingencies, choice proportion was determined by the molar contingencies, as indicated by high exponent values for the generalized matching law with long intertrial intervals, and lower values with short intertrial intervals. The results show that when molar contingencies of reinforcement and local contingencies are in opposition, both may have independent roles. Control by molar contingencies cannot generally be explained by local contingencies.     

Relations between neonatal states and 8-month developmental outcome in preterm infants

This study investigated longitudinal relations between measures of neonatal state behavior and developmental outcome in a sample of preterm infants (N = 16). Results indicate that irritability/reactivity in the neonatal period is positively associated with Bayley scores and exploratory play at 8 months. Conversely, neonatal alertness was not associated with these developmental measures. These preliminary findings, based on a small sample, are discussed in the context of preterm function.     

THE “WHERE IS IT?” REFLEX: AUTOSHAPING THE ORIENTING RESPONSE

The goal of this review is to compare two divergent lines of research on signal-centered behavior: the orienting reflex (OR) and autoshaping. A review of conditioning experiments in animals and humans suggests that the novelty hypothesis of the OR is no longer tenable. Only stimuli that represent biological “relevance” elicit ORs. A stimulus may be relevant a priori (i.e., unconditioned) or as a result of conditioning. Exposure to a conditioned stimulus (CS) that predicts a positive reinforcer causes the animal to orient to it throughout conditioning. Within the CS-US interval, the initial CS-directed orienting response is followed by US-directed tendencies. Experimental evidence is shown that the development and maintenance of the conditioned OR occur in a similar fashion both in response-independent (classical) and response-dependent (instrumental) paradigms. It is proposed that the conditioned OR and the signal-directed autoshaped response are identical. Signals predicting aversive events repel the subject from the source of the CS. It is suggested that the function of the CS is not only to signal the probability of US occurrence, but also to serve as a spatial cue to guide the animal in the environment.     

The second offspring of General Process Learning Theory: Overt behavior as the ambassador of the mind

Wasserman suggested in a recent book review that the study of intervening cognitive processes represents a current focus of interest in animal learning and that this has led to a revitalization of comparative psychology. An examination of the volume reviewed suggests that he may have overstated the case. Most of the authors to whom he refers expressed dissatisfaction with traditional stimulus-response associationism but few argued for the extreme (information processing) sort of cognitive approach described by Wasserman.     

The acquisition of observing.

Pigeons were exposed to stimuli correlated with the presence or absence of a variable-interval 60-second schedule of reinforcement only while they depressed a crossbar or "perch." In the first experiment, the stimuli were different tilts of a line displayed on the key. When the difference in brightness between the line and the background (salience) was maximal, seven of eight birds acquired the discrimination, but when the difference was reduced by 50%, only one succeeded. In the second experiment, wavelength of chamber illumination served as the relevant dimension. Neither experiment showed a large effect attributable to the magnitude of the difference (disparity) between the positive and the negative stimulus. Individual differences in time spent observing were positively correlated with level of discrimination in the presence of the stimuli. All birds produced the positive stimulus for a greater proportion of the available time than they did the negative stimulus. This may be the mechanism that provides selective reinforcement of observing. Finally, the formation of a discrimination was analyzed in terms of changes in the proportion of time spent in contact with the discriminative stimuli.     

PROCEDURAL VARIATIONS IN GROUP CONTINGENCIES: EFFECTS ON CHILDREN'S ACADEMIC AND SOCIAL BEHAVIORS

There has been little research on the effects of the many procedural variables in applied group contingencies. In the present study, an individualized contingency and three group contingencies with different “responder” criteria (e.g., reward based on the group average, reward based on the work of a designated, low-achieving student, or reward based on the work of a randomly selected student) were applied to the academic work of primary grade children in a learning disabilities classroom. Group social interaction during each contingency was measured systematically. Although there were large individual differences in students' academic and social responses to the different contingencies, some consistent effects were observed. Two of the four low-achieving target students did their best academic work during the group contingency which focused on their performance as a designated responder. This type of contingency also produced high levels of positive social interaction in three of four groups of children observed.     

Serial learning in the pigeon.

Three pigeons learned to peck four colors in a particular sequence, regardless of how these colors were positioned on four response keys and without feedback following each response. This demonstrates that serial learning is possible in subprimate animals.     

SELF-STIMULATION AND LEARNING IN AUTISTIC CHILDREN: PHYSICAL OR FUNCTIONAL INCOMPATIBILITY?1

This study investigated whether an observed inverse relationship between self-stimulation and learning in autistic children is due to a physical inability of the subject to use the same body part for self-stimulation and task responding, or whether self-stimulation “distracts” the subject from task responding. Four actively self-stimulating autistic children were taught two discrimination tasks; one required a response that physically interferred with their self-stimulation; the other did not. Results were: (a) all subjects responded similarly across both tasks; (b) the three subjects with higher mental age scores learned both tasks without external suppression of self-stimulation; and (c) none of the subjects showed an inverse relationship between self-stimulation and learning. The study demonstrated that elimination of self-stimulation is not a necessary prerequisite for the acquisition of a new behavior in all autistic children.     

THE ROLE OF FEEDBACK IN VOLUNTARY CONTROL OF BLOOD PRESSURE IN INSTRUCTED SUBJECTS1

Forty normal male volunteers were randomly assigned to one of four experimental conditions and instructed to raise and lower their systolic blood pressure. Subjects received either beat-to-beat feedback contingent on pressure changes, noncontingent beat-to-beat feedback, noncontingent feedback presented randomly with respect to the occurrence of each heart beat, or instructions alone. The order of increase and decrease trial blocks was counterbalanced across groups. Subjects receiving contingent feedback were monetarily rewarded for appropriate pressure changes. Subjects receiving noncontingent feedback received rewards and feedback equal to the mean received by the contingent group. Subjects in the instructions-only condition were also paid this bonus but were informed of their earnings only at the conclusion of the experiment. Results indicated that in the presence of instructions, feedback, whether contingent or noncontingent, added little to subjects' ability to control pressure during a single session. Theoretical and clinical implications are discussed.     

TWO-TO-ONE versus ONE-TO-ONE STUDENT-TEACHER RATIOS IN THE OPERANT VERBAL TRAINING OF RETARDED CHILDREN1

The operant training of two retarded children simultaneously on a picture-naming task was investigated as an alternative to the more commonly reported one-to-one student-teacher ratio. In Experiment I, two conditions were compared in which the children received primary reinforcement on a fixed-ratio schedule for responding correctly on prompt and probe trials in a standardized picture-naming procedure. During the “Group Condition”, the experimenter alternated from one child to the other after each primary reinforcement, after each incorrect response, after each response omission, and after each 10-sec period in which a child did not “attend” (by making a trial-initiating response) when it was his or her turn to be worked with. During the “Individual Condition”, the experimenter worked with only one child, and presented trials whenever the child made attending responses. Experiment I demonstrated that the Group Condition was more efficient than the Individual Condition in terms of total correct responses and total pictures learned per unit of training time. Incidental learning was also found in that the children learned some of each others' pictures as well as their own, thus indicating a further advantage of the larger student-teacher ratio. In Experiment II, an attempt was made to equate the two conditions, except for the presence of two children in the Group Condition, by ignoring the child in the Individual Condition for brief periods equal to those that occurred in the Group Condition when the experimenter presented training trials to the other child. The results demonstrated that the greater efficiency of the Group Condition was not due to the manner in which training time was allocated to the two members of a group. It also replicated the finding that the children learned some of each others' words in the Group Condition.