Effect of telencephalon ablation on the reinforcing and eliciting properties of species-specific events in Betta splendens

In male Betta splendens, aggressive behavior is drastically attenuated following telencephalon ablation. Because instrumental training and Pavlovian conditioning experiments with intact fish have suggested that associative factors may play an important role in the performance of agonistic behaviors, the effect of ablation on instrumental learning and Pavlovian conditioning was studied. In Experiment 1, ablation had no effect on the learning of the instrumental tunnel-swimming response reinforced by mirror presentation (i.e., viewing a conspecific), although the mirror presentations in yoked-control groups elicited fewer responses in ablates than in normal and sham-operated control fish. Yoked controls further established that instrumental responding was maintained by the reinforcement contingency and was not merely the result of increased motor activity. Experiment 2 studied Pavlovian conditioning of the components of the agonistic display. Unconditioned fin erection, gill erection, and tail beating (i.e., unconditioned responses, URs) to the mirror US all were less frequent in ablates than in normals or shams. Of these, only gill cover erection showed evidence of true conditioning (i.e., conditioned responses; CRs) in which responses to the conditioned stimulus (CS) are due to the pairings of CS and US (unconditioned stimulus). However, ablates suffered no impairment of conditioned gill erections. Ablates performed fewer fin erections to the CS; however, fin erection responses were not due to CS-US pairings but were attributable to pseudoconditioning. These results are related to hypotheses postulating the involvement of learning mechanisms in ablation-produced deficits and normal aggressive behavior.     

RITALIN VS. RESPONSE COST IN THE CONTROL OF HYPERACTIVE CHILDREN: A WITHIN-SUBJECT COMPARISON

A within-subject comparison was made of the effects of methylphenidate (Ritalin) and response cost in reducing the off-task behavior of two boys, 7 and 8 years of age, who had been diagnosed as having an attentional deficit disorder with hyperactivity. Several dosages of Ritalin (5 to 20 mg/day) were evaluated with the results indicating varying effects of the drug for both children. Response cost (with free-time as the reinforcer) was superior to Ritalin in raising levels of on-task behavior and in improving academic performance.     

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.     

The effect of the temporal locus of the introtact probe on the hypothesis-testing strategies of kindergarten children

The hypothesis-testing behavior of kindergarten children in discrimination learning was studied in a factorial design with two temporal placements of introtact probes (pretrial and posttrial) and two types of pretraining (unidimensional and multidimensional). Pretrial probes consisting of a request for the child's current hypothesis were administered in a conventional manner at the beginning of each trial with the stimuli in view and prior to the choice response. Posttrial probes were administered also with the stimuli in view, but after the choice response had occurred and feedback information had been provided. Learning-to-learn experience in solving three pretraining problems was given either with unidimensional simultaneous problems or with more complex multidimensional problems like the criterion tasks. The results indicated that posttrial probes produced superior local consistency, win-stay, and lose-shift probabilities, relative to pretrial probes, for both types of pretraining. Posttrial probes, however, facilitated learning and the testing of valid hypotheses only for multidimensional pretraining. These results are consistent with the hypothesis that posttrial probes constrain the child to be locally consistent and therefore improve short-term efficiency in hypothesis testing under both pretraining conditions. However, posttrial probes produce an improvement in long-term efficiency, and therefore in learning, only when other components of a successful strategy are acquired as in multidimensional pretraining.     

The relationship of impulse to response timing error

This paper examines the relationship between response impulse and timing error in 200 msec discrete timing responses over a range of movement velocities and system masses. The results from two experiments showed that variable timing error decreased as both movement velocity and the mass of the system to be moved increased. The variability of force proportional to force (measured either as impulse or peak force) decreased curvilinearly as force out-put increased. The correlations between each of these parameters and variable timing errors, calculated on a group mean basis, ranged between.91 and.95. The ability to predict the movement time outcome of each individual trial from impulse-related parameters was considerably reduced, although the relationship between the various kinematic and kinetic parameters did strengthen as the movement velocity approached maximum. Collectively, the findings show the size of impulse is related to movement timing error, although it is premature argue that impulse variability is a causal agent of timing error.     

Personality types as measured by the 16 PF

The possibility of isolating personality types using 16 PF profiles was studied by utilizing a Q-type factor analytic procedure. Four modal profiles, characteristic of major clusters of subjects, were derived and cross validated. These four major types successfully classified approximately 2/3 of the 16 PF protocols (n = 1037), and classified similar proportions of previously published profiles. Variation of classification rates as a function of race and sex was described, and strategies for utilizing the profiles for research and interpretive purposes were outlined.     

Skewness and asymmetry of distributions

The ‘skewness’ of a distribution, a poorly-defined term, is conventionally deemed to be invariant under linear transformations. A comparison is made of three criteria of it: the sign of odd central moments; the several relationships of the mean, the median and the mode; and asymmetry proper which is the set of ratios of the probability densities of all pairs of points equidistant above and below some arbitrary point, usually the principal mode. Some useful general relationships are discussed. The skeness of convolutions is briefly discussed. A class of distributions is identified for which the skewness of the minimum ofk competing processes is independent ofk. It has importance in the parametric study of survivorship.     

Abstraction of contingency in concept learning

It is generally agreed that concept learning involves the abstraction of some general representation or schema. Just what is abstracted, however, and how it is used in the classification of sets of stimuli in the natural world or in the laboratory, remain outstanding questions. In this paper a hypothesis involving contingency abstraction is described as a possible solution to these questions. An experiment which manipulated measured contingency in a concept-learning task, and which offered empirical support for the hypothesis, is reported. The advantages of a contingency-abstraction theory of concept learning are briefly discussed.     

Cognitive styles in the development of medical careers

Recent research has shown that academic choice and achievement may be partly a function of the student's standing on the field-dependence-independence cognitive-style dimension. The results of two longitudinal studies suggest that information about field dependence-independence may be of value for student guidance in the medical setting. The first, a study of college undergraduates who early expressed an interest in medicine, showed that these cognitive styles play a discernible role in determining who will eventually enter medical school. The second, a study of medical students, showed that field-dependent and field-independent students subsequently tend to choose different medical specialties. These results are consistent with cognitive-style theory, which proposes that field-independent people will choose vocations that require cognitive restructuring skills, whereas field-dependent people will choose vocations that require greater social-interpersonal involvement.