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At least 1,711 records · Page 95Linked to original sources
PubMed1976

Family interaction and adolescent suicidal behaviour: a preliminary investigation.

While investigators have emphasized the importance of familial relations in the production of suicidal behaviour in adolescence, experimental evaluation of specific family interaction processes has, thus far, been neglected. The aim of the present study was to investigate possible relationships between adolescent suicidal behaviour and total on-going family functioning. Hypotheses were advanced to evaluate the communication, interaction and reinforcement patterns in families. A modified revealed differences technique was employed to elicit standardized segments of interaction which were video-taped and later studied by two independent raters. The sample consisted of twelve individually matched, intact family tetrads, six normal (N) and six containing an adolescent female who had exhibited suicidal behaviour (SM). Results suggest that SM families constitute a malfunctioning system which can be differentiated from that of normal samples. As compared with the N group, SM family interaction evidenced less effective productivity, specificity, and adaptive interaction, and higher rates of conflict and negative reinforcement. Overall findings were discussed in terms of current family theory and their possible relationship to the genesis, maintenance and management of some classes of suicidal behaviour.

Adolescent↗
PubMedDate not supplied

[Interrelationship between immunologic and neurologic memory: learning ability of rats during immunostimulation].

Studies have been made on the effect of an immunostimulator - the complete Freund's adjuvant - upon the learning ability in Wistar rats for visual discrimination using food-obtaining and avoidance of the electric shock techniques. Injection of the adjuvant significantly increases learning ability provided negative reinforcement technique is used, but inhibits the former under the conditions of positive reinforcement. Analysis of the extinction of the conditioned reflexes yielded similar results. Possible relation of immunogenesis to the formation of memory is discussed.

Animals↗
PubMed1987

Effects of extract from Rhapontcum carthamoides (Willd) Iljin (Leuzea) on learning and memory in rats.

The effects of extract from Rhaponticum carthamoides (Willd) Ijin (Leuzea) on the processes of learning and memory in rats were investigated. R. carthamoides was administered orally in doses of 0.25, 0.5 and 2.5 g/kg body weight for 10 days prior to the training session. Using the maze-training method of active avoidance with punitive reinforcement, R. carthamoides improved the learning and memory indices to one degree or another depending on the dose applied. Using the "staircase-maze" method of training with food reinforcement, the low dose of R. carthamoides had no effect, while the high dose deteriorated learning. Using the method of step-through passive avoidance with punitive reinforcement, all three doses of R. carthamoides did not affect substantially the memory indices. R. carthamoides in a dose of 0.5 g/kg, administered orally for 10 days prior to the training, completely eliminated the scopolamine-induced memory impairment.

Animals↗
PubMed1996

Bidirectional instrumental conditioning.

Three experiments examined bidirectional instrumental conditioning by training hungry rats to push a pole in one direction for food pellets and in the other for either a sugar or a starch solution. In the first study we examined whether the animals learned about the action-reinforcer relations using a specific satiety procedure. Prefeeding one type of reinforcer before an extinction test selectively depressed the performance of the action that had been paired with this reinforcer during training. The second experiment investigated the sensitivity of the bidirectional actions to variations in the action-reinforcer contingencies. When the instrumental contingency was degraded by presenting unpaired reinforcers, the animals pushed less in the direction that was paired with the reinforcer type that was the same as the non-contiguous one. A third study revealed that increasing the rate of reinforcement for one action enhanced its rate of performance without significantly affecting the performance of the other action. We conclude that the effects of reinforcer devaluation, the action-outcome contingency, and the rate of reinforcement are not mediated by Pavlovian associations between the manipulandum and the reinforcer.

Animals↗
PubMedDate not supplied

[Effect of damage to the serotonin- and noradrenergic systems of the brain on alimentary and defensive conditioned reflexes in rats].

A study was made on 79 Wistar male rats of the influence of destruction of single nuclei in the brain serotonin- and noradrenergic systems on their learning with alimentary and pain reinforcements. Electrolytic lesion of the raphe dorsal and medial nuclei hindered the formation of alimentary conditioned reflexes, while facilitating the elaboration of a conditioned active avoidance reaction. Destruction of the locus coeruleus was attended with improved alimentary learning, while the elaboration of conditioned active avoidance reaction proved to be more difficult as compared with that in the control animals. A conclusion is drawn that the nature of the influence of local ablation of individual nuclei in the brain serotonin- and noradrenergic systems on animals' learning is determined by the emotional sign of the reinforcing stimulus.

Animals↗
PubMed1984

Operant theory and methodology in infant vocal conditioning.

The numerous mechanisms of behavior change in infant development are sometimes difficult to distinguish. Although it is agreed that elicitation and reinforcement both influence infant learning, the distinction between these two learning mechanisms was clarified in response to K. Bloom's (1984, Journal of Experimental Child Psychology, 38, 93-102) commentary. The theoretical and methodological assumptions of an functional analysis of infant behavior were made explicit in the context of the C. L. Poulson study (1983, Journal of Experimental Child Psychology, 36, 471-489). The rationale for the use of DRO schedules to control for elicitation effects of continuous reinforcement and the inadequacy of noncontingent schedules for this purpose were also discussed.

Conditioning, Operant↗
PubMed2002

Preference and resistance to change with constant- and variable-duration terminal links: independence of reinforcement rate and magnitude.

Pigeons responded in a three-component multiple concurrent-chains procedure in which the variable-interval reinforcement schedules were the same across components but magnitudes differed across components. The terminal links were arranged either as a variable delay followed by presentation of a reinforcer ("variable duration") or as a fixed period of access to the schedule during which a variable number of reinforcers could be earned ("constant duration"). Relative reinforcement rate was varied parametrically across both types of conditions. After baseline training in each condition, resistance to change of terminal-link responding was assessed by delivering food during the initial links according to a variable-time schedule. Both preference and resistance to change were more sensitive to reinforcement-rate differences in the constant-duration conditions. Sensitivities of preference and resistance to change to relative reinforcement rate did not change depending on relative reinforcement magnitude. Taken together, these results confirm and extend those of prior studies, and suggest that reinforcement rate and magnitude combine additively to determine preference and resistance to change. A single structural relation linking preference and resistance to change describes all the data from this and several related studies.

Animals↗
PubMedDate not supplied

Guidelines for making health education work.

The results of a number of studies which have indicated the limited effectiveness of health education efforts using the mass media are reviewed. The cause of these failures, according to the authors was the inability to apply a number of principles of effective design to the instructional materials used in the mass media. The basic slide show produced by the neighborhood health center for its own population may be more effective than a nationally televised spot announcement because locally prepared material can be sharply focused on the learner's characteristics and the specifically desired outcome behavior. The authors list 10 guidelines for the construction of effective instructional materials: define outcome measures, analyze relevant characteristics of the learner, gain and maintain the learner's attention, establish the learner's vulnerability, demonstrate the needs for action, establish the learner as an agent, establish the learner's effectiveness, provide for practice, repeat key facts, and generalize to similar situations. The principles of social reinforcement that must accompany health education instruction if behavior is to be modified are outlined. How environmental factors such as time, distance, expense, and the organization of health services hamper desired behavior outcomes is also discussed.

Audiovisual Aids↗
PubMed1985

Central action of substance P: possible role in reward.

A series of studies had revealed a dualistic role of post-trial injections of substance P in affecting avoidance behavior depending on the site of the brain in which it is applied. Based on these data, the hypothesis was formulated that substance P has brain site-dependent rewarding and punishing properties, a possibility which was assessed in rats trained on a modified T-maze task. Injections of substance P into the medial forebrain bundle (100 ng) or medial septal nucleus (500 ng) served as a positive reinforcer for conditioned place preference learning in the T maze. Injections into the amygdala (50 ng) or substantia nigra (100 ng) did not have such reinforcing properties.

Amygdala↗
PubMed1962

Response latency as a function of reinforcement schedule.

Four Ss were trained to press and hold down a telegraph key in the presence of a light. Subsequent release of the key during a tone was followed by water reinforcement. The schedule of reinforcement for key release was varied, and its effects on the latency (RT) of key release to the tone were studied. Both median RT and variability of RT were found to be inversely related to frequency of reinforcement as determined by the schedule.

Learning↗
PubMed1984

Isobias and alloiobias functions in animal psycophysics.

An analogue of the human yes-no detection task was used to train six pigeons to discriminate luminance differences under two different reinforcer-scheduling procedures. When a controlled reinforce-ratio procedure was used, relative stimulus frequency was constant at .5, and relative reinforcer frequency for correct detections was held constant at three different values for each of five luminance differences. When an uncontrolled reinforcer-ratio procedure (the typical detection paradigm) was used, relative reinforcer frequency for correct detections was allowed to covary with changes in relative stimulus frequency for each of five luminance differences. Two measures of bias, response bias (Davison & Tustin, 1978) and the detection-theory likelihood-ratio measure (beta obt), were compared. The controlled reinforcer-ratio procedure generated equal- or iso-response-bias functions, and the uncontrolled reinforcer-ratio procedure gave changing or alloio-response-bias functions. The Davison-Tustin model accounted for 88% and 93% of the data variance in the controlled and uncontrolled reinforcer-ratio procedures, respectively. The best-fitting equal-beta functions accounted for an average of 53% and 69%, respectively, in the two procedures. In addition, neither procedure gave constant measures of beta obt for constant bias manipulations across different discriminability measures.

Animals↗