Signalling and incentive processes in instrumental reinforcer devaluation

We have previously reported that conditioning an aversion to the reinforcer using an isotonic lithium chloride (LiCl) solution following instrumental training reduces performance in a subsequent extinction test only if animals are re-exposed to the reinforcer prior to the test. Rescorla (1992), in contrast, reported an immediate devaluation effect using a hypertonic LiCl solution that did not depend upon re-exposure. In two experiments we examined the effect of using a hypertonic LiCl solution to condition the aversion to the reinforcer on subsequent instrumental performance in extinction, with and without re-exposure. In Experiment 1 thirsty rats were trained to press a lever for a sucrose solution before being injected with 0.6 M LiCl either immediately or after a delay. Half of the immediate and delay groups were then re-exposed to the sucrose in the absence of the lever, with the remainder being exposed to water. Contrary to the previously reported effects of isotonic LiCl, a hypertonic solution induced a reinforcer devaluation effect in all the immediately poisoned animals, which did not depend upon re-exposure to the reinforcer. In Experiment 2 the possibility that this devaluation effect was induced by the discomfort associated with the hypertonicity of the solution was assessed by replicating Experiment 1 but, in addition, using two immediately poisoned groups given the LiCl injection under anaesthesia. In the absence of anaesthesia, the devaluation effect observed without re-exposure to the reinforcer in Experiment 1 was replicated. When the injection was given under anaesthesia, however, a reinforcer devaluation effect was observed only in animals that were re-exposed to the reinforcer prior to the extinction test. These results were interpreted as evidence that a reinforcer devaluation effect induced by pairing the reinforcer with illness depends upon a process of incentive learning, whereas a devaluation effect mediated by learning a signalling relationship between the reinforcer and somatic discomfort does not.     

Gender and temporal differences in identifying sources of stress

Much of the methodology in stress research focuses on stress manifestation and organismic reactions to life’s crises. In contrast, the present study sought to identify the major sources of stress and the nature of those sources. The results revealed a consistent pattern in high and low stressors throughout the 3-year period of the study, and differences only of intensity between males and females, not type of stress. Except for individuals’ temporal variations in critical events, the highest stressors for the groups were external, primarily financial and time management. Internal sources, such as personal relationships and self-absorption, were typically the lowest concerns. Everyday problems arising from current life styles seem to be significant sources of stress.     

Premissary relevance

Premissary relevance is a property of arguments understood as speech act complexes. It is explicable in terms of the idea of a premise's lending support to a conclusion. Premissary relevance is a function of premises belonging to a set which authoritatively warrants an inference to a conclusion. An authoritative inference warrant will have associated with it a conditional proposition which is true— that is to say, which can be justified. The study of the Aristotelian doctrine of topoi or argument schemes may contribute to the task of identifying authoritative warrants.     

Common problems and coping strategies II: Findings with adolescent suicide attempters

This study investigated the most common precipitants of adolescent suicide attempts and the strategies used to cope with such problems. Adolescent suicide attempters were compared with both distressed and nondistressed nonsuicidal adolescents on problems reported and coping strategies utilized. All three groups reported four problems as occurring most frequently: school, parents, friends, or boyfriend/girlfriend. The suicide attempters and distressed controls reported problems with parents more frequently than did nondistressed controls, while this latter group reported problems at school more frequently than did suicide attempters or distressed controls. Suicide attempters used social withdrawal, problem solving, and emotional regulation more than did nondistressed controls, but not more frequently than distressed controls. Distressed controls used wishful thinking and resignation more than did suicide atempters. Results are discussed in terms of the similarities between suicide attempters and nonsuicidal distressed adolescents and the need to more closely investigate specific subgroups of suicide attempters.     

Common problems and coping strategies I: Findings with normal adolescents

This study investigated problems commonly experienced by adolescents and the strategies they use to cope with these events. Coping strategies were examined across the subjects' omotional state and their evaluation of the problem. In general, adolescents reported four common Stressors that were similar across age groups and gender. However, males differed from females in the frequency of these problems. Further, while the Stressors were similar, the frequency with which the coping strategies were employed and the efficacy ascribed to them differed across sex and across problem type. These findings are discussed in terms of the stress and coping literature with adults and the implications for clinical assessment and treatment of adolescents.     

Lesbians' and gay men's experiences of discrimination and harassment in a university community

A survey of 125 lesbians and gay men in a university community was conducted to determine the incidence of discrimination, harassment, and violence. Nearly three fourths had experienced verbal abuse; 26% were threatened with violence; and 17% had personal property damaged. Students and roommates were most often those responsible. Most incidents were not reported to authorities, and many made changes in their daily routines to avoid harm. Over half of the sample feared for their personal safety; their fear was related to the amount of harassment and previous property damage. Men were more often victimized than women.     

Teaching self-treatment of cold symptoms to an anoxic brain injured adult

Traumatic brain injury can result in behavioral and physical deficits that require intensive post-acute residential rehabilitation. Behaviors targeted by such programs include basic self-care and living skills. We examined the efficacy of a behavioral training strategy to teach appropriate medical treatment of four different groups of simulated cold symptoms to an anoxic brain injured adult. The strategy included instructor prompting and feedback in the use of written task analyses and picture cues as self-administered prompts. Subsequent to baseline, the participant used written generic task analyses combined with picture cues and then, if necessary, written specific task analyses combined with picture cues to prompt appropriate self-treatment of the four types of colds. Written individualized task analyses, tailored to participant errors, were used to fade specific task analysis prompts and transfer stimulus control to the discriminative stimuli present in the picture cues. A multiple baseline design across responses showed that skill acquisition did not occur after generic task analysis training, but did so after specific task analysis training. The participant responded to all four types of colds for three consecutive trials at 100% correct under baseline conditions. Follow-up results indicated that transfer of stimulus control to the cold symptoms simulated by the picture cues alone did not maintain over time. Correct responding was retrained using generic and, if necessary, individualized task analysis training conditions.     

Teaching dancercise to persons who are mentally handicapped: Programming transfer of stimulus control to a community setting

This study demonstrated procedures to promote the acquisition and transfer of stimulus control of an age-appropriate exercise skill. Three young adults diagnosed as mentally handicapped in a residential setting were taught a commercial dancercise routine during individual training sessions using a package of instructional procedures. A combination of a multiple baseline across subjects and a multiple baseline across response groups design showed that skill acquisition occurred only after each subject received training, and that performance did not generalize across exercise response groups. Training progressively incorporated more participants, new teachers, and new settings. Ultimately, subjects performed in a community dancercise class attended by 100 nonhandicapped persons.     

Patterns of movement in the first 6 months of life: new directions

The field of infant perceptual development has relied heavily on the preferential-looking and habituation paradigms. Despite the obvious advantages of employing standardized methodologies, there is a need to study how perceptual variables give rise to and guide action beginning in the neonatal period. It is argued here that, in the first 5 months of life, it is important to distinguish reflexive patterns of movement from voluntary and cortically controlled patterns. Some criteria are defined. This paper describes three experiments which utilized movement counters to record developmental changes in the frequency and synchrony of limb movements in infants under 5 months. The results show that there is a general increase in frequency of limb movements from 1 to 5 months, but with a plateau or even a decrease in activity from the middle of the third month to the end of the fourth month. It was also demonstrated that synchrony scores (co-activation) for pairs of limbs showed significant increases from 1 month to 5 months. Finally, in all three experiments the presentation of an attractive toy resulted in suppression of activity. The results of the three experiments are interpreted to measure a gradual increase in cortically controlled movement patterns.