Delay discounting in the pigeon: In search of a magnitude effect

The magnitude effect, where larger outcomes are discounted proportionally less than smaller outcomes, is a well‐established phenomenon in delay discounting by human participants. To this point in the literature magnitude effects have not been reliably evidenced in nonhuman animals. , however, used a concurrent‐chains arrangement with pigeon and found evidence for a magnitude effect. Grace et al. suggested that in many delay discounting experimental arrangements with nonhuman animals (e.g., adjusting amount, adjusting delay) the organism is not given the opportunity to directly compare outcomes of different sizes. They suggest that because of the lack of direct comparison it is difficult for the organism to determine the relative size of each outcome, which in turn mutes the effect of the amount differences between outcomes. As a test of this “comparison hypothesis,” the present experiment was conducted to assess whether the magnitude effect would be evidenced in pigeon when using an adjusting amount procedure where outcomes of different amounts were presented proximally. In the present arrangement, pigeons were presented two choice panels in an operant chamber where each panel was associated with an independent adjusting amount delay discounting task, but with differing outcome amounts (i.e., a 32‐food pellet panel and an 8‐food pellet panel). In this arrangement the choice panels alternated in their availability within a session from trial block to trial block. The present findings indicate no reliable effect of amount, even when the outcomes were proximal and thus readily comparable. This result suggests that the lack of magnitude effect is not driven by the organism's ability to compare the difference in amount between choice alternatives.     

Making Sense of the Role of Assertions

Much of the literature on speech acts and semantics assigns a type of theoretical priority to assertions; many philosophers assume, as Robert Brandom has put it, that assertion is the fundamental speech act. Others take a more pluralistic approach, with many categories interwoven as peers, and no one category as fundamental. I suggest there is a way to embrace a pluralistic approach and explain the importance of assertions without making them fundamental. Their role instead becomes one of supporting connections between other categories, and surprisingly, turns on their unusually broad but very thin pragmatic character.     

Erfahrungsorientiertes Lernen in der Psychotherapie

Background

Based on principles of experiential learning, psychophysical exposure (PPE) on a tightrope course offers a promising intervention in the treatment of patients with mental disorders. A PPE program conducted on a hospital tightrope course is presented as an adjunct in inpatient psychotherapy.

Methods

The acceptance and effectiveness of the PPE were evaluated in a prospective controlled naturalistic study. A total of 155 patients, who were exposed at least once during their inpatient therapy, were compared with 92 control patients, who did not participate in the tightrope course. The main outcome criteria were self-reported depressive symptoms, state anxiety, locus of control, self-efficacy, and trait anxiety.

Results

The PPE was highly accepted by the participants. Patients who attended the tightrope courses showed greater improvement in the outcome criteria than patients who received inpatient treatment as usual. Particularly better effects were found on the personality variables.

Conclusions

Psychophysical exposure can successfully and effectively be integrated into a psychosomatic inpatient treatment program. Methodological limitations of the study, especially threats to internal validity, are discussed.     

Exemplars, prototypes, similarities, and rules in category representation: an example of hierarchical bayesian analysis

This article demonstrates the potential of using hierarchical Bayesian methods to relate models and data in the cognitive sciences. This is done using a worked example that considers an existing model of category representation, the Varying Abstraction Model (VAM), which attempts to infer the representations people use from their behavior in category learning tasks. The VAM allows for a wide variety of category representations to be inferred, but this article shows how a hierarchical Bayesian analysis can provide a unifying explanation of the representational possibilities using 2 parameters. One parameter controls the emphasis on abstraction in category representations, and the other controls the emphasis on similarity. Using 30 previously published data sets, this work shows how inferences about these parameters, and about the category representations they generate, can be used to evaluate data in terms of the ongoing exemplar versus prototype and similarity versus rules debates in the literature. Using this concrete example, this article emphasizes the advantages of hierarchical Bayesian models in converting model selection problems to parameter estimation problems, and providing one way of specifying theoretically based priors for competing models.     

Pragmatism, Pluralism, and Psychotherapy Relationships: An Interview with John C. Norcross, Ph.D.

John C. Norcross has made significant contributions in the areas of the transtheoretical model of change, psychotherapy integration, and empirically supported psychotherapy relationships. This interview explores the contributions of pragmatic philosophy and his personal upbringing to his work as a psychotherapy researcher and practitioner. Dr. Norcross discusses the status of the psychotherapy integration movement, the work of the Task Force on Empirically Supported Psychotherapy Relationships, and future trends in psychotherapy over the next 25 years. He emphasizes the importance of a methodological rigor that recognizes the unique characteristics of the psychotherapy relationship. He describes his current interest in the psychotherapy of psychotherapists, illustrating it with his personal challenges in balancing work and home.     

The Mind as a Process

Essentially all behavior is regulated by the brain in response to information received from within the body or from the environment. The tangible structures of the brain serve as devices for processing thoughts and emotions as well as information. Stored among the interacting neural structures are memories of past experiences and responses to them. These intangibles participate in determining the decisions made and the actions performed by the brain's structures. There are valuable studies of the clinical and neurological effects of environmental stimuli, but we need to learn more about the processes that lead to these effects. More definitive correlations could be made between environmental stimuli and the neurological pathways they create by studying individual's real life experiences rather than laboratory simulations alone.     

Stress impairs acquisition of delay eyeblink conditioning in men and women

In rodents stress impairs delay as well as trace eyelid conditioning in females, but enhances it in males. The present study tested the effects of acute psychosocial stress exposure on classical delay eyeblink conditioning in healthy men and women. In a between subject design, participants were exposed to psychosocial stress using the Trier Social Stress Test (TSST) or a control condition which was followed by a delay eyeblink classical conditioning procedure. Stress exposure led to a significant increase in salivary cortisol and impaired acquisition of conditioned eyeblink responses (CRs). This was evident by a later first CR and an overall lower CR rate of the stress group. The stress-induced acquisition impairment was observed in both women and men. Subjects failing to show a stress-induced cortisol increase (cortisol non-responder) were not impaired in acquisition. Our findings indicate that acute stress, possibly via activation of the hypothalamus–pituitary–adrenal (HPA) axis, reduces the ability to acquire a simple conditioned motor response in humans.