Variability of responding on a concurrent schedule as a function of body weight

Five pigeons pecked for food reinforcers on a concurrent variable-interval one-minute, variable-interval four-minute schedule. Each bird's body weight was varied from 80% of its free-feeding weight to 95% and then by 5% steps to 110% or until weight gains ceased. The coefficient of variation, but not the standard deviation, of the daily rate of responding on each of the component schedules increased with increases in body weight.     

A psychometric evaluation of the Rorschach comprehensive system's perceptual thinking index

In this study, we investigated evidence for reliability and validity of the Perceptual Thinking Index (PTI; Exner, 2000a, 2000b) among an adult inpatient population. We conducted reliability and validity analyses on 107 patients who met the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text revision; American Psychiatric Association, 2000) criteria for a schizophrenia-spectrum disorder (SSD) or mood disorder with no psychotic features (MD). Results provided support for interrater reliability as well as internal consistency of the PTI. Furthermore, the PTI was an effective index in differentiating SSD patients from patients diagnosed with an MD. Finally, the PTI demonstrated adequate diagnostic statistics that can be useful in the classification of patients diagnosed with SSD and MD. We discuss methodological issues, implications for assessment practice, and directions for future research.     

Association of pathological gambling with depression in Scotland

Is most research concerning gambling and depression has been conducted on clinical populations, the present study examined the relationship between gambling and depression across a large sample in Scotland in higher education and the community. A questionnaire-based cluster design involved the distribution of the South Oaks Gambling Screen and the Centre for Epidemiologic Studies Depression Scale mainly to students and staff of higher educational establishments, with small community and gambling samples also included. Thirty-seven colleges and universities across Scotland participated in the research, with a sample of 2259 people aged sixteen years of age or over (M = 28.9 yr., SD = 13.4) being obtained. It was found that past-year probable pathological gamblers had significantly higher depression than problem gamblers, nonproblem gamblers, and nongamblers. However, when probable pathological gamblers who had sought treatment were omitted from the analysis, the nontreatment-seeking probable pathological gambling group no longer had significantly higher depression than the problem gambling group. Female problem and probable pathological gamblers had particularly high depressive symptomatology, suggesting co-morbid depression may be a prominent feature of problematic female gambling.     

Is there a problem with enhancement?

This article examines arguments concerning enhancement of human persons recently presented by Michael Sandel (2004). In the first section, I briefly describe some of his arguments. In section two, I consider whether, as Sandel claims, the desire for mastery motivates enhancement and whether such a desire could be grounds for its impermissibility. Section three considers how Sandel draws the distinction between treatment and enhancement, and the relation to nature that he thinks each expresses. The fourth section examines Sandel's views about parent/child relations and also how enhancement would affect distributive justice and the duty to aid. In conclusion, I briefly offer an alternative suggestion as to why enhancement may be troubling and consider what we could safely enhance.     

An integrated model of group psychotherapy for patients with fibromyalgia

This study examined the effectiveness of an integrated model of brief group psychotherapy for treatment of fibromyalgia syndrome, using cognitive behavioral and supportive expressive techniques. In the context of an outpatient, multidisciplinary fibromyalgia treatment program, group psychotherapy was provided to 35 patients with 21 control patients. Pre-post treatment measures of depression, anxiety, fibromyalgia impact, pain, fatigue, and morning tiredness were obtained. Using a quasi-experimental design with validated psychometric instruments, the results showed a significant decrease in pre-versus post treatment measures of depression, fibromyalgia impact, fatigue, and pain for the treatment patients, suggesting that an integrated model of group psychotherapy may have beneficial psychological and functional effects for some patients with fibromyalgia.     

Categorical perception of tactile distance

The tactile surface forms a continuous sheet covering the body. And yet, the perceived distance between two touches varies across stimulation sites. Perceived tactile distance is larger when stimuli cross over the wrist, compared to when both fall on either the hand or the forearm. This effect could reflect a categorical distortion of tactile space across body-part boundaries (in which stimuli crossing the wrist boundary are perceptually elongated) or may simply reflect a localised increased in acuity surrounding anatomical landmarks (in which stimuli near the wrist are perceptually elongated). We tested these two interpretations across two experiments, by comparing a well-documented bias to perceive mediolateral tactile distances across the forearm/hand as larger than proximodistal ones along the forearm/hand at three different sites (hand, wrist, and forearm). According to the ‘categorical’ interpretation, tactile distances should be elongated selectively in the proximodistal axis thus reducing the anisotropy. According to the ‘localised acuity’ interpretation, distances will be perceptually elongated in the vicinity of the wrist regardless of orientation, leading to increased overall size without affecting anisotropy. Consistent with the categorical account, we found a reduction in the magnitude of anisotropy at the wrist, with no evidence of a corresponding localised increase in precision. These findings demonstrate that we reference touch to a representation of the body that is categorically segmented into discrete parts, which consequently influences the perception of tactile distance.