Schaffer's Demon

Jonathan Schaffer (2010) has summoned a new sort of demon – which he calls the debasing demon – that apparently threatens all of our purported knowledge. We show that any debasing skeptical argument must attack the justification condition and can do so only if a plausible thesis about justification is false.     

Modularity,mental retardation and speed of processing

This paper briefly outlines Anderson's (1992) theory of the minimal cognitive architecture underlying intelligence and development and briefly discusses its application to understanding mental retardation and specific cognitive deficits. An experiment on the relationship between face perception and mental retardation serves as an illustration of how the theory might be informative about the relationship between intelligence and cognitive architecture.     

The effects of reinforcement on the modification, maintenance, and generalization of social responses of mental patients

Social greeting responses of three withdrawn, chronic schizophrenics were experimentally modified. Initially, none of the subjects spoke to an experimenter. Prompts and cigarette reinforcement were employed to produce increases in the rates of greetings. Then, the prompts were faded so that the greetings came under the control of the presence of the experimenter. Reversal and subsequent reinforcement procedures were employed to demonstrate that the responses were controlled by their consequences. Next, the schedule of cigarette reinforcement was leaned out so that greetings continued to occur in the absence of cigarette reinforcement. However, low or zero rates of greetings occurred in the presence of a second experimenter. Five new experimenters employed the prompting, fading, reinforcement, and schedule-leaning procedures. Subsequently, all subjects emitted appropriately high rates of greetings in the presence of the second experimenter. Without further application of the experimental procedures, greetings were still occurring in the presence of both the first and second experimenters almost three months later.     

The Behavioral Dyscontrol Scale and Functional Status Among Elderly Medical and Surgical Rehabilitation Patients

This research was conducted in a sample of 150 older adults (mean age = 78.0) who were inpatients receiving rehabilitation services for a variety of medical and postsurgical conditions. The purpose of the study was to test the hypothesis that the Behavioral Dyscontrol Scale (BDS), a measure of the ability to use intentions to guide purposeful activity, would be strongly associated with concurrent functional status after controlling for age, sex, education, severity of pain, medical comorbidity, depression (Geriatric Depression Scale), and general mental status (Mini Mental State Exam [MMSE]). Functional status was assessed by rehabilitaion nurses' ratings of patients on 11 individual Activities of Daily Living (ADL) items and the Barthel Index. The hypothesis, tested by means of multiple regression analysis, was supported by the results. The BDS was the independent variable most strongly associated with all 11 ADL items and the Barthel Index. The MMSE contributed significantly to none of the models. Other covariates made minimal contributions to the variance shared with functional ability. Consistent with prior results in other samples, the ability to use intentions to guide purposeful behavior appears to be an important contributor to everyday functioning among older adults.     

The Political Consequences of Combat: Post‐Traumatic Stress and Political Alienation Among Vietnam Veterans

On average, veterans are more civically and politically engaged than civilians. Previous research on the effects of military service, however, did not account for differences in veterans’ combat experiences. Using survey data from a representative sample of Vietnam veterans, this study presents evidence that veterans who were exposed to severe combat trauma and veterans who exhibited attitudes and fears associated with post‐traumatic stress had significantly lower levels of political efficacy and trust. The negative consequences of combat exposure and post‐traumatic stress are not mitigated when veterans have quality social support or when they seek professional counseling. These findings inform political psychology and hold implications for claims regarding the empowering influence of service in the U.S. military, increased political engagement, in particular. Among Vietnam veterans, exposure to severe combat trauma and post‐traumatic stress were both associated with reduced political efficacy and trust.     

Religious coping,general coping strategies,perceived social support,PTSD symptoms,resilience, and posttraumatic growth among survivors of the 2010 earthquake in Haiti

This study examines the relationships between coping strategies, perceived social support, resilience, PTSD symptoms, and posttraumatic growth (PTG) in a sample of 256 survivors of the 2010 Haiti earthquake. The results of the bivariate analysis suggested a significant positive correlation between PTG and resilience, PTSD symptoms, perceived social support, positive religious coping, and active coping. There was a significant positive relationship between perceived social support and resilience and between resilience and active coping. PTSD symptoms were positively correlated with both positive and negative religious coping. Results of the multiple regression analysis indicated that positive religious coping, active coping, perceived social support, resilience, and PTSD symptoms accounted for 34% of the variance in the participants’ PTG. The strongest predictor of PTG was positive religious coping, followed by active coping, perceived social support, resilience, PTSD symptoms, and negative religious coping. Implications and recommendations for future research were discussed.     

Increased brain serotonin turnover in panic disorder patients in the absence of a panic attack: reduction by a selective serotonin reuptake inhibitor

Since the brain neurotransmitter changes characterising panic disorder remain uncertain, we quantified brain noradrenaline and serotonin turnover in patients with panic disorder, in the absence of a panic attack. Thirty-four untreated patients with panic disorder and 24 matched healthy volunteers were studied. A novel method utilising internal jugular venous sampling, with thermodilution measurement of jugular blood flow, was used to directly quantify brain monoamine turnover, by measuring the overflow of noradrenaline and serotonin metabolites from the brain. Radiographic depiction of brain venous sinuses allowed differential venous sampling from cortical and subcortical regions. The relation of brain serotonin turnover to serotonin transporter genotype and panic disorder severity were evaluated, and the influence of an SSRI drug, citalopram, on serotonin turnover investigated. Brain noradrenaline turnover in panic disorder patients was similar to that in healthy subjects. In contrast, brain serotonin turnover, estimated from jugular venous overflow of the metabolite, 5-hydroxyindole acetic acid, was increased approximately 4-fold in subcortical brain regions and in the cerebral cortex (P < 0.01). Serotonin turnover was highest in patients with the most severe disease, was unrelated to serotonin transporter genotype, and was reduced by citalopram (P < 0.01). Normal brain noradrenaline turnover in panic disorder patients argues against primary importance of the locus coeruleus in this condition. The marked increase in serotonin turnover, in the absence of a panic attack, possibly represents an important underlying neurotransmitter substrate for the disorder, although this point remains uncertain. Support for this interpretation comes from the direct relationship which existed between serotonin turnover and illness severity, and the finding that SSRI administration reduced serotonin turnover. Serotonin transporter genotyping suggested that increased whole brain serotonin turnover most likely derived not from impaired serotonin reuptake, but from increased firing in serotonergic midbrain raphe neurons projecting to both subcortical brain regions and the cerebral cortex.     

Context processing in older adults: evidence for a theory relating cognitive control to neurobiology in healthy aging.

A theory of cognitive aging is presented in which healthy older adults are hypothesized to suffer from disturbances in the processing of context that impair cognitive control function across multiple domains, including attention, inhibition, and working memory. These cognitive disturbances are postulated to be directly related to age-related decline in the function of the dopamine (DA) system in the prefrontal cortex (PFC). A connectionist computational model is described that implements specific mechanisms for the role of DA and PFC in context processing. The behavioral predictions of the model were tested in a large sample of older (N = 81) and young (N = 175) adults performing variants of a simple cognitive control task that placed differential demands on context processing. Older adults exhibited both performance decrements and, counterintuitively, performance improvements that are in close agreement with model predictions.