Salient material properties and haptic volume perception: The influences of surface texture, thermal conductivity, and compliance

We investigated the influences of surface texture, thermal conductivity, and compliance on the haptic perception of the volume of small cubes. It was hypothesized that an object containing highly salient material properties would be perceived as larger in volume than the same object without these properties. Blindfolded subjects were asked to explore pairs of cubes differing in their material properties and to select the one with the larger volume. The results showed that, counterintuitively, a smooth cube was perceived as being significantly larger than a rough cube of the same physical volume, with average biases of about 19 %. Furthermore, cubes with a higher thermal conductivity were perceived as significantly larger than cubes with a lower thermal conductivity (average bias of about 7 %). In addition, the magnitude of the bias in this condition was not changed by increasing or decreasing the temperature of the test objects, suggesting that the effect of thermal conductivity could not be attributed directly to the heat flow. Finally, a hard cube was perceived as significantly larger than a soft cube of equal physical volume, with an average bias of about 25 %. These results reveal that the studied material properties have significant and consistent influences on the haptic perception of volume. The observed biases provide an indication of the levels at which the processing of haptic information on volume and material properties occurs.     

EEG theta phase coupling during executive control of visual working memory investigated in individuals with schizophrenia and in healthy controls

In healthy humans, it has been shown that executive functions are associated with increased frontal-midline EEG theta activity and theta phase coupling between frontal and posterior brain regions. In individuals with schizophrenia, central executive functions are supposed to be heavily impaired. Given that theta phase coupling is causally involved in central executive functions, one would expect that patients with an executive function deficit should display abnormal EEG theta synchronization. We therefore investigated executive functioning in 21 healthy controls and 21 individuals with schizophrenia while they performed a visuospatial delayed match to sample task. The task required either high executive demands (manipulation of content in working memory [WM]) or low executive demands (retention of WM content). In addition, WM load (one vs. three items) was varied. Results indicated higher frontal theta activity for manipulation processes than for retention processes in patients with schizophrenia, as compared with healthy controls, independently of WM load. Furthermore, individuals with schizophrenia revealed a reduction in theta phase coupling during early stages of the delay period for retention, as well as for manipulation processes at high-WM loads. Deviations in theta phase coupling in individuals with schizophrenia were mainly characterized by aberrant fronto-posterior connections, but also by attenuated posterior connections during manipulation of high-WM load. To conclude, fronto-parietal theta coupling seems to be substantially involved in executive control, whereas frontal theta activity seems to reflect general task demands, such as deployment of attentional resources during WM.     

Groundless Truth

Abstract

?We defend two claims: (1) if one is attracted to a strong non-maximalist view about truthmaking, then it is natural to construe this as the view that there exist fundamental truths; (2) despite considerable aversion to fundamental truths, there is as yet no viable independent argument against them. That is, there is no argument against the existence of fundamental truths that is independent of any more specific arguments against the ontology accepted by the strong non-maximalist. Thus there is no argument that the strong non-maximalist herself will find dialectically motivating.     

The relationship between psychopathy and the Full Range Leadership Model

While emerging research suggests psychopathic traits and leadership behaviors may be linked, this proposition requires further empirical investigation. This study aims to examine the relationship between psychopathic traits and the Full Range Leadership Model which includes transformational, transactional, and passive leadership styles. Using a cross-sectional design, survey data was collected from 115 students who reported having management experience. Measures included the Multifactor Leadership Questionnaire and Self-Report Psychopathy Scale-Revised. A four-factor structure of psychopathy positively correlated with passive leadership behavior, namely passive-management-by-exception and laissez-faire, but negatively correlated with individual consideration. This study addresses a research need, and is one of the first to empirically examine the relationship between psychopathic traits and the Full Range Leadership Model. Theoretical and practical implications are discussed.     

Speech motor programming in hypokinetic and ataxic dysarthria

It is widely accepted that the cerebellar and basal ganglia control circuits contribute to the programming of movement. Converging evidence from neuroimaging, limb control, and neuropsychological studies suggests that (1) people with cerebellar disease have reduced ability to program movement sequences in advance of movement onset and (2) people with Parkinson's disease are unable to maintain a programmed response or to rapidly switch between responses. Despite a substantial supporting literature, no studies have addressed these potential areas of speech programming disruption for speakers with ataxic and hypokinetic dysarthria. Control participants and adults with dysarthria completed speech reaction time protocols designed to capture these aspects of utterance preparation. Results provided initial support for processing deficits in speakers with ataxic and hypokinetic dysarthria that are separable from motor execution impairments.     

Covariation between bizarre and nonbizarre speech as a function of the content of verbal attention

A functional analysis suggested that the bizarre speech of an individual with developmental disabilities was maintained by attention. The content of verbal attention was manipulated in two subsequent analyses and revealed that (a) bizarre speech was more frequent when attention was related to the participant's bizarre speech and (b) the participant's statements tended to reflect the content of the therapist's attention, whether bizarre or nonbizarre.