The role of constant curvature in 2-D contour shape representations

In early cortex, visual information is encoded by retinotopic orientation-selective units. Higher-level representations of abstract properties, such as shape, require encodings that are invariant to changes in size, position, and orientation. Within the domain of open, 2-D contours, we consider how an economical representation that supports viewpoint-invariant shape comparisons can be derived from early encodings. We explore the idea that 2-D contour shapes are encoded as joined segments of constant curvature. We report three experiments in which participants compared sequentially presented 2-D contour shapes comprised of constant curvature (CC) or non-constant curvature (NCC) segments. We show that, when shapes are compared across viewpoint or for a retention interval of 1000 ms, performance is better for CC shapes. Similar recognition performance is observed for both shape types, however, if they are compared at the same viewpoint and the retention interval is reduced to 500 ms. These findings are consistent with a symbolic encoding of 2-D contour shapes into CC parts when the retention intervals over which shapes must be stored exceed the duration of initial, transient, visual representations.     

Side of onset in Parkinson's disease and alterations in religiosity: novel behavioral phenotypes

Behavioral neurologists have long been interested in changes in religiosity following circumscribed brain lesions. Advances in neuroimaging and cognitive experimental techniques have been added to these classical lesion-correlational approaches in attempt to understand changes in religiosity due to brain damage. In this paper we assess processing dynamics of religious cognition in patients with Parkinson's disease (PD). We administered a four-condition story-based priming procedure, and then covertly probed for changes in religious belief. Story-based priming emphasized mortality salience, religious ritual, and beauty in nature (Aesthetic). In neurologically intact controls, religious belief-scores significantly increased following the Aesthetic prime condition. When comparing effects of right (RO) versus left onset (LO) in PD patients, a double-dissociation in religious belief-scores emerged based on prime condition. RO patients exhibited a significant increase in belief following the Aesthetic prime condition and LO patients significantly increased belief in the religious ritual prime condition. Results covaried with executive function measures. This suggests lateral cerebral specialization for ritual-based (left frontal) versus aesthetic-based (right frontal) religious cognition. Patient-centered individualized treatment plans should take religiosity into consideration as a complex disease-associated phenomenon connected to other clinical variables and health outcomes.     

From body form to biological motion: the apparent velocity of human movement biases subjective time

In two experiments, we investigated time perception during apparent biological motion. Pictures of initial, intermediate, and final positions of a single movement were presented, with interstimulus intervals that were constant within trials but varied across trials. Movement paths were manipulated by changing the sequential order of body postures. Increasing the path length produced an increase in perceived movement velocity. To produce an implicit measure of apparent movement dynamics, we also asked participants to judge the duration of a frame surrounding the stimuli. Longer paths with higher apparent movement velocity produced shorter perceived durations. This temporal bias was attenuated for nonbody (Experiment 1) and inverted-body (Experiment 2) control stimuli. As an explanation for these findings, we propose an automatic top-down mechanism of biological-motion perception that binds successive body postures into a continuous perception of movement. We show that this mechanism is associated with velocity-dependent temporal compression. Furthermore, this mechanism operates on-line, bridging the intervals between static stimuli, and is specific to configural processing of body form.     

Investigating Retesting Effects in a Personnel Selection Context

Repeat applicants to a fire‐fighter position undertook the same cognitive ability and situational judgment tests on multiple occasions and the resultant practice effects were investigated. Practice effects of approximately two fifths of a standard deviation were observed between Times 1 and 2 on timed tests of Abstract Reasoning and Mechanical Comprehension. Smaller practice effects were observed, however, on a timed test of numerical comprehension ability and the untimed Teamwork Knowledge Skills and Abilities situational judgment test. For all four tests, the additional practice effect observed at Time 3 were smaller and nonsignificant; a result supplemented by latent growth curve analyses.     

Cross-modal training induces changes in spatial representations early in the auditory processing pathway

In the ventriloquism aftereffect, brief exposure to a consistent spatial disparity between auditory and visual stimuli leads to a subsequent shift in subjective sound localization toward the positions of the visual stimuli. Such rapid adaptive changes probably play an important role in maintaining the coherence of spatial representations across the various sensory systems. In the research reported here, we used event-related potentials (ERPs) to identify the stage in the auditory processing stream that is modulated by audiovisual discrepancy training. Both before and after exposure to synchronous audiovisual stimuli that had a constant spatial disparity of 15°, participants reported the perceived location of brief auditory stimuli that were presented from central and lateral locations. In conjunction with a sound localization shift in the direction of the visual stimuli (the behavioral ventriloquism aftereffect), auditory ERPs as early as 100 ms poststimulus (N100) were systematically modulated by the disparity training. These results suggest that cross-modal learning was mediated by a relatively early stage in the auditory cortical processing stream.     

On Hylemorphism and Personal Identity

Abstract: There is no such thing as ‘the’ hylemorphic account of personal identity. There are several views that count as hylemorphic, and these views can be grouped into two main families—the corruptionist view, and the survivalist view. The differentiating factor is that the corruptionist view holds that the persistence of the soul is not sufficient for the persistence of the person, while the survivalist view holds that the persistence of the soul is sufficient for the persistence of the person. In this paper, I argue that hylemorphists should prefer the corruptionist view. This project ought to be of interest to anyone working on issues of personal identity, not only because hylemorphic views are historically important, but also because they are currently receiving significant attention in the personal identity literature.