Psychology Commons^™

Missing The Big Picture: Impaired Development Of Global Shape Processing In Autism, K. Suzanne Scherf, Beatriz Luna, Ruth Kimchi, Nancy Minshew, Marlene Behrmann

Marlene Behrmann

Individuals with autism exhibit hypersensitivity to local elements of the input, which may interfere with the ability to group visual elements perceptually. We investigated the development of perceptual grouping abilities in high-functioning individuals with autism (HFA) across a wide age range (8–30 years) using a classic compound letter global/local (GL) task and a more fine-grained microgenetic prime paradigm (MPP), including both few- and many-element hierarchical displays. In the GL task, contrary to the typically developing (TD) controls, HFA participants did not develop an increasing sensitivity to the global information with age. In the MPP, like the TD controls, individuals with …

Visual Attention Deficits In Alzheimer’S Disease: Relationship To Hmpao Spect Cortical Hypoperfusion, Brandon Vasquez, Brian Buck, Sandra Black, Farrell Leibovitch, Nancy Lobaugh, Curtis Caldwell, Marlene Behrmann

Marlene Behrmann

Patients with Alzheimer's disease (AD) display a multiplicity of cognitive deficits in domains such as memory, language, and attention, all of which can be clearly linked to the underlying neuropathological alterations. The typical degenerative changes occur early on in the disease in the temporal–parietal lobes, with other brain regions, such as the frontal cortex, becoming more affected as the disease progresses. In light of the importance of the parietal cortex in mediating visuospatial attentional processing, in the present study, we investigated a deficit in covert orienting of visual attention and its relationship to cortical hypoperfusion in AD. We characterized the …

Acquisition Of Long-Term Visual Representations: Psychological And Neural Mechanisms, Marlene Behrmann, Joy Geng, Chris Baker

Marlene Behrmann

How do we so rapidly achieve an organized, coherent visual percept of our superficially chaotic world? One way of reducing the complexity of the input is to take advantage of the statistical regularities and regular co-occurrences between aspects of objects and between objects and their spatial locations. In this chapter, converging data obtained from normal and brain-damaged individuals, as well as from single unit recording studies in monkeys, are presented, all of which address the psychological and neural mechanisms associated with statistical learning. The first section deals with learning regularities associated with particular spatial locations, presumably a function of the …

Detecting Structure In Glass Patterns: An Interocular Transfer Study, Dawn Vreven, Jarrod Berge

Dawn L Vreven

Glass patterns are visual stimuli used here to study how local orientation signals are spatially integrated into global pattern perception. We measured a form aftereffect from adaptation to both static and dynamic Glass patterns and calculated the amount of interocular transfer to determine the binocularity of the detectors responsible for the perception of global structure. Both static and dynamic adaptation produced significant form aftereffects and showed a very high degree of interocular transfer, suggesting that Glass-pattern perception involves cortical processing beyond primary visual cortex. Surprisingly, dynamic adaptation produced significantly greater interocular transfer than static adaptation. Our results suggest a functional …

The Role Of Vision In Detecting And Correcting Fingertip Force Errors During Object Lifting, Gavin Buckingham

Gavin Buckingham

No abstract provided.

Lifting Without Seeing: The Role Of Vision In Perceiving And Acting Upon The Size Weight Illusion, Gavin Buckingham, Melvyn Goodale

Gavin Buckingham

BACKGROUND: Our expectations of an object's heaviness not only drive our fingertip forces, but also our perception of heaviness. This effect is highlighted by the classic size-weight illusion (SWI), where different-sized objects of identical mass feel different weights. Here, we examined whether these expectations are sufficient to induce the SWI in a single wooden cube when lifted without visual feedback, by varying the size of the object seen prior to the lift.

METHODOLOGY/PRINCIPAL FINDINGS: Participants, who believed that they were lifting the same object that they had just seen, reported that the weight of the single, standard-sized cube that they …

Lifting Without Seeing: The Role Of Vision In Perceiving And Acting Upon The Size‐Weight Illusion, Gavin Buckingham, Melvyn Goodale

Gavin Buckingham

Our expectations of an object’s heaviness not only drive our fingertip forces, but also our perception of heaviness. This effect is highlighted by the classic size-weight illusion (SWI), where different‐sized objects of identical mass feel different weights (Charpentier, 1891) long after any initial errors in the application of fingertip forces have been corrected (Flanagan & Beltzner, 2000).

Here, we examined whether our expectations about the weight of an upcoming lift are sufficient to induce the SWI in a single wooden cube when lifted without visual feedback, by varying the size of the object seen prior to the lift during a …