Matching Items (3)
Description
Perceptual learning by means of coherent motion training paradigms has been shown to produce plasticity in lower and higher-level visual systems within the human occipital lobe both supra- and subliminally. However, efficiency of training methods that produce consolidation in the visual system via coherent motion has yet to be experimentally determined. Furthermore, the effects of coherent motion training on reading comprehension, in clinical and normal populations, are still nascent. In the present study, 20 participants were randomly assigned to one of four experimental conditions. Two conditions had a participation requirement of four days while two conditions required eight days of participation. These conditions were further divided into 500 or 1000 trials per day (4 x 500, 4 x 1000, 8 x 500, 8 x 1000). Additional pre-test and post-test days were used to attain timed pre- and post-tests on the Wide Range Achievement Test IV (WRAT IV) reading comprehension battery. Furthermore, a critical flicker fusion threshold (CFFT) score was taken on a macular pigment densitometer on the pre-test and post-test day. Participants showed significant improvement in CFFT levels, WRAT IV reading comprehension, and speed of completion between pre-test and post-test; however, degree of improvement did not vary as a function of training condition. An interaction between training condition and degree of improvement was evident in coherent dot motion contrast scores, with significant training plasticity occurring in the 4 x 1000 and 8 x 500 conditions.
ContributorsGroth, Anthony (Author) / Náñez, José E. (Thesis advisor) / Hall, Deborah (Committee member) / Risko, Evan F. (Committee member) / Arizona State University (Publisher)
Created2013
Description
The present study explores the role of motion in the perception of form from dynamic occlusion, employing color to help isolate the contributions of both visual pathways. Although the cells that respond to color cues in the environment usually feed into the ventral stream, humans can perceive motion based on chromatic cues. The current study was designed to use grey, green, and red stimuli to successively limit the amount of information available to the dorsal stream pathway, while providing roughly equal information to the ventral system. Twenty-one participants identified shapes that were presented in grey, green, and red and were defined by dynamic occlusion. The shapes were then presented again in a static condition where the maximum occlusions were presented as before, but without motion. Results showed an interaction between the motion and static conditions in that when the speed of presentation increased, performance in the motion conditions became significantly less accurate than in the static conditions. The grey and green motion conditions crossed static performance at the same point, whereas the red motion condition crossed at a much slower speed. These data are consistent with a model of neural processing in which the main visual systems share information. Moreover, they support the notion that presenting stimuli in specific colors may help isolate perceptual pathways for scientific investigation. Given the potential for chromatic cues to target specific visual systems in the performance of dynamic object recognition, exploring these perceptual parameters may help our understanding of human visual processing.
ContributorsHolloway, Steven R. (Author) / McBeath, Michael K. (Thesis advisor) / Homa, Donald (Committee member) / Macknik, Stephen L. (Committee member) / Arizona State University (Publisher)
Created2011
Description
The interplay between Post Traumatic Stress Disorder (PTSD) and self-efficacy lies in the efficacy-activated processes that comprise an individual’s cognitive and belief systems. Previous research shows that low self-efficacy contributes to development and maintenance of mental disorders like PTSD, while high self-efficacy influences ability to visualize, implement, and maintain success scenarios (resilience) related to effective mental coping. Negative cognition makes it difficult to pursue a coping success scenario in the presence of overriding self-doubt and often arises because a traumatic event has made it difficult to retrieve positive self-identities or has reactivated negative self-identities. Consistent with this model, we predict that a negative association exists between self-efficacy and PTSD onset susceptibility. We employed a pre-test/post-test design using a susceptibility/resilience questionnaire to assess predisposition to PTSD. Vignettes, designed to either raise or lower self-efficacy, were used to separate participants into groups and revealed a significant interaction between low and high self-efficacy across the pre- and post-tests, supporting the assertion that high self-efficacy guards against PTSD onset susceptibility while low self-efficacy may make someone more susceptible to developing PTSD-related symptoms.
ContributorsNightingale, Jeffrey W (Co-author) / Holloway, Steven R. (Thesis director) / Náñez, José E. (Committee member) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05