The influence of culture, attention, and visual feedback on perceptual grouping
Loading...
Date
2021-04-21
Authors
Carther-Krone (Lazar), Tiffany
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
What factors influence how we perceive the world around us? This dissertation describes a series of experiments using traditional cognitive and psychophysical methodologies, functional magnetic resonance imaging (fMRI), and advanced visuomotor paradigms to explore the effects of culture, attention, and visual feedback on visual perception. In the first study, psychophysical methodologies were used to test the potential mechanism underlying differences in global processing by examining the relative contributions of the magnocellular and parvocellular pathways in mediating global and local visual processing in Asian and Caucasian groups. Participants completed the Navon hierarchical letters task under divided-attention conditions, indicating whether a target letter “H” was present in stimuli that were either unbiased, or biased to predominantly process low-spatial frequency information through the magnocellular or parvocellular pathways. Caucasians processed stimuli more globally than Asians when low-spatial frequency information was projected through the parvocellular pathway. Asians showed a global processing advantage when low-spatial frequency information was projected through the magnocellular pathway, and to a lesser extent to the parvocellular pathway. These findings suggest that the global processing bias found in each group depends on the pathway through which visual information was transmitted. In the second study, fMRI was used to examine perceptual grouping under inattention and divided-attention conditions. Results showed involvement of the right supramarginal gyrus in grouping specifically under conditions of inattention, suggesting that even during implicit grouping complex processing occurs. In the third study, early, middle and late visuomotor control were examined in the context of the Sander Parallelogram illusion to better understand how visual feedback impacts our perceptual system’s ability to group elements of our environment together. Consistent with the Two Visual Streams Hypothesis, results showed a more robust illusion effect for perceptual estimations compared to grasping a target. An illusion effect was also observed when participants were asked to grasp targets under both early and no vision conditions, supporting the notion that while the two streams are distinct, they also interact. Collectively, this work demonstrates that perception is shaped by many factors, and that those factors - in different amounts - can alter how we perceive the world around us.
Description
Keywords
Perceptual grouping, Visual illusion, Culture, Inattention, Divided-attention, Visual feedback
Citation
APA