Exploring the Neural Foundations and Causal Mechanisms of Real-World Cognition
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Authors
Fairchild, Grant
Issue Date
2024
Type
Dissertation
Language
en_US
Keywords
Eye Tracking , fMRI , Images , Memory , Perception , Real Objects
Alternative Title
Abstract
The brain evolved to perceive and to facilitate interaction with an environment consisting of real, three-dimensional objects, an environment in which humans and animals still live most of their lives. However, our knowledge of visual cognition and visual neuroscience is based predominantly on studies that have used 2-D images as visual stimuli. If behavioral and brain responses to real objects and 2-D stimuli differ, then many of the traditional frameworks of cognitive neuroscience may need to be reevaluated. Recent studies have in fact shown that real objects elicit different behavioral responses than images in many cognitive domains, including perception, action, memory, and attention. However, neither the neural correlates underlying these differences, nor the causal mechanisms responsible for these differences, have been extensively investigated. Across three studies, this dissertation explores the neural and causal bases of real-object effects. In the first study, I use fMRI to compare the effects of distance and size on brain representations of real objects vs. printed pictures. In the second study, I use fMRI to compare the neural correlates of recognition memory for real objects vs. computer images. In the third study, I use eye tracking to compare gaze patterns for real objects, 2-D images, and 3-D images. My behavioral data shows that real objects are better remembered than images, and that gaze towards real objects, compared to both 2-D and 3-D images, gravitates more towards object parts relevant to the current task. My neuroimaging data show that the functions of the dorsal and ventral visual pathways may be more integrated during viewing of real objects than of pictures, and that regions supporting memory retrieval and object-action associations respond differently during recognition memory of real objects vs. images. My results suggest that the different responses to real objects vs. images depend largely on the potential of real objects for genuine physical interaction. These findings have major translational implications in an era of increased screen-time dominated by artificial, digital objects. These findings also reveal the limitations of 2-D experimental stimuli and highlight the value of real-world experimental stimuli in providing a comprehensive characterization of naturalistic visual cognition.