Attention reshapes the representational geometry of a perceptual feature space

Department of Psychological and Brain Sciences, Boston University Our perception of the world is transformed by attention, both in terms of the efficiency of information processing and the appearance of attended stimuli. A standard theory is that attention regulates how competing stimuli vie for resources. However, an alternative perspective is that attention alters the representational geometry of stimulus spaces, such that changes in processing are not isolated to the particular competing stimuli, but are reflected across the entire perceptual space. To test this representational hypothesis, we conducted an experiment in which participants reported the perceived similarity of orientations spanning the full stimulus space when attention was directed or not directed to specific orientations. We used these similarity judgments to measure the representational geometry of orientation, finding that attention reliably expanded the representational space in a narrow range around the attended orientations. We also found evidence for compression of the representational space in a broad range around unattended orientations. Our findings support the idea that attention acts to reshape the representation of entire perceptual spaces in a way that supports processing of relevant stimulus features. By simultaneously manipulating attention while measuring perceptual similarity, our methodological framework opens the door for future work investigating the interaction between cognitive and perceptual processes from the perspective of representational geometry.