Observers can gaze upon an image, process enough of that image to identify it, but completely fail to notice drastic changes to the periphery of that image

Cohen, M. A., Ostrand, C., Frontero, N., & Pham, P.-N. (2021). Characterizing a snapshot of perceptual experience. Journal of Experimental Psychology: General. Jan 2021. https://doi.org/10.1037/xge0000864

Abstract: What can we perceive in a single glance of the visual world? Although this question appears rather simple, answering it has been remarkably difficult and controversial. Traditionally, researchers have tried to infer the nature of perceptual experience by examining how many objects and what types of objects are not fully encoded within a scene (e.g., failing to notice a bowl disappearing/changing). Here, we took a different approach and asked how much we could alter an entire scene before observers noticed those global alterations. Surprisingly, we found that observers could fixate on a scene for hundreds of milliseconds yet routinely fail to notice drastic changes to that scene (e.g., scrambling the periphery so no object can be identified, putting the center of 1 scene on the background of another scene). In addition, we also found that as observers allocate more attention to their periphery, their ability to notice these changes to a scene increases. Together, these results show that although a single snapshot of perceptual experience can be remarkably impoverished, it is also not a fixed constant and is likely to be continuously changing from moment to moment depending on attention.

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Observers can gaze upon an image, process enough of that image to identify it, but completely fail to notice drastic changes to the periphery of that image