Expectation-Based Gist Facilitation: Rapid Scene Understanding and the Role of Top-Down Information

Abstract

Scene meaning is processed rapidly, with 'gist' extracted even when presentation duration spans a few dozen milliseconds. This has led some to suggest a primacy of bottom-up information. However, gist research has typically relied on showing successions of unrelated scene images, contrary to our everyday experience in which the world unfolds around us in a predictable manner. Thus, we investigated whether top-down information - in the form of observers' predictions of an upcoming scene - facilitates gist processing. Within each trial, participants (N=336) experienced a series of images, organised to represent an approach to a destination (e.g., walking down a sidewalk), followed by a final target scene either congruous or incongruous with the expected destination (e.g., a store interior or a bedroom). Over a series of behavioural experiments, we found that: appropriate expectations facilitated gist processing; inappropriate expectations interfered with gist processing; the effect of congruency was driven by provision of contextual information rather than the thematic coherence of approach images, and; expectation-based facilitation was most apparent when destination duration was most curtailed. We then investigated the neural correlates of predictability on scene processing using ERP (N=26). Congruency-related differences were found in a putative scene-selective ERP component, related to integrating visual properties (P2), and in later components related to contextual integration including semantic and syntactic coherence (N400 and P600, respectively). Taken together, these results suggest that in real-world situations, top-down predictions of an upcoming scene influence even the earliest stages of its processing, affecting both the integration of visual properties and meaning. Keywords: scene processing, gist, top-down information, event-related potentials, semantic integration

What can we experience and report on a rapidly presented image? Intersubjective measures of specificity of freely reported contents of consciousness

“…In previous studies, participants were told that the images would be one of a few categories (e.g., animal vs. non-animal; Fabre- Thorpe et al, 2001). High accuracy in rapid scene processing (e.g., Evans & Treisman, 2005;Fabre-Thorpe et al, 2001) may depend on expectation (McLean et al, 2021;Sun et al, 2017). In our paradigm participants could not expect the images, yet they still reported impressive details of the briefly presented images.…”

“…For example, asking participants to choose between "animal" and "non-animal" will tell them they might see an animal. This could help participants perceive more detailed information (McLean et al, 2021;Sun et al, 2017), while it can suppress seeing other aspects of rapidly presented scenes.…”

What can we experience and report on a rapidly presented image? Intersubjective measures of specificity of freely reported contents of consciousness

“…In previous studies, participants were told that the images would be one of a few categories (e.g., animal vs. non-animal; Fabre-Thorpe et al , 2001 ). High accuracy in rapid scene processing (e.g., Evans & Treisman, 2005 ; Fabre-Thorpe et al , 2001 ) may depend on expectation ( McLean et al , 2021 ; Sun et al , 2017 ). In our paradigm participants could not expect the images, yet they still reported impressive details of the briefly presented images.…”

Disentangling diagnostic object properties for human scene categorization

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