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Contributed Talk Session: Thursday, August 14, 10:00 – 11:00 am, Room C1.04
Poster Session C: Friday, August 15, 2:00 – 5:00 pm, de Brug & E‑Hall

Confidence in absence as confidence in counterfactual visibility

Maya Schipper¹, Matan Mazor¹; ¹University of Oxford

Presenter: Matan Mazor

When things are perceived clearly they can be detected with confidence. But when can one be confident that something is absent? Here, we used a meta-perceptual illusion to show that confidence in absence scales the belief that a target would have been visible if present. We manipulated stimulus size in two near-threshold detection tasks with confidence ratings. While participants believed that detection was easier for large stimuli (measured with prospective confidence ratings and post-experiment debriefing), their perceptual sensitivity was in fact higher for small stimuli. Accordingly, while confidence in presence scaled with true visibility, confidence in absence scaled with beliefs about visibility. Moreover, the effect of size on confidence in absence, but not in presence, correlated with a meta- perceptual parameter from an ideal observer model. Overall, we conclude that confidence in absence tracked model-derived expectations about the visibility of counterfactual stimuli.

Topic Area: Predictive Processing & Cognitive Control

Extended Abstract: Full Text PDF