Dissociating implicit and explicit ensemble representations reveals the limits of visual perception and the richness of behavior

• Published in: Scientific Reports
• Main Authors: Hansmann-Roth, Sabrina, Kristjánsson, Árni, Whitney, David, Chetverikov, Andrey
• Other Authors: Faculty of Psychology, Health Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Sjónskynjun; Ákvarðanataka; Sjón; article; decision making; dissaciation; human; noise; probability; vision; visual system; Multidisciplinary; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/3143; https://doi.org/10.1038/s41598-021-83358-y

Funding Information: S.H.R. and A.K. were supported by Grant IRF #173947-052 from the Icelandic research fund, and by a Grant from the Research Fund of the University of Iceland. A.C. is supported by a Radboud Excellence Fellowship. Publisher Copyright: © 2021, The Author(s). Our senses provide us with a rich experience of a detailed visual world, yet the empirical results seem to suggest severe limitations on our ability to perceive and remember. In recent attempts to reconcile the contradiction between what is experienced and what can be reported, it has been argued that the visual world is condensed to a set of summary statistics, explaining both the rich experience and the sparse reports. Here, we show that explicit reports of summary statistics underestimate the richness of ensemble perception. Our observers searched for an odd-one-out target among heterogeneous distractors and their representation of distractor characteristics was tested explicitly or implicitly. Observers could explicitly distinguish distractor sets with different mean and variance, but not differently-shaped probability distributions. In contrast, the implicit assessment revealed that the visual system encodes the mean, the variance, and even the shape of feature distributions. Furthermore, explicit measures had common noise sources that distinguished them from implicit measures. This suggests that explicit judgments of stimulus ensembles underestimate the richness of visual representations. We conclude that feature distributions are encoded in rich detail and can guide behavior implicitly, even when the information available for explicit summary judgments is coarse and limited. Peer reviewed