Learning improves conscious access at the bottom, but not the top: Reverse hierarchical effects in perceptual learning and metacognition

CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not. Abstract Experience with visual stimuli can improve their perceptual performance, a phenomenon termed visual perceptual learning (VPL), but how does VPL shape our conscious experience of learned stimuli? VPL has been found to improve measures of metacognition, suggesting increased conscious stimulus accessibility. Such studies however, have largely failed to control objective task accuracy, which typically correlates with metacognition. Here, using a staircase method to control this confound, we investigated whether VPL improves the metacognitive accuracy of perceptual judgements. Across three consecutive days, subjects learned to discriminate faces based on either their identity or contrast. Holding objective accuracy constant, perceptual thresholds improved in both tasks, while metacognitive accuracy diverged, with face contrast VPL improving metacognition, and face identity VPL failing to. Our findings can be interpreted in a reverse hierarchy theory-like model of VPL, which counterintuitively predicts that the VPL of low-but not high-level stimulus properties should improve conscious stimulus accessibility.. CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not. 3 Running head: Reverse hierarchies in perceptual learning and metacognition The relationship between subjective, conscious experience and learning remains a central topic in cognitive neuroscience (Bayne, Cleeremans, & Wilken, 2009). Learning effects however, have been largely investigated in the context of objective task performance. For instance, visual perceptual learning (VPL) describes the mechanisms whereby experience with visual stimuli improves their subsequent perceptual performance (e.g., discrimination accuracy; Fahle & Poggio, 2002). While VPL has been closely associated with non-conscious Sasaki, 2001), the exact relationship between VPL and consciousness is poorly understood. Investigating this issue, two parallel bodies of research have recently emerged. One investigates whether conscious stimulus awareness is necessary for VPL Addressing the latter, we investigated whether VPL could improve the metacognitive accuracy of perceptual judgements. Providing an account of VPL and visual consciousness is reverse hierarchy theoryup processing is sufficient for VPL occurring at the apex of the visual hierarchy (e.g., VPL of high-level stimulus properties), while top-down processing is needed to guide VPL to lower visual regions when greater spatial resolution is needed (e.g., VPL of low-level stimulus properties). Likewise, bottom-up processing enables conscious awareness of a stimulus' general, global information (i.e., its gist), while top-down guided processing towards lower visual regions …