The scope of unconscious processing is highly debated, with recent studies showing that even high-level functions such as perceptual integration and category-based attention occur unconsciously. For example, upright faces that are suppressed from awareness through interocular suppression break into awareness more quickly than inverted faces. Similarly, verbal object cues boost otherwise invisible objects into awareness. Here, we replicate these findings, but find that they reflect a general difference in detectability not specific to interocular suppression. To dissociate conscious and unconscious influences on visual detection effects, we use an additional discrimination task to rule out conscious processes as a cause for these differences. Results from this detection–discrimination dissociation paradigm reveal that, while face orientation is processed unconsciously, category-based attention requires awareness. These findings provide insights into the function of conscious perception and offer an experimental approach for mapping out the scope and limits of unconscious processing.
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Data from individual participants that formed the basis of the findings of this study are available at https://osf.io/sn8cr/.
Custom code that was used to extract individual participant results is available at https://osf.io/sn8cr/. Additional code is available from the corresponding author upon request.
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The authors thank S. Gayet and Y. Pinto for suggestions on earlier versions of this manuscript, and D. Awad, T. Ciorli, C. Laurent, M. Leitjens, C. Riddell, F. Roelofs and M. Wiggers for help with data collection. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 725970). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
The authors declare no competing interests.
Peer review information Nature Human Behaviour thanks Anthony Atkinson, Stefan Van der Stigchel and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. The editors also thank Sheng He for providing signed comments.
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Localization thresholds for low- and high-contrast upright and inverted faces from the four detection paradigms. Note the different scales. Every circles represents an individual participant.
Localization for accuracy for upright and inverted faces for the three different detection paradigms and presentation times. Every circles represents an individual participant.
Extended Data Fig. 3 Subject-level display of localization, detection and discrimination sensitivity in Experiment 3.
a, Localization sensitivity and (b) detection sensitivity for upright and inverted faces for the five different presentation times (values in square brackets refer to an additional blank screen of 8 ms between the face stimulus and the mask). For comparison, both panels also show discrimination sensitivity. c, Mean localization accuracy for upright and inverted faces shown for trials with correct (left panel) and incorrect (right panel) discrimination between upright and inverted faces. Every circle represents an individual participant, horizontal lines the means, and error bars 95% CIs.
Extended Data Fig. 4 Subject-level display of localization and discrimination sensitivity in Experiment 4.
Localization and discrimination sensitivity for the four different presentation times in (a) Experiment 4a and (b) Experiment 4b. (c) Mean localization accuracy for validly and invalidly cued objects for trials with correct (left panel) and incorrect (right panel) discrimination between valid and invalid cues (collapsed across Experiment 4a and 4b). Every circle represents an individual participant, horizontal lines the means, and error bars 95% CIs.
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Stein, T., Peelen, M.V. Dissociating conscious and unconscious influences on visual detection effects. Nat Hum Behav 5, 612–624 (2021). https://doi.org/10.1038/s41562-020-01004-5
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