1. Neuroscience

Human observers have optimal introspective access to perceptual processes even for visually masked stimuli

  1. Megan AK Peters  Is a corresponding author
  2. Hakwan Lau
  1. University of California, Los Angeles, United States
https://doi.org/10.7554/eLife.09651
Share this article
Cite this article
  1. Megan AK Peters
  2. Hakwan Lau
(2015)
Human observers have optimal introspective access to perceptual processes even for visually masked stimuli
eLife 4:e09651.
https://doi.org/10.7554/eLife.09651
  2. Download BibTeX
  3. Download .RIS

Abstract

Many believe that humans can 'perceive unconsciously' -- that for weak stimuli, briefly presented and masked, above-chance discrimination is possible without awareness. Interestingly, an online survey reveals that most experts in the field recognize the lack of convincing evidence for this phenomenon, and yet they persist in this belief. Using a recently-developed bias-free experimental procedure for measuring subjective introspection (confidence), we found no evidence for unconscious perception; participants' behavior matched that of a Bayesian ideal observer, even though the stimuli were visually masked. This surprising finding suggests that the thresholds for subjective awareness and objective discrimination are effectively the same: if objective task performance is above chance, there is likely conscious experience. These findings shed new light on decades-old methodological issues regarding what it takes to consider a neurobiological or behavioral effect to be 'unconscious,' and provide a platform for rigorously investigating unconscious perception in future studies.

Article and author information

Author details

  1. Megan AK Peters

    Department of Psychology, University of California, Los Angeles, Los Angeles, United States
    For correspondence
    meganakpeters@ucla.edu
    Competing interests
    The authors declare that no competing interests exist.

  2. Hakwan Lau

    Department of Psychology, University of California, Los Angeles, Los Angeles, United States
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Matteo Carandini, University College London, United Kingdom

Ethics

Human subjects: Twelve subjects (two women, ages 19-32, ten right-handed) gave written informed consent to participate in our behavioral experiments. All subjects had normal or corrected-to-normal eyesight, and wore the same corrective lenses for all sessions, if applicable. Behavioral experiments were conducted in accordance with the Declaration of Helsinki and were approved by the UCLA Institutional Review Board.Eighty-seven respondents replied to our informal online survey. Survey procedures were conducted in accordance with the Declaration of Helsinki and were approved by the UCLA Institutional Review Board.Thus, all survey respondents provided informed consent to participate in the informal online survey, and behavioral subjects provided written informed consent to participate in the behavioral experiments.

Version history

  1. Received: June 24, 2015
  2. Accepted: October 2, 2015
  3. Accepted Manuscript published: October 3, 2015 (version 1)
  4. Version of Record published: February 1, 2016 (version 2)
  5. Version of Record updated: March 31, 2016 (version 3)

Copyright

© 2015, Peters & Lau

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 6,151
    views
  • 1,272
    downloads
  • 90
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Megan AK Peters
  2. Hakwan Lau
(2015)
Human observers have optimal introspective access to perceptual processes even for visually masked stimuli
eLife 4:e09651.
https://doi.org/10.7554/eLife.09651

Share this article

https://doi.org/10.7554/eLife.09651

Categories and tags

Research organism

Further reading

  1. Now you see it: Listen to Megan Peters talk about unconscious perception

    Podcast

    Unconscious perception does not exist.

    1. Cell Biology
    2. Neuroscience

    KIS counteracts PTBP2 and regulates alternative exon usage in neurons

    Marcos Moreno-Aguilera, Alba M Neher ... Carme Gallego
    Research Article Updated

    Alternative RNA splicing is an essential and dynamic process in neuronal differentiation and synapse maturation, and dysregulation of this process has been associated with neurodegenerative diseases. Recent studies have revealed the importance of RNA-binding proteins in the regulation of neuronal splicing programs. However, the molecular mechanisms involved in the control of these splicing regulators are still unclear. Here, we show that KIS, a kinase upregulated in the developmental brain, imposes a genome-wide alteration in exon usage during neuronal differentiation in mice. KIS contains a protein-recognition domain common to spliceosomal components and phosphorylates PTBP2, counteracting the role of this splicing factor in exon exclusion. At the molecular level, phosphorylation of unstructured domains within PTBP2 causes its dissociation from two co-regulators, Matrin3 and hnRNPM, and hinders the RNA-binding capability of the complex. Furthermore, KIS and PTBP2 display strong and opposing functional interactions in synaptic spine emergence and maturation. Taken together, our data uncover a post-translational control of splicing regulators that link transcriptional and alternative exon usage programs in neuronal development.