1
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Lanfranco RC, Canales-Johnson A, Rabagliati H, Cleeremans A, Carmel D. Minimal exposure durations reveal visual processing priorities for different stimulus attributes. Nat Commun 2024; 15:8523. [PMID: 39358365 PMCID: PMC11447214 DOI: 10.1038/s41467-024-52778-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 09/19/2024] [Indexed: 10/04/2024] Open
Abstract
Human vision can detect a single photon, but the minimal exposure required to extract meaning from stimulation remains unknown. This requirement cannot be characterised by stimulus energy, because the system is differentially sensitive to attributes defined by configuration rather than physical amplitude. Determining minimal exposure durations required for processing various stimulus attributes can thus reveal the system's priorities. Using a tachistoscope enabling arbitrarily brief displays, we establish minimal durations for processing human faces, a stimulus category whose perception is associated with several well-characterised behavioural and neural markers. Neural and psychophysical measures show a sequence of distinct minimal exposures for stimulation detection, object-level detection, face-specific processing, and emotion-specific processing. Resolving ongoing debates, face orientation affects minimal exposure but emotional expression does not. Awareness emerges with detection, showing no evidence of subliminal perception. These findings inform theories of visual processing and awareness, elucidating the information to which the visual system is attuned.
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Affiliation(s)
- Renzo C Lanfranco
- Department of Psychology, University of Edinburgh, EH8 9JZ, Edinburgh, United Kingdom.
- Department of Neuroscience, Karolinska Institutet, 171 65, Stockholm, Sweden.
- Consciousness, Cognition & Computation Group, Center for Research in Cognition & Neurosciences, ULB Neuroscience Institute, Université libre de Bruxelles, B1050, Brussels, Belgium.
| | - Andrés Canales-Johnson
- Department of Psychology, University of Cambridge, CB2 2EB, Cambridge, United Kingdom
- Neuropsychology and Cognitive Neurosciences Research Center, Faculty of Health Sciences, Universidad Católica del Maule, Talca, Chile
| | - Hugh Rabagliati
- Department of Psychology, University of Edinburgh, EH8 9JZ, Edinburgh, United Kingdom
| | - Axel Cleeremans
- Consciousness, Cognition & Computation Group, Center for Research in Cognition & Neurosciences, ULB Neuroscience Institute, Université libre de Bruxelles, B1050, Brussels, Belgium
| | - David Carmel
- Department of Psychology, University of Edinburgh, EH8 9JZ, Edinburgh, United Kingdom.
- School of Psychology, Victoria University of Wellington, 6012, Wellington, New Zealand.
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2
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Xu L, Paffen CLE, Van der Stigchel S, Gayet S. Statistical Learning Facilitates Access to Awareness. Psychol Sci 2024; 35:1035-1047. [PMID: 39222160 DOI: 10.1177/09567976241263344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024] Open
Abstract
Statistical learning is a powerful mechanism that enables the rapid extraction of regularities from sensory inputs. Although numerous studies have established that statistical learning serves a wide range of cognitive functions, it remains unknown whether statistical learning impacts conscious access. To address this question, we applied multiple paradigms in a series of experiments (N = 153 adults): Two reaction-time-based breaking continuous flash suppression (b-CFS) experiments showed that probable objects break through suppression faster than improbable objects. A preregistered accuracy-based b-CFS experiment showed higher localization accuracy for suppressed probable (versus improbable) objects under identical presentation durations, thereby excluding the possibility of processing differences emerging after conscious access (e.g., criterion shifts). Consistent with these findings, a supplemental visual-masking experiment reaffirmed higher localization sensitivity to probable objects over improbable objects. Together, these findings demonstrate that statistical learning alters the competition for scarce conscious resources, thereby potentially contributing to established effects of statistical learning on higher-level cognitive processes that require consciousness.
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Affiliation(s)
- Luzi Xu
- Experimental Psychology, Helmholtz Institute, Utrecht University
| | - Chris L E Paffen
- Experimental Psychology, Helmholtz Institute, Utrecht University
| | | | - Surya Gayet
- Experimental Psychology, Helmholtz Institute, Utrecht University
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3
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Liuzzi P, Cassioli T, Secci S, Hakiki B, Scarpino M, Burali R, di Palma A, Toci T, Grippo A, Cecchi F, Frosini A, Mannini A. A neurophysiological profiling of the heartbeat-evoked potential in severe acquired brain injuries: A focus on unconsciousness. Eur J Neurosci 2024; 60:4201-4216. [PMID: 38797841 DOI: 10.1111/ejn.16394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 04/26/2024] [Accepted: 05/01/2024] [Indexed: 05/29/2024]
Abstract
Unconsciousness in severe acquired brain injury (sABI) patients occurs with different cognitive and neural profiles. Perturbational approaches, which enable the estimation of proxies for brain reorganization, have added a new avenue for investigating the non-behavioural diagnosis of consciousness. In this prospective observational study, we conducted a comparative analysis of the topological patterns of heartbeat-evoked potentials (HEP) between patients experiencing a prolonged disorder of consciousness (pDoC) and patients emerging from a minimally consciousness state (eMCS). A total of 219 sABI patients were enrolled, each undergoing a synchronous EEG-ECG resting-state recording, together with a standardized consciousness diagnosis. A number of graph metrics were computed before/after the HEP (Before/After) using the R-peak on the ECG signal. The peak value of the global field power of the HEP was found to be significantly higher in eMCS patients with no difference in latency. Power spectrum was not able to discriminate consciousness neither Before nor After. Node assortativity and global efficiency were found to vary with different trends at unconsciousness. Lastly, the Perturbational Complexity Index of the HEP was found to be significantly higher in eMCS patients compared with pDoC. Given that cortical elaboration of peripheral inputs may serve as a non-behavioural determinant of consciousness, we have devised a low-cost and translatable technique capable of estimating causal proxies of brain functionality with an endogenous, non-invasive stimulus. Thus, we present an effective means to enhance consciousness assessment by incorporating the interaction between the autonomic nervous system (ANS) and central nervous system (CNS) into the loop.
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Affiliation(s)
- Piergiuseppe Liuzzi
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Florence, Italy
- Istituto di BioRobotica, Scuola Superiore Sant'Anna, Pisa, Italy
| | | | - Sara Secci
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Florence, Italy
| | - Bahia Hakiki
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Florence, Italy
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | | | - Rachele Burali
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Florence, Italy
| | | | - Tanita Toci
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Florence, Italy
| | | | - Francesca Cecchi
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Florence, Italy
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - Andrea Frosini
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Florence, Italy
- Dipartimento di Matematica Ulisse Dini, Università di Firenze, Florence, Italy
| | - Andrea Mannini
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Florence, Italy
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4
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Ciorli T, Pia L. The role of identity priming on the (unconscious) bodily self-attribution. PSYCHOLOGICAL RESEARCH 2024; 88:1331-1338. [PMID: 38492085 PMCID: PMC11143043 DOI: 10.1007/s00426-024-01944-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/23/2024] [Indexed: 03/18/2024]
Abstract
It has been recently demonstrated that hand stimuli presented in a first-, with respect to a third-, person perspective were prioritized before awareness independently from their identity (i.e., self, or other). This pattern would represent an unconscious advantage for self-related bodily stimuli rooted in spatial perspective. To deeper investigate the role of identity, we employed a breaking-Continuous Flash Suppression paradigm in which a self- or other-hand presented in first- or third-person perspective was displayed after a conscious identity-related prime (i.e., self or other face). We replicated the unconscious advantage of the first-person perspective but, crucially, we reported that within the first-person perspective, other-hand stimuli preceded by other-face priming slowed down the conscious access with respect to the other conditions. These findings demonstrate that a top-down conscious identity context modulates the unconscious self-attribution of bodily stimuli. Within a predictive processing framework, we suggest that, by adding ambiguous information, the prime forces a prediction update that slows conscious access.
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Affiliation(s)
- Tommaso Ciorli
- SAMBA (SpAtial, Motor and Bodily Awareness) Research Group, Department of Psychology, University of Turin, Via Verdi 10, 10123, Turin, Italy
| | - Lorenzo Pia
- SAMBA (SpAtial, Motor and Bodily Awareness) Research Group, Department of Psychology, University of Turin, Via Verdi 10, 10123, Turin, Italy.
- NIT (Neuroscience Institute of Turin), Turin, Italy.
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5
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Stein T, van Gaal S, Fahrenfort JJ. How (not) to demonstrate unconscious priming: Overcoming issues with post-hoc data selection, low power, and frequentist statistics. Conscious Cogn 2024; 119:103669. [PMID: 38395013 DOI: 10.1016/j.concog.2024.103669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 02/16/2024] [Accepted: 02/16/2024] [Indexed: 02/25/2024]
Abstract
One widely used scientific approach to studying consciousness involves contrasting conscious operations with unconscious ones. However, challenges in establishing the absence of conscious awareness have led to debates about the extent and existence of unconscious processes. We collected experimental data on unconscious semantic priming, manipulating prime presentation duration to highlight the critical role of the analysis approach in attributing priming effects to unconscious processing. We demonstrate that common practices like post-hoc data selection, low statistical power, and frequentist statistical testing can erroneously support claims of unconscious priming. Conversely, adopting best practices like direct performance-awareness contrasts, Bayesian tests, and increased statistical power can prevent such erroneous conclusions. Many past experiments, including our own, fail to meet these standards, casting doubt on previous claims about unconscious processing. Implementing these robust practices will enhance our understanding of unconscious processing and shed light on the functions and neural mechanisms of consciousness.
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Affiliation(s)
- Timo Stein
- Department of Psychology, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands.
| | - Simon van Gaal
- Department of Psychology, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands
| | - Johannes J Fahrenfort
- Department of Psychology, University of Amsterdam, Amsterdam, the Netherlands; Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands; Department of Applied and Experimental Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
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6
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Ding X, Ji H, Yu W, Xu L, Lin Y, Sun Y. Dissociation between temporal attention and Consciousness: Unconscious temporal cue induces temporal expectation effect. Conscious Cogn 2024; 119:103670. [PMID: 38422759 DOI: 10.1016/j.concog.2024.103670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 02/21/2024] [Accepted: 02/21/2024] [Indexed: 03/02/2024]
Abstract
The debate over the independence of attention and consciousness is ongoing. Prior studies have established that invisible spatial cues can direct attention. However, our exploration extends beyond spatial dimensions to temporal information as a potent guide for attention. A intriguing question arises: Can unconscious temporal cues trigger attentional orienting? To investigate, we employed a modified reaction-time task in Experiments 1 and 2, using Gabor stimuli or human facial stimuli as temporal cues rendered invisible through continuous flash suppression. We aimed to uncover temporal expectation effects (TE effects) without conscious awareness. Moreover, Experiments 3 and 4 probed the boundaries of this unconscious processing, assessing whether conscious temporal cues could modulate TE effects. Our results confirm that invisible temporal cues can induce TE effects, and these effects can be overridden by conscious temporal cues. This dissociation between temporal attention and consciousness provide a new perspective on our understanding of their relationship.
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Affiliation(s)
- Xiaowei Ding
- Department of Psychology, Guangdong Provincial Key Laboratory of Social Cognitive Neuroscience and Mental Health, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Huichao Ji
- Department of Psychology, Guangdong Provincial Key Laboratory of Social Cognitive Neuroscience and Mental Health, Sun Yat-sen University, Guangzhou, People's Republic of China; Department of Psychology, Yale University, New Haven, USA
| | - Wenhao Yu
- School of Psychology, Shandong Normal University, Jinan, People's Republic of China
| | - Luzi Xu
- Department of Psychology, Guangdong Provincial Key Laboratory of Social Cognitive Neuroscience and Mental Health, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Youting Lin
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, People's Republic of China.
| | - Yanliang Sun
- School of Psychology, Shandong Normal University, Jinan, People's Republic of China.
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7
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Schmidt T, Biafora M. A theory of visibility measures in the dissociation paradigm. Psychon Bull Rev 2024; 31:65-88. [PMID: 37528279 PMCID: PMC10977871 DOI: 10.3758/s13423-023-02332-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2023] [Indexed: 08/03/2023]
Abstract
Research on perception without awareness primarily relies on the dissociation paradigm, which compares a measure of awareness of a critical stimulus (direct measure) with a measure indicating that the stimulus has been processed at all (indirect measure). We argue that dissociations between direct and indirect measures can only be demonstrated with respect to the critical stimulus feature that generates the indirect effect, and the observer's awareness of that feature, the critical cue. We expand Kahneman's (Psychological Bulletin, 70, 404-425, 1968) concept of criterion content to comprise the set of all cues that an observer actually uses to perform the direct task. Different direct measures can then be compared by studying the overlap of their criterion contents and their containment of the critical cue. Because objective and subjective measures may integrate different sets of cues, one measure generally cannot replace the other without sacrificing important information. Using a simple mathematical formalization, we redefine and clarify the concepts of validity, exclusiveness, and exhaustiveness in the dissociation paradigm, show how dissociations among different awareness measures falsify both single-valued measures and monocausal theories of "consciousness," and formulate the demand that theories of visual awareness should be sufficiently specific to explain dissociations among different facets of awareness.
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Affiliation(s)
- Thomas Schmidt
- Faculty of Social Sciences, Visual Attention and Awareness Laboratory, University of Kaiserslautern-Landau (RPTU), Erwin-Schrödinger-Str. Geb. 57, D-67663, Kaiserslautern, Germany.
| | - Melanie Biafora
- Faculty of Social Sciences, Visual Attention and Awareness Laboratory, University of Kaiserslautern-Landau (RPTU), Erwin-Schrödinger-Str. Geb. 57, D-67663, Kaiserslautern, Germany
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8
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Ciorli T, Pia L. Spatial perspective and identity in visual awareness of the bodily self-other distinction. Sci Rep 2023; 13:14994. [PMID: 37696861 PMCID: PMC10495455 DOI: 10.1038/s41598-023-42107-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/05/2023] [Indexed: 09/13/2023] Open
Abstract
Spatial perspective and identity of visual bodily stimuli are two key cues for the self-other distinction. However, how they emerge into visual awareness is largely unknown. Here, self- or other-hands presented in first- or third-person perspective were compared in a breaking-Continuous Flash Suppression paradigm (Experiment 1) measuring the time the stimuli need to access visual awareness, and in a Binocular Rivalry paradigm (Experiment 2), measuring predominance in perceptual awareness. Results showed that, irrespectively of identity, first-person perspective speeded up the access, whereas the third-person one increased the dominance. We suggest that the effect of first-person perspective represents an unconscious prioritization of an egocentric body coding important for visuomotor control. On the other hand, the effect of third-person perspective indicates a conscious advantage of an allocentric body representation fundamental for detecting the presence of another intentional agent. Summarizing, the emergence of self-other distinction into visual awareness would strongly depend on the interplay between spatial perspectives, with an inverse prioritization before and after conscious perception. On the other hand, identity features might rely on post-perceptual processes.
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Affiliation(s)
- Tommaso Ciorli
- SAMBA (SpAtial, Motor and Bodily Awareness) Research Group, Department of Psychology, University of Turin, Via Verdi 10, 10123, Turin, Italy
| | - Lorenzo Pia
- SAMBA (SpAtial, Motor and Bodily Awareness) Research Group, Department of Psychology, University of Turin, Via Verdi 10, 10123, Turin, Italy.
- NIT (Neuroscience Institute of Turin), Turin, Italy.
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9
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Lanfranco RC, Rabagliati H, Carmel D. The importance of awareness in face processing: A critical review of interocular suppression studies. Behav Brain Res 2023; 437:114116. [PMID: 36113728 DOI: 10.1016/j.bbr.2022.114116] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 08/15/2022] [Accepted: 09/12/2022] [Indexed: 10/14/2022]
Abstract
Human faces convey essential information for understanding others' mental states and intentions. The importance of faces in social interaction has prompted suggestions that some relevant facial features such as configural information, emotional expression, and gaze direction may promote preferential access to awareness. This evidence has predominantly come from interocular suppression studies, with the most common method being the Breaking Continuous Flash Suppression (bCFS) procedure, which measures the time it takes different stimuli to overcome interocular suppression. However, the procedures employed in such studies suffer from multiple methodological limitations. For example, they are unable to disentangle detection from identification processes, their results may be confounded by participants' response bias and decision criteria, they typically use small stimulus sets, and some of their results attributed to detecting high-level facial features (e.g., emotional expression) may be confounded by differences in low-level visual features (e.g., contrast, spatial frequency). In this article, we review the evidence from the bCFS procedure on whether relevant facial features promote access to awareness, discuss the main limitations of this very popular method, and propose strategies to address these issues.
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Affiliation(s)
- Renzo C Lanfranco
- Department of Psychology, University of Edinburgh, Edinburgh, United Kingdom; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | - Hugh Rabagliati
- Department of Psychology, University of Edinburgh, Edinburgh, United Kingdom
| | - David Carmel
- Department of Psychology, University of Edinburgh, Edinburgh, United Kingdom; School of Psychology, Victoria University of Wellington, Wellington, New Zealand.
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10
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Ludwig D. The functions of consciousness in visual processing. Neurosci Conscious 2023; 2023:niac018. [PMID: 36628118 PMCID: PMC9825248 DOI: 10.1093/nc/niac018] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/24/2022] [Accepted: 12/06/2022] [Indexed: 01/09/2023] Open
Abstract
Conscious experiences form a relatively diverse class of psychological phenomena, supported by a range of distinct neurobiological mechanisms. This diversity suggests that consciousness occupies a variety of different functional roles across different task domains, individuals, and species; a position I call functional pluralism. In this paper, I begin to tease out some of the functional contributions that consciousness makes to (human) visual processing. Consolidating research from across the cognitive sciences, I discuss semantic and spatiotemporal processing as specific points of comparison between the functional capabilities of the visual system in the presence and absence of conscious awareness. I argue that consciousness contributes a cluster of functions to visual processing; facilitating, among other things, (i) increased capacities for semantically processing informationally complex visual stimuli, (ii) increased spatiotemporal precision, and (iii) increased capacities for representational integration over large spatiotemporal intervals. This sort of analysis should ultimately yield a plurality of functional markers that can be used to guide future research in the philosophy and science of consciousness, some of which are not captured by popular theoretical frameworks like global workspace theory and information integration theory.
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Affiliation(s)
- Dylan Ludwig
- Department of Philosophy, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
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11
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Prochazkova E, Venneker D, de Zwart R, Tamietto M, Kret ME. Conscious awareness is necessary to assess trust and mimic facial expressions, while pupils impact trust unconsciously. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210183. [PMID: 36126669 PMCID: PMC9489300 DOI: 10.1098/rstb.2021.0183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 03/17/2022] [Indexed: 11/12/2022] Open
Abstract
People make rapid inferences about others' thoughts and intentions. For example, they observe facial movements and pupil size of others and unwittingly make use of this information when deciding whether to trust someone or not. However, whether spontaneous mimicry depends on visual awareness of the stimulus and whether these processes underlie trust decisions is still unknown. To investigate whether visual awareness modulates the relationship between emotional expressions, mimicry and trust, participants played a series of trust games and saw either their partners' faces with a neutral, happy or fearful expression, or their partners' eyes in which the pupil size was large, medium or small. Subjects' trust investments, facial movements and pupil responses were measured. In half of the trials, the stimuli were rendered invisible by continuous flash suppression. Results showed that facial expressions were mimicked and influenced trust decisions during the conscious condition, but not during the unconscious (suppressed) condition. The opposite was found for pupil size, which influenced trust decisions during states of unawareness. These results suggest that the neurobiological pathway linking the observation of facial expressions to mimicry and trust is predominantly conscious, whereas partner pupil size influences trust primarily when presented unconsciously. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.
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Affiliation(s)
- E. Prochazkova
- Institute of Psychology, Cognitive Psychology Unit, Leiden Institute for Brain and Cognition (LIBC), Albinusdreef 2, Leiden 2300 RC, The Netherlands
- Leiden Institute for Brain and Cognition (LIBC), Albinusdreef 2, Leiden 2300 RC, The Netherlands
| | - D. Venneker
- Leiden Institute For Brain and Cognition, Leiden University, Wassenaarseweg 52, 2333 AK Leiden, The Netherlands
| | - R. de Zwart
- Institute of Psychology, Cognitive Psychology Unit, Leiden Institute for Brain and Cognition (LIBC), Albinusdreef 2, Leiden 2300 RC, The Netherlands
| | - M. Tamietto
- Department of Medical and Clinical Psychology, and CoRPS - Center of Research on Psychology in Somatic diseases - Tilburg University, PO Box 90153, 5000 LE Tilburg, The Netherlands
- Department of Psychology, University of Torino, Via G. Verdi 10, 10124, Torino, Italy
| | - M. E. Kret
- Institute of Psychology, Cognitive Psychology Unit, Leiden Institute for Brain and Cognition (LIBC), Albinusdreef 2, Leiden 2300 RC, The Netherlands
- Leiden Institute for Brain and Cognition (LIBC), Albinusdreef 2, Leiden 2300 RC, The Netherlands
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12
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McFadyen J, Tsuchiya N, Mattingley JB, Garrido MI. Surprising Threats Accelerate Conscious Perception. Front Behav Neurosci 2022; 16:797119. [PMID: 35645748 PMCID: PMC9137416 DOI: 10.3389/fnbeh.2022.797119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 04/05/2022] [Indexed: 11/15/2022] Open
Abstract
The folk psychological notion that "we see what we expect to see" is supported by evidence that we become consciously aware of visual stimuli that match our prior expectations more quickly than stimuli that violate our expectations. Similarly, "we see what we want to see," such that more biologically-relevant stimuli are also prioritised for conscious perception. How, then, is perception shaped by biologically-relevant stimuli that we did not expect? Here, we conducted two experiments using breaking continuous flash suppression (bCFS) to investigate how prior expectations modulated response times to neutral and fearful faces. In both experiments, we found that prior expectations for neutral faces hastened responses, whereas the opposite was true for fearful faces. This interaction between emotional expression and prior expectations was driven predominantly by participants with higher trait anxiety. Electroencephalography (EEG) data collected in Experiment 2 revealed an interaction evident in the earliest stages of sensory encoding, suggesting prediction errors expedite sensory encoding of fearful faces. These findings support a survival hypothesis, where biologically-relevant fearful stimuli are prioritised for conscious access even more so when unexpected, especially for people with high trait anxiety.
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Affiliation(s)
- Jessica McFadyen
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
- Max Planck UCL Centre for Computational Psychiatry and Ageing Research, University College London, London, United Kingdom
- Australian Research Council Centre of Excellence for Integrative Brain Function, Clayton, VIC, Australia
| | - Naotsugu Tsuchiya
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT), Osaka, Japan
- Advanced Telecommunications Research Computational Neuroscience Laboratories, Kyoto, Japan
| | - Jason B. Mattingley
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, Clayton, VIC, Australia
- School of Psychology, University of Queensland, Brisbane, QLD, Australia
- Canadian Institute for Advanced Research, Toronto, ON, Canada
| | - Marta I. Garrido
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, Clayton, VIC, Australia
- Melbourne School of Psychological Sciences, The University of Melbourne, Melbourne, VIC, Australia
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13
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Jackson CD, Seymour KK. Holistic processing of gaze cues during interocular suppression. Sci Rep 2022; 12:7717. [PMID: 35546346 PMCID: PMC9095640 DOI: 10.1038/s41598-022-11927-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 04/28/2022] [Indexed: 11/09/2022] Open
Abstract
Direct eye contact is preferentially processed over averted gaze and has been shown to gain privileged access to conscious awareness during interocular suppression. This advantage might be driven by local features associated with direct gaze, such as the amount of visible sclera. Alternatively, a holistic representation of gaze direction, which depends on the integration of head and eye information, might drive the effects. Resolving this question is interesting because it speaks to whether the processing of higher-level social information in the visual system, such as facial characteristics that rely on holistic processing, is dependent on conscious awareness. The Wollaston Illusion is a visual illusion that allows researchers to manipulate perceived gaze direction while keeping local eye features constant. Here we used this illusion to elucidate the driving factor facilitating the direct gaze advantage during interocular suppression. Using continuous flash suppression, we rendered Wollaston faces with direct and averted gaze (initially) invisible. These faces conveyed different gaze directions but contained identical eye regions. Our results showed clear evidence for a direct gaze advantage with Wollaston faces, indicating that holistic representations of gaze direction may drive the direct gaze advantage during interocular suppression.
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Affiliation(s)
- Cooper D Jackson
- School of Psychology, Western Sydney University, Penrith, NSW, Australia
| | - Kiley K Seymour
- School of Psychology, Western Sydney University, Penrith, NSW, Australia. .,The MARCS Institute, Western Sydney University, Westmead, NSW, Australia. .,Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
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14
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Lanfranco RC, Stein T, Rabagliati H, Carmel D. Gaze direction and face orientation modulate perceptual sensitivity to faces under interocular suppression. Sci Rep 2022; 12:7640. [PMID: 35538138 PMCID: PMC9090921 DOI: 10.1038/s41598-022-11717-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 04/28/2022] [Indexed: 01/03/2023] Open
Abstract
Faces convey information essential for social interaction. Their importance has prompted suggestions that some facial features may be processed unconsciously. Although some studies have provided empirical support for this idea, it remains unclear whether these findings were due to perceptual processing or to post-perceptual decisional factors. Evidence for unconscious processing of facial features has predominantly come from the Breaking Continuous Flash Suppression (b-CFS) paradigm, which measures the time it takes different stimuli to overcome interocular suppression. For example, previous studies have found that upright faces are reported faster than inverted faces, and direct-gaze faces are reported faster than averted-gaze faces. However, this procedure suffers from important problems: observers can decide how much information they receive before committing to a report, so their detection responses may be influenced by differences in decision criteria and by stimulus identification. Here, we developed a new procedure that uses predefined exposure durations, enabling independent measurement of perceptual sensitivity and decision criteria. We found higher detection sensitivity to both upright and direct-gaze (compared to inverted and averted-gaze) faces, with no effects on decisional factors. For identification, we found both greater sensitivity and more liberal criteria for upright faces. Our findings demonstrate that face orientation and gaze direction influence perceptual sensitivity, indicating that these facial features may be processed unconsciously.
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Affiliation(s)
- Renzo C Lanfranco
- Department of Psychology, University of Edinburgh, Edinburgh, UK.
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
| | - Timo Stein
- Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
| | - Hugh Rabagliati
- Department of Psychology, University of Edinburgh, Edinburgh, UK
| | - David Carmel
- Department of Psychology, University of Edinburgh, Edinburgh, UK.
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand.
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15
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Gambarota F, Tsuchiya N, Pastore M, Di Polito N, Sessa P. Unconscious Visual Working Memory: A critical review and Bayesian meta-analysis. Neurosci Biobehav Rev 2022; 136:104618. [PMID: 35289273 DOI: 10.1016/j.neubiorev.2022.104618] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 11/16/2022]
Abstract
The relationship between consciousness and working memory (WM) has been recently debated both at the theoretical and methodological levels (Persuh et al., 2018; Velichkovsky, 2017). While there is behavioral and neural evidence that argues for the existence of unconscious WM, several methodological concerns have been raised, rendering this issue highly controversial. To address the robustness of the previous findings, here we adopt a meta-analytic approach to estimate the effect size and heterogeneity of the previously reported unconscious WM results, also including unpublished results. We used meta-regression to isolate relevant experimental variables, in particular, consciousness manipulation and the WM paradigm to identify the source of the heterogeneity in the reported effect size of the unconscious WM. Our meta-analysis supports the existence of the unconscious WM effect and critically reveals several experimental variables that contribute to relevant heterogeneity. Our analysis clarifies several theoretical and methodological issues. We recommend that future studies explicitly operationalize the definition of consciousness, standardize the methodology and systematically explore the role of critical variables for the unconscious WM effect.
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Affiliation(s)
- Filippo Gambarota
- Department of Developmental and Social Psychology, University of Padova, Via Venezia 8, 35131, Padova, Italy; Padova Neuroscience Center, University of Padova, Via Giuseppe Orus, 2, 35131 Padova, Italy.
| | - Naotsugu Tsuchiya
- Turner Institute for Brain and Mental Health & School of Psychological Sciences, Faculty of Medicine, Nursing, and Health Sciences, Monash University, Melbourne, Victoria, Australia; Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology (NICT), Suita, Osaka 565-0871, Japan; Advanced Telecommunications Research Computational Neuroscience Laboratories, 2-2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto 619-0288, Japan.
| | - Massimiliano Pastore
- Department of Developmental and Social Psychology, University of Padova, Via Venezia 8, 35131, Padova, Italy.
| | - Nicola Di Polito
- Medical Neurosciences Program, Charité Universitätsmedizin, Charitépl 1, 10117, Berlin, Germany.
| | - Paola Sessa
- Department of Developmental and Social Psychology, University of Padova, Via Venezia 8, 35131, Padova, Italy; Padova Neuroscience Center, University of Padova, Via Giuseppe Orus, 2, 35131 Padova, Italy.
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16
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Unconscious information integration: A replication and the role of spatial window in masking experiments. Cognition 2022; 225:105113. [PMID: 35366487 DOI: 10.1016/j.cognition.2022.105113] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/17/2022] [Accepted: 03/23/2022] [Indexed: 11/20/2022]
Abstract
Consciousness and high-level information integration have commonly been closely related to each other (Baars, 2002; Dehaene & Naccache, 2001; Tononi, 2004). Different results, however, have challenged this assumption by showing that information integration can occur for stimuli presented outside of conscious awareness. More recently, a re-examination of some of the data and different replication attempts questioned these results thereby again suggesting a close link between consciousness and information integration. The current study aimed at (i) replicating another piece of evidence for unconscious information integration and (ii) investigating if the size of the spatial window in which the information to be integrated is presented could explain why unconscious information integration sometimes fails. Results showed a reliable replication so providing further evidence for unconscious information integration in a subliminal priming paradigm. Furthermore, our results revealed that unconscious integration depends on the size of the spatial window in which the information is presented.
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17
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Caruana N, Seymour K. Objects that induce face pareidolia are prioritized by the visual system. Br J Psychol 2021; 113:496-507. [PMID: 34923634 DOI: 10.1111/bjop.12546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/03/2021] [Indexed: 11/25/2022]
Abstract
The human visual system has evolved specialized neural mechanisms to rapidly detect faces. Its broad tuning for facial features is thought to underlie the illusory perception of faces in inanimate objects, a phenomenon called face pareidolia. Recent studies on face pareidolia suggest that the mechanisms underlying face processing, at least at the early stages of visual encoding, may treat objects that resemble faces as real faces; prioritizing their detection. In our study, we used breaking continuous flash suppression (b-CFS) to examine whether the human visual system prioritizes the detection of objects that induce face pareidolia over stimuli matched for object content. Similar to previous b-CFS results using real face stimuli, we found that participants detected the objects with pareidolia faces faster than object-matched control stimuli. Given that face pareidolia has been more frequently reported amongst individuals prone to hallucinations, we also explored whether this rapid prioritization is intact in individuals with schizophrenia, and found evidence suggesting that it was. Our findings suggest that face pareidolia engages a broadly tuned mechanism that facilitates rapid face detection. This may involve the proposed fast subcortical pathway that operates outside of visual awareness.
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Affiliation(s)
- Nathan Caruana
- Department of Cognitive Science, Macquarie University, Sydney, New South Wales, Australia.,Perception in Action Research Centre, Macquarie University, Sydney, New South Wales, Australia
| | - Kiley Seymour
- School of Psychology, Western Sydney University, Sydney, New South Wales, Australia.,The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Sydney, New South Wales, Australia.,Max Planck Institute for Biological Cybernetics, Tübingen, Germany
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18
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Mazor M, Moran R, Fleming SM. Metacognitive asymmetries in visual perception. Neurosci Conscious 2021; 2021:niab025. [PMID: 34676104 PMCID: PMC8524176 DOI: 10.1093/nc/niab025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/26/2021] [Accepted: 08/10/2021] [Indexed: 11/25/2022] Open
Abstract
Representing the absence of objects is psychologically demanding. People are slower, less confident and show lower metacognitive sensitivity (the alignment between subjective confidence and objective accuracy) when reporting the absence compared with presence of visual stimuli. However, what counts as a stimulus absence remains only loosely defined. In this Registered Report, we ask whether such processing asymmetries extend beyond the absence of whole objects to absences defined by stimulus features or expectation violations. Our pre-registered prediction was that differences in the processing of presence and absence reflect a default mode of reasoning: we assume an absence unless evidence is available to the contrary. We predicted asymmetries in response time, confidence, and metacognitive sensitivity in discriminating between stimulus categories that vary in the presence or absence of a distinguishing feature, or in their compliance with an expected default state. Using six pairs of stimuli in six experiments, we find evidence that the absence of local and global stimulus features gives rise to slower, less confident responses, similar to absences of entire stimuli. Contrary to our hypothesis, however, the presence or absence of a local feature has no effect on metacognitive sensitivity. Our results weigh against a proposal of a link between the detection metacognitive asymmetry and default reasoning, and are instead consistent with a low-level visual origin of metacognitive asymmetries for presence and absence.
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Affiliation(s)
- Matan Mazor
- Institute of Neurology, Wellcome Centre for Human
Neuroimaging, University College London, London WC1N 3BG, UK
| | - Rani Moran
- Institute of Neurology, Wellcome Centre for Human
Neuroimaging, University College London, London WC1N 3BG, UK
- Institute of Neurology, Max Planck UCL Centre for
Computational Psychiatry and Ageing Research, London WC1B 5EH, UK
| | - Stephen M Fleming
- Institute of Neurology, Wellcome Centre for Human
Neuroimaging, University College London, London WC1N 3BG, UK
- Institute of Neurology, Max Planck UCL Centre for
Computational Psychiatry and Ageing Research, London WC1B 5EH, UK
- Department of Experimental Psychology, University
College London, London WC1H 0AP, UK
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19
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Colombatto C, van Buren B, Scholl BJ. Hidden intentions: Visual awareness prioritizes perceived attention even without eyes or faces. Cognition 2021; 217:104901. [PMID: 34592478 DOI: 10.1016/j.cognition.2021.104901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 08/29/2021] [Accepted: 08/31/2021] [Indexed: 01/01/2023]
Abstract
Eye contact is a powerful social signal, and it readily captures attention. Recent work has suggested that direct gaze is prioritized even unconsciously: faces rendered invisible via interocular suppression enter awareness faster when they look directly at (vs. away from) you. Such effects may be driven in a relatively low level way by the special visual properties of eyes, per se, but here we asked whether they might instead arise from the perception of a deeper property: being the focus of another agent's attention and/or intentions. We report five experiments which collectively explore whether visual awareness also prioritizes distinctly non-eye-like stimuli that nevertheless convey directedness. We first showed that directed (vs. averted) 'mouth' shapes also break through into awareness faster, after being rendered invisible by continuous flash suppression - a direct 'gaze' effect without any eyes. But such effects could still be specific to faces (if not eyes), so we next asked whether the prioritization of directed intentions would still occur even for stimuli that have no faces at all. In fact, even simple geometric shapes can be seen as intentional, as when numerous randomly scattered cones are all consistently pointing at you. And indeed, even such directed (vs. averted) cones entered awareness faster - a direct 'gaze' effect without any facial cues. Additional control experiments ruled out effects of both symmetry and response biases. We conclude that the perception of directed intentions is sufficient to boost objects into awareness, and that putative eye-contact effects might instead reflect more general phenomena of 'mind contact'.
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20
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Korisky U, Mudrik L. Dimensions of Perception: 3D Real-Life Objects Are More Readily Detected Than Their 2D Images. Psychol Sci 2021; 32:1636-1648. [PMID: 34555305 DOI: 10.1177/09567976211010718] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Most of our interactions with our environment involve manipulating real 3D objects. Accordingly, 3D objects seem to enjoy preferential processing compared with 2D images, for example, in capturing attention or being better remembered. But are they also more readily perceived? Thus far, the possibility of preferred detection for real 3D objects could not be empirically tested because suppression from awareness has been applied only to on-screen stimuli. Here, using a variant of continuous flash suppression (CFS) with augmented-reality goggles ("real-life" CFS), we managed to suppress both real 3D objects and their 2D representations. In 20 healthy young adults, real objects broke suppression faster than their photographs. Using 3D printing, we also showed in 50 healthy young adults that this finding held only for meaningful objects, whereas no difference was found for meaningless, novel ones (a similar trend was observed in another experiment with 20 subjects, yet it did not reach significance). This suggests that the effect might be mediated by affordances facilitating detection of 3D objects under interocular suppression.
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Affiliation(s)
- Uri Korisky
- School of Psychological Sciences, Tel Aviv University
| | - Liad Mudrik
- School of Psychological Sciences, Tel Aviv University.,Sagol School of Neuroscience, Tel Aviv University
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21
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Eiserbeck A, Enge A, Rabovsky M, Abdel Rahman R. Electrophysiological Chronometry of Graded Consciousness during the Attentional Blink. Cereb Cortex 2021; 32:1244-1259. [PMID: 34435621 DOI: 10.1093/cercor/bhab289] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 11/13/2022] Open
Abstract
One of the ongoing debates about visual consciousness is whether it can be considered as an all-or-none or a graded phenomenon. While there is increasing evidence for the existence of graded states of conscious awareness based on paradigms such as visual masking, only little and mixed evidence is available for the attentional blink paradigm, specifically in regard to electrophysiological measures. Thereby, the all-or-none pattern reported in some attentional blink studies might have originated from specifics of the experimental design, suggesting the need to examine the generalizability of results. In the present event-related potential (ERP) study (N = 32), visual awareness of T2 face targets was assessed via subjective visibility ratings on a perceptual awareness scale in combination with ERPs time-locked to T2 onset (components P1, N1, N2, and P3). Furthermore, a classification task preceding visibility ratings allowed to track task performance. The behavioral results indicate a graded rather than an all-or-none pattern of visual awareness. Corresponding graded differences in the N1, N2, and P3 components were observed for the comparison of visibility levels. These findings suggest that conscious perception during the attentional blink can occur in a graded fashion.
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Affiliation(s)
- Anna Eiserbeck
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin 12489, Germany
| | - Alexander Enge
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin 12489, Germany.,Research Group Learning in Early Childhood, Max Planck Institute for Human Cognitive & Brain Sciences, Leipzig 04103, Germany
| | - Milena Rabovsky
- Department of Psychology, University of Potsdam, Potsdam 14476, Germany
| | - Rasha Abdel Rahman
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin 12489, Germany
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22
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Grave J, Madeira N, Martins MJ, Silva S, Korb S, Soares SC. Slower access to visual awareness but otherwise intact implicit perception of emotional faces in schizophrenia-spectrum disorders. Conscious Cogn 2021; 93:103165. [PMID: 34274640 DOI: 10.1016/j.concog.2021.103165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 06/17/2021] [Accepted: 06/17/2021] [Indexed: 11/28/2022]
Abstract
Schizophrenia-spectrum disorders are characterized by deficits in social domains. Extant research has reported an impaired ability to perceive emotional faces in schizophrenia. Yet, it is unclear if these deficits occur already in the access to visual awareness. To investigate this question, 23 people with schizophrenia or schizoaffective disorder and 22 healthy controls performed a breaking continuous flash suppression task with fearful, happy, and neutral faces. Response times were analysed with generalized linear mixed models. People with schizophrenia-spectrum disorders were slower than controls in detecting faces, but did not show emotion-specific impairments. Moreover, happy faces were detected faster than neutral and fearful faces, across all participants. Although caution is needed when interpreting the main effect of group, our findings may suggest an elevated threshold for visual awareness in schizophrenia-spectrum disorders, but an intact implicit emotion perception. Our study provides a new insight into the mechanisms underlying emotion perception in schizophrenia-spectrum disorders.
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Affiliation(s)
- Joana Grave
- William James Center for Research, Department of Education and Psychology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; Center for Health Technology and Services Research, Department of Education and Psychology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
| | - Nuno Madeira
- Psychiatry Department, Centro Hospitalar e Universitário de Coimbra, Praceta Prof. Mota Pinto, 3000-075 Coimbra, Portugal; Institute of Psychological Medicine, Faculty of Medicine - University of Coimbra, Portugal, Rua Larga, 3004-504 Coimbra, Portugal
| | - Maria João Martins
- Institute of Psychological Medicine, Faculty of Medicine - University of Coimbra, Portugal, Rua Larga, 3004-504 Coimbra, Portugal; Ocupational Health and Safety Management Services, University of Coimbra Social Services, Rua Doutor Guilherme Moreira 12, 3000-210 Coimbra, Portugal
| | - Samuel Silva
- Department of Electronics, Telecommunication and Informatics (DETI)/Institute of Electronics and Informatics Engineering (IEETA), University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Sebastian Korb
- Department of Psychology, University of Essex, CO4 3SQ Colchester, United Kingdom; Department of Cognition, Emotion, and Methods in Psychology, University of Vienna, Liebiggasse 5 1010, Vienna, Austria
| | - Sandra Cristina Soares
- William James Center for Research, Department of Education and Psychology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; Center for Health Technology and Services Research, Department of Education and Psychology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
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23
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Railo H, Piccin R, Lukasik KM. Subliminal perception is continuous with conscious vision and can be predicted from prestimulus electroencephalographic activity. Eur J Neurosci 2021; 54:4985-4999. [PMID: 34128284 DOI: 10.1111/ejn.15354] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 11/30/2022]
Abstract
Individuals are able to discriminate visual stimuli they report not consciously seeing. This phenomenon is known as "subliminal perception." Such capacity is often assumed to be relatively automatic in nature and rely on stimulus-driven activity in low-level cortical areas. Instead, here we asked to what extent neural activity before stimulus presentation influences subliminal perception. We asked participants to discriminate the location of a briefly presented low-contrast visual stimulus and then rate how well they saw the stimulus. Consistent with previous studies, participants correctly discriminated with slightly above chance-level accuracy the location of a stimulus they reported not seeing. Signal detection analyses indicated that while subjects categorized their percepts as "unconscious," their capacity to discriminate these stimuli lay on the same continuum as conscious vision. We show that the accuracy of discriminating the location of a subliminal stimulus could be predicted with relatively high accuracy (AUC = 0.70) based on lateralized electroencephalographic (EEG) activity before the stimulus, the hemifield where the stimulus was presented, and the accuracy of previous trial's discrimination response. Altogether, our results suggest that rather than being a separate unconscious capacity, subliminal perception is based on similar processes as conscious vision.
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Affiliation(s)
- Henry Railo
- Department of Clinical Neurophysiology, University of Turku, Turku, Finland.,Turku Brain and Mind Centre, University of Turku, Turku, Finland.,Department of Psychology, University of Turku, Turku, Finland
| | - Roberto Piccin
- Department of Life Sciences, University of Trieste, Trieste, Italy
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24
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Delong P, Noppeney U. Semantic and spatial congruency mould audiovisual integration depending on perceptual awareness. Sci Rep 2021; 11:10832. [PMID: 34035358 PMCID: PMC8149651 DOI: 10.1038/s41598-021-90183-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 04/22/2021] [Indexed: 11/09/2022] Open
Abstract
Information integration is considered a hallmark of human consciousness. Recent research has challenged this tenet by showing multisensory interactions in the absence of awareness. This psychophysics study assessed the impact of spatial and semantic correspondences on audiovisual binding in the presence and absence of visual awareness by combining forward-backward masking with spatial ventriloquism. Observers were presented with object pictures and synchronous sounds that were spatially and/or semantically congruent or incongruent. On each trial observers located the sound, identified the picture and rated the picture's visibility. We observed a robust ventriloquist effect for subjectively visible and invisible pictures indicating that pictures that evade our perceptual awareness influence where we perceive sounds. Critically, semantic congruency enhanced these visual biases on perceived sound location only when the picture entered observers' awareness. Our results demonstrate that crossmodal influences operating from vision to audition and vice versa are interactively controlled by spatial and semantic congruency in the presence of awareness. However, when visual processing is disrupted by masking procedures audiovisual interactions no longer depend on semantic correspondences.
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Affiliation(s)
- Patrycja Delong
- Centre for Computational Neuroscience and Cognitive Robotics, University of Birmingham, Birmingham, UK.
| | - Uta Noppeney
- Centre for Computational Neuroscience and Cognitive Robotics, University of Birmingham, Birmingham, UK.,Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
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