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Kleckner IR, Anderson EC, Betz NJ, Wormwood JB, Eskew RT, Barrett LF. Conscious awareness is necessary for affective faces to influence social judgments. JOURNAL OF EXPERIMENTAL SOCIAL PSYCHOLOGY 2018; 79:181-187. [PMID: 31097841 DOI: 10.1016/j.jesp.2018.07.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A growing body of research claims that stimuli presented outside conscious awareness can influence affect, speech perception, decision-making, eating behavior, and social judgments. However, research has shown that conscious awareness is a continuous phenomenon. Using a continuous flash suppression (CFS) paradigm to suppress awareness of affective faces (smiling and scowling), we demonstrate that some awareness of suppressed stimuli is required for the stimuli to influence social judgments. We discovered this using a rigorous within-participants psychophysics method that allowed us to assess awareness at very low levels, which is difficult using traditional methods. Our findings place boundary conditions on claims (made previously by us and others) that stimuli presented completely outside conscious awareness influence judgments. This work contributes to the literature highlighting the need to study conscious awareness as a continuous phenomenon and provides a framework for researchers to ask and answer questions regarding conscious awareness and its relation to judgment and behavior.
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Affiliation(s)
- Ian R Kleckner
- Department of Psychology, Northeastern University, Boston, MA.,University of Rochester Medical Center, Rochester, NY
| | - Eric C Anderson
- Department of Psychology, Northeastern University, Boston, MA.,Center for Outcomes Research and Evaluation, Maine Medical Center.,Tufts University School of Medicine
| | - Nicole J Betz
- Department of Psychology, Northeastern University, Boston, MA
| | | | - Rhea T Eskew
- Department of Psychology, Northeastern University, Boston, MA
| | - Lisa Feldman Barrett
- Department of Psychology, Northeastern University, Boston, MA.,Department of Psychiatry and the Martinos Center for Biomedical Imaging, Harvard Medical School, Massachusetts General Hospital, Boston, MA
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52
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Typical visual-field locations facilitate access to awareness for everyday objects. Cognition 2018; 180:118-122. [PMID: 30029067 DOI: 10.1016/j.cognition.2018.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 11/20/2022]
Abstract
In real-world vision, humans are constantly confronted with complex environments that contain a multitude of objects. These environments are spatially structured, so that objects have different likelihoods of appearing in specific parts of the visual space. Our massive experience with such positional regularities prompts the hypothesis that the processing of individual objects varies in efficiency across the visual field: when objects are encountered in their typical locations (e.g., we are used to seeing lamps in the upper visual field and carpets in the lower visual field), they should be more efficiently perceived than when they are encountered in atypical locations (e.g., a lamp in the lower visual field and a carpet in the upper visual field). Here, we provide evidence for this hypothesis by showing that typical positioning facilitates an object's access to awareness. In two continuous flash suppression experiments, objects more efficiently overcame inter-ocular suppression when they were presented in visual-field locations that matched their typical locations in the environment, as compared to non-typical locations. This finding suggests that through extensive experience the visual system has adapted to the statistics of the environment. This adaptation may be particularly useful for rapid object individuation in natural scenes.
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53
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Han S, Alais D. Battle of the Mondrians: Investigating the Role of Unpredictability in Continuous Flash Suppression. Iperception 2018; 9:2041669518792930. [PMID: 30151096 PMCID: PMC6108022 DOI: 10.1177/2041669518792930] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/11/2018] [Indexed: 11/24/2022] Open
Abstract
In continuous flash suppression (CFS), a dynamic sequence of Mondrian patterns presented to one eye suppresses a static target in the other eye for several seconds at a time. Its effectiveness has been linked to low-level properties such as spatial frequency and orientation, but the role of higher order influences remains unstudied. Here, using a tracking paradigm, we asked if the spatial and temporal predictability of the Mondrian sequence affects CFS dynamics. Predictable temporal sequences were regularly updated every 100 ms or modulated sinusoidally in pixel luminance at 2 Hz. Unpredictable temporal sequences were irregularly updated or had stochastic pixel luminance changes across time. To vary spatial predictability, sequences were either updated with different Mondrian patterns or had a fixed spatial pattern. We found a modest effect of spatial uncertainty when the target modulation was low (0.125 Hz) but not temporal uncertainty, which had no significant effects regardless of target modulation. Similar results were obtained when we pitted the standard Mondrian sequence against sequences with a fixed spatial pattern and temporally low-pass filtered sequences in a binocular rivalry paradigm. Thus, not only was the effect of information predictability was modest and spatial, but it was also dependent on the presence of higher temporal frequencies. Together, the results demonstrate the significance of low-level properties in affecting CFS dynamics and the possible involvement of pattern structure masking in CFS.
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Affiliation(s)
- Shui’Er Han
- School of Psychology, The University of Sydney, New South Wales, Australia
| | - David Alais
- School of Psychology, The University of Sydney, New South Wales, Australia
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55
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Bulut NS, Würz A, Yorguner Küpeli N, Çarkaxhıu Bulut G, Sungur MZ. Heart rate variability response to affective pictures processed in and outside of conscious awareness: Three consecutive studies on emotional regulation. Int J Psychophysiol 2018; 129:18-30. [PMID: 29787784 DOI: 10.1016/j.ijpsycho.2018.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/12/2018] [Accepted: 05/14/2018] [Indexed: 11/30/2022]
Abstract
Previous research has increased understanding of the neurobiological basis of emotional regulation. However, less is known concerning the unconscious processing of affective information. Three experiments were performed to investigate the extent to which complex affective stimuli can be processed outside of consciousness and demonstrate possible mechanisms for regulation of resulting emotional responses. In Experiment 1, participants were either instructed to passively observe blocked-picture cues (neutral and negative) or to downregulate their emotions by distancing. Resulting emotional regulation activity was assessed with 0.1-Hz heart rate variability (HRV) indices. In Experiment 2, participants were presented with affective pictures that were rendered consciously invisible by means of continuous flash suppression (CFS). In Experiment 3, two equivalent sets of negative affective pictures were covertly presented and the effect of a cognitive task on emotional regulation was evaluated. Our findings revealed that 0.1-Hz HRV indices exhibited greater change over baseline in response to negative compared to neutral stimuli for both presentation conditions (consciously perceived or not). The implementation of distancing and the cognitive task were both associated with higher 0.1-Hz HRV change scores. These results indicate that even complex affective stimuli can be processed without awareness, resulting in a congruent emotional response that is physiologically detectable. Cognitive strategies can help more effectively regulate this response, implying that conscious perception of a triggering stimulus may not be essential for cognitive regulation.
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Affiliation(s)
- Necati Serkut Bulut
- Department of Psychiatry, Sakarya University Training and Research Hospital, Turkey.
| | - Axel Würz
- Department of Psychiatry, Marmara University Medical School, Turkey
| | | | - Gresa Çarkaxhıu Bulut
- Department of Child and Adolescent Psychiatry, Sakarya University Medical School, Turkey
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56
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Peel HJ, Sperandio I, Laycock R, Chouinard PA. Perceptual Discrimination of Basic Object Features Is Not Facilitated When Priming Stimuli Are Prevented From Reaching Awareness by Means of Visual Masking. Front Integr Neurosci 2018; 12:13. [PMID: 29725292 PMCID: PMC5917041 DOI: 10.3389/fnint.2018.00013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 03/29/2018] [Indexed: 01/12/2023] Open
Abstract
Our understanding of how form, orientation and size are processed within and outside of awareness is limited and requires further investigation. Therefore, we investigated whether or not the visual discrimination of basic object features can be influenced by subliminal processing of stimuli presented beforehand. Visual masking was used to render stimuli perceptually invisible. Three experiments examined if visible and invisible primes could facilitate the subsequent feature discrimination of visible targets. The experiments differed in the kind of perceptual discrimination that participants had to make. Namely, participants were asked to discriminate visual stimuli on the basis of their form, orientation, or size. In all three experiments, we demonstrated reliable priming effects when the primes were visible but not when the primes were made invisible. Our findings underscore the importance of conscious awareness in facilitating the perceptual discrimination of basic object features.
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Affiliation(s)
- Hayden J Peel
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Irene Sperandio
- School of Psychology, University of East Anglia, Norwich, United Kingdom
| | - Robin Laycock
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Philippe A Chouinard
- Department of Psychology and Counselling, School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
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57
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Persuh M. The Fata Morgana of Unconscious Perception. Front Hum Neurosci 2018; 12:120. [PMID: 29692714 PMCID: PMC5902557 DOI: 10.3389/fnhum.2018.00120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Accepted: 03/12/2018] [Indexed: 01/09/2023] Open
Affiliation(s)
- Marjan Persuh
- Department of Social Sciences, Human Services and Criminal Justice, Borough of Manhattan Community College, City University of New York, New York, NY, United States
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59
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Meijs EL, Slagter HA, de Lange FP, van Gaal S. Dynamic Interactions between Top-Down Expectations and Conscious Awareness. J Neurosci 2018; 38:2318-2327. [PMID: 29386259 PMCID: PMC6596276 DOI: 10.1523/jneurosci.1952-17.2017] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 11/09/2017] [Accepted: 11/26/2017] [Indexed: 11/21/2022] Open
Abstract
It is well known that top-down expectations affect perceptual processes. Yet, remarkably little is known about the relationship between expectations and conscious awareness. We address three crucial outstanding questions: (1) how do expectations affect the likelihood of conscious stimulus perception?; (2) does the brain register violations of expectations nonconsciously?; and (3) do expectations need to be conscious to influence perceptual decisions? Using human participants, we performed three experiments in which we manipulated stimulus predictability within the attentional blink paradigm, while combining visual psychophysics with electrophysiological recordings. We found that valid stimulus expectations increase the likelihood of conscious access of stimuli. Furthermore, our findings suggest a clear dissociation in the interaction between expectations and consciousness: conscious awareness seems crucial for the implementation of top-down expectations, but not for the generation of bottom-up stimulus-evoked prediction errors. These results constrain and update influential theories about the role of consciousness in the predictive brain.SIGNIFICANCE STATEMENT While the relationship between expectations and conscious awareness plays a major role in many prediction-based theories of brain functioning, thus far few empirical studies have examined this relationship. Here, we address this gap in knowledge in a set of three experiments. Our results suggest that the effect of expectations on conscious awareness varies between different steps of the hierarchy of predictive processing. While the active use of top-down expectations for perceptual decisions requires conscious awareness, prediction errors can be triggered outside of conscious awareness. These results constrain and update influential theories about the role of consciousness in the predictive brain.
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Affiliation(s)
- Erik L Meijs
- Donders Institute for Brain, Cognition and Behaviour, Radboud University and Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Heleen A Slagter
- Donders Institute for Brain, Cognition and Behaviour, Radboud University and Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
- Department of Psychology, and
| | - Floris P de Lange
- Donders Institute for Brain, Cognition and Behaviour, Radboud University and Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Simon van Gaal
- Donders Institute for Brain, Cognition and Behaviour, Radboud University and Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands,
- Department of Psychology, and
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60
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Ventral and Dorsal Pathways Relate Differently to Visual Awareness of Body Postures under Continuous Flash Suppression. eNeuro 2018; 5:eN-NWR-0285-17. [PMID: 29445766 PMCID: PMC5810040 DOI: 10.1523/eneuro.0285-17.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 12/08/2017] [Accepted: 12/14/2017] [Indexed: 11/21/2022] Open
Abstract
Visual perception includes ventral and dorsal stream processes. However, it is still unclear whether the former is predominantly related to conscious and the latter to nonconscious visual perception as argued in the literature. In this study upright and inverted body postures were rendered either visible or invisible under continuous flash suppression (CFS), while brain activity of human participants was measured with functional MRI (fMRI). Activity in the ventral body-sensitive areas was higher during visible conditions. In comparison, activity in the posterior part of the bilateral intraparietal sulcus (IPS) showed a significant interaction of stimulus orientation and visibility. Our results provide evidence that dorsal stream areas are less associated with visual awareness.
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61
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Chanes L, Wormwood JB, Betz N, Barrett LF. Facial expression predictions as drivers of social perception. J Pers Soc Psychol 2018; 114:380-396. [PMID: 29369657 DOI: 10.1037/pspa0000108] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Emerging perspectives in neuroscience indicate that the brain functions predictively, constantly anticipating sensory input based on past experience. According to these perspectives, prediction signals impact perception, guiding and constraining experience. In a series of six behavioral experiments, we show that predictions about facial expressions drive social perception, deeply influencing how others are evaluated: individuals are judged as more likable and trustworthy when their facial expressions are anticipated, even in the absence of any conscious changes in felt affect. Moreover, the effect of predictions on social judgments extends to both real-world situations where such judgments have particularly high consequence (i.e., evaluating presidential candidates for an upcoming election), as well as to more basic perceptual processes that may underlie judgment (i.e., facilitated visual processing of expected expressions). The implications of these findings, including relevance for cross-cultural interactions, social stereotypes and mental illness, are discussed. (PsycINFO Database Record
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Affiliation(s)
| | | | - Nicole Betz
- Department of Psychology, Northeastern University
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62
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No differential effects to facial expressions under continuous flash suppression: An event-related potentials study. Neuroimage 2017; 163:276-285. [DOI: 10.1016/j.neuroimage.2017.09.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/11/2017] [Accepted: 09/18/2017] [Indexed: 11/20/2022] Open
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63
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Sun Y, Stein T, Liu W, Ding X, Nie QY. Biphasic attentional orienting triggered by invisible social signals. Cognition 2017; 168:129-139. [DOI: 10.1016/j.cognition.2017.06.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 06/18/2017] [Accepted: 06/19/2017] [Indexed: 11/30/2022]
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64
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Tooley MD, Carmel D, Chapman A, Grimshaw GM. Dissociating the physiological components of unconscious emotional responses. Neurosci Conscious 2017; 2017:nix021. [PMID: 30042852 PMCID: PMC6007137 DOI: 10.1093/nc/nix021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 09/03/2017] [Accepted: 09/12/2017] [Indexed: 01/10/2023] Open
Abstract
Conscious emotional processing is characterized by a coordinated set of responses across multiple physiological systems. Although emotional stimuli can evoke certain physiological responses even when they are suppressed from awareness, it is not known whether unconscious emotional responses comprise a similar constellation or are confined to specific systems. To compare physiological responses to emotional stimuli with and without awareness, we measured a range of responses while participants viewed positive, negative and neutral images that were accompanied by noise bursts to elicit startle reflexes. We measured four responses simultaneously - skin conductance and heart rate changes in response to the images themselves; and startle eye-blink and post-auricular reflexes in response to the noise bursts that occurred during image presentation. For half of the participants, the images were masked from awareness using continuous flash suppression. The aware group showed the expected pattern of response across physiological systems: emotional images (regardless of valence) evoked larger skin conductance responses (SCRs) and greater heart rate deceleration than neutral images, negative images enhanced eye-blink reflexes and positive images enhanced post-auricular reflexes. In contrast, we found a striking dissociation between measures for the unaware group: typical modulation of SCRs and post-auricular reflexes, but no modulation of heart rate deceleration or eye-blink reflexes. Our findings suggest that although some physiological systems respond to emotional stimuli presented outside of awareness, conscious emotional processing may be characterized by a broad and coordinated set of responses across systems.
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Affiliation(s)
- Michael D Tooley
- School of Psychology, Victoria University of Wellington, PO Box 600, Wellington 6012, New Zealand
| | - David Carmel
- Department of Psychology, University of Edinburgh, 7 George Square, Edinburgh EH8 9JZ, UK; Department of Psychology, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0109, USA
| | - Angus Chapman
- School of Psychology, Victoria University of Wellington, PO Box 600, Wellington 6012, New Zealand
| | - Gina M Grimshaw
- School of Psychology, Victoria University of Wellington, PO Box 600, Wellington 6012, New Zealand
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65
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Unaware Processing of Tools in the Neural System for Object-Directed Action Representation. J Neurosci 2017; 37:10712-10724. [PMID: 28978664 DOI: 10.1523/jneurosci.1061-17.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 09/12/2017] [Accepted: 09/14/2017] [Indexed: 11/21/2022] Open
Abstract
The hypothesis that the brain constitutively encodes observed manipulable objects for the actions they afford is still debated. Yet, crucial evidence demonstrating that, even in the absence of perceptual awareness, the mere visual appearance of a manipulable object triggers a visuomotor coding in the action representation system including the premotor cortex, has hitherto not been provided. In this fMRI study, we instantiated reliable unaware visual perception conditions by means of continuous flash suppression, and we tested in 24 healthy human participants (13 females) whether the visuomotor object-directed action representation system that includes left-hemispheric premotor, parietal, and posterior temporal cortices is activated even under subliminal perceptual conditions. We found consistent activation in the target visuomotor cortices, both with and without perceptual awareness, specifically for pictures of manipulable versus non-manipulable objects. By means of a multivariate searchlight analysis, we also found that the brain activation patterns in this visuomotor network enabled the decoding of manipulable versus non-manipulable object picture processing, both with and without awareness. These findings demonstrate the intimate neural coupling between visual perception and motor representation that underlies manipulable object processing: manipulable object stimuli specifically engage the visuomotor object-directed action representation system, in a constitutive manner that is independent from perceptual awareness. This perceptuo-motor coupling endows the brain with an efficient mechanism for monitoring and planning reactions to external stimuli in the absence of awareness.SIGNIFICANCE STATEMENT Our brain constantly encodes the visual information that hits the retina, leading to a stimulus-specific activation of sensory and semantic representations, even for objects that we do not consciously perceive. Do these unconscious representations encompass the motor programming of actions that could be accomplished congruently with the objects' functions? In this fMRI study, we instantiated unaware visual perception conditions, by dynamically suppressing the visibility of manipulable object pictures with mondrian masks. Despite escaping conscious perception, manipulable objects activated an object-directed action representation system that includes left-hemispheric premotor, parietal, and posterior temporal cortices. This demonstrates that visuomotor encoding occurs independently of conscious object perception.
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66
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Laycock R, Sherman JA, Sperandio I, Chouinard PA. Size Aftereffects Are Eliminated When Adaptor Stimuli Are Prevented from Reaching Awareness by Continuous Flash Suppression. Front Hum Neurosci 2017; 11:479. [PMID: 29033808 PMCID: PMC5626861 DOI: 10.3389/fnhum.2017.00479] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 09/15/2017] [Indexed: 11/20/2022] Open
Abstract
Size aftereffects are a compelling perceptual phenomenon in which we perceive the size of a stimulus as being different than it actually is following a period of visual stimulation of an adapter stimulus with a different size. Here, we used continuous flash suppression (CFS) to determine if size aftereffects require a high-level appraisal of the adapter stimulus. The strength of size aftereffects was quantified following a 3-s exposure to perceptually visible and invisible adapters. Participants judged the size of a target that followed the adapter in comparison to a subsequent reference. Our experiments demonstrate that the adapter no longer influenced the perceived size of the subsequent target stimulus under CFS. We conclude that the perception of size aftereffects is prevented when CFS is used to suppress the conscious awarness of the adapting stimulus.
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Affiliation(s)
- Robin Laycock
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Joshua A Sherman
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Irene Sperandio
- School of Psychology, University of East Anglia, Norwich, United Kingdom
| | - Philippe A Chouinard
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
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67
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Baroni F, van Kempen J, Kawasaki H, Kovach CK, Oya H, Howard MA, Adolphs R, Tsuchiya N. Intracranial markers of conscious face perception in humans. Neuroimage 2017; 162:322-343. [PMID: 28882629 DOI: 10.1016/j.neuroimage.2017.08.074] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 08/15/2017] [Accepted: 08/24/2017] [Indexed: 12/29/2022] Open
Abstract
Investigations of the neural basis of consciousness have greatly benefited from protocols that involve the presentation of stimuli at perceptual threshold, enabling the assessment of the patterns of brain activity that correlate with conscious perception, independently of any changes in sensory input. However, the comparison between perceived and unperceived trials would be expected to reveal not only the core neural substrate of a particular conscious perception, but also aspects of brain activity that facilitate, hinder or tend to follow conscious perception. We take a step towards the resolution of these confounds by combining an analysis of neural responses observed during the presentation of faces partially masked by Continuous Flash Suppression, and those responses observed during the unmasked presentation of faces and other images in the same subjects. We employed multidimensional classifiers to decode physical properties of stimuli or perceptual states from spectrotemporal representations of electrocorticographic signals (1071 channels in 5 subjects). Neural activity in certain face responsive areas located in both the fusiform gyrus and in the lateral-temporal/inferior-parietal cortex discriminated seen vs. unseen faces in the masked paradigm and upright faces vs. other categories in the unmasked paradigm. However, only the former discriminated upright vs. inverted faces in the unmasked paradigm. Our results suggest a prominent role for the fusiform gyrus in the configural perception of faces, and possibly other objects that are holistically processed. More generally, we advocate comparative analysis of neural recordings obtained during different, but related, experimental protocols as a promising direction towards elucidating the functional specificities of the patterns of neural activation that accompany our conscious experiences.
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Affiliation(s)
- Fabiano Baroni
- School of Psychological Sciences, Faculty of Biomedical and Psychological Sciences, Monash University, Australia; NeuroEngineering Laboratory, Department of Electrical & Electronic Engineering, The University of Melbourne, Australia.
| | - Jochem van Kempen
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom; School of Psychological Sciences, Faculty of Biomedical and Psychological Sciences, Monash University, Australia
| | - Hiroto Kawasaki
- Department of Neurosurgery, University of Iowa, Iowa City, IA, USA
| | | | - Hiroyuki Oya
- Department of Neurosurgery, University of Iowa, Iowa City, IA, USA
| | - Matthew A Howard
- Department of Neurosurgery, University of Iowa, Iowa City, IA, USA
| | - Ralph Adolphs
- Division of Humanities and Social Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Naotsugu Tsuchiya
- School of Psychological Sciences, Faculty of Biomedical and Psychological Sciences, Monash University, Australia; Monash Institute of Cognitive and Clinical Neuroscience, Monash University, Australia; Decoding and Controlling Brain Information, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, Japan.
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68
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The Insula Mediates Access to Awareness of Visual Stimuli Presented Synchronously to the Heartbeat. J Neurosci 2017; 36:5115-27. [PMID: 27147663 DOI: 10.1523/jneurosci.4262-15.2016] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 03/29/2016] [Indexed: 01/28/2023] Open
Abstract
UNLABELLED The processing of interoceptive signals in the insular cortex is thought to underlie self-awareness. However, the influence of interoception on visual awareness and the role of the insular cortex in this process remain unclear. Here, we show in a series of experiments that the relative timing of visual stimuli with respect to the heartbeat modulates visual awareness. We used two masking techniques and show that conscious access for visual stimuli synchronous to participants' heartbeat is suppressed compared with the same stimuli presented asynchronously to their heartbeat. Two independent brain imaging experiments using high-resolution fMRI revealed that the insular cortex was sensitive to both visible and invisible cardio-visual stimulation, showing reduced activation for visual stimuli presented synchronously to the heartbeat. Our results show that interoceptive insular processing affects visual awareness, demonstrating the role of the insula in integrating interoceptive and exteroceptive signals and in the processing of conscious signals beyond self-awareness. SIGNIFICANCE STATEMENT There is growing evidence that interoceptive signals conveying information regarding the internal state of the body influence perception and self-awareness. The insular cortex, which receives sensory inputs from both interoceptive and exteroceptive sources, is thought to integrate these multimodal signals. This study shows that cardiac interoceptive signals modulate awareness for visual stimuli such that visual stimuli occurring at the cardiac frequency take longer to access visual awareness and are more difficult to discriminate. Two fMRI experiments show that the insular region is sensitive to this cardio-visual synchrony even when the visual stimuli are rendered invisible through interocular masking. The results indicate a perceptual and neural suppression for visual events coinciding with cardiac interoceptive signals.
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69
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Affiliation(s)
- Severi Luoto
- English, Drama and Writing Studies, University of AucklandAuckland, New Zealand.,School of Psychology, University of AucklandAuckland, New Zealand
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70
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Kobylka F, Persike M, Meinhardt G. Object Localization Does Not Imply Awareness of Object Category at the Break of Continuous Flash Suppression. Front Hum Neurosci 2017; 11:312. [PMID: 28663728 PMCID: PMC5471597 DOI: 10.3389/fnhum.2017.00312] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/31/2017] [Indexed: 11/28/2022] Open
Abstract
In continuous flash suppression (CFS), a dynamic noise masker, presented to one eye, suppresses conscious perception of a test stimulus, presented to the other eye, until the suppressed stimulus comes to awareness after few seconds. But what do we see breaking the dominance of the masker in the transition period? We addressed this question with a dual-task in which observers indicated (i) whether the test object was left or right of the fixation mark (localization) and (ii) whether it was a face or a house (categorization). As done recently Stein et al. (2011a), we used two experimental varieties to rule out confounds with decisional strategy. In the terminated mode, stimulus and masker were presented for distinct durations, and the observers were asked to give both judgments at the end of the trial. In the self-paced mode, presentation lasted until the observers responded. In the self-paced mode, b-CFS durations for object categorization were about half a second longer than for object localization. In the terminated mode, correct categorization rates were consistently lower than correct detection rates, measured at five duration intervals ranging up to 2 s. In both experiments we observed an upright face advantage compared to inverted faces and houses, as concurrently reported in b-CFS studies. Our findings reveal that more time is necessary to enable observers judging the nature of the object, compared to judging that there is “something other” than the noise which can be localized, but not recognized. This suggests gradual transitions in the first break of CFS. Further, the results imply that suppression is such that no cues to object identity are conveyed in potential “leaks” of CFS (Gelbard-Sagiv et al., 2016).
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Affiliation(s)
- Florian Kobylka
- Research Methods and Statistics, Department of Psychology, Institute of Psychology, Johannes Gutenberg University MainzMainz, Germany
| | - Malte Persike
- Research Methods and Statistics, Department of Psychology, Institute of Psychology, Johannes Gutenberg University MainzMainz, Germany
| | - Günter Meinhardt
- Research Methods and Statistics, Department of Psychology, Institute of Psychology, Johannes Gutenberg University MainzMainz, Germany
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71
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Less Is More: Semantic Information Survives Interocular Suppression When Attention Is Diverted. J Neurosci 2017; 36:5489-97. [PMID: 27194329 DOI: 10.1523/jneurosci.3018-15.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 04/16/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The extent of unconscious semantic processing has been debated. It is well established that semantic information is registered in the absence of awareness induced by inattention. However, it has been debated whether semantic information of invisible stimuli is processed during interocular suppression, a procedure that renders one eye's view invisible by presenting a dissimilar stimulus to the other eye. Inspired by recent evidence demonstrating that reduced attention attenuates interocular suppression, we tested a counterintuitive hypothesis that attention withdrawn from the suppressed target location facilitates semantic processing in the absence of awareness induced by interocular suppression. We obtained an electrophysiological marker of semantic processing (N400 component) while human participants' spatial attention was being manipulated with a cueing paradigm during interocular suppression. We found that N400 modulation was absent when participants' attention was directed to the target location, but present when diverted elsewhere. In addition, the correlation analysis across participants indicated that the N400 amplitude was reduced with more attention being directed to the target location. Together, these results indicate that inattention attenuates interocular suppression and thereby makes semantic processing available unconsciously, reconciling conflicting evidence in the literature. We discuss a tight link among interocular suppression, attention, and conscious awareness. SIGNIFICANCE STATEMENT Interocular suppression offers a powerful means of studying the extent of unconscious processing by rendering a salient stimulus presented to one eye invisible. Here, we provide evidence that attention is a determining factor for unconscious semantic processing. An electrophysiological marker for semantic processing (N400 component) was present when attention was diverted away from the suppressed stimulus but absent when attention was directed to that stimulus, indicating that inattention facilitates unconscious semantic processing during the interocular suppression. Although contrary to the common sense assumption that attention facilitates information processing, this result is in accordance with recent studies showing that attention modulates interocular suppression but is not necessary for semantic processing. Our finding reconciles the conflicting evidence and advances theories of consciousness.
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72
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73
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Lei Y, Dou H, Liu Q, Zhang W, Zhang Z, Li H. Automatic Processing of Emotional Words in the Absence of Awareness: The Critical Role of P2. Front Psychol 2017; 8:592. [PMID: 28473785 PMCID: PMC5397533 DOI: 10.3389/fpsyg.2017.00592] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 03/30/2017] [Indexed: 01/22/2023] Open
Abstract
It has been long debated to what extent emotional words can be processed in the absence of awareness. Behavioral studies have shown that the meaning of emotional words can be accessed even without any awareness. However, functional magnetic resonance imaging studies have revealed that emotional words that are unconsciously presented do not activate the brain regions involved in semantic or emotional processing. To clarify this point, we used continuous flash suppression (CFS) and event-related potential (ERP) techniques to distinguish between semantic and emotional processing. In CFS, we successively flashed some Mondrian-style images into one participant's eye steadily, which suppressed the images projected to the other eye. Negative, neutral, and scrambled words were presented to 16 healthy participants for 500 ms. Whenever the participants saw the stimuli—in both visible and invisible conditions—they pressed specific keyboard buttons. Behavioral data revealed that there was no difference in reaction time to negative words and to neutral words in the invisible condition, although negative words were processed faster than neutral words in the visible condition. The ERP results showed that negative words elicited a larger P2 amplitude in the invisible condition than in the visible condition. The P2 component was enhanced for the neutral words compared with the scrambled words in the visible condition; however, the scrambled words elicited larger P2 amplitudes than the neutral words in the invisible condition. These results suggest that the emotional processing of words is more sensitive than semantic processing in the conscious condition. Semantic processing was found to be attenuated in the absence of awareness. Our findings indicate that P2 plays an important role in the unconscious processing of emotional words, which highlights the fact that emotional processing may be automatic and prioritized compared with semantic processing in the absence of awareness.
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Affiliation(s)
- Yi Lei
- College of Psychology and Sociology, Shenzhen UniversityShenzhen, China
| | - Haoran Dou
- College of Psychology and Sociology, Shenzhen UniversityShenzhen, China.,Research Center for Brain and Cognitive Neuroscience, Liaoning Normal UniversityDalian, China
| | - Qingming Liu
- School of Psychology, Nanjing Normal UniversityNanjing, China
| | - Wenhai Zhang
- Research Center for Brain and Cognitive Neuroscience, Liaoning Normal UniversityDalian, China.,College of Education Science, Chengdu UniversityChengdu, China
| | - Zhonglu Zhang
- Research Center for Brain and Cognitive Neuroscience, Liaoning Normal UniversityDalian, China
| | - Hong Li
- College of Psychology and Sociology, Shenzhen UniversityShenzhen, China.,Research Center for Brain and Cognitive Neuroscience, Liaoning Normal UniversityDalian, China.,College of Education Science, Chengdu UniversityChengdu, China
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74
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Gayet S, Stein T. Between-Subject Variability in the Breaking Continuous Flash Suppression Paradigm: Potential Causes, Consequences, and Solutions. Front Psychol 2017; 8:437. [PMID: 28396645 PMCID: PMC5366331 DOI: 10.3389/fpsyg.2017.00437] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/08/2017] [Indexed: 11/13/2022] Open
Abstract
A recent focus in the field of consciousness research involves investigating the propensity of initially non-conscious visual information to gain access to consciousness. A critical tool for measuring conscious access is the so-called breaking continuous flash suppression paradigm (b-CFS). In this paradigm, a high contrast dynamic pattern is presented to one eye, thereby temporarily suppressing a target stimulus that is presented to the other eye. The time it takes for observers to report (e.g., the location of) the initially suppressed stimulus provides a measure of conscious access. Typical observations in b-CFS studies include the finding that upright faces are released from suppression faster than inverted faces, and the finding that stimuli that match the current content of visual working memory are released from suppression faster than mismatching stimuli. Interestingly, the extent to which observers exhibit these effects varies extensively (in the range of hundreds of milliseconds). By re-analyzing existing datasets and a new dataset we establish that the difference in RTs between conditions in b-CFS tasks (i.e., the effect of interest) is highly correlated with participants' overall suppression durations, and with their trial-to-trial variability in RTs. We advocate the usage of a simple latency- normalization method, which (1) removes the between-subject variability in suppression duration from the effect of interest, while (2) providing distributions of RT differences that are better suited for parametric testing. We next compare this latency-normalization method to two other transformations that are widely applied on within-subject RT data (z-transformations and log-transformations). Finally, we tentatively discuss how trial-to-trial variability and overall suppression duration might relate to prolonged phases of shallow suppression that are more prone to modulations of conscious access.
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Affiliation(s)
- Surya Gayet
- Department of Experimental Psychology, Utrecht UniveristyUtrecht, Netherlands
| | - Timo Stein
- Center for Mind/Brain Sciences, University of TrentoRovereto, Italy
- Amsterdam Brain and Cognition, University of AmsterdamAmsterdam, Netherlands
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75
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Hung SM, Styles SJ, Hsieh PJ. Can a Word Sound Like a Shape Before You Have Seen It? Sound-Shape Mapping Prior to Conscious Awareness. Psychol Sci 2017; 28:263-275. [PMID: 28112997 DOI: 10.1177/0956797616677313] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Nonarbitrary mappings between sound and shape (i.e., the bouba-kiki effect) have been shown across different cultures and early in development; however, the level of processing at which this effect arises remains unclear. Here we show that the mapping occurs prior to conscious awareness of the visual stimuli. Under continuous flash suppression, congruent stimuli (e.g., "kiki" inside an angular shape) broke through to conscious awareness faster than incongruent stimuli. This was true even when we trained people to pair unfamiliar letters with auditory word forms, a result showing that the effect was driven by the phonology, not the visual features, of the letters. Furthermore, visibility thresholds of the shapes decreased when they were preceded by a congruent auditory word form in a masking paradigm. Taken together, our results suggest that sound-shape mapping can occur automatically prior to conscious awareness of visual shapes, and that sensory congruence facilitates conscious awareness of a stimulus being present.
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Affiliation(s)
- Shao-Min Hung
- 1 Neuroscience and Behavioral Disorders Program, Duke-NUS Medical School
| | - Suzy J Styles
- 2 Division of Psychology, School of Humanities and Social Sciences, Nanyang Technological University
| | - Po-Jang Hsieh
- 1 Neuroscience and Behavioral Disorders Program, Duke-NUS Medical School
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76
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Han S, Lunghi C, Alais D. The temporal frequency tuning of continuous flash suppression reveals peak suppression at very low frequencies. Sci Rep 2016; 6:35723. [PMID: 27767078 PMCID: PMC5073327 DOI: 10.1038/srep35723] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 10/03/2016] [Indexed: 11/09/2022] Open
Abstract
Continuous flash suppression (CFS) is a psychophysical technique where a rapidly changing Mondrian pattern viewed by one eye suppresses the target in the other eye for several seconds. Despite the widespread use of CFS to study unconscious visual processes, the temporal tuning of CFS suppression is currently unknown. In the present study we used spatiotemporally filtered dynamic noise as masking stimuli to probe the temporal characteristics of CFS. Surprisingly, we find that suppression in CFS peaks very prominently at approximately 1 Hz, well below the rates typically used in CFS studies (10 Hz or more). As well as a strong bias to low temporal frequencies, CFS suppression is greater for high spatial frequencies and increases with increasing masker contrast, indicating involvement of parvocellular/ventral mechanisms in the suppression process. These results are reminiscent of binocular rivalry, and unifies two phenomenon previously thought to require different explanations.
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Affiliation(s)
- Shui'er Han
- School of Psychology, University of Sydney, NSW 2006, Australia
| | - Claudia Lunghi
- Department of Translational Research on New Technologies in Medicine and Surgery, Via Savi 10, 56100 Pisa, Italy.,Neuroscience Institute, National Research Council (CNR), Via Moruzzi 1, 56100, Pisa, Italy
| | - David Alais
- School of Psychology, University of Sydney, NSW 2006, Australia
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77
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Time for Awareness: The Influence of Temporal Properties of the Mask on Continuous Flash Suppression Effectiveness. PLoS One 2016; 11:e0159206. [PMID: 27416317 PMCID: PMC4945020 DOI: 10.1371/journal.pone.0159206] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/28/2016] [Indexed: 11/22/2022] Open
Abstract
Visual processing is not instantaneous, but instead our conscious perception depends on the integration of sensory input over time. In the case of Continuous Flash Suppression (CFS), masks are flashed to one eye, suppressing awareness of stimuli presented to the other eye. One potential explanation of CFS is that it depends, at least in part, on the flashing mask continually interrupting visual processing before the stimulus reaches awareness. We investigated the temporal features of masks in two ways. First, we measured the suppression effectiveness of a wide range of masking frequencies (0-32Hz), using both complex (faces/houses) and simple (closed/open geometric shapes) stimuli. Second, we varied whether the different frequencies were interleaved within blocks or separated in homogenous blocks, in order to see if suppression was stronger or weaker when the frequency remained constant across trials. We found that break-through contrast differed dramatically between masking frequencies, with mask effectiveness following a skewed-normal curve peaking around 6Hz and little or no masking for low and high temporal frequencies. Peak frequency was similar for trial-randomized and block randomized conditions. In terms of type of stimulus, we found no significant difference in peak frequency between the stimulus groups (complex/simple, face/house, closed/open). These findings suggest that temporal factors play a critical role in perceptual awareness, perhaps due to interactions between mask frequency and the time frame of visual processing.
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78
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de Borst AW, de Gelder B. Clear signals or mixed messages: inter-individual emotion congruency modulates brain activity underlying affective body perception. Soc Cogn Affect Neurosci 2016; 11:1299-309. [PMID: 27025242 DOI: 10.1093/scan/nsw039] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 03/17/2016] [Indexed: 11/12/2022] Open
Abstract
The neural basis of emotion perception has mostly been investigated with single face or body stimuli. However, in daily life one may also encounter affective expressions by groups, e.g. an angry mob or an exhilarated concert crowd. In what way is brain activity modulated when several individuals express similar rather than different emotions? We investigated this question using an experimental design in which we presented two stimuli simultaneously, with same or different emotional expressions. We hypothesized that, in the case of two same-emotion stimuli, brain activity would be enhanced, while in the case of two different emotions, one emotion would interfere with the effect of the other. The results showed that the simultaneous perception of different affective body expressions leads to a deactivation of the amygdala and a reduction of cortical activity. It was revealed that the processing of fearful bodies, compared with different-emotion bodies, relied more strongly on saliency and action triggering regions in inferior parietal lobe and insula, while happy bodies drove the occipito-temporal cortex more strongly. We showed that this design could be used to uncover important differences between brain networks underlying fearful and happy emotions. The enhancement of brain activity for unambiguous affective signals expressed by several people simultaneously supports adaptive behaviour in critical situations.
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Affiliation(s)
- A W de Borst
- Department of Cognitive Neuroscience, Brain and Emotion Laboratory, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - B de Gelder
- Department of Cognitive Neuroscience, Brain and Emotion Laboratory, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
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79
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Salomon R, Kaliuzhna M, Herbelin B, Blanke O. Balancing awareness: Vestibular signals modulate visual consciousness in the absence of awareness. Conscious Cogn 2015. [DOI: 10.1016/j.concog.2015.07.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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80
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Zhan M, Hortensius R, de Gelder B. The Body as a Tool for Anger Awareness--Differential Effects of Angry Facial and Bodily Expressions on Suppression from Awareness. PLoS One 2015; 10:e0139768. [PMID: 26469878 PMCID: PMC4607361 DOI: 10.1371/journal.pone.0139768] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/17/2015] [Indexed: 12/31/2022] Open
Abstract
Emotional signals are perceived whether or not we are aware of it. The evidence so far mostly came from studies with facial expressions. Here, we investigated whether the pattern of non-conscious face expression perception is found for whole body expressions. Continuous flash suppression (CFS) was used to measure the time for neutral, fearful, and angry facial or bodily expressions to break from suppression. We observed different suppression time patterns for emotions depending on whether the stimuli were faces or bodies. The suppression time for anger was shortest for bodily expressions, but longest for the facial expressions. This pattern indicates different processing and detection mechanisms for faces and bodies outside awareness, and suggests that awareness mechanisms associated with dorsal structures might play a role in becoming conscious of angry bodily expressions.
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Affiliation(s)
- Minye Zhan
- Brain and Emotion Laboratory, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, The Netherlands
| | - Ruud Hortensius
- Brain and Emotion Laboratory, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, The Netherlands
- Cognitive and Affective Neuroscience Laboratory, Tilburg University, Tilburg, The Netherlands
| | - Beatrice de Gelder
- Brain and Emotion Laboratory, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, The Netherlands
- * E-mail:
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81
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Bergström F, Eriksson J. The conjunction of non-consciously perceived object identity and spatial position can be retained during a visual short-term memory task. Front Psychol 2015; 6:1470. [PMID: 26483726 PMCID: PMC4588213 DOI: 10.3389/fpsyg.2015.01470] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/14/2015] [Indexed: 11/13/2022] Open
Abstract
Although non-consciously perceived information has previously been assumed to be short-lived (< 500 ms), recent findings show that non-consciously perceived information can be maintained for at least 15 s. Such findings can be explained as working memory without a conscious experience of the information to be retained. However, whether or not working memory can operate on non-consciously perceived information remains controversial, and little is known about the nature of such non-conscious visual short-term memory (VSTM). Here we used continuous flash suppression to render stimuli non-conscious, to investigate the properties of non-consciously perceived representations in delayed match-to-sample (DMS) tasks. In Experiment I we used variable delays (5 or 15 s) and found that performance was significantly better than chance and was unaffected by delay duration, thereby replicating previous findings. In Experiment II the DMS task required participants to combine information of spatial position and object identity on a trial-by-trial basis to successfully solve the task. We found that the conjunction of spatial position and object identity was retained, thereby verifying that non-conscious, trial-specific information can be maintained for prospective use. We conclude that our results are consistent with a working memory interpretation, but that more research is needed to verify this interpretation.
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Affiliation(s)
- Fredrik Bergström
- Umeå Center for Functional Brain Imaging, Umeå University Umeå, Sweden ; Department of Integrative Medical Biology, Physiology Section, Umeå University Umeå, Sweden
| | - Johan Eriksson
- Umeå Center for Functional Brain Imaging, Umeå University Umeå, Sweden ; Department of Integrative Medical Biology, Physiology Section, Umeå University Umeå, Sweden
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82
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Wu Q, Lo Voi JTH, Lee TY, Mackie MA, Wu Y, Fan J. Interocular suppression prevents interference in a flanker task. Front Psychol 2015; 6:1110. [PMID: 26321969 PMCID: PMC4531229 DOI: 10.3389/fpsyg.2015.01110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/20/2015] [Indexed: 11/17/2022] Open
Abstract
Executive control of attention refers to processes that detect and resolve conflict among competing thoughts and actions. Despite the high-level nature of this faculty, the role of awareness in executive control of attention is not well understood. In this study, we used interocular suppression to mask the flankers in an arrow flanker task, in which the flankers and the target arrow were presented simultaneously in order to elicit executive control of attention. Participants were unable to detect the flanker arrows or to reliably identify their direction when masked. There was a typical conflict effect (prolonged reaction time and increased error rate under flanker-target incongruent condition compared to congruent condition) when the flanker arrows were unmasked, while the conflict effect was absent when the flanker arrows were masked with interocular suppression. These results suggest that blocking awareness of competing stimuli with interocular suppression prevents the involvement of executive control of attention.
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Affiliation(s)
- Qiong Wu
- Department of Psychology, Peking University , Beijing, China
| | - Jonathan T H Lo Voi
- The Graduate Center, City University of New York , New York, NY, USA ; Department of Psychology, Queens College, City University of New York , Queens, NY, USA
| | - Thomas Y Lee
- Department of Psychology, Queens College, City University of New York , Queens, NY, USA
| | - Melissa-Ann Mackie
- The Graduate Center, City University of New York , New York, NY, USA ; Department of Psychology, Queens College, City University of New York , Queens, NY, USA
| | - Yanhong Wu
- Department of Psychology, Peking University , Beijing, China ; Beijing Key Laboratory of Behavior and Mental Health, Peking University , Beijing, China ; Key Laboratory of Machine Perception (Ministry of Education), Peking University , Beijing, China
| | - Jin Fan
- The Graduate Center, City University of New York , New York, NY, USA ; Department of Psychology, Queens College, City University of New York , Queens, NY, USA ; Department of Psychiatry, Icahn School of Medicine at Mount Sinai , New York, NY, USA ; Department of Neuroscience, Icahn School of Medicine at Mount Sinai , New York, NY, USA
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83
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Hesselmann G, Moors P. Definitely maybe: can unconscious processes perform the same functions as conscious processes? Front Psychol 2015; 6:584. [PMID: 25999896 PMCID: PMC4421938 DOI: 10.3389/fpsyg.2015.00584] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 04/21/2015] [Indexed: 12/03/2022] Open
Abstract
Hassin recently proposed the “Yes It Can” (YIC) principle to describe the division of labor between conscious and unconscious processes in human cognition. According to this principle, unconscious processes can carry out every fundamental high-level cognitive function that conscious processes can perform. In our commentary, we argue that the author presents an overly idealized review of the literature in support of the YIC principle. Furthermore, we point out that the dissimilar trends observed in social and cognitive psychology, with respect to published evidence of strong unconscious effects, can better be explained by the way how awareness is defined and measured in both research fields. Finally, we show that the experimental paradigm chosen by Hassin to rule out remaining objections against the YIC principle is unsuited to verify the new default notion that all high-level cognitive functions can unfold unconsciously.
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Affiliation(s)
- Guido Hesselmann
- Visual Perception Laboratory, Department of Psychiatry and Psychotherapy, Charité-Universitätsmedizin Berlin , Berlin, Germany
| | - Pieter Moors
- Laboratory of Experimental Psychology, University of Leuven (KU Leuven) , Leuven, Belgium
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84
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Acting without seeing: eye movements reveal visual processing without awareness. Trends Neurosci 2015; 38:247-58. [PMID: 25765322 DOI: 10.1016/j.tins.2015.02.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/03/2015] [Accepted: 02/09/2015] [Indexed: 11/23/2022]
Abstract
Visual perception and eye movements are considered to be tightly linked. Diverse fields, ranging from developmental psychology to computer science, utilize eye tracking to measure visual perception. However, this prevailing view has been challenged by recent behavioral studies. Here, we review converging evidence revealing dissociations between the contents of perceptual awareness and different types of eye movement. Such dissociations reveal situations in which eye movements are sensitive to particular visual features that fail to modulate perceptual reports. We also discuss neurophysiological, neuroimaging, and clinical studies supporting the role of subcortical pathways for visual processing without awareness. Our review links awareness to perceptual-eye movement dissociations and furthers our understanding of the brain pathways underlying vision and movement with and without awareness.
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85
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Psychophysical "blinding" methods reveal a functional hierarchy of unconscious visual processing. Conscious Cogn 2015; 35:234-50. [PMID: 25704454 DOI: 10.1016/j.concog.2015.01.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/16/2015] [Accepted: 01/20/2015] [Indexed: 11/22/2022]
Abstract
Numerous non-invasive experimental "blinding" methods exist for suppressing the phenomenal awareness of visual stimuli. Not all of these suppressive methods occur at, and thus index, the same level of unconscious visual processing. This suggests that a functional hierarchy of unconscious visual processing can in principle be established. The empirical results of extant studies that have used a number of different methods and additional reasonable theoretical considerations suggest the following tentative hierarchy. At the highest levels in this hierarchy is unconscious processing indexed by object-substitution masking. The functional levels indexed by crowding, the attentional blink (and other attentional blinding methods), backward pattern masking, metacontrast masking, continuous flash suppression, sandwich masking, and single-flash interocular suppression, fall at progressively lower levels, while unconscious processing at the lowest levels is indexed by eye-based binocular-rivalry suppression. Although unconscious processing levels indexed by additional blinding methods is yet to be determined, a tentative placement at lower levels in the hierarchy is also given for unconscious processing indexed by Troxler fading and adaptation-induced blindness, and at higher levels in the hierarchy indexed by attentional blinding effects in addition to the level indexed by the attentional blink. The full mapping of levels in the functional hierarchy onto cortical activation sites and levels is yet to be determined. The existence of such a hierarchy bears importantly on the search for, and the distinctions between, neural correlates of conscious and unconscious vision.
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86
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Hesselmann G, Darcy N, Sterzer P, Knops A. Exploring the boundary conditions of unconscious numerical priming effects with continuous flash suppression. Conscious Cogn 2015; 31:60-72. [DOI: 10.1016/j.concog.2014.10.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/21/2014] [Accepted: 10/22/2014] [Indexed: 11/27/2022]
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87
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Dubois J, Faivre N. Invisible, but how? The depth of unconscious processing as inferred from different suppression techniques. Front Psychol 2014; 5:1117. [PMID: 25324817 PMCID: PMC4181232 DOI: 10.3389/fpsyg.2014.01117] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 09/15/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Julien Dubois
- Division of Biology, California Institute of Technology Pasadena, CA, USA
| | - Nathan Faivre
- Division of Biology, California Institute of Technology Pasadena, CA, USA
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