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Early visual processing relevant to the reduction of adaptation-induced perceptual bias. Sci Rep 2021; 11:15407. [PMID: 34326366 PMCID: PMC8322081 DOI: 10.1038/s41598-021-94091-x] [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: 10/20/2020] [Accepted: 07/06/2021] [Indexed: 11/22/2022] Open
Abstract
Visual perception is biased by the preceding visual environment. A well-known perceptual bias is the negative bias where a current percept is biased away from the preceding image (adaptor). The preceding adaptor induces augmentation of early visual evoked potential (the P1 enhancement) of the following test image; the adaptor may invoke certain visual processing for the subsequent test image. However, the visual mechanism underlying P1 enhancement remains unclear. The present study assessed what the P1 alteration reflects in relation to the occurrence of the negative bias. In terms of inter-individual differences, we report that the P1 enhancement of the Necker lattice significantly correlated with the reduction of the reverse-bias effect. Further analyses revealed that the P1 enhancement was insusceptible to neural adaptation to the adaptor at the level of perceptual configuration. The present study suggests that prolonged exposure to a visual image induces modulatory visual processing for the subsequent image (reflected in the P1 enhancement), which is relevant to counteraction of the negative bias.
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Abstract
When facing ambiguous images, the brain switches between mutually exclusive interpretations, a phenomenon known as bistable perception. Despite years of research, a consensus on whether bistability is driven primarily by bottom-up or top-down mechanisms has not been achieved. Here, we adopted a Bayesian approach to reconcile these two theories. Fifty-five healthy participants were exposed to an adaptation of the Necker cube paradigm, in which we manipulated sensory evidence and prior knowledge. Manipulations of both sensory evidence and priors significantly affected the way participants perceived the Necker cube. However, we observed an interaction between the effect of the cue and the effect of the instructions, a finding that is incompatible with Bayes-optimal integration. In contrast, the data were well predicted by a circular inference model. In this model, ambiguous sensory evidence is systematically biased in the direction of current expectations, ultimately resulting in a bistable percept.
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Loued-Khenissi L, Preuschoff K. A Bird's eye view from below: Activity in the temporo-parietal junction predicts from-above Necker Cube percepts. Neuropsychologia 2020; 149:107654. [PMID: 33069790 DOI: 10.1016/j.neuropsychologia.2020.107654] [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: 02/29/2020] [Revised: 08/30/2020] [Accepted: 10/12/2020] [Indexed: 01/04/2023]
Abstract
The temporo-parietal junction (TPJ) consistently emerges in other-regarding behavior, including tasks probing affective phenomena such as morality and empathy. Yet the TPJ is also recruited in processes with no affective or social component, such as visuo-spatial processing and mathematical cognition. We present serendipitous findings from a perceptual decision-making task on a bistable stimulus, the Necker Cube, performed in an MRI scanner. The stimulus in question is a transparent, wire-frame cube that evokes spontaneous switches in perception. Individuals can view the cube from below or from above, though a consistent bias is shown towards seeing the cube from above. We replicate this bias, finding participants spend more time in the from-above percept. However, in testing for BOLD differences between percept orientations, we found robust responses in bilateral TPJ for the from-above > from-below perceptual state. We speculate that this neural response comes from the sensory incongruence of viewing an object from above while lying supine in the scanner. We further speculate that the TPJ resolves this incongruence by facilitating an egocentric projection. Such a function would explain the TPJ's ubiquitous response to other-regarding, visuo-spatial and mathematical cognition, as all these phenomena demand an ability to ambulate through the coordinate space. Our findings suggest the TPJ may not play a specific role in social or moral components of other-regarding behavior, such as altruism, and further indirectly suggest that "pure", allocentric altruism may not correlate with the TPJ. Results further have implications on how the TPJ may be modulated by activities such as flight or drone operation. Finally, this study highlights the possible need for congruence between stimuli and body position in neuroimaging studies.
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Affiliation(s)
- Leyla Loued-Khenissi
- Brain Mind Institute, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland; Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland.
| | - Kerstin Preuschoff
- Geneva Finance Research Institute, University of Geneva, Geneva, Switzerland; Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
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Leptourgos P, Corlett PR. Embodied Predictions, Agency, and Psychosis. Front Big Data 2020; 3:27. [PMID: 33693400 PMCID: PMC7931869 DOI: 10.3389/fdata.2020.00027] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/14/2020] [Indexed: 01/11/2023] Open
Abstract
Psychotic symptoms, i.e., hallucinations and delusions, involve gross departures from conscious apprehension of consensual reality; respectively, perceiving and believing things that, according to same culture peers, do not obtain. In schizophrenia, those experiences are often related to abnormal sense of control over one's own actions, often expressed as a distorted sense of agency (i.e., passivity symptoms). Cognitive and computational neuroscience have furnished an account of these experiences and beliefs in terms of the brain's generative model of the world, which underwrites inferences to the best explanation of current and future states, in order to behave adaptively. Inference then involves a reliability-based trade off of predictions and prediction errors, and psychotic symptoms may arise as departures from this inference process, either an over- or under-weighting of priors relative to prediction errors. Surprisingly, there is empirical evidence in favor of both positions. Relatedly, there is evidence for both an enhanced and a diminished sense of agency in schizophrenia. How can this be? We argue that there is more than one generative model in the brain, and that ego- and allo-centric models operate in tandem. In brief, ego-centric models implement corollary discharge signals that cancel out the effects of self-generated actions while allo-centric models compare several hypothesis regarding the causes of sensory inputs (including the self among the potential causes). The two parallel hierarchies give rise to different levels of agency, with ego-centric models subserving "feelings of agency" and allo-centric predictions giving rise to "judgements of agency." Those two components are weighted according to their reliability and combined, generating a higher-level "sense of agency." We suggest that in schizophrenia a failure of corollary discharges to suppress self-generated inputs results in the absence of a "feeling of agency" and in a compensatory enhancement of allo-centric priors, which might underlie hallucinations, delusions of control but also, under certain circumstances, the enhancement of "judgments of agency." We discuss the consequences of such a model, and potential courses of action that could lead to its falsification.
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Affiliation(s)
| | - Philip R. Corlett
- Department of Psychiatry, Connecticut Mental Health Center, Yale University, New Haven, CT, United States
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Intaitė M, Georgescu AL, Noreika V, von Saldern MA, Vogeley K, Falter-Wagner CM. Adults with autism spectrum condition have atypical perception of ambiguous figures when bottom-up and top-down interactions are incongruous. AUTISM : THE INTERNATIONAL JOURNAL OF RESEARCH AND PRACTICE 2018; 23:1133-1142. [PMID: 30288989 DOI: 10.1177/1362361318782221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We examined the perception of an ambiguous squares stimulus evoking bistable perception in a sample of 31 individuals with autistic spectrum condition and 22 matched typical adults. The perception of the ambiguous figure was manipulated by adaptation to unambiguous figures and/or by placing the ambiguous figure into a context of unambiguous figures. This resulted in four conditions testing the independent and combined (congruent and incongruent) manipulations of adaptation (bottom-up) and spatial context (top-down) effects. The strength of perception, as measured by perception of the first reported orientation of the ambiguous stimulus, was affected comparably between groups. Nevertheless, the strength of perception, as measured by perceptual durations, was affected differently between groups: the perceptual effect was strongest for the autistic spectrum condition group when combined bottom-up and top-down conditions were congruent. In contrast, the strength of the perceptual effect in response to the same condition in the typical adults group was comparable to the adaptation, but stronger than both the context and the incongruent combined bottom-up and top-down conditions. Furthermore, the context condition was stronger than the incongruent combined bottom-up and top-down conditions for the typical adults group. Thus, our findings support the view of stimulus-specific top-down modulation in autistic spectrum condition.
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Affiliation(s)
| | | | | | | | - Kai Vogeley
- 3 University Hospital of Cologne, Germany.,6 Research Center Jülich, Germany
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Liaci E, Fischer A, Atmanspacher H, Heinrichs M, Tebartz van Elst L, Kornmeier J. Positive and negative hysteresis effects for the perception of geometric and emotional ambiguities. PLoS One 2018; 13:e0202398. [PMID: 30256789 PMCID: PMC6157843 DOI: 10.1371/journal.pone.0202398] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 08/02/2018] [Indexed: 12/21/2022] Open
Abstract
AIM The present study utilizes perceptual hysteresis effects to compare the ambiguity of Mona Lisa's emotional face expression (high-level ambiguity) and of geometric cube stimuli (low-level ambiguity). METHODS In two experiments we presented series of nine Mona Lisa variants and nine cube variants. Stimulus ambiguity was manipulated by changing Mona Lisa's mouth curvature (Exp. 1) and the cubes' back-layer luminance (Exp. 2). Each experiment consisted of three conditions, two with opposite stimulus presentation sequences with increasing and decreasing degrees of ambiguity, respectively, and a third condition with a random presentation sequence. Participants indicated happy or sad face percepts (Exp. 1) and alternative 3D cube percepts (Exp. 2) by key presses. We studied the influences of a priori perceptual biases (long-term memory) and presentation order (short-term memory) on perception. RESULTS Perception followed sigmoidal functions of the stimulus ambiguity morphing parameters. The morphing parameter for the functions' inflection points depended strongly on stimulus presentation order with similar effect sizes but different signs for the two stimulus types (positive hysteresis / priming for the cubes; negative hysteresis / adaptation for Mona Lisa). In the random conditions, the inflection points were located in the middle between those from the two directional conditions for the Mona Lisa stimuli. For the cube stimuli, they were superimposed on one sigmoidal function for the ordered condition. DISCUSSION The hysteresis effects reflect the influence of short-term memory during the perceptual disambiguation of ambiguous sensory information. The effects for the two stimulus types are of similar size, explaining up to 34% of the perceptual variance introduced by the paradigm. We explain the qualitative difference between positive and negative hysteresis with adaptation for Mona Lisa and with priming for the cubes. In addition, the hysteresis paradigm allows a quantitative determination of the impact of adaptation and priming during the resolution of perceptual ambiguities. The asymmetric shifts of inflection points in the case of the cube stimuli is likely due to an a priori perceptual bias, reflecting an influence of long-term memory. Whether corresponding influences also exist for the Mona Lisa variants is so far unclear.
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Affiliation(s)
- Emanuela Liaci
- Institute for Frontier Areas of Psychology and Mental Health, Freiburg, Germany
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Psychology, University of Freiburg, Freiburg, Germany
| | - Andreas Fischer
- Institute for Frontier Areas of Psychology and Mental Health, Freiburg, Germany
| | - Harald Atmanspacher
- Institute for Frontier Areas of Psychology and Mental Health, Freiburg, Germany
- Collegium Helveticum, Zürich, Switzerland
| | - Markus Heinrichs
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Psychology, University of Freiburg, Freiburg, Germany
| | - Ludger Tebartz van Elst
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jürgen Kornmeier
- Institute for Frontier Areas of Psychology and Mental Health, Freiburg, Germany
- Section for Experimental Neuropsychiatry, Department for Psychiatry & Psychotherapy, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Kim SH, Choi JY. Directional Bias for Vertical Integration of Motion Trajectories. Exp Psychol 2018; 65:218-225. [DOI: 10.1027/1618-3169/a000410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract. Here we report a new ambiguous continuous motion display, in which two objects appear at the diagonally opposite corners of an imaginary square, move along the diagonal axis toward each other, and after meeting in the center, shift their trajectories to the other two diagonal corners. This display can be seen as two objects’ colliding and bouncing off each other, with two competing interpretations of trajectory configuration requiring either vertical or horizontal integration of trajectory segments. Despite the fact that both percepts are equally plausible, the current study revealed a perceptual preference toward a vertical integration interpretation. We compared this bias with the similar vertical bias in a bistable apparent motion quartet, which suggests that the directional anisotropy found here is quite a new, and distinct phenomenon in both its perceptual characteristics and underlying mechanism.
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Affiliation(s)
- Sung-Ho Kim
- Department of Psychology, Ewha Womans University, Seoul, Republic of Korea
| | - Jeong-Yoon Choi
- Department of Psychology, Ewha Womans University, Seoul, Republic of Korea
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Abstract
Objects rotating in depth with an ambiguous rotation direction frequently appear to
rotate together. Corotation is especially strong when the objects are interpretable as
having a shared axis. We manipulated the initial conditions of the experiment by having
pairs of objects initially appear to be unambiguous, and then make either a sudden or
gradual transition to ambiguous spin. We find that in neither case do coaxial
counter-rotating objects persist in being perceived as counter-rotating. This implies that
the perceptual constraint that favors coaxial corotation overrides the initial perceptual
state of the objects.
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Affiliation(s)
- Allan C Dobbins
- Department of Biomedical Engineering, Vision Science Research Center, University of Alabama at Birmingham, AL, USA
| | - Jon K Grossmann
- Department of Biomedical Engineering, Vision Science Research Center, University of Alabama at Birmingham, AL, USA
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A different view on the Necker cube-Differences in multistable perception dynamics between Asperger and non-Asperger observers. PLoS One 2017; 12:e0189197. [PMID: 29244813 PMCID: PMC5731733 DOI: 10.1371/journal.pone.0189197] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/21/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND During observation of the Necker cube perception becomes unstable and alternates repeatedly between a from-above-perspective ("fap") and a from-below-perspective ("fbp") interpretation. Both interpretations are physically equally plausible, however, observers usually show an a priori top-down bias in favor of the fap interpretation. Patients with Autism spectrum disorder are known to show an altered pattern of perception with a focus on sensory details. In the present study we tested whether this altered perceptual processing affects their reversal dynamics and reduces the perceptual bias during Necker cube observation. METHODS 19 participants with Asperger syndrome and 16 healthy controls observed a Necker cube stimulus continuously for 5 minutes and indicated perceptual reversals by key press. We compared reversal rates (number of reversals per minute) and the distributions of dwell times for the two interpretations between observer groups. RESULTS Asperger participants showed less perceptual reversal than controls. Six Asperger participants did not perceive any reversal at all, whereas all observers from the control group perceived at least five reversals within the five minutes observation time. Further, control participants showed the typical perceptual bias with significant longer median dwell times for the fap compared to the fbp interpretation. No such perceptual bias was found in the Asperger group. DISCUSSION The perceptual system weights the incomplete and ambiguous sensory input with memorized concepts in order to construct stable and reliable percepts. In the case of the Necker cube stimulus, two perceptual interpretations are equally compatible with the sensory information and internal fluctuations may cause perceptual alternations between them-with a slightly larger probability value for the fap interpretation (perceptual bias). Smaller reversal rates in Asperger observers may result from the dominance of bottom-up sensory input over endogenous top-down factors. The latter may also explain the absence of a fap bias.
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10
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Ouhnana M, Jennings BJ, Kingdom FAA. Common contextual influences in ambiguous and rivalrous figures. PLoS One 2017; 12:e0176842. [PMID: 28459854 PMCID: PMC5411032 DOI: 10.1371/journal.pone.0176842] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/18/2017] [Indexed: 11/19/2022] Open
Abstract
Images that resist binocular fusion undergo alternating periods of dominance and suppression, similarly to ambiguous figures whose percepts alternate between two interpretations. It has been well documented that the perceptual interpretations of both rivalrous and ambiguous figures are influenced by their spatio-temporal context. Here we consider whether an identical spatial context similarly influences the interpretation of a similar rivalrous and ambiguous figure. We developed a binocularly rivalrous stimulus whose perceptual experience mirrors that of a Necker cube. We employed a paradigm similar to that of Ouhnana and Kingdom (2016) to correlate the magnitude of influence of context between the rivalrous and ambiguous target. Our results showed that the magnitude of contextual influence is significantly correlated within observers between both binocularly rivalrous and ambiguous target figures. This points to a similar contextual-influence mechanism operating on a common mechanism underlying the perceptual instability in both ambiguous and rivalrous figures.
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Affiliation(s)
- Marouane Ouhnana
- McGill Vision Research Unit, Department of Ophthalmology, Montreal General Hospital, Montreal, Quebec, Canada
- * E-mail:
| | - Ben J. Jennings
- McGill Vision Research Unit, Department of Ophthalmology, Montreal General Hospital, Montreal, Quebec, Canada
| | - Frederick A. A. Kingdom
- McGill Vision Research Unit, Department of Ophthalmology, Montreal General Hospital, Montreal, Quebec, Canada
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11
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Zhang X, Xu Q, Jiang Y, Wang Y. The interaction of perceptual biases in bistable perception. Sci Rep 2017; 7:42018. [PMID: 28165061 PMCID: PMC5292733 DOI: 10.1038/srep42018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 01/06/2017] [Indexed: 11/09/2022] Open
Abstract
When viewing ambiguous stimuli, people tend to perceive some interpretations more frequently than others. Such perceptual biases impose various types of constraints on visual perception, and accordingly, have been assumed to serve distinct adaptive functions. Here we demonstrated the interaction of two functionally distinct biases in bistable biological motion perception, one regulating perception based on the statistics of the environment – the viewing-from-above (VFA) bias, and the other with the potential to reduce costly errors resulting from perceptual inference – the facing-the-viewer (FTV) bias. When compatible, the two biases reinforced each other to enhance the bias strength and induced less perceptual reversals relative to when they were in conflict. Whereas in the conflicting condition, the biases competed with each other, with the dominant percept varying with visual cues that modulate the two biases separately in opposite directions. Crucially, the way the two biases interact does not depend on the dominant bias at the individual level, and cannot be accounted for by a single bias alone. These findings provide compelling evidence that humans robustly integrate biases with different adaptive functions in visual perception. It may be evolutionarily advantageous to dynamically reweight diverse biases in the sensory context to resolve perceptual ambiguity.
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Affiliation(s)
- Xue Zhang
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, 16 Lincui Road, Beijing 100101, P. R. China.,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Qian Xu
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, 16 Lincui Road, Beijing 100101, P. R. China.,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Yi Jiang
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, 16 Lincui Road, Beijing 100101, P. R. China.,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Ying Wang
- State Key Laboratory of Brain and Cognitive Science, CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Psychology, Chinese Academy of Sciences, 16 Lincui Road, Beijing 100101, P. R. China.,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
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12
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Abstract
Perceiving the world around us requires that we resolve ambiguity. This process is often studied in the lab using ambiguous figures whose structures can be interpreted in multiple ways. One class of figures contains ambiguity in its depth relations, such that either of two surfaces could be seen as being the "front" of an object. Previous research suggests that selectively attending to a given location on such objects can bias the perception of that region as the front. This study asks whether selectively attending to a distributed feature can also bias that region toward the front. Participants viewed a structure-from-motion display of a rotating cylinder that could be perceived as rotating clockwise or counterclockwise (as imagined viewing from the top), depending on whether a set of red or green moving dots were seen as being in the front. A secondary task encouraged observers to globally attend to either red or green. Results from both Experiment 1 and 2 showed that the dots on the cylinder that shared the attended feature, and its corresponding surface, were more likely to be seen as being in the front, as measured by participants' clockwise versus counterclockwise percept reports. Feature-based attention, like location-based attention, is capable of biasing competition among potential interpretations of figures with ambiguous structure in depth.
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13
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Perceptual-binding in a rotating Necker cube: The effect of context motion and position. Vision Res 2016; 126:59-68. [DOI: 10.1016/j.visres.2016.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 02/09/2016] [Accepted: 02/10/2016] [Indexed: 11/21/2022]
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14
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Lucafò C, Marzoli D, Prete G, Tommasi L. Laterality effects in the spinning dancer illusion: The viewing-from-above bias is only part of the story. Br J Psychol 2015; 107:698-709. [PMID: 26666983 DOI: 10.1111/bjop.12166] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 10/29/2015] [Indexed: 11/29/2022]
Abstract
The 'silhouette illusion', representing the silhouette of a female dancer pirouetting about her vertical axis, is a bistable stimulus created by Japanese web designer Nobuyuki Kayahara. Although the dancer can be perceived as spinning either clockwise or counterclockwise, the clockwise rotation is usually preferred. Troje and McAdam (i-Perception, 2010, 1, 143) showed that this clockwise bias can be attributed to the tendency to assume a viewpoint from above rather than from below, given that the dancer is portrayed from a vantage point that is not perpendicular to the axis of rotation. Here, we tested whether another possible factor contributing to the observers' interpretation of this bistable stimulus might be the tendency to perceive movements of the right rather than the left foot. We confirmed both the viewing-from-above bias and our hypothesis. The bias to perceive movements of the right leg might be a generalization to lower limbs of a perceptual frequency effect already observed for upper limbs. Such a perceptual and attentional bias towards the right hand/foot could account for the greater ability to predict the outcome of sport actions when observing right- rather than left-limbed movements, and thus the left-handers' and left-footers' advantage observed in a variety of interactive sports.
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Affiliation(s)
- Chiara Lucafò
- Department of Psychological Sciences, Health and Territory, University of Chieti, Italy
| | - Daniele Marzoli
- Department of Psychological Sciences, Health and Territory, University of Chieti, Italy.
| | - Giulia Prete
- Department of Psychological Sciences, Health and Territory, University of Chieti, Italy
| | - Luca Tommasi
- Department of Psychological Sciences, Health and Territory, University of Chieti, Italy
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15
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Proulx MJ. The perception of shape from shading in a new light. PeerJ 2014; 2:e363. [PMID: 24795853 PMCID: PMC4006223 DOI: 10.7717/peerj.363] [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: 12/17/2013] [Accepted: 04/05/2014] [Indexed: 11/20/2022] Open
Abstract
How do humans see three-dimensional shape based on two-dimensional shading? Much research has assumed that a ‘light from above’ bias solves the ambiguity of shape from shading. Counter to the ‘light from above’ bias, studies of Bayesian priors have found that such a bias can be swayed by other light cues. Despite the persuasive power of the Bayesian models, many new studies and books cite the original ‘light from above’ findings. Here I present a version of the Bayesian result that can be experienced. The perception of shape-from-shading was found here to be influenced by an external light source, even when the light was obstructed and did not directly illuminate a two-dimensional stimulus. The results imply that this effect is robust and not low-level in nature. The perception of shape from shading is not necessarily based on a hard-wired internal representation of lighting direction, but rather assesses the direction of lighting in the scene adaptively. Here, for the first time, is an experiential opportunity to see what the Bayesian models have supported all along.
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Affiliation(s)
- Michael J Proulx
- Crossmodal Cognition Laboratory, Department of Psychology, University of Bath , UK
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16
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Stanley J, Forte JD, Cavanagh P, Carter O. Onset rivalry: the initial dominance phase is independent of ongoing perceptual alternations. Front Hum Neurosci 2011; 5:140. [PMID: 22319483 PMCID: PMC3258971 DOI: 10.3389/fnhum.2011.00140] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 11/01/2011] [Indexed: 11/13/2022] Open
Abstract
Binocular rivalry has been used to study a wide range of visual processes, from the integration of low-level features to the selection of signals that reach awareness. However, many of these studies do not distinguish between early and late phases of rivalry. There is clear evidence that the “onset” stage of rivalry is characterized by stable, yet idiosyncratic biases that are not evident in the average dominance of sustained rivalry viewing. Low-level stimulus features also have robust effects in the onset phase that are not seen in sustained rivalry, suggesting these phases may be driven at least partly by different neural mechanisms. The effects of high-level cognitive and affective factors at onset are less clear but also show differences from their effects in sustained viewing. These findings have important implications for the interpretation of any rivalry experiments using brief presentation paradigms and for understanding how the brain copes with binocular discrepancies in natural viewing conditions in which our eyes constantly move around an ever-changing environment. This review will summarize current research and explore the factors influencing this “onset” stage.
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Affiliation(s)
- Jody Stanley
- Psychological Sciences, University of Melbourne Parkville, VIC, Australia
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