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Moazzen H, Gharibzadeh S, Bakouie F. Exploring perceptual grouping by proximity principle in multistable dot lattices: Dissociation between vision-for-perception and vision-for-action. Atten Percept Psychophys 2024:10.3758/s13414-024-02928-0. [PMID: 39090511 DOI: 10.3758/s13414-024-02928-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2024] [Indexed: 08/04/2024]
Abstract
Perceptual grouping, a fundamental mechanism in our visual system, significantly influences our interpretation of and interaction with the surrounding world. This study explores the impact of the proximity principle from the perspective of the Two Visual Systems (TVS) model. The TVS model argues that the visual system comprises two distinct streams: the ventral stream, which forms the neural basis for "vision-for-perception," and the dorsal stream, which underlies "vision-for-action." We designed a perceptual grouping task using dot lattices as well as a line-orientation discrimination task. Data were collected using vocal and mouse methods for the vision-for-perception mode, and joystick and pen-paper methods for the vision-for-action mode. Each method, except for vocal, included separate blocks for right and left hands. The proximity data were fitted using exponential and power models. Linear mixed-effects models were used for the statistical analyses. The results revealed similar line-orientation discrimination accuracy across all conditions. The exponential model emerged as the best fit, demonstrating adherence to the Pure Distance Law in both perceptual modes. Sensitivity to the proximity principle was higher in the vision-for-action mode compared to the vision-for-perception. In terms of orientation biases, a strong preference for vertical orientation was observed in the vision-for-perception mode, whereas a noticeable preference toward either of the oblique orientations was detected in the vision-for-action mode. Analysis of free-drawn lines demonstrated an affordance bias in the vision-for-action mode. This suggests a remarkable tendency to perceive organizations within specific orientations that offer more affordances due to the interaction between the body postures and tools.
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Affiliation(s)
- Hamze Moazzen
- Institute for Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran
| | - Shahriar Gharibzadeh
- Institute for Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran
| | - Fatemeh Bakouie
- Institute for Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran.
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2
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Wincza R, Hartley C, Readman M, Linkenauger S, Crawford T. Susceptibility to geometrical visual illusions in Parkinson's disorder. Front Psychol 2024; 14:1289160. [PMID: 38259525 PMCID: PMC10800652 DOI: 10.3389/fpsyg.2023.1289160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/15/2023] [Indexed: 01/24/2024] Open
Abstract
Parkinson's disorder (PD) is a common neurodegenerative disorder affecting approximately 1-3% of the population aged 60 years and older. In addition to motor difficulties, PD is also marked by visual disturbances, including depth perception, abnormalities in basal ganglia functioning, and dopamine deficiency. Reduced ability to perceive depth has been linked to an increased risk of falling in this population. The purpose of this paper was to determine whether disturbances in PD patients' visual processing manifest through atypical performance on visual illusion (VI) tasks. This insight will advance understanding of high-level perception in PD, as well as indicate the role of dopamine deficiency and basal ganglia pathophysiology in VIs susceptibility. Groups of 28 PD patients (Mage = 63.46, SD = 7.55) and 28 neurotypical controls (Mage = 63.18, SD = 9.39) matched on age, general cognitive abilities (memory, numeracy, attention, language), and mood responded to Ebbinghaus, Ponzo, and Müller-Lyer illusions in a computer-based task. Our results revealed no reliable differences in VI susceptibility between PD and neurotypical groups. In the early- to mid-stage of PD, abnormalities of the basal ganglia and dopamine deficiency are unlikely to be involved in top-down processing or depth perception, which are both thought to be related to VI susceptibility. Furthermore, depth-related issues experienced by PD patients (e.g., increased risk for falling) may not be subserved by the same cognitive mechanisms as VIs. Further research is needed to investigate if more explicit presentations of illusory depth are affected in PD, which might help to understand the depth processing deficits in PD.
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Affiliation(s)
- Radoslaw Wincza
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
| | - Calum Hartley
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
| | - Megan Readman
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
- University of Liverpool, Liverpool, United Kingdom
| | - Sally Linkenauger
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
| | - Trevor Crawford
- Department of Psychology, Lancaster University, Lancaster, United Kingdom
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Whitwell RL, Hasan HA, MacNeil RR, Enns JT. Coming to grips with reality: Real grasps, but not pantomimed grasps, resist a simultaneous tilt illusion. Neuropsychologia 2023; 191:108726. [PMID: 37931746 DOI: 10.1016/j.neuropsychologia.2023.108726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/27/2023] [Accepted: 11/03/2023] [Indexed: 11/08/2023]
Abstract
Investigations of grasping real, 3D objects subjected to illusory effects from a pictorial background often choose in-flight grasp aperture as the primary variable to test the hypothesis that the visuomotor system resists the illusion. Here we test an equally important feature of grasps that has received less attention: in-flight grasp orientation. The current study tested a variant of the simultaneous tilt illusion using a mirror-apparatus to manipulate the availability of haptic feedback. Participants performed grasps with haptic feedback (real grasps) and without it (pantomime grasps), reaching for the reflection of a real, 3D bar atop a background grating that induced a 1.1° bias in the perceived orientation of the bar in a separate sample of participants. Analysis of the hand's in-flight grasp orientation at early, late, and end stages of the reach showed that at no point were the real grasps biased by the illusion. In contrast, pantomimed grasps were affected by the illusion at the late and end stages of the reach. At each stage, the effect on the real grasps was significantly weaker than the effect of the illusion as measured by the mean point of subjective equality (PSE) in a two-alternative forced-choice task. In contrast, the effect on the pantomime grasps was statistically indistinguishable from the mean PSE at all three stages of the reach. These findings reinforce the idea that in-flight grasp orientation, like grasp aperture to pictorial illusions of target size, is refractory to pictorial backgrounds that bias perceived orientation.
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Affiliation(s)
- R L Whitwell
- Department of Physiology & Pharmacology, The University of Western University, Canada; Department of Psychology, The University of Western University, Canada.
| | - H A Hasan
- Department of Psychology, The University of British Columbia, Canada
| | - R R MacNeil
- Department of Psychology, The University of British Columbia, Canada
| | - J T Enns
- Department of Psychology, The University of British Columbia, Canada
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Mazuz Y, Kessler Y, Ganel T. The BTPI: An online battery for measuring susceptibility to visual illusions. J Vis 2023; 23:2. [PMID: 37669069 PMCID: PMC10484025 DOI: 10.1167/jov.23.10.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 07/31/2023] [Indexed: 09/06/2023] Open
Abstract
Visual illusions provide a powerful tool for probing the mechanisms that underlie perception. While most previous studies of visual illusions focused on average group-level performance, less attention has been devoted to individual differences in susceptibility to illusions. Unlike in other perceptual domains, in which there are established, validated tools to measure individual differences, such tools are not yet available in the domain of visual illusions. Here, we describe the development and validation of the BTPI (Ben-Gurion University Test for Perceptual Illusions), a new online battery designed to measure susceptibility to the influence of three prominent size illusions: the Ebbinghaus, the Ponzo, and the height-width illusions. The BTPI also measures perceptual resolution, reflected by the just noticeable difference (JND), to detect size differences in the context of each illusion. In Experiment 1 (N = 143), we examined performance in typical self-paced tasks, whereas in Experiment 2 (N = 69), we employed a fixed presentation duration paradigm. High test-retest reliability scores were found for all illusions, with little evidence for intercorrelations between different illusions. In addition, lower perceptual resolution (larger JND) was associated with a larger susceptibility to the illusory effect. The computerized task battery and analysis codes are freely available online.
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Affiliation(s)
- Yarden Mazuz
- Department of Psychology and School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yoav Kessler
- Department of Psychology and School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Tzvi Ganel
- Department of Psychology and School of Brain Sciences and Cognition, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Whitwell RL, Garach MA, Goodale MA, Sperandio I. Looking at the Ebbinghaus illusion: differences in neurocomputational requirements, not gaze-mediated attention, explain a classic perception-action dissociation. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210459. [PMID: 36511402 PMCID: PMC9745866 DOI: 10.1098/rstb.2021.0459] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Perceiving and grasping an object present an animal with different sets of computational problems. The solution in primates entails the specialization of separate neural networks for visual processing with different object representations. This explains why the Ebbinghaus illusion minimally affects the grasping hand's in-flight aperture, which normally scales with target size, even though the size of the target disc remains misperceived. An attractive alternative account, however, posits that grasps are refractory to the illusion because participants fixate on the target and fail to attend to the surrounding context. To test this account, we tracked both limb and gaze while participants made forced-choice judgments of relative disc size in the Ebbinghaus illusion or did so in combination with grasping or manually estimating the size of one of the discs. We replicated the classic dissociation: grasp aperture was refractory to the measured illusory effect on perceived size, while judgments and manual estimates of disc size were not. Importantly, the number of display-wide saccades per second and the percentage of total fixation time or fixations directed at the selected disc failed to explain the dissociation. Our findings support the contention that object perception and goal-directed action rely on distinct visual representations. This article is part of a discussion meeting issue 'New approaches to 3D vision'.
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Affiliation(s)
- Robert L. Whitwell
- Department of Psychology, University of Western Ontario, London, Ontario, Canada N6A 5C2
| | - Mehul A. Garach
- Division of Orthopaedics, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada M5B 1W8
| | - Melvyn A. Goodale
- Department of Psychology, University of Western Ontario, London, Ontario, Canada N6A 5C2
| | - Irene Sperandio
- Department of Psychology and Cognitive Science, University of Trento, Rovereto (TN) 38068, Italy
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The Riemannian Geometry Theory of Visually-Guided Movement Accounts for Afterimage Illusions and Size Constancy. Vision (Basel) 2022; 6:vision6020037. [PMID: 35737424 PMCID: PMC9231332 DOI: 10.3390/vision6020037] [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: 03/25/2022] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 11/17/2022] Open
Abstract
This discussion paper supplements our two theoretical contributions previously published in this journal on the geometric nature of visual space. We first show here how our Riemannian formulation explains the recent experimental finding (published in this special issue on size constancy) that, contrary to conclusions from past work, vergence does not affect perceived size. We then turn to afterimage experiments connected to that work. Beginning with the Taylor illusion, we explore how our proposed Riemannian visual–somatosensory–hippocampal association memory network accounts in the following way for perceptions that occur when afterimages are viewed in conjunction with body movement. The Riemannian metric incorporated in the association memory network accurately emulates the warping of 3D visual space that is intrinsically introduced by the eye. The network thus accurately anticipates the change in size of retinal images of objects with a change in Euclidean distance between the egocentre and the object. An object will only be perceived to change in size when there is a difference between the actual size of its image on the retina and the anticipated size of that image provided by the network. This provides a central mechanism for size constancy. If the retinal image is the afterimage of a body part, typically a hand, and that hand moves relative to the egocentre, the afterimage remains constant but the proprioceptive signals change to give the new hand position. When the network gives the anticipated size of the hand at its new position this no longer matches the fixed afterimage, hence a size-change illusion occurs.
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Neilson PD, Neilson MD, Bye RT. A Riemannian Geometry Theory of Synergy Selection for Visually-Guided Movement. Vision (Basel) 2021; 5:26. [PMID: 34070234 PMCID: PMC8163178 DOI: 10.3390/vision5020026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/06/2021] [Accepted: 05/08/2021] [Indexed: 11/16/2022] Open
Abstract
Bringing together a Riemannian geometry account of visual space with a complementary account of human movement synergies we present a neurally-feasible computational formulation of visuomotor task performance. This cohesive geometric theory addresses inherent nonlinear complications underlying the match between a visual goal and an optimal action to achieve that goal: (i) the warped geometry of visual space causes the position, size, outline, curvature, velocity and acceleration of images to change with changes in the place and orientation of the head, (ii) the relationship between head place and body posture is ill-defined, and (iii) mass-inertia loads on muscles vary with body configuration and affect the planning of minimum-effort movement. We describe a partitioned visuospatial memory consisting of the warped posture-and-place-encoded images of the environment, including images of visible body parts. We depict synergies as low-dimensional submanifolds embedded in the warped posture-and-place manifold of the body. A task-appropriate synergy corresponds to a submanifold containing those postures and places that match the posture-and-place-encoded visual images that encompass the required visual goal. We set out a reinforcement learning process that tunes an error-reducing association memory network to minimize any mismatch, thereby coupling visual goals with compatible movement synergies. A simulation of a two-degrees-of-freedom arm illustrates that, despite warping of both visual space and posture space, there exists a smooth one-to-one and onto invertible mapping between vision and proprioception.
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Affiliation(s)
- Peter D. Neilson
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052, Australia
| | - Megan D. Neilson
- Independent Researcher, late School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052, Australia;
| | - Robin T. Bye
- Cyber-Physical Systems Laboratory, Department of ICT and Natural Sciences, NTNU—Norwegian University of Science and Technology, Postboks 1517, NO-6009 Ålesund, Norway;
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Senanayake SA, Carther-Krone T, Marotta JJ. Priming of the Sander Parallelogram illusion separates perception from action. Exp Brain Res 2021; 239:2207-2220. [PMID: 34013396 DOI: 10.1007/s00221-021-06076-x] [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: 09/03/2020] [Accepted: 03/02/2021] [Indexed: 10/21/2022]
Abstract
The two-visual stream hypothesis posits that the dorsal stream is less susceptible than the ventral stream to the effects of illusions and visual priming. While previous studies have separately examined these perceptual manipulations, the present study combined the effects of a visual illusion and priming to examine the possibility of dorsally guided actions being susceptible to the perceptual stimuli due to interactions between the two streams. Thirty-four participants were primed with a 'long' or 'short' version of the Sander Parallelogram illusion and were asked to either reach out and grasp or manually estimate the length of a rod placed on a version of the illusion that was on some trials the same as the prime (congruent) and on other trials was the inverse (incongruent). Due to the context-focused nature of ventral processing, we predicted that estimations would be more susceptible to the effects of the illusion and priming than grasps. Results showed that while participants' manual estimations were susceptible to both priming and the illusion, the grasps were only affected by the illusion, not by priming. The influence of the illusion on grip aperture was greater during manual estimations than it was during grasping. These findings support the notion that the functionally distinct dorsal and ventral streams interact under the current experimental paradigm. Outcomes of the study help better understand the nature of stimuli that promote interactions between the dorsal and ventral streams.
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Affiliation(s)
- Shannon A Senanayake
- Perception and Action Lab, Department of Psychology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada.
| | - Tiffany Carther-Krone
- Perception and Action Lab, Department of Psychology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Jonathan J Marotta
- Perception and Action Lab, Department of Psychology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
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Ozana A, Berman S, Ganel T. Grasping Weber's Law in a Virtual Environment: The Effect of Haptic Feedback. Front Psychol 2020; 11:573352. [PMID: 33329216 PMCID: PMC7710620 DOI: 10.3389/fpsyg.2020.573352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 10/05/2020] [Indexed: 11/13/2022] Open
Abstract
Recent findings suggest that the functional separation between vision-for-action and vision-for-perception does not generalize to situations in which virtual objects are used as targets. For instance, unlike actions toward real objects that violate Weber's law, a basic law of visual perception, actions toward virtual objects presented on flat-screens, or in remote virtual environments, obey to Weber's law. These results suggest that actions in virtual environments are performed in an inefficient manner and are subjected to perceptual effects. It is unclear, however, whether this inefficiency reflects extensive variation in the way in which visual information is processed in virtual environments or more local aspects related to the settings of the virtual environment. In the current study, we focused on grasping performance in a state-of-the-art virtual reality system that provides an accurate representation of the 3D space. Within this environment, we tested the effect of haptic feedback on grasping trajectories. Participants were asked to perform bimanual grasping movements toward the edges of virtual targets. In the haptic feedback condition, physical stimuli of matching dimensions were embedded in the virtual environment. Haptic feedback was not provided in the no-feedback condition. The results showed that grasping trajectories in the feedback, but not in the no-feedback condition, could be performed more efficiently, and evade the influence of Weber's law. These findings are discussed in relevance to previous literature on 2D and 3D grasping.
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Affiliation(s)
- Aviad Ozana
- Department of Psychology, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Zlotowski Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Sigal Berman
- Zlotowski Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Department of Industrial Engineering and Management, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Tzvi Ganel
- Department of Psychology, Ben-Gurion University of the Negev, Beer-Sheva, Israel.,Zlotowski Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Consciously monitored grasping is vulnerable to perceptual intrusions. Conscious Cogn 2020; 85:103019. [DOI: 10.1016/j.concog.2020.103019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/09/2020] [Accepted: 09/01/2020] [Indexed: 11/17/2022]
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