Slide
Centre Interdisciplinaire
de Recherche et d’Innovation
en Cybersécurité et Société
de Recherche et d’Innovation
en Cybersécurité et Société
1.
Simon, J.; Grogna, D.; Rivard, M. -C.; Heck, M.; Bouchard, S.; Quertemont, E.
Assessing attentional bias for alcohol-related cues using eye tracking in a virtual reality environment Journal Article
In: Frontiers in Virtual Reality, vol. 3, 2022, ISSN: 26734192 (ISSN), (Publisher: Frontiers Media S.A.).
Abstract | Links | BibTeX | Tags: craving, cue exposure, eye tracking, immersion, virtual reality
@article{simon_assessing_2022,
title = {Assessing attentional bias for alcohol-related cues using eye tracking in a virtual reality environment},
author = {J. Simon and D. Grogna and M. -C. Rivard and M. Heck and S. Bouchard and E. Quertemont},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85139027341&doi=10.3389%2ffrvir.2022.849840&partnerID=40&md5=22d08446b9b6bf184867d77efa11932a},
doi = {10.3389/frvir.2022.849840},
issn = {26734192 (ISSN)},
year = {2022},
date = {2022-01-01},
journal = {Frontiers in Virtual Reality},
volume = {3},
abstract = {Several experimental paradigms were developed to measure attentional biases towards alcohol-related cues. However, most of them are based on reaction times to two-dimensional stimuli displayed on a computer screen, such that their ecological validity has been questioned. To address this, we integrated an eye tracking system into a virtual reality headset (ET-VR) and measured attentional biases in a subclinical population of alcohol users. In this exploratory study, forty social drinkers were recruited and immersed in a virtual bar including alcohol-related stimuli. Attentional focus was assessed using dwell time and number of fixations for these alcohol-related stimuli as well as for neutral stimuli unrelated to alcohol consumption. The results show that the number of fixations and, to a lesser extent, the dwell time for alcohol-related cues were positively correlated with the drinking motivation of the participants. In contrast, no significant correlation was found for neutral stimuli. In conclusion, the present study shows that alcohol-induced attentional biases can be studied using an ET-VR device in a subclinical population of alcohol users. Copyright © 2022 Simon, Grogna, Rivard, Heck, Bouchard and Quertemont.},
note = {Publisher: Frontiers Media S.A.},
keywords = {craving, cue exposure, eye tracking, immersion, virtual reality},
pubstate = {published},
tppubtype = {article}
}
Several experimental paradigms were developed to measure attentional biases towards alcohol-related cues. However, most of them are based on reaction times to two-dimensional stimuli displayed on a computer screen, such that their ecological validity has been questioned. To address this, we integrated an eye tracking system into a virtual reality headset (ET-VR) and measured attentional biases in a subclinical population of alcohol users. In this exploratory study, forty social drinkers were recruited and immersed in a virtual bar including alcohol-related stimuli. Attentional focus was assessed using dwell time and number of fixations for these alcohol-related stimuli as well as for neutral stimuli unrelated to alcohol consumption. The results show that the number of fixations and, to a lesser extent, the dwell time for alcohol-related cues were positively correlated with the drinking motivation of the participants. In contrast, no significant correlation was found for neutral stimuli. In conclusion, the present study shows that alcohol-induced attentional biases can be studied using an ET-VR device in a subclinical population of alcohol users. Copyright © 2022 Simon, Grogna, Rivard, Heck, Bouchard and Quertemont.
2.
Blais, C.; Fiset, D.; Roy, C.; Régimbald, C. S.; Gosselin, F.
Eye fixation patterns for categorizing static and dynamic facial Expressions Journal Article
In: Emotion, vol. 17, no. 7, pp. 1107–1119, 2017, ISSN: 15283542 (ISSN), (Publisher: American Psychological Association Inc.).
Abstract | Links | BibTeX | Tags: adult, anatomy and histology, Bubbles, Dynamic, emotion, Emotions, Eye, eye fixation, Eye movements, eye tracking, Facial Expression, facial expressions, female, Fixation, human, Humans, male, Mouth, Ocular, Photic Stimulation, photostimulation, physiology, PsycINFO, stimulus, Visual strategies, Young Adult
@article{blais_eye_2017,
title = {Eye fixation patterns for categorizing static and dynamic facial Expressions},
author = {C. Blais and D. Fiset and C. Roy and C. S. Régimbald and F. Gosselin},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85016754655&doi=10.1037%2femo0000283&partnerID=40&md5=baecd8d6500d1447d48a399497611ccd},
doi = {10.1037/emo0000283},
issn = {15283542 (ISSN)},
year = {2017},
date = {2017-01-01},
journal = {Emotion},
volume = {17},
number = {7},
pages = {1107–1119},
abstract = {Facial expressions of emotion are dynamic in nature, but most studies on the visual strategies underlying the recognition of facial emotions have used static stimuli. The present study directly compared the visual strategies underlying the recognition of static and dynamic facial expressions using eye tracking and the Bubbles technique. The results revealed different eye fixation patterns with the 2 kinds of stimuli, with fewer fixations on the eye and mouth area during the recognition of dynamic than static expressions. However, these differences in eye fixations were not accompanied by any systematic differences in the facial information that was actually processed to recognize the expressions. © 2017 American Psychological Association.},
note = {Publisher: American Psychological Association Inc.},
keywords = {adult, anatomy and histology, Bubbles, Dynamic, emotion, Emotions, Eye, eye fixation, Eye movements, eye tracking, Facial Expression, facial expressions, female, Fixation, human, Humans, male, Mouth, Ocular, Photic Stimulation, photostimulation, physiology, PsycINFO, stimulus, Visual strategies, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Facial expressions of emotion are dynamic in nature, but most studies on the visual strategies underlying the recognition of facial emotions have used static stimuli. The present study directly compared the visual strategies underlying the recognition of static and dynamic facial expressions using eye tracking and the Bubbles technique. The results revealed different eye fixation patterns with the 2 kinds of stimuli, with fewer fixations on the eye and mouth area during the recognition of dynamic than static expressions. However, these differences in eye fixations were not accompanied by any systematic differences in the facial information that was actually processed to recognize the expressions. © 2017 American Psychological Association.
3.
Conti, J.; Ozell, B.; Paquette, E.; Renaud, P.
Adjusting stereoscopic parameters by evaluating the point of regard in a virtual environment Journal Article
In: Computers and Graphics (Pergamon), vol. 69, pp. 24–35, 2017, ISSN: 00978493 (ISSN), (Publisher: Elsevier Ltd).
Abstract | Links | BibTeX | Tags: Cameras, Cave automatic virtual environments, Cell proliferation, Depth of field blur, Depth-of-field blur, eye tracking, Immersive virtual environments, Inter-camera distance, Point of regard tracking, Point of regards, Research and development, Stereo image processing, Stereoscopic parameters, Subjective evaluations, virtual reality
@article{conti_adjusting_2017,
title = {Adjusting stereoscopic parameters by evaluating the point of regard in a virtual environment},
author = {J. Conti and B. Ozell and E. Paquette and P. Renaud},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032854314&doi=10.1016%2fj.cag.2017.08.017&partnerID=40&md5=529b21bdd959c209d79b5262fae53516},
doi = {10.1016/j.cag.2017.08.017},
issn = {00978493 (ISSN)},
year = {2017},
date = {2017-01-01},
journal = {Computers and Graphics (Pergamon)},
volume = {69},
pages = {24–35},
abstract = {Despite the growth in research and development in the area of virtual reality over the past few years, virtual worlds do not yet convey a feeling of presence that matches reality. This is particularly due to the difference in visual perception of flat images as compared to actual 3D. We studied the impact of two parameters of the stereoscopic configuration, namely, the inter-camera distance (ICD) and the presence of a depth of field blur (DOF blur). We conducted an experiment involving 18 participants in order to evaluate this impact, based on both subjective and objective criteria. We examined six configurations which differed in the presence or absence of DOF blur and the value of the ICD: fixed and equal to the anatomical interpupillary distance, fixed and chosen by the participant, or variable, depending on the depth of the viewer's point of regard (POR). The DOF blur and the variable ICD require the use of an eye tracking system in order to be adjusted with respect to the POR. To our knowledge, no previously published research has tested a gaze-contingent variable ICD along with dynamic DOF blur in a Cave Automatic Virtual Environment. Our results show that the anatomical and variable ICD performed similarly regarding each criterion of the experiment, both being more efficient than the fixed ICD. Besides, as with earlier similar attempts, the configurations with DOF blur obtained lower subjective evaluations. Although mainly not significant, the results obtained by the variable ICD and DOF blur are likely due to a noticeable delay in the parameters update. We also designed a new methodology to objectively compare the geometry and depth rendering, based on the reproduction of the same scene in the real and virtual setups, and then on the study of resulting ocular convergence and angular deviation from a target. This leads to a new comparative criterion for the perceptual realism of immersive virtual environments based on the visual behavior similarity between real and virtual setups. © 2017 Elsevier Ltd},
note = {Publisher: Elsevier Ltd},
keywords = {Cameras, Cave automatic virtual environments, Cell proliferation, Depth of field blur, Depth-of-field blur, eye tracking, Immersive virtual environments, Inter-camera distance, Point of regard tracking, Point of regards, Research and development, Stereo image processing, Stereoscopic parameters, Subjective evaluations, virtual reality},
pubstate = {published},
tppubtype = {article}
}
Despite the growth in research and development in the area of virtual reality over the past few years, virtual worlds do not yet convey a feeling of presence that matches reality. This is particularly due to the difference in visual perception of flat images as compared to actual 3D. We studied the impact of two parameters of the stereoscopic configuration, namely, the inter-camera distance (ICD) and the presence of a depth of field blur (DOF blur). We conducted an experiment involving 18 participants in order to evaluate this impact, based on both subjective and objective criteria. We examined six configurations which differed in the presence or absence of DOF blur and the value of the ICD: fixed and equal to the anatomical interpupillary distance, fixed and chosen by the participant, or variable, depending on the depth of the viewer's point of regard (POR). The DOF blur and the variable ICD require the use of an eye tracking system in order to be adjusted with respect to the POR. To our knowledge, no previously published research has tested a gaze-contingent variable ICD along with dynamic DOF blur in a Cave Automatic Virtual Environment. Our results show that the anatomical and variable ICD performed similarly regarding each criterion of the experiment, both being more efficient than the fixed ICD. Besides, as with earlier similar attempts, the configurations with DOF blur obtained lower subjective evaluations. Although mainly not significant, the results obtained by the variable ICD and DOF blur are likely due to a noticeable delay in the parameters update. We also designed a new methodology to objectively compare the geometry and depth rendering, based on the reproduction of the same scene in the real and virtual setups, and then on the study of resulting ocular convergence and angular deviation from a target. This leads to a new comparative criterion for the perceptual realism of immersive virtual environments based on the visual behavior similarity between real and virtual setups. © 2017 Elsevier Ltd
4.
Boukhalfi, T.; Joyal, C.; Bouchard, S.; Neveu, S. M.; Renaud, P.
Tools and techniques for real-time data acquisition and analysis in brain computer interface studies using qEEG and eye tracking in virtual reality environment Proceedings Article
In: A., Zaremba M. Sasiadek J. Dolgui (Ed.): IFAC-PapersOnLine, pp. 46–51, 2015, (ISSN: 24058963 Issue: 3).
Abstract | Links | BibTeX | Tags: Acquisition, Analysis, brain computer interface, Data acquisition, Electroencephalography, eye tracking, Eye-tracking, Forensic, Forensic engineering, Heat maps, Interfaces (computer), Psychiatry, Real time, virtual reality
@inproceedings{boukhalfi_tools_2015,
title = {Tools and techniques for real-time data acquisition and analysis in brain computer interface studies using qEEG and eye tracking in virtual reality environment},
author = {T. Boukhalfi and C. Joyal and S. Bouchard and S. M. Neveu and P. Renaud},
editor = {Zaremba M. Sasiadek J. Dolgui A.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84953850845&doi=10.1016%2fj.ifacol.2015.06.056&partnerID=40&md5=5eaa3cab6df7946f02c74e4aded68eac},
doi = {10.1016/j.ifacol.2015.06.056},
year = {2015},
date = {2015-01-01},
booktitle = {IFAC-PapersOnLine},
volume = {28},
pages = {46–51},
abstract = {In this paper, we present the pipeline of data acquisition and analysis used in the ARViPL lab at the Montreal Philippe-Pinel Institute for different studies related to forensic psychiatry in Virtual Reality (VR) environment and we discuss the different challenges that we encounter during the experiments when combining different new technologies that help researchers to better understand the underlying mechanisms of various mental health disorders. © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.},
note = {ISSN: 24058963
Issue: 3},
keywords = {Acquisition, Analysis, brain computer interface, Data acquisition, Electroencephalography, eye tracking, Eye-tracking, Forensic, Forensic engineering, Heat maps, Interfaces (computer), Psychiatry, Real time, virtual reality},
pubstate = {published},
tppubtype = {inproceedings}
}
In this paper, we present the pipeline of data acquisition and analysis used in the ARViPL lab at the Montreal Philippe-Pinel Institute for different studies related to forensic psychiatry in Virtual Reality (VR) environment and we discuss the different challenges that we encounter during the experiments when combining different new technologies that help researchers to better understand the underlying mechanisms of various mental health disorders. © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
5.
Renaud, P.; Joyal, C.; Stoleru, S.; Goyette, M.; Weiskopf, N.; Birbaumer, N.
Real-time functional magnetic imaging-brain-computer interface and virtual reality. promising tools for the treatment of pedophilia. Journal Article
In: Progress in Brain Research, vol. 192, pp. 263–272, 2011, ISSN: 00796123, (Publisher: Elsevier B.V.).
Abstract | Links | BibTeX | Tags: anterior cingulate, book, brain computer interface, brain region, cognitive therapy, electroencephalogram, eye tracking, functional magnetic resonance imaging, human, neuroanatomy, Pedophilia, Plethysmography, priority journal, Sensitivity and Specificity, sexual arousal, Sexual Behavior, sexual crime, sexual deviation, virtual reality
@article{renaud_real-time_2011,
title = {Real-time functional magnetic imaging-brain-computer interface and virtual reality. promising tools for the treatment of pedophilia.},
author = {P. Renaud and C. Joyal and S. Stoleru and M. Goyette and N. Weiskopf and N. Birbaumer},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960222279&doi=10.1016%2fB978-0-444-53355-5.00014-2&partnerID=40&md5=5d87cef8357da4e209f81c7d19b9afa2},
doi = {10.1016/B978-0-444-53355-5.00014-2},
issn = {00796123},
year = {2011},
date = {2011-01-01},
journal = {Progress in Brain Research},
volume = {192},
pages = {263–272},
abstract = {This chapter proposes a prospective view on using a real-time functional magnetic imaging (rt-fMRI) brain-computer interface (BCI) application as a new treatment for pedophilia. Neurofeedback mediated by interactive virtual stimuli is presented as the key process in this new BCI application. Results on the diagnostic discriminant power of virtual characters depicting sexual stimuli relevant to pedophilia are given. Finally, practical and ethical implications are briefly addressed. © 2011 Elsevier B.V.},
note = {Publisher: Elsevier B.V.},
keywords = {anterior cingulate, book, brain computer interface, brain region, cognitive therapy, electroencephalogram, eye tracking, functional magnetic resonance imaging, human, neuroanatomy, Pedophilia, Plethysmography, priority journal, Sensitivity and Specificity, sexual arousal, Sexual Behavior, sexual crime, sexual deviation, virtual reality},
pubstate = {published},
tppubtype = {article}
}
This chapter proposes a prospective view on using a real-time functional magnetic imaging (rt-fMRI) brain-computer interface (BCI) application as a new treatment for pedophilia. Neurofeedback mediated by interactive virtual stimuli is presented as the key process in this new BCI application. Results on the diagnostic discriminant power of virtual characters depicting sexual stimuli relevant to pedophilia are given. Finally, practical and ethical implications are briefly addressed. © 2011 Elsevier B.V.
6.
Blais, C.; Fiset, D.; Arguin, M.; Jolicoeur, P.; Bub, D.; Gosselin, F.
Reading between eye saccades Journal Article
In: PLoS ONE, vol. 4, no. 7, 2009, ISSN: 19326203.
Abstract | Links | BibTeX | Tags: adult, article, Computer Simulation, eye tracking, human, human experiment, Humans, letter, normal human, Reading, Saccades, saccadic eye movement, skill, spatial discrimination, task performance, visual stimulation, word recognition
@article{blais_reading_2009,
title = {Reading between eye saccades},
author = {C. Blais and D. Fiset and M. Arguin and P. Jolicoeur and D. Bub and F. Gosselin},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-68149091880&doi=10.1371%2fjournal.pone.0006448&partnerID=40&md5=661dc6218ea707a1934bf90a66d57051},
doi = {10.1371/journal.pone.0006448},
issn = {19326203},
year = {2009},
date = {2009-01-01},
journal = {PLoS ONE},
volume = {4},
number = {7},
abstract = {Background: Skilled adult readers, in contrast to beginners, show no or little increase in reading latencies as a function of the number of letters in words up to seven letters. The information extraction strategy underlying such efficiency in word identification is still largely unknown, and methods that allow tracking of the letter information extraction through time between eye saccades are needed to fully address this question. Methodology/Principal Findings: The present study examined the use of letter information during reading, by means of the Bubbles technique. Ten participants each read 5,000 five-letter French words sampled in space-time within a 200 ms window. On the temporal dimension, our results show that two moments are especially important during the information extraction process. On the spatial dimension, we found a bias for the upper half of words. We also show for the first time that letter positions four, one, and three are particularly important for the identification of five-letter words. Conclusions/Significance: Our findings are consistent with either a partially parallel reading strategy or an optimal serial reading strategy. We show using computer simulations that this serial reading strategy predicts an absence of a word-length effect for words from four- to seven letters in length. We believe that the Bubbles technique will play an important role in further examining the nature of reading between eye saccades. © 2009 Blais et al.},
keywords = {adult, article, Computer Simulation, eye tracking, human, human experiment, Humans, letter, normal human, Reading, Saccades, saccadic eye movement, skill, spatial discrimination, task performance, visual stimulation, word recognition},
pubstate = {published},
tppubtype = {article}
}
Background: Skilled adult readers, in contrast to beginners, show no or little increase in reading latencies as a function of the number of letters in words up to seven letters. The information extraction strategy underlying such efficiency in word identification is still largely unknown, and methods that allow tracking of the letter information extraction through time between eye saccades are needed to fully address this question. Methodology/Principal Findings: The present study examined the use of letter information during reading, by means of the Bubbles technique. Ten participants each read 5,000 five-letter French words sampled in space-time within a 200 ms window. On the temporal dimension, our results show that two moments are especially important during the information extraction process. On the spatial dimension, we found a bias for the upper half of words. We also show for the first time that letter positions four, one, and three are particularly important for the identification of five-letter words. Conclusions/Significance: Our findings are consistent with either a partially parallel reading strategy or an optimal serial reading strategy. We show using computer simulations that this serial reading strategy predicts an absence of a word-length effect for words from four- to seven letters in length. We believe that the Bubbles technique will play an important role in further examining the nature of reading between eye saccades. © 2009 Blais et al.
7.
Renaud, P.; Albert, G.; Chartier, S.; Bonin, M. -P.; DeCourville-Nicol, P.; Bouchard, S.; Proulx, J.
Mesures et rétroactions psychophysiologiques en immersion virtuelle: Le cas des réponses oculomotrices et sexuelles Proceedings Article
In: ACM International Conference Proceeding Series, pp. 175–178, Montreal, QC, 2006, ISBN: 1-59593-350-6 978-1-59593-350-8.
Abstract | Links | BibTeX | Tags: Biofeedback, Eye movements, eye tracking, Human sexuality, Immersive vault, Plethysmography, Psychophysiology, Tracking (position), virtual reality
@inproceedings{renaud_mesures_2006,
title = {Mesures et rétroactions psychophysiologiques en immersion virtuelle: Le cas des réponses oculomotrices et sexuelles},
author = {P. Renaud and G. Albert and S. Chartier and M. -P. Bonin and P. DeCourville-Nicol and S. Bouchard and J. Proulx},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250824286&doi=10.1145%2f1132736.1132762&partnerID=40&md5=86971d30c037a0b686765242a5c3e852},
doi = {10.1145/1132736.1132762},
isbn = {1-59593-350-6 978-1-59593-350-8},
year = {2006},
date = {2006-01-01},
booktitle = {ACM International Conference Proceeding Series},
volume = {133},
pages = {175–178},
address = {Montreal, QC},
abstract = {This paper presents a new paradigm in sexual and perceptual motor psychophysiology. This paradigm is based on the integration of an immersive vault, sexual plethysmography, eye tracking and a device of mediated biofeedback. © 2006 ACM.},
keywords = {Biofeedback, Eye movements, eye tracking, Human sexuality, Immersive vault, Plethysmography, Psychophysiology, Tracking (position), virtual reality},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper presents a new paradigm in sexual and perceptual motor psychophysiology. This paradigm is based on the integration of an immersive vault, sexual plethysmography, eye tracking and a device of mediated biofeedback. © 2006 ACM.
8.
Renaud, P.; Décarie, J.; Gourd, S. -P.; Paquin, L. -C.; Bouchard, S.
Eye-Tracking in Immersive Environments: A General Methodology to Analyze Affordance-Based Interactions from Oculomotor Dynamics Journal Article
In: Cyberpsychology and Behavior, vol. 6, no. 5, pp. 519–526, 2003, ISSN: 10949313 (ISSN).
Abstract | Links | BibTeX | Tags: Adaptation, article, Computer Simulation, Data Display, device, eye movement control, Eye movements, eye tracking, Fixation, Head, head movement, head position, human, human experiment, Humans, male, methodology, Models, motor performance, Movement, normal human, Ocular, perception, Physiological, Psychological, Reference Values, User-Computer Interface, virtual reality, visual information, Visual Perception, visual stimulation
@article{renaud_eye-tracking_2003,
title = {Eye-Tracking in Immersive Environments: A General Methodology to Analyze Affordance-Based Interactions from Oculomotor Dynamics},
author = {P. Renaud and J. Décarie and S. -P. Gourd and L. -C. Paquin and S. Bouchard},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0142126405&doi=10.1089%2f109493103769710541&partnerID=40&md5=ee95606b1ed832fcc154d27b22f8bd3a},
doi = {10.1089/109493103769710541},
issn = {10949313 (ISSN)},
year = {2003},
date = {2003-01-01},
journal = {Cyberpsychology and Behavior},
volume = {6},
number = {5},
pages = {519–526},
abstract = {This paper aims at presenting a new methodology to study how perceptual and motor processes organized themselves in order to achieve invariant visual information picking-up in virtual immersions. From a head-mounted display, head and eye movements were recorded using tracking devices (magnetic and infrared) that render the six degrees-of-freedom associated with the position and orientation of head movements, and two degrees-of-freedom from one eye. We measured the continuous line of sight's deviation from a pre-selected area on a virtual stimulus. Some preliminary analyses of the dynamical properties of the emergent perceptual and motor patterns are presented as they are considered to be representative of the process of affordance extraction.},
keywords = {Adaptation, article, Computer Simulation, Data Display, device, eye movement control, Eye movements, eye tracking, Fixation, Head, head movement, head position, human, human experiment, Humans, male, methodology, Models, motor performance, Movement, normal human, Ocular, perception, Physiological, Psychological, Reference Values, User-Computer Interface, virtual reality, visual information, Visual Perception, visual stimulation},
pubstate = {published},
tppubtype = {article}
}
This paper aims at presenting a new methodology to study how perceptual and motor processes organized themselves in order to achieve invariant visual information picking-up in virtual immersions. From a head-mounted display, head and eye movements were recorded using tracking devices (magnetic and infrared) that render the six degrees-of-freedom associated with the position and orientation of head movements, and two degrees-of-freedom from one eye. We measured the continuous line of sight's deviation from a pre-selected area on a virtual stimulus. Some preliminary analyses of the dynamical properties of the emergent perceptual and motor patterns are presented as they are considered to be representative of the process of affordance extraction.