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Perception, 2008, volume 37, supplement, pages 1 ^ 180 Thirty-first European Conference on Visual Perception Utrecht, The Netherlands 24 ^ 28 August 2008 Abstracts SUNDAY WEDNESDAY The Perception Lecture (I P Howard) 1 ORAL PRESENTATIONS Objects and shapes 88 MONDAY Shifts and distribution of spatial attention 89 ORAL PRESENTATIONS POSTERS Binocular processing 1 Analogous concepts in haptics and vision 91 Low-level processes of attention and 3 Attention and related issues 93 modelling Binocular vision and spatial localisation 99 POSTERS Clinical aspects 103 Analogous concepts in haptics and vision 5 Colour and brightness 104 Attention and related issues 7 Eye, hand and body movements 107 Binocular vision and spatial localisation 13 Motion perception and temporal issues 110 Clinical aspects 16 Objects, faces and shapes 115 Colour and brightness 18 Segmentation and grouping 121 Eye, hand and body movements 21 ORAL PRESENTATIONS Motion perception and temporal issues 25 Binocular depth perception 123 Objects, faces and shapes 30 Objects/shape perception 125 Segmentation and grouping 36 MARBURG + 30 126 ORAL PRESENTATIONS Constructing the visual world 127 Brightness 38 Object motion and optic flow 40 THURSDAY Visually guided hand and body motion 41 ORAL PRESENTATIONS Clinical vision 43 Binocular space perception 130 Saccades and perception 131 TUESDAY POSTERS ORAL PRESENTATIONS Analogous concepts in haptics and vision 133 Temporal structuring of attention 45 Attention and related issues 135 and memory Binocular vision and spatial localisation 141 Objects, faces and shapes 46 Clinical aspects 144 POSTERS Colour and brightness 145 Analogous concepts in haptics and vision 48 Eye, hand and body movements 149 Attention and related issues 50 Motion perception and temporal issues 152 Binocular vision and spatial localisation 56 Objects, faces and shapes 157 Clinical aspects 60 Segmentation and grouping 163 Colour and brightness 61 ORAL PRESENTATIONS Motion perception and temporal issues 67 Motion 165 Objects, faces and shapes 73 Objects and shapes 166 Segmentation and grouping 78 Synaesthesia 168 ORAL PRESENTATIONS Crowding 169 Segmentation, grouping and crowding 81 Erratum 172 Motion and temporal issues 82 Colour 84 Author index 173 Aftereffects and adaptation 85 The Rank Lecture 87 Publisher's note The abstracts in this year's ECVP supplement have been published with virtually no copy editing by Pion, thus the standards of grammar and style may not match those of regular Perception articles. Local organisers Frans Verstraten (coordinator) Raymond van Ee Chris Paffen Bert van den Berg Casper Erkelens Susan te Pas Eli Brenner Wim van de Grind Maarten van der Smagt Anne-Marie Brouwer Ignace Hooge Richard van Wezel Abstract referees Tiziano Agostini Andrew Glennerster Marc de Lussanet Ben Backus Denise de Grave Stephen Macknik Rob van Beers Mark Greenlee Donald MacLeod Bert van den Berg Michael Herzog Pascal Mamassian Frank Bremmer Paul Hibbard Susana Martinez-Conde Eli Brenner Ian Howard Robert O'Shea Heinrich Bu« lthoff Alumit Ishai Thomas Papathomas Olivia Carter Ryota Kanai Frank Pollick Eric Castet Astrid Kappers Sylvia Pont Frans Cornelissen Dirk Kerzel Mathijs Raemaekers Loes van Dam Chris Klink Jenny Read Fulvio Domini Arni Kristjansson Dave Rose Mark Edwards Juergen Kornmeier Kai Schreiber Raymond van Ee Zoe Kourtzi Jan Souman Casper Erkelens David Knill Jim Todd Marc Ernst Martin Lages Nick Wade Manfred Fahle Markus Lappe Charles de Weert Roland Fleming Timothy Ledgeway Andrew Welchman Tom Freeman Luz Leiros Richard van Wezel David Foster Joan Lopez-Moliner Johannes Zanker Mark Georgeson Marcel Lucassen Suncica Zdravkovic Supporting organisations Association for Biophysics & Biomedical Technology (Vereniging voor Biofysica & Biomedisch Technologie) (www.vvb-bmt.nl) Cambridge Research Systems (www.crsltd.com) Dimensional Imaging (www.di3d.com) Dutch Psychonomics Society (Nederlandse Vereniging voor Psychonomie, NVP) (nvp.nici.kun.nl) Helmholtz Institute (www.phys.uu.nl/wwwfm) KyberVision (www.kybervision.com) MIT Press (www.mitpress-mit.edu) Netherlands Organisation for Scientific Research (NWO) (www.nwo.nl) Oxford University Press (www.oup.co.uk) Pion Ltd (www.pion.co.uk) SensoMotoric Instruments GmbH (www.smivision.com) Smart Eye (www.smarteye.se) SR Research Ltd (www.sr-research.com) The Rank Prize Funds University museum Utrecht (www.museum.uu.nl) Utrecht University (www.uu.nl) ECVP The European Conference on Visual Perception is an annual event. Previous conferences took place in: 1978 Marburg (D) 1986 Bad Nauheim (D) 1994 Eindhoven (NL) 2002 Glasgow (GB) 1979 Noordwijkerhout (NL) 1987 Varna (BG) 1995 Tu« bingen (D) 2003 Paris (F) 1980 Brighton (GB) 1988 Bristol (GB) 1996 Strasbourg (F) 2004 Budapest (H) 1981 Gouvieux (F) 1989 Zichron Yaakov (IL) 1997 Helsinki (FI) 2005 A Corun¬ a(E) 1982 Leuven (B) 1990 Paris (F) 1998 Oxford (GB) 2006 St Petersburg (RU) 1983 Lucca (I) 1991 Vilnius (LT) 1999 Trieste (I) 2007 Arezzo (I) 1984 Cambridge (GB) 1992 Pisa (I) 2000 Groningen (NL) 1985 Pen¬ iscola (E) 1993 Edinburgh (GB) 2001 Kus°adas| (TR) ß 2008 a Pion publication printed in Great Britain The Perception Lecture; Binocular processing 1 Sunday/Monday ECVP '08 Abstracts SUNDAY THE LECTURE ^Exploringmotionindepthwiththedichoptiscope I P Howard (Centre for Vision Research, York University, Toronto, Canada; e-mail: [email protected]) I have constructed an instrument that provides independent control of all cues to motion in depth. I call it the dichoptiscope. A conventional stereoscope combines disparate 2-D images. The dichoptiscope modulates the disparity of a real 3-D object, leaving accommodation and motion parallax normal. Two identical 3-D image objects are viewed through 458 mirrors to form a binocular object. Each image object moves in depth along a track within arm's reach. Vergence (absolute disparity) is controlled by changing the angle between each track and the midline. Internal relative disparity is controlled by rotating the image objects in opposite directions as they move along the tracks. External relative disparity is controlled by adding a stationary object. Looming is controlled by the velocity of motion or by using radial stimuli that do not loom. I have used the instrument to investigate the relative strengths of these cues to motion in depth. Perceived motion in depth was indicated by the tracking motion of the unseen hand. Looming was the dominant cue but changing vergence was an effective cue when looming was neutralized. Constancy of the perceived 3-D shape of an object requires that we scale rela- tive disparity by perceived distance. I am now using the dichoptiscope to investigate the stimulus factors that allow a person to achieve depth constancy in an approaching object. I will report whatever results I have obtained by the time of the conference. MONDAY ORAL PRESENTATIONS BINOCULAR PROCESSING ^ A common factor underlying binocular rivalry and dichoptic masking D H Baker, E W Graf (School of Psychology, University of Southampton, UK; e-mail: [email protected]) When incompatible images are shown to the two eyes, two empirical phenomena are observed: monocular detection thresholds are elevated (dichoptic masking) and the perceived image changes over time (binocular rivalry). It has recently been shown [van Boxtel et al, 2007 Journal of Vision 7(14.3)] that these two phenomena have similar perceptual dynamics when images are presented successively. Here, we report a common underlying factor between rivalry and dichoptic masking during simultaneous presentation. Using orthogonal Gabor patches (2 cycles deg1 ) we measured threshold elevation for dichoptic masking, as well as the mean dominance duration of binocular rivalry, in a group of forty-one subjects. Both threshold eleva- tion and dominance durations varied substantially across observers, and were highly correlated (r 0:44, p 5 0:01) such that stronger dichoptic masking was associated with longer dominance durations. Within subjects, we also varied the angle between dichoptic Gabors, producing a similar pattern of results. These findings are accounted for by a single computational model in which the weight of interocular suppression determines both threshold elevation and dominance durations. [Supported by BBSRC grant no BB-E012698-1.] ^ Illusory size changes influence the tuning of spatial coding interactions D H Arnold, A Birt, T S A Wallis (School of Psychology, The University of Queensland, Australia; e-mail: [email protected]) Images of the same physical dimensions on the retina can appear to represent different sized objects. One reason for this is that the human visual system can take viewing distance into account when judging apparent size. Sequentially presented images can also prompt spatial coding interactions. Here we show, using a spatial coding phenomenon (the tilt after-effect) in tandem with viewing distance cues, that the tuning of such interactions is not simply determined by the physical dimensions of retinal input. Rather, we find that they are contingent upon 2 Binocular processing Monday apparent size. Our data therefore reveal that spatial coding interactions in human vision are modulated by processes involved in the determination of apparent size. [Supported by a Discovery Project Grant awarded to DHA by the Australian Research Council.] ^ Sound induces binocular rivalry alternations A Parker, D Alais (Department of Psychology, University of Sydney, Australia; e-mail: [email protected]) Binocular rivalry