Squeezing Uncertainty from Saccadic Compression

Brief visual stimuli presented before and during a saccade are often mislocalized due to spatial compression. This saccadic compression effect is thought to have a perceptual basis, and results in visual objects being squeezed together and their number underestimated. Here we show that observers are also uncertain about their visual experiences just before and during a saccade. It is known that responses tend to be biased away from extreme values under conditions of uncertainty. Thus, a plausible alternative explanation of compression is that it reflects the uncertainty-bias to underestimate the number of items that were presented. We test this hypothesis and find that saccadic compression is independent of certainty, and is significantly modulated by orientation, with larger effects for stimuli oriented horizontally, in the direction of the saccade. These findings confirm that saccadic compression is a perceptual phenomenon that may enable seamless perceptual continuity across saccades

Saccadic Behavior during the Response to Pure Vergence Stimuli I: General Properties

If two targets are carefully aligned so that they fall along the cyclopean axis, the required eye movement will be symmetrical with the two eyes turning equally inward or outward. When such “pure vergence stimuli” are used only a “pure vergence movement” is required, yet almost all responses include saccadic eye movements, a rapid tandem movement of the eyes. When saccades occur, they must either produce an error in the desired symmetrical response or correct an error from an asymmetrical vergence response. A series of eye movement responses to pure convergence stimuli (4.0 deg step stimuli) were measured in 12 subjects and the occurrence, timing and amplitude of saccades was measured. Early saccades (within 400 msec of the stimulus onset) appeared in 80% to 100% of the responses. In most subjects, the first saccade increased the asymmetry of the response, taking the eyes away from the midline position. In three subjects, these asymmetry-inducing saccades brought one eye, the preferred or dominant eye, close to the target, but in the other subjects these asymmetry-inducing saccades were probably due to the distraction caused by the transient diplopic image generated by a pure vergence stimulus. While many of these asymmetry-inducing saccades showed saccade-like enhancements of vergence, they were, with the exception of two subjects, primarily divergent and did not facilitate the ongoing convergence movement. All subjects had some responses where the first saccade improved response symmetry, correcting an asymmetry brought about by unequal vergence movements in the two eyes. In five subjects, large symmetry-inducing saccades corrected an asymmetrical vergence response, bringing the eyes back to the midline (to within a few tenths of a degree)

Why do we look at people\u27s eyes?

oai:ojs.bop.unibe.ch:article/2231We have previously shown that when observers are presented with complex natural scenes that contain a number of objects and people, observers look mostly at the eyes of the people. Why is this? It cannot be because eyes are merely the most salient area in a scene, as relative to other objects they are fairly inconspicuous. We hypothesized that people look at the eyes because they consider the eyes to be a rich source of information. To test this idea, we tested two groups of participants. One set of participants, called the Told Group, was informed that there would be a recognition test after they were shown the natural scenes. The second set, the Not Told Group, was not informed that there would be a subsequent recognition test. Our data showed that during the initial and test viewings, the Told Group fixated the eyes more frequently than the Not Told group, supporting the idea that the eyes are considered an informative region in social scenes. Converging evidence for this interpretation is that the Not Told Group fixated the eyes more frequently in the test session than in the study session

Abstracts of the 13th European Conference on Eye Movements 2005

This issue contains the abstracts submitted for presentation at the Thirteenth European Conference on Eye Movements (ECEM13), Bern, August 14 – 18, 2005, and reviewed by the Scientific Board, consisting of W. Becker, Ulm; C.J. Erkelens, Utrecht; J.M. Findlay, Durham; A.G. Gale, Derby; C.W. Hess, Bern; J. Hyönä, Turku; A. Kennedy, Dundee; K. Koga, Nagoya; G. Lüer, Göttingen; M. Menozzi, Zürich; W. Perrig, Bern; G. d’Ydewalle, Leuven; D. Zambarbieri, Pavia. A quarter of a century ago, in 1980 initiated by Rudolf Groner and Dieter Heller, a transdisciplinary network called European Group of Scientists active in Eye Movement Research was founded. This group included scientists who used eye movement registration as a research tool and developed models based on oculomotor data obtained from a wide spectrum of phenomena, ranging from the neurophysiological to the perceptual and the cognitive level. The group was intended to serve the purpose of (1) exchanging information about current research, equipment and software, (2) organizing a conference (ECEM) at a different location all over Europe every other year. Over the years ECEM has grown. At the first conference in Bern the relatively small number of participants made it possible for the organisers to avoid conflicting parallel sessions, whereas with the ECEM’s steady growth, the introduction of parallel sessions soon became necessary. Although we are very happy about this year’s new record of 273 scientific contributions, we regret at the same time that this large number of participants necessitated the introduction of no less than four parallel sessions for oral presentations. Part of the ECEM culture are the books with a selection of edited contributions which have traditionally always been published after the conferences. Unfortunately, over the years the sale prices of books have become prohibitively expensive and book chapters have increasingly been given a low rating in comparison to publications in peer reviewed journals. As a consequence of this trend, we are now considering to launch an online journal Eye Movement Research which would publish scientific papers either on the base of individual submissions by the authors or as a follow-up of workshops or thematic sessions at ECEM. In either case, a fair peer reviewing process should guarantee a high quality of the contributions. Acknowledgements Last but not least, we are happy to express our deep gratitude to the main sponsors of our conference and to all the people who helped to keep it going. The Max and Elsa Beer-Brawand Foundation generously funded the invited speakers. The Swiss Academy of Humanities and Social Sciences (SAGW) sponsored the organization of workshops and made it possible for us to reduce fees for students. Novartis Neuroscience sponsored the reception at the Zentrum Paul Klee Bern. The University of Bern hosted the conference in its magnificent historical building. A team of devoted young scientists acted as staff during the conference: Eva Siegenthaler, Liliane Braun, Miriam Lörtscher, Esther Schollerer, Daniel Stricker, Simon Raess, Philipp Sury, Bartholomäus Wissmath, Linda Bodmer, Martina Brunnthaler, Daniela Häberli, Nadine Messerli, Felicie Notter, Didier Plaschy, Svetlana Ognjanovi, David Weibel, Yves Steiner and Dominik Moser. We dedicate this book to the memory of two important men in eye movement research: Dieter Heller as one of the founders of the ECEM group, and Lawrence W. Stark as pioneer in cognitive modelling of oculomotor control. In an early planning stage of ECEM13 both had been invited as keynote speakers, but their untimely death made this plan impossible. In many sessions of ECEM13 the influence of their work will prevail

Schedule of the 13th European Conference on Eye Movements 2005

This document contains the schedule of the 13th European Conference on Eye Movements, August 14-18 2005 in Bern, Switzerlan

Abstracts of the 16th European Conference on Eye Movements 2011

This document contains all abstracts of the 16th European Conference on Eye Movements, August 21-25 2011 in Marseille, France. It was a real honour and a great pleasure to welcome more than 500 delegates to Marseille for the 16th edition of the European Conference on Eye Movements. The series of ECEM conferences started in 1981 under the auspices of Rudolf Groner in Bern. This year, we therefore celebrated the 30th Anniversary of ECEM. For this special occasion we had as a special guest Rudolf Groner, and honoured Alan Kennedy and George W. McConkie for their contributions to our field in two special symposia. We had the pleasure of listening to six keynote lectures given respectively by Patrick Cavanagh, Ralf Engbert, Edward L. Keller, Eileen Kowler, Rich Krauzlis and Gordon E. Legge. These exceptional scientific events were nicely complemented by all submissions, which made the ECEM 2011 program a very rich and interdisciplinary endeavor, comprising 19 symposia, 243 talks and 287 poster presentations, and a total of about 550 participants. The conference opened with an address given by Denis Bertin, vice president of the scientific committee of the University of Provence, and representing Jean-Paul Caverni, President of the University of Provence. It closed with Rudolf Groner’s address and the awarding of the best poster contributions by students and postdocs. This year, three posters were awarded; the first prize was offered by SR Research, the second prize was given by the Cognitive Science Society, and the third, the Rudolf Groner Prize, was offered by the ECEM organizing committee. The conference was held on the St Charles campus of the University of Provence, and to mark the return of ECEM in Southern Europe, many events including lunches, coffee breaks, aperitifs and poster sessions took place outside under the trees of our campus. Luckily, the sun was with us for the five days of the conference ! Françoise, Stéphanie, Stéphane, Eric & Lauren

Author index of the 16th European Conference on Eye Movements 2011

This document contains the author index of the 16th European Conference on Eye Movements, August 21-25 2011 in Marseille, Franc