Journal of Eye Movement Research

12 pages, 700 KiB

Open AccessArticle

Fixation Region Overlap: A Quantitative Method for the Analysis of Fixational Eye Movement Patterns

by Stephen J. Johnston and E. Charles Leek

J. Eye Mov. Res. 2007, 1(3), 1-12; https://doi.org/10.16910/jemr.1.3.5 - 9 Feb 2009

Cited by 2 | Viewed by 48

This article presents a new method for the quantitative analyses of fixation patterns in eye tracking data. The Fixation Region Overlap Analysis (FROA) uses thresholded spatial distributions of fixation frequency or duration to determine regions-of-interest (ROIs). The locations of these ROIs are contrasted with fixation regions of other empirically-derived, or modeled, data patterns by comparing region pixel overlap. A Monte Carlo procedure is used to assess the statistical significance of fixation region overlap based on 95% confidence intervals (C.I.) of the distribution of random overlap for each set of thresholded ROIs. The value of the FROA method is demonstrated by applying it to data acquired in an object recognition task to determine which of two potential models best account for the observed fixation patterns. Full article

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7 pages, 733 KiB

Open AccessArticle

Probing Bottom-Up Processing with Multistable Images

by Ozgur E. Akman, Richard A. Clement, David S. Broomhead, Sabira Mannan, Ian Moorhead and Hugh R. Wilson

J. Eye Mov. Res. 2007, 1(3), 1-7; https://doi.org/10.16910/jemr.1.3.4 - 9 Feb 2009

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Abstract

The selection of fixation targets involves a combination of top-down and bottom-up processing. The role of bottom-up processing can be enhanced by using multistable stimuli because their constantly changing appearance seems to depend predominantly on stimulusdriven factors. We used this approach to investigate whether visual processing models based on V1 need to be extended to incorporate specific computations attributed to V4. Eye movements of 8 subjects were recorded during free viewing of the Marroquin pattern in which illusory circles appear and disappear. Fixations were concentrated on features arranged in concentric rings within the pattern. Comparison with simulated fixation data demonstrated that the saliency of these features can be predicted with appropriate weighting of lateral connections in existing V1 models. Full article

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12 pages, 211 KiB

Open AccessArticle

Effects of Aging on Regular and Express Latencies of Vergence

by Qing Yang, Thanh-Thuan Lê and Zoi Kapoula

J. Eye Mov. Res. 2007, 1(3), 1-12; https://doi.org/10.16910/jemr.1.3.3 - 15 Jan 2009

Cited by 3 | Viewed by 48

Abstract

Vergence eye movements are frequent in every day life and important for depth perception. Yet, studies of vergence in elderly are rare. We examined convergence and divergence between targets placed along median line at 20, 40 or 150 cm. Thirteen elderly (70 ± 11 years) and ten young (25 ± 3 years) adults participated in the study. The gap paradigm (i.e., the fixed stimulus is extinguished prior to target onset) and the overlap paradigm (the fixed stimulus remains illuminated after target onset) were used to elicit reflexive or voluntary eye movements. Latency of convergence and divergence increased with age in both gap and overlap conditions. Both young subjects and elderly showed shorter latency of vergence under the gap condition than under the overlap condition. In the overlap condition, for elderly only, convergence resulted in longer latencies than divergence. In the gap condition express convergence was rare, while express latencies (80–120 ms) were frequent for divergence starting from a near fixation point (at 20 cm). The rates of express divergence were similar for young (23%) and elderly (21%). These results were in line with prior studies of saccades and indicated different aging effects on regular and express latencies. Full article

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14 pages, 713 KiB

Open AccessArticle

Multimodal Comprehension of Language and Graphics: Graphs with and Without Annotations

by Cengiz Acarturk, Christopher Habel, Kursat Cagiltay and Ozge Alacam

J. Eye Mov. Res. 2007, 1(3), 1-14; https://doi.org/10.16910/jemr.1.3.2 - 26 Nov 2008

Cited by 8 | Viewed by 49

Abstract

An experimental investigation into interaction between language and information graphics in multimodal documents served as the basis for this study. More specifically, our purpose was to investigate the role of linguistic annotations in graph-text documents. Participants were presented with three newspaper articles in the following conditions: one text-only, one text plus non-annotated graph, and one text plus annotated graph. Results of the experiment showed that, on one hand, annotations play a bridging role for integration of information contributed by different representational modalities. On the other hand, linguistic annotations have negative effects on recall, possibly due to attention divided by the different parts of a document. Full article

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8 pages, 1183 KiB

Open AccessArticle

Microsaccade-Induced Prolongation of Saccade Latencies Depends on Microsaccade Amplitude

by Martin Rolfs, Jochen Laubrock and Reinhold Kliegl

J. Eye Mov. Res. 2007, 1(3), 1-8; https://doi.org/10.16910/jemr.1.3.1 - 18 Sep 2008

Cited by 14 | Viewed by 43

Abstract

Fixations consist of small movements including microsaccades, i.e., rapid flicks in eye position that replace the retinal image by up to 1 degree of visual angle. Recently, we showed in a delayed-saccade task (1) that the rate of microsaccades decreased in the course of saccade preparation and (2) that microsaccades occurring around the time of a go signal were associated with prolonged saccade latencies (Rolfs et al., 2006). A re-analysis of the same data set revealed a strong dependence of these findings on microsaccade amplitude. First, microsaccade amplitude dropped to a minimum just before the generation of a saccade. Second, the delay of response saccades was a function of microsaccade amplitude: Microsaccades with larger amplitudes were followed by longer response latencies. These finding were predicted by a recently proposed model that attributes microsaccade generation to fixation-related activity in a saccadic motor map that is in competition with the generation of large saccades (Rolfs et al., 2008). We propose, therefore, that microsaccade statistics provide a behavioral correlate of fixation-related activity in the oculomotor system. Full article

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J. Eye Mov. Res., Volume 1, Issue 3 (February 2007) – 5 articles

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