Fixation sequences made during visual examination of briefly presented 2D images

Abstract

Eye movements made by eighteen observers in response to brief (3 s) presentations of eleven different images, each in three forms (unfiltered, high-pass filtered and low-pass filtered), have been analysed in order to identify both repeated sequences of fixations and image locations which attract re-fixations. It is shown that eye-movement traces made by different observers in response to the same image have few common temporal sequences involving the same fixation locations, even for sequences of only two fixations. There is a greater incidence of such sequences in eye-movement traces made by the same observer in response to two presentations of the same image, but average numbers are still low. Conserved sequences involving more than two identical locations occur at a much lower frequency, and the incidence of repeated sequences is not increased if consideration is restricted to regions of the image which attract large numbers of fixations. It is concluded that the temporal sequence in which fixations are made is not a significant factor in the analysis of the eye-movement data considered in this report. Calculations based on a least squares index of similarity are consistent with this conclusion. The analysis shows a relatively high incidence of re-fixation on certain locations in the images and there is evidence that such re-fixations are a significant factor in the high similarity between fixation locations established by different observers when viewing the same image.

Visual saliency does not account for eye movements during visual search in real-world scenes

“…Image statistics of areas selected for eye fixation within scenes differ in systematic ways from areas that are not fixated. A possible interpretation of these results is that fixation position can be accounted for by low-level image statistics (Krieger et al, 2000;Mannan et al, 1995Mannan et al, , 1996Mannan et al, , 1997aParkhust & Niebur, 2003;Reinagel & Zador, 1999). The present results, however, call this interpretation into question.…”

“…Several studies have demonstrated that the image properties of fixated regions tend to differ in systematic ways from regions that are not fixated (Krieger et al, 2000;Mannan, et al, 1995Mannan, et al, , 1996Mannan, Ruddock, & Wooding, 1997a;Parkhurst & Niebur, 2003;Reinagel & Zador, 1999). Specifically, fixated scene regions tend to be lower in intensity but higher in edge density and local contrast, and are more likely to contain third-order spatial relationships such as T-junctions and curves, than non-fixated regions.…”

An evaluation of scanpath-comparison and machine-learning classification algorithms used to study the dynamics of analogy making

“…These algorithms compare two scanpaths by computing how long various locations are looked at, how far each fixation point in one scanpath is from the closest fixation point in the other scanpath, and so forth. One of the earliest algorithms based on attention measures is the Mannan distance algorithm (Mannan, Ruddock, & Wooding, 1997). However, this class of scanpath-comparison techniques has a number of drawbacks-most importantly for our purposes, the temporal order of fixations is lost.…”

Do object refixations during scene viewing indicate rehearsal in visual working memory?

“…Refixations are operationally defined as a shift in gaze back to the target object before the scene-terminating intervening-object criterion was achieved. We isolated and analyzed those trials in which observers made at least one target refixation and found an overall refixation rate of 35%, a rate somewhat higher than is typically found in visual search or picture viewing tasks (Dickinson & Zelinsky, 2005;Mannan et al, 1997). This refixation rate also varied with intervening-object condition.…”

“…Refixations are a ubiquitous property of normal gaze behavior and have been noted in tasks as diverse as reading (Rayner, 1978(Rayner, , 1998, pattern copying or block sorting (Ballard, Hayhoe, & Pelz, 1995;Droll & Hayhoe, 2007;Hayhoe, Bensinger, & Ballard, 1998), portrait painting (Locher, 1996;Nodine, Locher, & Krupinski, 1993), solving arithmetic and geometry problems (Epelboim & Suppes, 1996;Hegarty, Mayer, & Green, 1992), visual search (Gilchrist & Harvey, 2000;Peterson, Kramer, Wang, Irwin, & McCarley, 2001), and undirected picture viewing (Mannan, Ruddock, & Wooding, 1996, 1997. Refixations can also comprise a significant portion of the gaze behavior accompanying a task-by one estimate, up to 25% of the observed fixations (Mannan et al, 1997).…”