The effect of the first glimpse at a scene on eye movements during search

Abstract

Previewing scenes briefly makes finding target objects more efficient when viewing is through a gazecontingent window (windowed viewing). In contrast, showing a preview of a randomly arranged search display does not benefit search efficiency when viewing during search is of the full display. Here, we tested whether a scene preview is beneficial when the scene is fully visible during search. Scene previews, when presented, were 250 ms in duration. During search, the scene was either fully visible or windowed. A preview always provided an advantage, in terms of decreasing the time to initially fixate and respond to targets and in terms of the total number of fixations. In windowed visibility, a preview reduced the distance of fixations from the target position until at least the fourth fixation. In full visibility, previewing reduced the distance of the second fixation but not of later fixations. The gist information derived from the initial glimpse of a scene allowed for placement of the first one or two fixations at information-rich locations, but when nonfoveal information was available, subsequent eye movements were only guided by online information.

Worth a quick look? Initial scene previews can guide eye movements as a function of domain-specific expertise but can also have unforeseen costs.

“…The scene preview benefit has so far been demonstrated as a robust effect that diminishes after the first few fixations (Hillstrom et al, 2012). However, like Experiment 1, in all FPMW studies different scenes and targets are used across trials and this maximises the advantage of the scene preview.…”

“…To assess the efficiency of search as a function of preview and expertise, we examined the time until first target fixation (search latency) and number of fixations until first target fixation. We also examined the initial saccadic latency and initial saccadic amplitude of the first eye movement as these measures represent the first response relating to the rapid processing of the scene preview and the readiness to initiate search (Hillstrom, et al, 2012;Võ & Henderson, 2010; for a recent medical imaging equivalent, see Pietrzyk, McEntee, Evanoff, Brennan, & Mello-Thoms, 2014).…”

Looking for Cancer: Expertise Related Differences in Searching and Decision Making

“…This one second difference may not seem much, but given that the advantage of the initial glimpse diminishes quickly with time and each successive fixation (Hillstrom et al, 2012), this may in fact be crucial in highlighting the problem of associating Visual Scanning Behaviour -15 -time-to-first hit with mechanistic explanations involving holistic processing, and particularly in chest x-ray studies where abnormal regions are not immediately fixated.…”

“…Whilst it is likely that both processes are running in parallel, the timings of such processes involve clear differences in perceptual and cognitive involvement (e.g., Wolfe et al, 2011). Moreover, the advantage in fixation guidance based on the holistic processing of the initial glimpse would likely diminish with time, and this has recently found to be the case; the initial glimpse facilitates up to the fourth fixation (Hillstrom, Schloley, Liversedge, & Benson 2012). Therefore, any supposed links of time-to-first hit with holistic processing would depend on the speed and difficulty of finding the abnormal regions within this time.…”

The Flash-Preview Moving Window Paradigm: Unpacking Visual Expertise One Glimpse at a Time

“…Although 250ms is the standard preview duration, previews as short as 75ms can lead to search advantages compared to no preview conditions, and even as low as 50ms, provided the integration time between scene preview, target word and search was extended from 500ms to 3000ms (Võ & Henderson, 2010). Moreover, preview benefits in search diminish with time, and in fact, the benefit of an initial glimpse of a scene facilitates search only up to the fourth fixation (Hillstrom, Schloley, Liversedge, & Benson, 2012). Indeed, based on these latter FPMW findings we argued that the benefit of the initial glimpse in medical image perception would depend on the difficulty of finding abnormalities within this short time-frame (Donovan & Litchfield, 2013).…”