Using a model of hypothesis generation to predict eye movements in a visual search task (original) (raw)
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What do eye movements reveal about the role of memory in visual search
Quarterly Journal of Experimental Psychology, 2007
have challenged the view that serial visual search involves memory processes that keep track of already inspected locations. The present study used a search paradigm similar to Horowitz and Wolfe's (1998), comparing a standard static search condition with a dynamic condition in which display elements changed locations randomly every 111 ms. In addition to measuring search reaction times, observers' eye movements were recorded. For target-present trials, the search rates were near-identical in the two search conditions, replicating Horowitz and Wolfe's findings. However, the number of fixations and saccade amplitude were larger in the static than in the dynamic condition, whereas fixation duration and the latency of the first saccade were longer in the dynamic condition. These results indicate that an active, memory-guided search strategy was adopted in the static condition, and a passive "sit-and-wait" strategy in the dynamic condition.
Journal of Experimental Psychology: Human Perception and Performance, 2006
Paying attention to an object facilitates its storage in working memory. The authors investigate whether the opposite is also true: whether items in working memory influence the deployment of attention. Participants performed a search for a prespecified target while they held another item in working memory. In some trials this memory item was present in the search display as a distractor. Such a distractor has no effect on search time if the search target is in the display. In that case, the item in working memory is unlikely to be selected as a target for an eye movement, and if the eyes do land on it, fixation duration is short. In the absence of the target, however, there is a small but significant effect of the memory item on search time. The authors conclude that the target for visual search has a special status in working memory that allows it to guide attention. Guidance of attention by other items in working memory is much weaker and can be observed only if the search target is not present in the display.
Eye Tracking in Visual Search Experiments
Spatial Learning and Attention Guidance
Over the last 30 years, eye tracking has grown in popularity as a method to understand attention during visual search, principally because it provides a means to characterize the spatiotemporal properties of selective operations across a trial. In the present chapter, we review the motivations, methods, and measures for using eye tracking in visual search experiments. This includes a discussion of the advantages (and some disadvantages) of eye tracking data as a measure spatial attention, compared with more traditional reaction time paradigms. In addition, we discuss stimulus and design considerations for implementing experiments of this type. Finally, we will discuss the major measures that can be extracted from an eye tracking record and discuss the inferences that each allow. In the course of this discussion, we address both experiments using abstract arrays and experiments using real-world scene stimuli.
Looking versus seeing: Strategies alter eye movements during visual search
2010
Visual search can be made more efficient by adopting a passive cognitive strategy (i.e., letting the target "pop" into mind) rather than by trying to actively guide attention. In the present study, we examined how this strategic benefit is linked to eye movements. Results show that participants using a passive strategy wait longer before beginning to move their eyes and make fewer saccades than do active participants. Moreover, the passive advantage stems from more efficient use of the information in a fixation, rather than from a wider attentional window. Individual difference analyses indicate that strategies also change the way eye movements are related to search success, with a rapid saccade rate predicting success among active participants, and fewer and larger amplitude saccades predicting success among passive participants. A change in mindset, therefore, alters how oculomotor behaviors are harnessed in the service of visual search.
In sight, out of mind: The role of eye movements in the rapid resumption of visual search
Perception & Psychophysics, 2007
Three experiments investigated the role of eye movements in the rapid resumption of an interrupted search. Passive monitoring of eye position in Experiment 1 showed that rapid resumption was associated with a short distance between the eye and the target on the next-to-last look before target detection. Experiments 2 and 3 used two different methods for presenting the target to the point of eye fixation on some trials. If eye position alone is predictive, rapid resumption should increase when the target is near fixation. The results showed that gaze-contingent targets increased overall search success, but that the proportion of rapid responses decreased dramatically. We conclude that rather than depending on a high-quality single look at a search target, rapid resumption of search depends on two glances; a first glance in which a hypothesis is formed, and a second glance in which the hypothesis is confirmed.
Subjective report of eye fixations during serial search
Consciousness and Cognition, 2015
Humans readily introspect upon their thoughts and their behavior, but how reliable are these subjective reports? In the present study, we explored the consistencies of and differences between the observer's subjective report and actual behavior within a single trial. On each trial of a serial search task, we recorded eye movements and the participants' beliefs of where their eyes moved. The comparison of reported versus real eye movements revealed that subjects successfully reported a subset of their eye movements. Limits in subjective reports stemmed from both the number and the type of eye movements. Furthermore, subjects sometimes reported eye movements they actually never made. A detailed examination of these reports suggests that they could reflect covert shifts of attention during overt serial search. Our data provide quantitative and qualitative measures of observers' subjective reports and reveal experimental effects of visual search that would otherwise be inaccessible.
Memory models of visual search - searching in-the-head vs. in-the-world?
Journal of Vision, 2010
Visual search takes place whenever we are looking for something. But when a stimulus has been visually encoded on a previous occasion, memory processes can supplement or compete with eye movements during search. While previous research has mostly focused on the perceptual features that allow us to identify a target among distractors in single shot searches (Wolfe, 1998, Psych. Science), recent findings have highlighted the contributions of visual short-term memory (VSTM) to search processes (Alvarez & Cavanagh, 2004, Psych. Science). We present a paradigm of repeated serial search that attempts to illuminate the potential roles of working memory (Anderson & Matessa, 1997, Psych. Review) and VSTM in visual search. A series of simple process models exemplifies various ways in which memory for items and/or locations can facilitate or obliterate search. Within a cognitive engineering approach, we developed multiple computational models that allowed us to explore and explicate the consequences of assumptions about VSTM capacity and organization, and the interaction between long-term memory and VSTM. Each model yielded distinct performance profiles based on the sequential order of target stimuli. We investigated our model predictions through an experiment that employed a serial search paradigm. Each of 10 targets (showing alphanumeric captions) had to be found on average twice per trial. As some items could be mere distractors and next targets were presented (auditorily) whenever the current target was found, participants could not anticipate the target sequence. Detailed comparisons between search performance, eye data and our computational models show clear evidence for memory processes for both target and distractor information, both within a single search and across multiple searches. Also, a between-subjects manipulation of target visibility shows that the use of knowledge-in-the-head (or memory) increases as the perceptual-motor costs of visual access are increased.
Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 2017
We explored the influence of early scene analysis and visible object characteristics on eye movements when searching for objects in photographs of scenes. On each trial, participants were shown sequentially either a scene preview or a uniform grey screen (250 ms), a visual mask, the name of the target and the scene, now including the target at a likely location. During the participant's first saccade during search, the target location was changed to: (i) a different likely location, (ii) an unlikely but possible location or (iii) a very implausible location. The results showed that the first saccade landed more often on the likely location in which the target re-appeared than on unlikely or implausible locations, and overall the first saccade landed nearer the first target location with a preview than without. Hence, rapid scene analysis influenced initial eye movement planning, but availability of the target rapidly modified that plan. After the target moved, it was found more ...