How does knowing what you are looking for change visual search behavior?

Abstract

When searching a display, users sometimes know what the target is but sometimes do not. It has generally been assumed that for this latter case people must engage in a deeper semantic evaluation of items during the search process. This idea is central to Information Foraging theory. But do people actually spend longer assessing items when engaged in a semantically demanding search task? We investigate this by having participants locate target items in 16-item menus. Participants were either told exactly what to look for (known-item search) or they were told the category that the target belonged to (semantic search). Participants were faster and more accurate at known-item searches. Eyemovement data show that this was because participants were more likely to skip over items when performing known-item searches. Contrary to expectation, we found limited empirical evidence to support the idea that deeper semantic evaluations of items lead to longer gaze durations (this occurred only when items were arranged very close together). This finding is important because it reveals how people adopt different eye gaze strategies depending on the kind of search activity they are engaged in.

Visual Grouping in Menu Interfaces

“…We generated these menus from the same database of words as used in previous studies [2,3,6]. This database is useful because it contains 560 unique words (with character length M = 6.2, SD = 2.0, range: 2 -12), organized into natural categories.…”

“…But often the user only has a vague idea of how the target will be specified (semantic search). This distinction is interesting because users adopt different eye gaze strategies depending on the kind of activity they are engaged in [3]. We might expect visual grouping cues, which highlight the fine-grained semantic structure of the menu, to offer even greater benefit to users engaged in a semantic search (because they cannot adopt simple letter-matching strategies that would be otherwise insensitive to visual grouping effects).…”

“…An extensive literature has sought to understand the factors that influence search time during menu interactions [2,3,4,6,7]. One important finding is that organizing the content of menus into semantically related groups helps users locate items faster [4].…”

“…A further benefit of using boxes is that the presence/absence of visual grouping can be varied without impacting other aspects of the display. In contrast, using spatial proximity to group items would increase the physical distance between groups of items, and this is known to affect search behavior [3].…”

The Emergence of Interactive Behavior

“…Sometimes users appear to skip over some items but not others [6]. They also search differently when looking for a known-word than when looking for a semantically related item [7]. There are many further possibilities and refinements and many subtle variations that determine, for example, where to look next, when to make a guess, and when to search in a different menu entirely.…”