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Gaze in Visual Search Is Guided More Efficiently by Positive Cues than by Negative Cues.

Kugler G, 't Hart BM, Kohlbecher S, Einhäuser W, Schneider E - PLoS ONE (2015)

Bottom Line: Participants exhibited longer response times when provided with negative cues compared to positive cues.Negative cues resulted in smaller proportions of fixations on relevant items, longer duration of fixations and in higher rates of fixations per item as compared to positive cues.The effectiveness of both cue types, as measured by fixations on relevant items, increased over the course of each search.

View Article: PubMed Central - PubMed

Affiliation: Institute of Clinical Neurosciences, University of Munich, Munich, Germany.

ABSTRACT
Visual search can be accelerated when properties of the target are known. Such knowledge allows the searcher to direct attention to items sharing these properties. Recent work indicates that information about properties of non-targets (i.e., negative cues) can also guide search. In the present study, we examine whether negative cues lead to different search behavior compared to positive cues. We asked observers to search for a target defined by a certain shape singleton (broken line among solid lines). Each line was embedded in a colored disk. In "positive cue" blocks, participants were informed about possible colors of the target item. In "negative cue" blocks, the participants were informed about colors that could not contain the target. Search displays were designed such that with both the positive and negative cues, the same number of items could potentially contain the broken line ("relevant items"). Thus, both cues were equally informative. We measured response times and eye movements. Participants exhibited longer response times when provided with negative cues compared to positive cues. Although negative cues did guide the eyes to relevant items, there were marked differences in eye movements. Negative cues resulted in smaller proportions of fixations on relevant items, longer duration of fixations and in higher rates of fixations per item as compared to positive cues. The effectiveness of both cue types, as measured by fixations on relevant items, increased over the course of each search. In sum, a negative color cue can guide attention to relevant items, but it is less efficient than a positive cue of the same informational value.

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Fixations in experiment 1.(Top) The proportion of fixations on the relevant half of items is shown (only target absent trials). In positive cue (blue), relevant items are of the color given in the instruction. These items are spatially identical in the negative cue (red), but of various colors. Dots depict mean values of each individual, lines are the means for each group. As half of the items are relevant and half of the items irrelevant, 0.5 represents chance level. (Bottom) Number of fixations per fixated item. Items are refixated significantly more often in negative cue (red) compared to positive cue (blue), despite high individual variation.
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pone.0145910.g005: Fixations in experiment 1.(Top) The proportion of fixations on the relevant half of items is shown (only target absent trials). In positive cue (blue), relevant items are of the color given in the instruction. These items are spatially identical in the negative cue (red), but of various colors. Dots depict mean values of each individual, lines are the means for each group. As half of the items are relevant and half of the items irrelevant, 0.5 represents chance level. (Bottom) Number of fixations per fixated item. Items are refixated significantly more often in negative cue (red) compared to positive cue (blue), despite high individual variation.

Mentions: Both positive and negative cues were used to guide gaze toward relevant locations, although positive cues lead to more efficient guidance of gaze. This is reflected by the proportion of fixations landing on relevant locations (only fixations that were attributed to items are taken into account), which was above chance level for both positive (t(13) = 32.9; p < .001) and negative cues (t(13) = 11.4; p < .001). However, the proportion of fixations on relevant locations was higher in positive-cue blocks than in negative-cue blocks (Fig 5A), although the number of relevant locations was the same across conditions. This was confirmed by a main effect for cue type (F(1,13) = 225.2, p < .001) as well as for array set size (F(4,52) = 18.1, p < .001), with no interaction (F(4,52) = 2.02, p = .105, repeated measures ANOVA).


Gaze in Visual Search Is Guided More Efficiently by Positive Cues than by Negative Cues.

Kugler G, 't Hart BM, Kohlbecher S, Einhäuser W, Schneider E - PLoS ONE (2015)

Fixations in experiment 1.(Top) The proportion of fixations on the relevant half of items is shown (only target absent trials). In positive cue (blue), relevant items are of the color given in the instruction. These items are spatially identical in the negative cue (red), but of various colors. Dots depict mean values of each individual, lines are the means for each group. As half of the items are relevant and half of the items irrelevant, 0.5 represents chance level. (Bottom) Number of fixations per fixated item. Items are refixated significantly more often in negative cue (red) compared to positive cue (blue), despite high individual variation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4696836&req=5

pone.0145910.g005: Fixations in experiment 1.(Top) The proportion of fixations on the relevant half of items is shown (only target absent trials). In positive cue (blue), relevant items are of the color given in the instruction. These items are spatially identical in the negative cue (red), but of various colors. Dots depict mean values of each individual, lines are the means for each group. As half of the items are relevant and half of the items irrelevant, 0.5 represents chance level. (Bottom) Number of fixations per fixated item. Items are refixated significantly more often in negative cue (red) compared to positive cue (blue), despite high individual variation.
Mentions: Both positive and negative cues were used to guide gaze toward relevant locations, although positive cues lead to more efficient guidance of gaze. This is reflected by the proportion of fixations landing on relevant locations (only fixations that were attributed to items are taken into account), which was above chance level for both positive (t(13) = 32.9; p < .001) and negative cues (t(13) = 11.4; p < .001). However, the proportion of fixations on relevant locations was higher in positive-cue blocks than in negative-cue blocks (Fig 5A), although the number of relevant locations was the same across conditions. This was confirmed by a main effect for cue type (F(1,13) = 225.2, p < .001) as well as for array set size (F(4,52) = 18.1, p < .001), with no interaction (F(4,52) = 2.02, p = .105, repeated measures ANOVA).

Bottom Line: Participants exhibited longer response times when provided with negative cues compared to positive cues.Negative cues resulted in smaller proportions of fixations on relevant items, longer duration of fixations and in higher rates of fixations per item as compared to positive cues.The effectiveness of both cue types, as measured by fixations on relevant items, increased over the course of each search.

View Article: PubMed Central - PubMed

Affiliation: Institute of Clinical Neurosciences, University of Munich, Munich, Germany.

ABSTRACT
Visual search can be accelerated when properties of the target are known. Such knowledge allows the searcher to direct attention to items sharing these properties. Recent work indicates that information about properties of non-targets (i.e., negative cues) can also guide search. In the present study, we examine whether negative cues lead to different search behavior compared to positive cues. We asked observers to search for a target defined by a certain shape singleton (broken line among solid lines). Each line was embedded in a colored disk. In "positive cue" blocks, participants were informed about possible colors of the target item. In "negative cue" blocks, the participants were informed about colors that could not contain the target. Search displays were designed such that with both the positive and negative cues, the same number of items could potentially contain the broken line ("relevant items"). Thus, both cues were equally informative. We measured response times and eye movements. Participants exhibited longer response times when provided with negative cues compared to positive cues. Although negative cues did guide the eyes to relevant items, there were marked differences in eye movements. Negative cues resulted in smaller proportions of fixations on relevant items, longer duration of fixations and in higher rates of fixations per item as compared to positive cues. The effectiveness of both cue types, as measured by fixations on relevant items, increased over the course of each search. In sum, a negative color cue can guide attention to relevant items, but it is less efficient than a positive cue of the same informational value.

Show MeSH