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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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Response Times in experiment 1.Shown are the response times in target present trials (top) and target absent trials (bottom) in both cue types; positive (blue) and negative (red). Dots denote mean values for correct answers of each individual and number of items, lines the means for each group. The slopes of linear fits were determined for target absent trials for set sizes 6–24, where linearity seems to be satisfied. All participants exhibited a higher slope in “negative cue” (mean value 236ms/item) versus “positive cue” (mean value 158ms/item) condition.
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pone.0145910.g004: Response Times in experiment 1.Shown are the response times in target present trials (top) and target absent trials (bottom) in both cue types; positive (blue) and negative (red). Dots denote mean values for correct answers of each individual and number of items, lines the means for each group. The slopes of linear fits were determined for target absent trials for set sizes 6–24, where linearity seems to be satisfied. All participants exhibited a higher slope in “negative cue” (mean value 236ms/item) versus “positive cue” (mean value 158ms/item) condition.

Mentions: In both the target-absent and the target-present conditions, positive cues resulted in shorter response times as compared to negative cues. The response time increased with array set size. This indicates that participants indeed engaged in a serial-type search, where response time is dependent on the array set size. The response times (Fig 4) were analyzed with separate repeated measures ANOVAs for target absent and present. For target absent, the two-way ANOVA yielded significant main effects for cue type (F(1,13) = 128.7, p < .001), and array set size (F(4,52) = 119.6, p < .001), and a significant interaction between array set size and cue type (F(4,52) = 13.4, p < .001). For target present, the two-way ANOVA yielded significant main effects for cue type (F(1,13) = 21.2, p < .001), and array set size (F(4,52) = 64.8, p < .001). The interaction between array set size and cue type was not significant after Greenhouse-Geisser correction (F(4,52) = 1.9, p = .18).


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)

Response Times in experiment 1.Shown are the response times in target present trials (top) and target absent trials (bottom) in both cue types; positive (blue) and negative (red). Dots denote mean values for correct answers of each individual and number of items, lines the means for each group. The slopes of linear fits were determined for target absent trials for set sizes 6–24, where linearity seems to be satisfied. All participants exhibited a higher slope in “negative cue” (mean value 236ms/item) versus “positive cue” (mean value 158ms/item) condition.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0145910.g004: Response Times in experiment 1.Shown are the response times in target present trials (top) and target absent trials (bottom) in both cue types; positive (blue) and negative (red). Dots denote mean values for correct answers of each individual and number of items, lines the means for each group. The slopes of linear fits were determined for target absent trials for set sizes 6–24, where linearity seems to be satisfied. All participants exhibited a higher slope in “negative cue” (mean value 236ms/item) versus “positive cue” (mean value 158ms/item) condition.
Mentions: In both the target-absent and the target-present conditions, positive cues resulted in shorter response times as compared to negative cues. The response time increased with array set size. This indicates that participants indeed engaged in a serial-type search, where response time is dependent on the array set size. The response times (Fig 4) were analyzed with separate repeated measures ANOVAs for target absent and present. For target absent, the two-way ANOVA yielded significant main effects for cue type (F(1,13) = 128.7, p < .001), and array set size (F(4,52) = 119.6, p < .001), and a significant interaction between array set size and cue type (F(4,52) = 13.4, p < .001). For target present, the two-way ANOVA yielded significant main effects for cue type (F(1,13) = 21.2, p < .001), and array set size (F(4,52) = 64.8, p < .001). The interaction between array set size and cue type was not significant after Greenhouse-Geisser correction (F(4,52) = 1.9, p = .18).

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
Related in: MedlinePlus