When Cuing Visual Search, Sometimes More Is Less.Richard A. Abrams

Washington Universityin St. LouisWilliam H. Knapp III

Istanbul Şehir University &

AbstractTypically in guided visual search tasks, the more information a cue provides about the target of one’s search, the better participants perform. Although our participants showed the typical pattern when searching for targets identified by picture cues, we found the opposite results with verbal cues.

The Maxim

=Cute kid. Male. Blonde.Caucasian. Blue eyes. Outside.Fair skin. Happy. Sunset. Red jacket.Plaid shirt. Wide aperture. Approximately 6 years old.Eye-length bangs. Impish grin. Slightly curly hair…

1 picture 1000 words

For Guiding Search, What’s Better?

= BIG RED

Wolfe and colleagues (2004) had participants search for colored bars amongst distractors. Participants received either a picture of the target or two words describing it.Participants performed better with the picture.The maxim suggests, maybe there weren’t enough words.

Manipulating InformativenessTargets varied on three dimensions. Size: Big ( ) or small ( ) Color: Red ( ) or Green ( ) Tilt: Vertical ( ) or Horizontal ( )

BIG RED HORIZONTAL

More Informative CuesIndicated All Three Dimensions

Less Informative CuesIndicated Only 2 Dimensions

BIG HORIZONTAL

More MethodsIndependent Variables

SOA (Separating the cue and search display): 1000, 2500, or 4000 ms.

Cue Type: Word or Picture.Cue Informativeness: More or Less.

Target Presence: Present or Absent.Search Display Size: 6, 12, or 18 objects.

N=24 (1 dropped for excessive errors)P’s completed the full design 7 times (504 total test trials)Analyses

5-Factor, within-subjects, repeated-measures ANOVA forMedian correct response timesError rates

When more is less!

F(1,

22)=

19.5

, p<

.001

, η2

=0.4

7

Response Times:

Otherwise more doesn’t help.ts(22)<1.9, ns

Errors:With picture cues, more information helps.

With word cues, more information hurts.

t(22)=2.7, p<.05, Cohen’s d=.28

t(22)=3.2, p<.01, Cohen’s d=.47

Other Results

F(2,44)=8.4, p<.05, η2=0.17

More information is better when the cue is a picture and the target is present.t(22)=1.4, p<.05, Cohen’s

d=.18

F(1,

22)=

4.7,

p<.0

5,

η2=0

.17

With increasing display sizes,

response times increased more for target-absent trials,

and errors increased more for target-present trials.

F(2,44)=27.1, p<.001, η2=0.55

F(2,44)=8.1, p<.001, η2=0.27Potential speed-accuracy trade-off

(although see Zenger & Fahle, 1997).

Greater effects of target-presence with

lessinformation

F(2,44)=30.3, p<.001, η2=0.58

orpictures.F(2,44)=8.8,

p<.01, η2=0.28

Errors stabilize after the shortest SOA.

F(2,44)=30.3, p<.001, η2=0.58

Conclusions

References:

• More information doesn’t always help visual search.

• Participants are able to complete their searches better with pictorial cues.

• With more longer SOAs, RTs and error rates stabilize suggesting encoding is complete.

Wolfe, J. M., Horowitz, T. S., Kenner, N., Hyle, M., & Vasan, N. (2004). How fast can you change your mind? The speed of top-down guidance in visual search. Vision Research, 44, 1411-1426.

Zenger, B., & Fahle, M. (1997). Missed targets are more frequent than false alarms, a model for error rates in visual search. Journal of Experimental Psychology: Human Perception and Performance, 23, 1783-1791.

With increasing SOAs, response times converged with pictures and words only for target present trials.