Visual Search

Why is it harder to look for the car key among 6 other keys than among 2 keys? Is it because our attention system needs to serially process each item? Why is it more difficult to find the car key among other car keys than house keys? Why is it that if we are searching for something (i.e. target) that differs from all the distracting things (distractors) along two visual attributes (features), it is easier to find the target?



What are the mechnaisms by which cues and context aid search performance? How do these principles apply to a real world task such as searching for tumors in real scenes and medical images?

Our approach is computational and we have worked on testing the ability of different computational models to quantitatively predict visual search accuracy including: a) serial model, b) noisy-parallel model (SDT model); c) noisy-serial model (hybrid model); d) limited samples model; e) Guided search model for visual search accuracy.

Here is some more detail on specific projects:

Why are conjunction targets harder to find than feature defined targets?

Unlimited capacity noisy parallel vs. Guided Search model

Internet-based fitting of computational models to visual search accuracy data

Publications:

Zhang S., Eckstein M.P., Evolution and Optimality of similar neural mechanisms for perception actions during search, PLoS Comput Biol., 9, 6, (2010)

Zhang, S, Abbey, CK, Eckstein, MP,Virtual evolution for visual search in natural images results in behavioral receptive fields with inhibitory sourrounds, Visual Neuroscience, Special Issue on Natural Systems Analysis, 26, 93-108, (2009)

Droll, JA, Abbey CK, Eckstein MP, Learning cue validity through performance feedback, Journal of Vision, 9(2):18, 1-22, (2009)


Droll JA, Eckstein MP, Gaze control and memory for objects while walking in a real world environment.Visual Cognition, Special Issue on Eye Guidance in Natural Scenes, 17(6),1159 -1184 (2009)

Schoonveld, W., Shimozaki, S. S., & Eckstein, M. P. (2007). Optimal observer model of single-fixation oddity search predicts a shallow set-size function. Journal of Vision, 7(10):1, 1-16, http://journalofvision.org/7/10/1/, doi:10.1167/7.10.1

Shimozaki SS, Chen K, Abbey CK, Eckstein MP, The temporal dynamics of selective attention of the visual periphery as measured by classification images, Journal of Vision, 7(12):10, 1-20, (2007)

Eckstein, M.P., Drescher B., Shimozaki, S.S., Attentional cues in real scenes, saccadic targeting and Bayesian priors, Psychological Science, 17, 973-80 (2006)

Bochud, F.O., Abbey, C.K., Eckstein, M.P., Search for lesions in mammograms: statistical characterization of observer responses. Medical Physics, 31, 24-36 (2004)

Cameron, E.L., Tai, J.C., Eckstein, M.P. & Carrasco, M. (2004). Signal detection theory applied to three visual search tasks: Identification, Yes/No detection and localization. Spatial Vision, 17, 295-325.

Shimozaki, S. S., Eckstein, M. P., & Abbey, C. K. (2003). Comparison of two weighted integration models for the cueing task: linear and likelihood. Journal of Vision, 3(3), 209-229, http://journalofvision.org/3/3/3/, DOI 10.1167/3.3.3.

Eckstein, M.P., Shimozaki, S.S., Abbey, C.K., The footprints of visual attention in the Posner paradigm revealed by classification images. Journal of Vision, 2(1), 25-45, http://journalofvision.org/2/1/3 (2002)

Eckstein, M. P, Thomas, Palmer, J.,J.P, Shimozaki,S.S., A signal detection model predicts effects of set size on visual search accuracy for feature, conjunction and disjunction displays, Perception & Psychophysics,  62,425-451, (2000) 

Eckstein, M.P., Beutter B.R., Stone L.S., Analytic Guided-Search Model of human performance accuracy in target localization search tasks, NASA/TM 209-594 (2000)

Eckstein, M.P., The lower efficiency for conjunctions is due to noise and not serial attentional processing, Psychological Science, 9, 111-118, (1998) 

Eckstein M.P., Whiting J.S., Visual Signal Detection in structured backgrounds I: Effect of number of possible spatial locations and signal contrast.  Journal of the Opt. Soc. Am. A, 13, 1777-1787,(1996).