Paper available on a model of visual search

[Dr Zhaoping Li]

Title: Contextual influences in V1 as a basis for pop out 
        and asymmetry in visual search

Author: Zhaoping Li

Published in 
Proc Natl Acad Sci, USA Volumn 96, 1999. Page 10530-10535

Available at
http://www.gatsby.ucl.ac.uk/~zhaoping/preattentivevision.html
or at
http://www.pnas.org/content/vol96/issue18/#PSYCHOLOGY-BS

Abstract:

I use a model to show how simple, bottom-up, neural 
mechanisms in primary visual cortex can qualitatively 
explain the preattentive component of complex
psychophysical phenomena of visual search for a 
target among distracters. Depending on the image 
features, the speed of search ranges from fast, when a
target pops-out or is instantaneously detectable, 
to very slow, and it can be asymmetric with respect to 
switches between the target and distracter objects.
It has been unclear which neural mechanisms or even 
cortical areas control the ease of search, and no 
physiological correlate has been found for search
asymmetry. My model suggests that contextual influences 
in V1 play a significant role.