Feature-conjunction search performance was investigated as a function
of the target's location in three-dimensional (3-D) space. Ten subject
s viewed a display that contained 36 shapes, one of which was the targ
et. The targets were presented in one of four quadrants, three depths,
and three eccentricities. On a given trial, nontarget distractor shap
es were presented at the other 35 locations. The ability to find a tar
get shape was best when it was presented in the upper and right visual
fields and was closest to the fixation point in both its depth and ec
centricity. These nonuniformities may be partly derived from the link
between visual search and an extrapersonal attentional mechanism.