Abstract
Purpose
Detection of a central low-contrast Gabor target often improves when it is flanked by suprathreshold collinear patches. We recently reported that such ‘lateral interactions’ depend on whether the collinear flankers are attended for a secondary task (Freeman et al., 2002, Nat. Neurosc. 4(10):1032–1036). Here we tested whether attended flankers facilitate the target more because they have higher effective contrast than when unattended. If true, increasing flanker contrast should overcome the attentional effect.
Method
Two pairs of flankers were displayed in an ‘X’ configuration around a central target Gabor, which was collinear with one flanker-pair and orthogonal to the other. A Vernier task was performed on one flanker-pair while the other pair was task-irrelevant. The contrast of all flankers was varied together over a wide range of values.