Fig 4.

(a) Psychometric functions for probes pitted against small competitors, after contrast has been adjusted for the reduction in perceived contrast with a surround. Although the physical contrast of the competitor was lower, we still found a contrast gain shift (b), as well as a drop in the response gain of the psychometric functions (c) –thus ruling out an alternative, surround suppression-based explanation for our large-suppressor results. Error bars are bootstrapped 95% confidence intervals.