Model architecture. Perceptual evidence supporting a saccade to the target, vT, and supporting a saccade to a distractor, vD, were derived directly from observed discharge rates of FEF visually selective neurons (see text for details). These inputs were integrated by accumulator units representing a saccade to the target, mT, or a saccade to a distractor, mD. A response was initiated when accumulated support for a particular saccade reached a fixed threshold, ⊖, plus ~15 ms ballistic time for the eye movement to be executed. The parameter k determined the strength of leakage and g determined the level of the gate. The parameter u determined the strength of feed-forward inhibition and was fixed to one for the diffusion model. Beta determined the strength of lateral inhibition and was free to vary for the competitive model.