Illustration of the decision timing model. Top panel. Asynchronous hierarchical decisions in two separate, parallel perceptual channels (color, form) are illustrated. The color-overlap distractor, but not the other distractors, reaches response preparation in the temporal gap between the offset of the color decision and the onset of the form decision. It is therefore rejected by late selection. Bottom panel. Synchronous hierarchical decisions are illustrated. None of the distractors reaches response preparation because the color decision and the form decision overlap in time. All distractors are therefore rejected by early selection. P = duration of perceptual processes; D = duration of decisional processes; M = duration of response preparation (and execution, if adequate); S = stimulus onset; R = response; C+F+ = target stimulus; C+F- = color-overlap distractor; C-F+ = form-overlap distractor; C+F* = stimuli with target-compatible color attributes; C-F* = stimuli with target-incompatible color attributes; C*F+ = stimuli with target-compatible form attributes; C*F- = stimuli with target-incompatible form attributes. See Discussion for details.