Fig. 5.

Idealized theoretical predictions for observer DU. We plot a response surface, as in Fig. 4. The Inset corresponds to the range of contrasts we tested the observer on (the exact range differed between observers). (Left) Contrast heuristic. The observer chooses the crowded stimulus whenever it has higher contrast than the uncrowded one. (Center) Crowdedness heuristic. The observer systematically chooses the uncrowded stimulus. (Right) Performance-based strategy. The observer chooses the crowded stimulus only if it affords higher expected performance.