Figure 2: Trial protocol and stimulus space.
From: Universal and uniquely human factors in spontaneous number perception
(a) Example trial protocol. Subjects saw a neutral start screen, followed by presentation of a dot-array sample stimulus, followed by two choice icons for categorizing the dot-array as little (star) or a lot (diamond). During training, correct choices resulted in positive feedback, incorrect choices resulted in negative feedback. For probe stimuli, all choices were treated as correct responses. (b) Example stimulus space used in training (red outline) and testing (no outline).
