A. Humans’ performance on a density discrimination with trial-by-trial feedback using the titrating threshold method. Grey diamonds, grey triangles, and black squares represent the proportion of Sparse, Dense, and Uncertain responses, respectively. Error bars indicate 95% confidence intervals at selected data bins as described in the text. B. Humans’ performance on a continuity discrimination with deferred feedback using the threshold method. Grey diamonds, grey triangles, and black squares represent the proportion of Discontinuous, Continuous, and Uncertain responses, respectively. Error bars indicate 95% confidence intervals at selected data bins. C. Humans’ performance on an ellipse discrimination with deferred feedback using the threshold method. Grey diamonds, grey triangles, and black squares represent the proportion of Round, Flattened, and Uncertain responses, respectively.