Fig. 3.

Results of Experiment 2, in which subjects were given feedback when classifying vernier offsets as “up” versus “down” relative to a criterion of zero (red curves), –1.75 (green), or +1.75 (blue). The units of displacement are Weber fractions as percentages (100 * target shift/interpatch distance). The nonzero criteria are marked by vertical lines. For further explanations, see the text and the legend of Fig. 1