Figure 3
From: Idiosyncratic selection of active touch for shape perception
Focal palpation. (A) An example demonstrating the calculation of a trial’s focal index. Left: x–y plot of one example trial. Overlapping circles with a radius of 10 mm (gray) were plotted over the objects' outline (red). The traveled distance in each circle was calculated. Circles with the maximal and minimal value of traveled distance (pink and green, correspondingly) are marked. Right: calculated traveled distance (y-axis) as a function of the location of the circle’s center (x-axis). The trial’s focal index is defined as the ratio of the difference between the trial’s maximal and minimal values of traveled distance (pink and green) and their sum. (B) The distributions (medians and quartiles) of the focal index for CF and SC trials across all trials of all participants and all sessions (henceforth ’grand distributions’) (p < 0.001). Ns of subjects, sessions and trials are as specified in Fig. 2D. (C) Grand distributions of the focal index per object in SC and CF trials. (D) Each data point represents the object grand median focal index (y-axis) and the object sharpest angle (x-axis) for CF trials. Objects’ sharpest angle: Triangle = 43.5°, trapezoid = 68.2°, parallelogram = 69.2°, diamond = 70.3°, square, rectangle, L shape = 90°, hexagon = 120°.Ntrials per shape, panels B-D: Triangle, 70; Circle, 128; Rectangle, 68; Square, 83; Parallelogram, 80; Ellipse, 121; Hexagon, 66; L, 104; Trapezoid, 117; Diamond, 95. (E) x–y plots of two trajectories differing in their focal indices (Triangle, focal index (FI) = 0.77; Hexagon, FI = 0.34). (F) Mean visit rates for two example objects (triangle and L, all subject and trial types included).
