Figure 1
Experimental stimuli and procedure. Stimuli consisted of a small number of elements, either 3, 4, 5 or 6. The elements were positioned either (a) on the vertices of simple shapes, e.g., equilateral triangle, square, pentagons and hexagon or (b) randomly. (c) Equilateral triangle configuration sampled by either 3, 4, 5 or 6 elements, with three elements always positioned on the vertices and the remaining elements placed randomly anywhere within and including the virtual contour-path. (d) random only condition, which is the same as (c) except that no elements were placed on the vertices. (e) Stimuli made of different (white and black) luminance-polarity elements, with three elements always positioned on the vertices of a triangle and the remaining elements placed randomly anywhere within and including the virtual contour-path. Examples of same luminance-polarity (all white or all black) condition used in Experiment 3 is shown in (c). For all experiments, the orientation of each virtual shape configuration was randomized from trial to trial.
