FIGURE 4.

Learning non-accidental properties of objects. The stimuli used to investigate non-accidental properties (NAP) vs. metric properties (MP) of encoding in VisNet. Each object is shown as white on a gray background. Objects 1–3 all have the non-accidental property of concave edges. Objects 1–3 are different in their metric properties, the amount of curvature. Object 4 has the non-accidental property of parallel edges. Objects 5–7 have the non-accidental property of convex edges, and different metric properties from each other, the amount of the convexity. The vertical view of each object was at 0° of tilt, with the images at –6 and 6° of tilt illustrated. Different amounts of tilt of the top toward or away from the viewer are shown at the tilt angles indicated. Each object was thin, and was cut off near at the top and bottom of each object to ensure that any view of the top or bottom of the object did not appear, so that the type of curvature of the edges (concave, straight, or convex) was the main cue available. (After Rolls and Mills, 2018).