Figure 1

<p>Stimuli and Experimental Design. (A) Geometry (line) and Cartesian coordinates (markers) of the biological stimuli. The arrow indicates the direction of motion. The circular outline shows the starting position and the relative size of the light-spot with respect to the trajectory. (B) Tangential velocity of the elliptical (line) and circular (dashed line) biological stimuli. (C) Non-biological motions derived from the biological coordinates. Geometry and kinematics were inverted. (D) Experimental design. The neonates were assigned to one of the four sub-groups defined by the combination of the stimulus geometry (ellipse or circle) and of the screen (left or right) displaying the biological motion (white points)