AZIMUTH ERRORS IN POINTING TO REMEMBERED TARGETS UNDER EXTREME HEAD ROTATIONS

Errors in pointing to remembered target locations in 3-D space were studied when subjects were free to move their heads, and when they rotated their heads to the extreme right or left. Relative to pointing when the head was free to move, head rotations to the right shifted the final position of the responding arm to the left, whereas head rotations to the left shifted the final position of arm to the right. Horizontal rotation of the head had no systematic influence on elevation and radial distance errors. The influence of head rotations on pointing errors may be mediated by small shifts in the internal representation of external space, shifting the presentation of space in the opposite direction of the head rotation.