UC San Diego

Torsional eye movements are triggered by head tilt and a rotating visual field. We examined whether attention to a misoriented form could also induce torsion. 36 observers viewed an adapting field containing a bright vertical line, followed by a display composed of two misoriented words (one rotated clockwise, the other counterclockwise, 15, 30 or 45 degrees). Subjects were instructed to attend to one of the words. Their adjustments of a reference line to match the tilt of the afterimage showed that attending to a misoriented word produced a torsional eye movement (verified with direct measurements on four additional individuals). The eye movement reduced the retinal misorientation of the word by about 1 degree. The results reinforce the linkage between selective attention and eye movements, and may provide a useful tool in dissecting different forms of “mental rotation” and other adjustments in internal reference frames.