Effect of a directional cue on line bisection

Normal participants display a leftward bias when bisecting horizontal lines. It has been proposed that bisection errors can be affected by representational biases. We investigated the possibility that this effect could also be explained as the result of perceptual cueing. Participants bisected horizontal lines with identical arrows arranged around the lines, all pointing to the same end. The arrows significantly affected bisection placement, although participants bisected significantly away from the direction the arrows pointed to. The findings favor the hypothesis that cueing, rather than representation, can affect bisection errors.