Abstract
Pseudoneglect refers to a leftward bias of the subjective bisection point of a horizontal line. Visual illusions can be weakened in judgments involving manual movements. We hypothesized that graspable objects (e.g., sticks) affording manual movements, as well as manual movements during judgments, would weaken pseudoneglect. In our experiment, subjective bisection points of a stick and a line were measured using the method of adjustment and the method of single stimuli. In the method of adjustment, participants reported the bisection point through their upper limb movements in horizontal directions. In the method of single stimuli, participants reported whether a landmark on the stimulus deviated leftward or rightward from the center of the stimulus. Results showed that the subjective bisection point was significantly less biased to the left for sticks than for lines. We did not find main or interactive effects of measurement methods. These results suggest that graspable objects weaken pseudoneglect.
