Spatial cues affect mental number line bisections

Numerical magnitude is coded left-to-right along a mental number line (MNL). The MNL can be distorted by an attentional bias directed to the left side, known as pseudoneglect - making the left of the MNL appear longer. We investigated whether this distortion can be corrected using spatial cues. Participants (n = 17) made forced-choice discriminations of relative numerical length while spatial cues were presented to the left, right, and both sides. Overall, participants overestimated the leftward length of the MNL, consistent with the effect of pseudoneglect. The bias was present for left- and neutral-cues, but was eliminated by right-cues. The results demonstrate that low-level manipulation of attention in physical space affects attention for high-level mental representations. The effect of cueing may reflect common activation of overlapping neural circuits that are thought to underlie attention in physical and representational space.