An investigation of the time course of flanker effects in the landmark task.

ABSTRACT

To assess attentional, perceptual and motor contributions to pseudoneglect, the landmark task requires pointing to the subjectively shorter end of accurately pre-transected horizontal lines. We presented irrelevant flankers 317, 567 or 967 ms prior to the line transector on a touch screen and recorded reaction times, movement times, landing points and uncertainty of pointing decisions. Flankers were visible for 167 ms to exclude perceptual biases and lines disappeared upon response initiation to prevent subsequent corrections. Healthy participants showed pseudoneglect and a response bias toward the flanker. This finding is interpreted as evidence for inhibition of return and casts doubt on an attentional interpretation of previously reported flanker effects.