Shifts of spatial attention cued by irrelevant numbers: Electrophysiological evidence from a target discrimination task

Abstract

Fischer et al. demonstrated that a centrally presented number can shift attention to the left/right when its magnitude is small/large. Two electrophysiological studies described these attentional effects as event-related potentials (ERPs) at centro-parietal sites. Since both studies used target detection tasks, it remains currently unknown whether similar results would be obtained with a discrimination task. We used ERPs to test whether digit cues also induce attention shifts when participants perform a feature-discrimination task on targets. ERPs were recorded whereas subjects discriminated the colour of lateral targets that were preceded by a central non-predictive digit. Analysis of cue-locked controlateral vs. ipsilateral ERP activity showed the emergence of early preparatory attention-directing components in parietal and frontal regions. Moreover, target-locked P1 components at occipito-parietal sites were significantly modulated by digit magnitude-target side congruency. These results demonstrate that irrelevant digit cues also bias sensory processing when embedded in a feature-discrimination task.

Keywords:

• Embodiment
• ERPs
• Numerical cognition
• Visuo-spatial attention

Additional information

Funding

This work was funded by the University of Luxembourg [grant number F3R-EMA-PUL-09NSP2] and DH was supported by a PHD-AFR grant from the Fond National de la Recherche, Luxembourg [grant number PHD-09-160].