The middle range of the number line orients attention to the left side of visual space

Abstract

Mental representation of numbers is believed to be spatial in nature, with small numbers occupying the left and large numbers the right side of a putative mental number line. Consistent with this, presentation of numbers from the low and high ends of the mental number line induces covert shifts of spatial attention to the left and right side of visual space, respectively. However, the effect of the presentation of the middle range (containing numbers below and above the midpoint) of the number line on visual perception has so far not been studied. Here we show in two experiments, using a line bisection task and a simple target detection task, that processing of middle-range numbers affects allocation of visuospatial attention in a similar way as processing of small numbers, with attention shifted to the left side of space. We suggest that this pattern of results arises due to “anchoring” heuristics that participants use in number processing.

Keywords:

• Line bisection
• Target detection
• Spatial priming
• Mental number line
• Number processing
• Visual attention

Acknowledgments

This work was supported by NIH K24 RR018875 to APL and the Harvard Clinical and Translational Science Center (UL1 RR025758). JS was supported by NIH R01 NS33975 and LB by NIH R01-DC006842.

Additional information

Notes on contributors

Zaira Cattaneo

Zaira Cattaneo and Juha Silvanto both contributed equally.