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Updated: Jun 23, 2026

Measuring Attention and Visual Processing Speed by Model-based Analysis of Temporal-order Judgments
Published on: January 23, 2017
The middle range of the number line orients attention to the left side of visual space
Zaira Cattaneo1, Juha Silvanto, Alvaro Pascual-Leone
1Department of Psychology, University of Milano-Bicocca, Italy. zaira.cattaneo@unimib.it
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.
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