Numbers and space: A cognitive illusion?

Maria Dolores De Hevia, Luisa Girelli, Giuseppe Vallar

Research output: Contribution to journalArticlepeer-review


This study investigated the relationships between numerical and spatial representations by means of a bisection task, exploring the view that the core representation of number meaning is spatially organized as a mental number line. In Experiment nos. 1 (bisection of digit strings) and 2 (bisection of flanked lines) spatial biases towards the larger digit were found to be related only to processing of relative magnitude. Experiment nos. 3 (bisection of an unfilled space) and 4 (bisection of flanked lines/unfilled spaces) aimed at disclosing perceptual, attentional, and numerical constraints on the bias induced by the position of the larger digit. This effect is interpreted in terms of a cognitive illusion of length, whereby a spatial bias compensates for the numerical disparity. This seems to operate in a categorical fashion ("small/ large"), and to be congruent with the assumption that relatively large numbers are associated with the right side of a mental representational space.

Original languageEnglish
Pages (from-to)254-264
Number of pages11
JournalExperimental Brain Research
Issue number1-2
Publication statusPublished - Jan 2006


  • Cognitive illusion
  • Line bisection
  • Magnitude representation
  • Mental number line
  • Number processing

ASJC Scopus subject areas

  • Neuroscience(all)


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