The representational space of numerical magnitude: illusions of length

Q J Exp Psychol (Hove). 2008 Oct;61(10):1496-514. doi: 10.1080/17470210701560674.


In recent years, a growing amount of evidence concerning the relationships between numerical and spatial representations has been interpreted, by and large, in favour of the mental number line hypothesis--namely, the analogue continuum where numbers are spatially represented (Dehaene, 1992; Dehaene, Piazza, Pinel, & Cohen, 2003). This numerical representation is considered the core of number meaning and, accordingly, needs to be accessed whenever numbers are semantically processed. The present study explored, by means of a length reproduction task, whether besides the activation of lateralized spatial codes, numerical processing modulates the mental representation of a horizontal spatial extension. Mis-estimations of length induced by Arabic numbers are interpreted in terms of a cognitive illusion, according to which the elaboration of magnitude information brings about an expansion or compression of the mental representation of spatial extension. These results support the hypothesis that visuo-spatial resources are involved in the representation of numerical magnitude.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Attention
  • Comprehension*
  • Discrimination Learning
  • Distance Perception
  • Female
  • Humans
  • Imagination
  • Male
  • Mathematics*
  • Optical Illusions*
  • Orientation*
  • Pattern Recognition, Visual*
  • Problem Solving*
  • Psychomotor Performance
  • Psychophysics
  • Space Perception*
  • Young Adult