Although few of us think of numbers in spatial terms 5, psychophysical evidence suggests that the mental representation of numbers has a spatial nature, possibly with a left–right orientation 6. First ...

Various behavioural paradigms indicate that numbers are represented along a left-to-right oriented 'mental number line'. In the spatial–numerical association of response codes (SNARC) effect, small ...

Lateralization of the brain—the tendency for the left and right hemispheres to specialize in different functions—underlies the development of a left-to-right mental number line, according to a study ...

Crows recently demonstrated an understanding of the concept of zero. It’s only the latest evidence of animals’ talents for numerical abstraction — which may still differ from our own grasp of numbers.