The seminar brought together several hundred people from a wide range of disciplines (cognitive science, developmental psychology, neuropsychology, neuroscience, philosophy, anthropology), a good half of them students.
The aim was to take stock of the interactions between numbers and space, exactly twenty years after Stanislas Dehaene, Serge Bossini and Pascal Giraux (1993) published an article highlighting a systematic and automatic association: as soon as a person from a Western culture thinks about numbers, they can't help associating small numbers with the left-hand side of space, and large numbers with the right. This phenomenon has been called theSNARC effect (spatial-numerical association of response codes).
Why are the concepts of number, space and time so closely linked? No fewer than a thousand publications have explored the origins of this effect. Even babies, and other animal species, consider the dimensions of number, size, intensity and duration as magnitudes with a common polarity, the small-large axis. A systematic association between small numbers and the left is even found in chicks! This suggests that the mechanisms of the SNARC effect go back a long way in evolution. In humans, brain imaging suggests that the parietal cortex, home to multiple neural codes for numerical and spatial dimensions, may be the seat of this interaction. But how are these representations modified by culture and education, particularly the meaning of writing, which we now know can modify and even reverse the SNARC effect? Twenty years on, the "SNARC hunt" continues.