Doing math with your body

When learning to do math, it helps to see that two marbles take up less space than twenty. Or to feel that a bag with ten apples weighs more than a bag with just one. During his PhD at Radboud University's Donders Institute, Krause investigated which brain areas represent size and how these areas work together. He concludes that number size is associated with sizes experienced by our body.

Physically perceived size

Krause asked tests subjects to find the physically largest number in an image with eighteen numbers. Sometimes this number was also the largest in terms of meaning, but sometimes it wasn't. Subjects found the largest number faster when it was also the largest in terms of meaning. 'This shows how sensory information about small and large is associated with our understanding of numbers', Krause says. 'Combining this knowledge about size makes our processing of numbers more effective.'

More fruit, more force

Even very young children have a sensory understanding of size. In a computer game, Krause asked them to lift up a platform carrying a few or many pieces of fruit by pressing a button. Although the amount of force applied to the button did not matter -- simply pressing it was adequate -- children pushed harder when there was a lot of fruit on the platform and less hard when there was little fruit on the platform.

Applications in education

Krause believes his results can provide applications in math education. 'If numerical size and other body-related size information are indeed represented together in the brain, strengthening this link during education might be beneficial. For instance by using a 'rekenstok' which makes you experience how long a meter or ten centimeter is when holding it with both hands. This general idea can be extended to other experiencable magnitudes besides spatial length, by developing tools which make you see an amount of light or hear an amount of sound that correlates with the number size in a calculation.'