Psychologists have argued that mathematical ability depends on the same cognitive skills and processes that underlie language. But now a study by psychologists at the University of Sheffield shows you don't need language to do maths. They tested three men, all of whom had damage to the left perisylvian region of their brain, known to subserve language ability.
The men were unable to distinguish between sentences like 'The man killed the lion' and 'The lion killed the man', yet they were able to perform comparable maths tasks that depend on analogous syntactic rules, like distinguishing between '59 minus 13' and '13 minus 59'.
Similarly, the men - referred to in the research report as S.A., S.O. and P.R. - were able to use a pencil and paper to solve simple mathematical expressions like '36 divided by (3 x 2)' that depend on understanding embedded clauses, yet they couldn't understand the verbal equivalent - sentences like 'This is the dog that worried the cat that ate the rat that ate the malt that lay in the house that Jack built'.
Rosemary Varley and her collaborators argue this shows the functional and neuroanatomical independence of maths and language: "...mathematics can be sustained without the grammatical and lexical resources of the language faculty", they said. Their findings also undermine the argument that complex thought cannot occur without language.
However, because the participants in this study were not brain damaged from birth, this research does not rule out the possibility that the acquisition of mathematical ability might depend on language, either in an individual's development, or evolutionarily.
Varley, R.A., Klessinger, N.J.C., Romanowski, C.A.J. & Siegal, M. (2005). Agrammatic but numerate. Proceedings of the National Academy of Sciences, 102, 3519-3524.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.