Er der kønsforskelle i hjernens bearbejdning af sprog?

Abstract

It is a common assumption, also in a Danish context, that sex-differences exist in the way language is processed by the brain. This paper reviews data investigating sex differences in language and language cortex using many different methods. Girls have an early advantage during language acquisition, but this seems to disappear around the age of six years. Differences in the neural underpinnings of language have been reported, e.g. as a greater lateralization of language in males compared to females. This difference is thought to be mediated by a larger corpus callosum in females (the fiber bundle connecting the two cerebral hemispheres). But a look at recent meta-analyses of the findings from this field shows that neither of these assumptions is supported by evidence. Further, larger studies of the regional gray matter distribution in the brain show no systematical language related differences between males and females. Apparent differences can be found in deficits such as stuttering, dyslexia, schizophrenia and autism that have a certain connection to language. Common to these deficits, however, is that language problems seem to be secondary traits. Language function, as measured by the WADA-test, as studied in patients with aphasia and in normal ageing also fails to exhibit sex differences. The overall conclusion therefore is that outspoken sex-differences in language processing is not supported by data.