Symposium: Human language mechanisms as revealed by the MMN
Friday, Sep 11, 2015
Can the MMN measure proficiency in a second language?
1Brain Language Lab, Freie Universität Berlin, Berlin, Germany
Humans show variable degrees of success in acquiring a second language (L2). In many cases, morphological and syntactic knowledge remain deficient, although some learners succeed in reaching nativelike levels, even if they acquire their L2 relatively late. We use psycholinguistic, online language proficiency tests and the syntactic mismatch negativity, a neurophysiological index of automatic syntactic processing that occurs less than 200ms after stimulus onset, to compare neural grammar mechanisms of native speakers (NS) of English with non-native speakers (NNS). Variable grammar proficiency was measured by standard psycholinguistic tests. When NS heard ungrammatical word sequences lacking agreement between subject and verb (e.g. *we kicks), this brain response was increased compared with syntactically legal sentences (e.g. he kicks). More proficient NNS also showed this difference, but less proficient NNS did not. The cortical sources of the MMNm responses were localised in bilateral superior temporal perisylvian areas. Crucially, activation peaks in bilateral superior temporal areas revealed correlations between the magnitude of MMNm sources and grammatical proficiency. We conclude that grammar knowledge is manifest in the early neurophysiological response to grammar violations and that the corresponding brain indices of morphosyntactic mechanisms can become indistinguishable from those in NS, even among late-acquiring NNS.