Previous studies using event-related brain potentials (ERPs) on adults have led to the identification of brain potential patterns associated with language processing (e.g. Kutas & Van Petten 1994, Friederici, 1998). However, little is known as to how these language-relevant brain potentials emerge during child language development. The present study addresses this question and examines the processing of German plural nouns in adults and children of different ages adopting the ERP violation design from Weyerts et al. (1997).
Taking the dual route model of inflection (Pinker & Prince, 1991; Marcus et al., 1995; Clahsen, 1999) as a point of departure, we selected an irregular and a regular group of nouns and created incorrectly formed plurals for both by regularizing the irregulars and irregularizing the regulars. The nouns were then incorporated into sentences.
Examples:
The experimental sentences were presented to participants auditorily. We examined one group of adults and three groups of children: (a) aged 6.0-7.11, (b) aged 8.0-9.11, and (c) aged 11.0-12.11.
For the adults, incorrect feminine nouns elicited a LAN/P600 pattern in comparison to their correct counterparts, an ERP pattern which is often observed in correlation with syntactic violations (Friederici, 1998). The incorrect loan words additionally gave rise to an N400 component, which is generally observable during the processing of semantic problems or non words (e.g. Kutas & VanPetten, 1994).
The three groups of children showed a clear development with regard to the ERP pattern observable for the feminine nouns. Thus, group (a) showed a broadly distributed negativity for the incorrect feminine items, while group (b) showed a fronto-centrally distributed negativity as well as a positivity which was restricted to occipital sites, and group (c) showed a frontal negativity with maxima at F7 and F8 and a centro-parietal positivity. By contrast, there was no clear pattern and no obvious developmental effect for the loan word condition.
These results show that, despite the nearly perfect production abilities of even the youngest age group, children's comprehension of inflected words clearly differs from that of adults. Most interesting in this regard is the development of the late positive component (P600) and the focusing of a negativity, which both appear to take place up to the age of 12.
References
Clahsen, H. (1999). Lexical entries and rules of language: A multidisciplinary study of German inflection. Behavioral and Brain Sciences, 22, 991-1013.
Friederici, A. D. (1998). The Neurobiology of Language Processing. In: A. D. Friederici (ed.), Language comprehension: a biological perspective 263-301. Berlin: Springer.
Kutas, M. & Van Petten, C. (1994). Psycholinguistics electrified. Event-related brain potential investigations. In M. A. Gernsbacher (ed.), Handbook of Psycholinguistics 83-143. San Diego: Academic Press.
Marcus, G. F., Brinkmann, U., Clahsen, H., Wiese, R. & Pinker, S. (1995). German Inflection: the exception that proves the rule. Cognitive Psychology, 29, 189-256.
Pinker, S. & Prince, A. (1991). Regular and irregular morphology and the psychological status of rules of grammar. Proceedings of the 17th Annual Meeting of the Berkeley Linguistics Society. Berkeley, CA.
Weyerts, H., Penke, M., Dohm, U., Clahsen, H. & Muente, T. (1997). Brain potentials indicate differences between regular and irregular German noun plurals. NeuroReport, 8 957-962