Poster #: 111
Topic: Speech and language (incl. deficits)
Friday, Sep 11, 2015
Dynamics of memory-trace formation for morphologically complex words in adults and children
1Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland
2Department of Clinical Medicine, Aarhus University, Denmark
3Department of Phoniatrics, Helsinki University Central Hospital, Finland
Human ability to rapidly acquire new words is the basis of successful language learning and efficient communication. It has been shown that within minutes of passive listening, MMN amplitudes for monomorphemic words increase in adults, suggesting memory-trace formation for novel words. However, it is unknown what happens if the new word is built from two or more morphemes (i.e., complex words, such as, ‘sing+er’). Is automatic rapid learning of novel complex word forms possible, and, if so, are there differences between these processes in adults and children?
To address this, we presented adults and typically developing 3-4-year-old children with derived and inflected words, along with novel complex pseudowords with real inflectional suffix. Acoustically, the suffix was identical in all stimuli. The results showed that after just 5 minutes of passive exposure, adult MMN responses to all complex stimuli declined, likely due to response habituation. This is in contrast with previous findings using monomorphemic stimuli that showed learning-related activation increase reflecting memory trace build-up. In children, however, MMNs for inflected and pseudo-complex forms were enhanced during this short exposure. This suggests automatic learning of complex forms in children’s brain, which, strikingly, includes not only memory trace build-up for novel pseudowords, but also lexicalisation of existing inflectional forms. In sum, using MMN as a tool to probe memory trace formation in the brain, we here document different learning mechanisms for complex word acquisition in children and adults.