Browsing by Author "Käkönen, Taru"

New words are acquired during childhood but also in adulthood, for example by learning neologisms or foreign languages. Known words differ from novel, previously unknown, words in that their phonological forms as well as meanings are stored in neural memory traces. This difference between familiar and novel words can also be seen in the event-related potentials (ERPs) for these stimuli measured by electroencephalogram (EEG). Earlier studies observed that when novel spoken words are presented repeatedly within a short (~14 – 30 min) exposure, the ERP response increases and begins to resemble the response to familiar words. This phenomenon is called rapid word learning, which purportedly reflects cortical memory trace formation for the newly acquired words. The neural memory trace formation for novel words with unfamiliar phonology, on the other hand, has been observed to be weaker. This Master’s thesis investigated the effect of articulatory rehearsal on rapid learning of novel words. Participants (n = 19) listened to familiar Finnish words and two types of novel words: wordforms with familiar phonology and non-native wordforms with unfamiliar phonology. Continuous EEG was recorded in two conditions with different tasks: participants were instructed to either attentively listen to and memorise the spoken word stimuli or repeat the words. aloud. The active training conditions were preceded and followed by passive listening of the same stimuli. Behavioural learning was tested with a word recognition test after both conditions. In this study the focus is on the results of the active training sessions. ERPs were analysed by comparing responses to each word type in the early, middle and late phases of attentive and articulatory training. An ERP response to novel wordforms (~50 ms after the point at which the word could be identified) was modulated by the type of training and word type. During the attentive training the response to novel wordforms with familiar phonology increased, as expected. Responses to novel non-native wordforms and familiar words showed no significant changes during attentive listening. Within the articulatory rehearsal condition, however, responses to novel non-native wordforms but also to familiar words enhanced significantly. A later response ~135 ms after word disambiguation point increased during training irrespective of condition or word type. Behavioural word recognition did not differ between training conditions, and familiar words were recognised with highest precision. The ERP-results of this study suggest that attentive training enhances learning of novel words with native phonology while repeated articulation seems to enhance the formation of neural memory traces for novel non-native words.