Proceedings Fonetik 2009 - Institutionen för lingvistik

Proceedings, FONETIK 2009, Dept. of Linguistics, Stockholm UniversityDiscussionContrary to our initial hypotheses, no palpableactivation was observed in either Broca orWernicke related areas.However, the observed − and somewhatunexpected − effect in Primary Motor Cortex isno less interesting. The presence of a P300component in or around the Primary MotorCortex could suggest that the listener ispreparing to engage in speech, and that filledpauses could act as a cue to the listener toinitiate speech.The fact that it can often be difficult todetermine where the boundary between medialfilled pauses and the rest of the utterance iscould provide an explanation as to why it isdifficult to discern distinct ERPs connected tomedial filled pauses.In contrast to the aforementioned study byCorley, MacGregor & Donaldson (2007) whichused the word following the filled pause asERP onset and examined whether the presenceof a filled pause helped the listener or not, thisstudy instead examined the immediateneurological response to the filled pause per se.Previous research material has mainlyconsisted of laboratory speech. However, it ispotentially problematic to use results from suchstudies to make far-reaching conclusions aboutprocessing of natural speech. In this respect thepresent study − using spontaneous speech −differs from past studies, although ecologicallyvalid speech material makes it harder to controlfor confounding effects.A larger participant number could result inmore consistent results and a stronger effect.Future studies could compare ERPsgenerated by utterance-initial filled pauses onthe one hand and initial function words and/orinitial content words on the other hand, assyntactically related function words andsemantically related content words have beenshown to generate different ERPs (Kutas &Hillyard, 1980; Luck, 2005; Osterhout &Holcomb, 1992). Results from such studiescould provide information about how the braindeals with filled pauses in terms of semanticsand syntax.AcknowledgementsThe data and basic experimental design used inthis paper were provided by Robert Eklund aspart of his post-doctoral fMRI project ofdisfluency perception at Karolinska Institute/Stockholm Brain Institute, Dept of ClinicalNeuroscience, MR-Center, with ProfessorMartin Ingvar as supervisor. This study wasfurther funded by the Swedish ResearchCouncil (VR 421-2007-6400) and the Knut andAlice Wallenberg Foundation (KAW2005.0115).ReferencesCorley, M. & Hartsuiker, R.J. (2003).Hesitation in speech can… um… help alistener understand. In Proceedings of the25th Meeting of the Cognitive ScienceSociety, 276−281.Corley, M., MacGregor, L.J., & Donaldson,D.I. (2007). It’s the way that you, er, say it:Hesitations in speech affect languagecomprehension. Cognition, 105, 658−668.Eklund, R. (2004). Disfluency in Swedishhuman-human and human-machine travelbooking dialogues. PhD thesis, LinköpingStudies in Science and Technology,Dissertation No. 882, Department ofComputer and Information Science,Linköping University, Sweden.Fox Tree, J.E. (1995). The effect of false startsand repetitions on the processing ofsubsequent words in spontaneous speech.Journal of Memory and Language, 34,709−738.Kutas, M. & Hillyard, S.A. (1980). Readingsenseless sentences: Brain potentials reflectsemantic incongruity. Science, 207, 203−205.Luck S.J. (2005). An introduction to the eventrelatedpotential technique. Cambridge,MA: MIT Press.Osterhout, L. & Holcomb, P.J. (1992). Eventrelatedpotentials elicited by syntacticanomaly. Journal of Memory andLanguage, 31, 785−806.95