Computational Linguistics Colloquium

Thursday, 10 January 2013, 16:15
Conference room, Building C7.4

The neural correlates of filled pauses. An fMRI study of disfluency perception

A characteristic of spontaneous spoken language is that no one is completely fluent. When speaking (or signing) everyone exhibits a certain degree of disfluency, to use the most common term. The average frequency of disfluency has been reported to be around 6% at word-level (Eklund, 2004; Bortfeld et al., 2001; Brennan & Schober, 2001; Fox Tree, 1995; Oviatt, 1995).

This talk presents results from a perception study of spontaneous and ecologically valid unfilled (silent; UPs) and filled ("uh"; FPs) pauses. FPs and UPs, excerpted from spontaneously produced speech, were played to subjects in an fMRI experiment.

The results exhibited increased activity in Primary Auditory Cortex for both types of stimuli. However, and more interestingly, FPs, but not UPs, also elicited significant modulation in the Supplementary Motor Area (Brodmann Area 6), which makes this study the first neurocognitive confirmation of the well-known difference between FPs and all other kinds of speech disfluency. The results also provide an explanation for the previously reported beneficial effect of FPs on reaction times in speech perception, and is also interesting from the alleged role of FPs as "floor-holding devices" in human dialog, since FPs seemingly activate motor programs in the listener.

The observed activation also has implications for various other perspectives of human communicative and motor actions, such as mirror neuron theory, motor theory of speech perception, and the oft-reported very short inter-speaker intervals (ISIs) in human-human dialog.

If you would like to meet with the speaker, please contact Jürgen Trouvain.