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Abstract:
Spontaneous speech is rarely fluent, resulting in
hesitations, fillers ("um" / "uh"), repeated or repaired words, or
pronouncing "the" as /thiy/ (Fox Tree & Clark, 1997). Yet
these features are generally considered to not affect the core
processes of language comprehension. While disfluencies have
been argued to signal that the speaker is having difficulty (Clark
& Wasow, 1998; Fox Tree & Clark, 1997), this metalinguistic
knowledge has not been linked to specific language comprehension
phenomena.
A corpus analysis showed that speakers are
disfluent more often when referring to entities that are new
(rather than given) in the discourse. If listeners are
sensitive to this correlation, disfluencies at the start of a noun
phrase should lead them to focus on objects that are visible but
have not yet been mentioned.
Eye movements of 24 native speakers of English
were recorded as they listened to pairs of instructions to move
objects on a computer screen (Table 1). Each display
contained 4 colored pictures (Rossion & Purtois, 2001),
including two cohorts (e.g., camel/candle). We investigated
the time course of referent identification for the first noun in
the second instruction, manipulating whether: 1) the critical NP
was fluent (the camel) or disfluent (thiy, uh, camel), and 2) the
referent was discourse-new, or was given but unfocused, having just
been mentioned as the goal of the first instruction. All NPs
were accented.
Disfluent NPs should lead to faster target looks
in the new condition, and increased cohort competition in the given
condition. By contrast, fluent, accented NPs provide an
initial bias toward the given but nonfocused object (Dahan et al.,
in press), so we expected fluent NPs to lead to faster target looks
in the given condition and more cohort competition in the new
condition. Results showed precisely this interaction,
beginning 200 msec after the onset of the head noun ("ca-").
Prior to the noun, there was also a preference for new objects in
the disfluent condition and given objects in the fluent condition,
emerging 200 msec after the determiner (the/thiy), which provided
the first information about fluency.
Thus, comprehenders immediately use information
provided by disfluencies. This may stem from use of purely
distributional information about disfluencies and discourse status,
or may result from inferring that the speaker is having difficulty
in lexical retrieval (which would be less likely for a
just-mentioned referent). Regardless, information about
fluency affects the earliest moments of reference
resolution.
Table 1: Sample instructions (target NP is
underlined)
Given (Discourse-Old) Context: Put the grapes
below the candle.
Discourse-new Context: Put the grapes below the camel.
a. fluent (accented): Now put the candle below the
salt shaker.
b. disfluent: Now put thiy, uh, CANDLE below the salt
shaker.
References
Clark, H. H., & Wasow, T. (1998).
Repeating Words in Spontaneous Speech. Cognitive Psychology,
37, 201-242.
Dahan, D., Tanenhaus, M. K. & Chambers, C. G.
(in press). Accent and reference resolution in
spoken-language comprehension. Journal of Memory and
Language.
Fox Tree, J. E., & Clark, H. H. (1997).
Pronouncing "the" as "thee" to signal problems in speaking.
Cognition, 62, 151-167.
Rossion, B., & Pourtois, G. (2001).
Revisiting Snodgrass and Vanderwart's object database: Color and
texture improve object recognition. Paper presented at the
1st Vision Science Conference, Sarasota, Florida, May,
2001.
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