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Abstract:
We introduce a new lexical priming technique
designed for use during uninterrupted spoken language
comprehension. Subjects' eye movements were recorded as
they heard a male voice giving instructions to move objects on a
table. Target sentences contained a prepositional phrase
attachment ambiguity (e.g., "Now, I'd like you to feel the frog
with the feather"), where "with the feather" could indicate an
instrument or a noun phrase modifier. At the onset of the
target verb, a prime verb of matched duration was uttered by a
female and mixed into the digitized audio-track. Two types
of primes were compared: Instrument-biased primes (e.g., "hit")
which strongly prefer to take Instrument roles; and
Modifier-biased primes (e.g., "move") which rarely take
Instrument roles.
Referential scenes were designed to support an
instrument interpretation: One-Referent scenes, containing, e.g.,
a single frog holding a small feather; a horse wearing a bow; a
large feather; and an unrelated object. Looks to the
potential instrument (the large feather) and hand-actions
involving this object (i.e., picking it up and using it to feel
the frog) can be taken as on-line and off-line measures
respectively of listeners' commitment to an instrument
interpretation.
Although subjects reported that they rarely
identified prime words, the structural preferences of these
primes influenced parsing processes. In particular,
Modifier-biased primes, as compared to Instrument-biased primes,
reliably reduced the proportion of time listeners spent looking
at the potential instrument upon hearing "with the feather" (both
p's<.05). In addition, hand-actions involving the
potential instrument were less for Modifier-biased primes (34%)
than Instrument-biased primes (44%), being marginally significant
by subjects only (p=.06). Fine-grained eye movement
analyses showed that the effect of prime type emerges reliably
600 ms after the onset of "feather" (both p's<.05). A
second experiment was conducted with scenes that supported a
modifier analysis, i.e., Two-Referent scenes, replacing the horse
with another frog. As expected, these scenes eliminated
almost all instrument actions, and showed a small but potentially
spurious influence of prime-type on the amount of time listeners
spent inspecting the potential instrument.
The findings indicate that auditory verb
recognition activates semantic roles that are tied to specific
syntactic forms. Priming was obtained despite using
instrument objects that were poor instruments for the prime
verbs, suggesting that the overlap in verb argument structure
between targets and primes was the source of these effects.
Thus, primes activated abstract information either about their
preferred event structure and/or their preferred syntactic
complements. We will discuss some post-hoc analyses of the
data which support event structure preferences playing an
important role in the priming effects. Studies are being
prepared that further disentangle syntactic and semantic
contributions by comparing primes with similar syntactic
preferences but different role preferences (e.g., Instrument vs.
Manner PPs). We hope to present preliminary results of this
at the conference. Finally, we will discuss implications
for exposure-based models of comprehension, which support an
important role for lexical-distribution cues in on-line parsing
decisions.
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