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Abstract:
Distributional information --- e.g., the frequency
of word or phoneme co-occurrences --- plays an important role in
phonological production (Dell, Reed, Adams & Meyer, 2000),
but most accounts of grammatical encoding have not posited a
large role for distributional information. We examined this
issue in the case of producing subject-verb agreement, a
component of grammatical encoding. In English, which has
strong word-order constraints, the verb and subject noun are
typically adjacent (about 80% for declarative sentences in the
Wall Street Journal corpus). If agreement computations make
use of this distributional information, verbs will tend to agree
with the nearest noun --- a "proximity" constraint.
Agreement "attraction" errors occur when the verb
agrees with a non-subject noun within the subject noun phrase,
e.g., "The key to the cabinets were missing". Vigliocco
& Nicol (1998) found no difference in the rate of attraction
errors for declarative sentences such as "The helicopter for the
flights is safe" (where errors could be attributed to proximity
of "flights" to the verb) vs. questions such as "Is the
helicopter for the flights safe?" (where the non-subject noun is
distant from the verb). This result argues against a
proximity constraint in agreement. However, subtle
agreement constraints can be obscured by strong grammatical and
semantic cues (Haskell & MacDonald, 2001). We decided
to look for proximity effects in a case where the usual cues to
agreement are absent --- disjunctions of nouns with differing
number, such as "the hat or the gloves". Here either noun
could potentially control agreement. We used a game-playing
task with picture cards to elicit questions such as "Can you tell
me whether the hat or the gloves is/are red?" (verb follows the
two nouns), or "Is/Are the hat or the gloves red?" (verb precedes
the nouns). In both cases, participants overwhelmingly
produced agreement with the noun closest to the verb.
Moreover, the proximity effect was significantly larger in the
verb-precedes than the verb-follows condition, suggesting a
distributional origin to the effect: When the verb precedes the
subject in English, the subject noun and verb are overwhelmingly
adjacent, whereas when the verb follows the subject there is
frequently intervening material. Thus, proximity is a more
reliable distributional cue when the verb precedes the subject
than when it follows it.
These findings suggest that distributional
information plays a role in grammatical encoding as well as
phonological encoding, and that similar mechanisms are important
in both domains.
References
Dell, G., Reed, K., Adams, D., & Meyer, A.
(2000). Speech errors, phonotactic constraints, and
implicit learning: A study of the role of experience in language
production. Journal of Experimental Psychology: Learning,
Memory and Cognition, 26, 1355-1367.
Haskell, T., & MacDonald, M. (2001).
Semantic and phonological factors in subject-verb
agreement. Manuscript submitted for publication.
Vigliocco, G., & Nicol, J. (1998).
Separating hierarchical relations and word order in language
production: Is proximity concord syntactic or linear?
Cognition, 68, B13-B29.
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