Ir)regularity and semantic density
Harald Baayen
Interfaculty Research Unit for Language and Speech, \&
Max Planck Institute For Psycholinguistics, Nijmegen
The interdisciplinary nature of psycholinguistic research is perhaps most
clearly visible in the current debate about regular and irregular verbs.
Distributional linguistic data, experimental behavioral data, neuroimaging
data, as well as data from language disorders are all brought to bear on the
question of how we process regular and irregular verbs.
A fascinating development in the past-tense debate is the accumulation of
electrophysiological and neuroimaging evidence suggesting that different
regions of the brain are involved to different degrees in the processing of
regular and irregular verbs (e.g., Beretta et al, 2003). Many researchers,
both psychologists and linguists, take this evidence as supporting Pinker's
dual route model, according to which irregulars would be stored in some
associative memory while regulars would be processed by means of rules. Thus,
it would seem that the linguistic distinction between regular and irregular and
the 70-year old linguistic theory of the lexicon as the repository of the
irregular is completely vindicated.
A second fascinating development in the past-tense debate is that the
linguistic, purely form-based, distinction between regular and irregular as a
fundamental cognitive dichotomy is being questioned. There is clear evidence
for 'associative', 'analogical' relations between regular verbs, both for
English (Albright and Hayes, 2002) and for Dutch (Ernestus and Baayen, 2003).
Moreover, there are grades of (ir)regularity among the irregular verbs (Bybee
and Slobin, 1982; Sonnenstuhl and Huth, 2002). Finally, the claim advanced by
Pinker that past-tense formation is based on form and form only, has its
problems. Bybee (1985) called attention to the fact that irregulars that are
similar in form and meaning are more likely to be exchanged in speech errors,
and Ramscar (2002) reported evidence likewise suggesting the importance of
semantic attractors for past-tense formation. This evidence provides clear
evidence for at least local, item-based semantic attraction. It does not
necessarily show that semantic structure as such might be important for past
tense formation. In fact, the general consensus seems to be that there would
be no systematic semantic structure that might be relevant to past-tense
formation.
In my presentation, I will discuss new data that show that this general
consensus is based on tradition rather than on fact. By studying linguistic
resources (CELEX, WordNet, corpora), it can be shown that irregulars tend to
differ from regulars in their semantic characteristics. More specifically,
irregulars tend to have more densely populated semantic neighborhoods than
regulars. This difference in semantic density turns out to be reflected
in lexical decision and word naming latencies, as well as in
association norms.
These results challenge the idea that past tense formation rules would be
encapsulated to be sensitive to form only. They explain why semantic
attraction effects appear so easily in the WUG task, and they point to a
potential semantic contribution of semantics to the dissociation between
regulars and irregulars in the neuroimaging data.
References
Albright, A. and Hayes, B. (2001), Rules vs. Analogy in English Past Tenses: A
Computational/Experimental Study. Manuscript UCLA.
Balota, D.A., Cortese, M.J., & Pilotti, M. (1999), Item-level analyses of
lexical decision performance: Results from a mega-study. In Abstracts of the
40th Annual Meeting of the Psychonomics Society (p. 44). Los Angeles, CA:
Psychonomic Society.
Beretta, A., Campbell, C., Carr, T.H., Huang, J., Schmitt, L.M., Christianson,
K. and Cao, Y. (2003), An ER-fMRIO investigation of morphological
inflection in German reveals that the brain makes a distinction between
regular and irregular forms. Brain and Language 85, 67-92.
Bybee, J. L. (1985), Morphology: A study of the Relation between Meaning and
Form, Benjamins, Amsterdam
Bybee, J. L. and Slobin, D. I. (1982), Rules and schemas in the development and
use of the English past tense, Language, 58, 265-289.
Ernestus, M. and Baayen, R. H. (2003), Predicting the unpredictable:
Interpreting neutralized segments in Dutch, Language (in press).
Pinker, S. (1999), Words and Rules: The Ingredients of Language, Weidenfeld and
Nicolson, London.
Ramscar, M. (2002), The role of meaning in inflection: Why the past tense
doesn't require a rule, Cognitive Psychology, 45, 45-94.
Sonnenstuhl, I. and Huth, A. (2002), Processing and representation of German -n
plurals: a dual mechanism approach, Brain and Language 81, 276-290.