Semantic Processing and Irregularly Inflected Forms
Michele Miozzo & Peter Gordon
Columbia University
A case study in the dissociation of semantic
processing and irregular inflection
Introduction
Recent models of lexical representation suggest that
semantic processing is involved in the production and
comprehension of irregularly inflected forms such as feelfelt, or break-broke.
According to these models, irregular inflections and
semantic processing should show parallel associations of
processing and breakdown
The single-level connectionist model of Joanisse and
Seidenberg (1999) proposes that “lesions” of semantic
memory will lead to deficits in processing of irregularly
inflected words, but not regulars
The dual model of Ullman (2001) proposes that language is
subserved within the declarative/ procedural distinction in
memory. Deficits in semantic/declarative memory should go
hand-in-hand with specific deficits on irregular but not
regular inflections
Patient VP showed a semantic processing impairment
Is VP’s production of irregular forms also impaired?
Patient VP
•College educated, Native English Speaker
•86 yrs old, right-handed, female
•Secretary for scientific Lab
•November 2001, hospitalized after intraparenchymal, lobar
hemorrhage
•Left superior parietal lesion (CT Scan)
•No grammatical errors detected in spontaneous speech
•Auditory grammaticality judgment task: (EX: “They want to
meet the girl that you said were pretty”) (10/10 correct)
•Reading aloud words and non-words was intact
•Writing and oral spelling mildly impaired for both words and
non-words
•Picture visual recognition intact (EX: Able to recognize
whether two pictures represented a target object from
different perspectives)
Tests of Semantic Memory
VP performed poorly in semantic memory tasks demanding the
retrieval of detailed semantic information
Picture-picture Matching Task
(Hillis & Caramazza, 1995; Riddoch & Humphreys, 1993).
Verb synonym task
(Miozzo, 2003)
“To which item is the top
picture more related?”
Elicitation Task:
•Inflected form is given in response to citation form presented
orally by experimenter (EX: walk – “walked”)
•Tasks included: past tense, past participle, and noun plural.
•Equal numbers of regular and irregular forms matched for
frequency and imageability presented in each task.
walk
stroll
VP’s Production of Regular and Irregular Inflected Forms
run
“Is walk more related to
stroll or to run?”
•VP performed as well as age-matched controls with both
regular and irregular forms (Table 4).
Table 4
Inflection Task % Correct responses
n items
VP
Control
Past tense
Table 1 % Correct responses: Semantic memory tasks
Regular forms walk “walked”
Irregular forms eat “ate”
95
95
99%
97%
98%
96%
97
97
99%
95%
99%
97%
21
21
100%
90%
100%
100%
Past participle
Picture Matching 1
Picture Matching 2
Synonym judgment
Controls
100%
92%
99%
VP
78%
70%
86%
VP’s poor verbal definitions of auditorily presented concepts (Table
2) and her numerous semantic errors in the picture naming task
(Table 3) also suggest impaired semantic memory.
Table 2 Examples of VP’ s verbal descriptions
Concept
Maze
Ghost
Chisel
Beaver
VP’s Description
Made out of ground dirt. I’ve gone to one of these.
Havent’s heard much about ghosts. Nothing special. A
spiritual character.
Chiseling out something…
An animal. They burrow, so they dig out from
underground… messing up a lot of ground.
Table 3 Examples of VP’ s semantic errors* in picture naming
Target
Hammer
Hamburger
Bus
Guitar
Mustache
Dinosaur
Helicopter
Strawberries
Eskimo
VP’s Response
“Screwdriver”
“Pie”
“Van”
“Violin”
“Wig”
“Giraffe”
“Plane”
“Potatoes”
“Igloo”
* Semantic errors represented 58% (38/65) of VP’s erroneous responses
Regular forms walk “walked”
Irregular forms eat “eaten”
Noun plural
Regular forms mouse “mice”
Irregular forms mink “minks”
Conclusions
VP’s clear-cut dissociation between impaired semantic
processing and preserved production of irregular forms
challenges the view that semantic mechanisms are critical for
the retrieval of irregular forms. Rather, VP’s data support a
more modular view in which semantic processing is not
selectively involved in the retrieval of irregular forms.
References
Hillis, A. E., & Caramazza, A. (1995). Cognitive and neural mechanisms
underlying visual and semantic processing: Implications from “optic
aphaisa.” Journal of Cognitive Neuroscience, 7, 457-478.
Joanisse, M. F., & Seidenberg, M. S. (1999). Impairments in verb
morphology after brain injury: A connectionist model. Proceedings of the
National Academy of Sciences, 96, 7592-7597.
Miozzo, M. (2003). On the processing of regular and irregular forms of
verbs and nouns: Evidence from neuropsychology. Cognition, 87, 101127.
Riddoch, M. J., & Humphreys, G. W. (1993). BORB Birmingham object
recognition battery. Hove: Erlbaum.
Ullman, M. T. (2001). A neurocognitive perspective on language: the
declarative/procedural model. Nature Reviews Neurosicence, 2, 717-726.