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A note on Kolk's “Judgment of sentence structure in Broca's aphasia”
Neuropsychologia, Vol. 18, pp. 357 to 360. 0 Pergamon Press Ltd. 1980. Printed in Great Britain.
028-3932/80/0601-0357$02.00/0
NOTE A NOTE ON KOLK’S “JUDGMENT
OF SENTENCE
STRUCTURE
MARY-LOUISE
IN BROCA’S
APHASIA”*
KEAN
School of Social Sciences, University of California, Irvine, California 92717 (Received
26 August
1979)
Abstract-Hierarchical clustering studies of the performance of agrammatic aphasics have been taken as providing evidence that agrammatism is: (a) a syntactic deficit; and (b) that the category Adjective may, like the class of function words, be impaired. It will be argued here that neither the assumptions of the analytic paradigm employed nor the actual data adduced provide evidence supporting either conclusion. KOLK [l] reports a hierarchical clustering study in which the performance on a triadic comparison task of “severe” Broca’s aphasics is compared with that of “recovered” Broca’s aphasics. Kolk used two classes of sentences as stimuli: (a) DET-N-V-DET-N (e.g. My dog chased their cut); (b) ADJ-N-V-ADJ-N (e.g. Old sailors telf sad tales). In previous clustering studies [2, 31 it has been shown that the performance of agrammatic Broca’s aphasics is distinct from that of normals for sentences of the (a) class; of particular note in those studies is that the aphasic subjects showed a neglect of the function words in the sentence, a result indicating a metalinguistic analogue to their agrammatism in production. In Kolk’s study, the “severe” group showed a neglect of function words in the (a) sentences parallel to that found in the previous studies, whereas the “recovered” group’s performance paralleled the performance which has previously been reported for normals. The striking result of Kolk’s study is that on the sentences of the (b) class the “severe” group neglected the adjectives in the same way they neglected the determiners in the (a) sentences, while the “recovered” group showed no neglect of the adjectives. On the basis of these data, Kolk draws a series of conclusions about the nature of the deficit of Broca’s aphasia; it will be argued here that Kolk’s major conclusions are not supported by the data he presents. (1) Kolk states that the “impairment of Broca’s aphasics is apparently not limited to function words alone, but is also found within adjectives, as was demonstrated by both the group data and the individual data” (p. 622). This qualified conclusion is not supported on the basis of the central assumption of the paradigm used. The assumption behind this experimental approach is that the task is sensitive to a subject’s sensitivity to the constituent structure of sentences, a sensitivity revealed through the clustering analysis of the subject’s relatedness judgments. The constituent structure of a sentence can be projected in a number of ways, e.g. with or without category specifications, with the minimal bracketings required to give the gross constituent structure of the sentence, with the maximal full bracketing of the sentence, etc. The clustering paradigm Kolk used is taken to be sensitive only to gross constituent structure; it is not sensitive to category. Consider now the non-categorically specified gross constituent structures of DET-N and ADJ-N sequences.
I (a) [-4DJ[Nll
@) IDE’WI 1
[old[sailors] ] [the[sailors] ]
As is evident from (l), DET-N and ADJ-N noun phrases Therefore, for any group of subjects, if that group treats given the assumption of the paradigm, one would have to were indeed sensitive to the parallel constituent structures
have exactly the same gross constituent structure. determiners and adjectives in a parallel fashion, conclude that the subjects were showing that they of the categorically distinct sequences.
*This work was supported in part by NIMH fellowship I-F32-MH07189-01. for his comments on an earlier version of this note. 357
My thanks to Herman Kolk
358
NOTE
In this context it is irrelevant that there was a distinction in the performance of the “severe” group from the “recovered” group; what is relevant is that each group treated both classes of sentences in exactly the same fashion. This is in no way to ignore the fact that the clusterings of the “severe” group are indeed quite different from those found for normal subjects in previous studies and for Kolk’s “recovered” group. Rather, it is simply to point out that as a matter of the logic of the situation, on the basis of these data alone the conclusion that the category adjective may be impaired is inconsistent with the central assumption of the paradigm. TO provide evidence bearing on Kolk’s suggestion that the category adjective may be compromised in Broca’s aphasia one would have to consider the full set of sentences in (2). 2 (a) DET-N-V-DET-N
My dog chases their cat
(b) ADJ-N-V-ADJ-N (c) DET-N-V-ADJ-N
Old sailors tell sad tales
(d) ADJ-N-V-DET-N
The sailors tell sad tales Big dogs chased the cat
(e) DET-ADJ-V-ADJ-N (f) ADJ-N-V-DET-ADJ
The rich pay high taxes Rich bankers cheat the poor
(g) DET-ADJ-V-DET-N (h) DET-N-V-DET-ADJ
The young ate those hamburgers Those bankers cheat the poor.
The sentences (2 C, d) are required to contrast ADJ-N with DET-N in a string, controlling for position. By Kolk’s hypothesis the parsings of (2 c, d) should be the same as the parsings of (2 a, b) both for individual data and group data. The sentences (2 e, f) contrast the category adjective in distinct constituent structures. That in (2 e, f) there are deadjectival nouns is not demonstrably relevant since lexically such items are adjectives with a clear productive morphology. As controls for (2 e, f) the sentences (2 g, h) are required. Under Kolk’s hypothesis it would be predicted that there would be an anomaly in the treatment of deadjectival nominals in (2 e-h) by Broca’s aphasics which is not found in their treatment of nouns in (2 a-d). Kolk does not provide any such necessary data. (2) Kolk considers three hypotheses for the linguistic analysis of agrammatism: the lexical hypothesis, the phonological hypothesis, and the syntactic hypothesis. The lexical hypothesis will not be considered here as it is not a hypothesis which (as far as either Kolk or I know) has been put forward in the literature, and there is independent evidence against the viability of such an hypothesis [4]. Kolk’s data have no bearing on deciding among the other hypotheses he considers. There are two phonological hypotheses which Kolk considers [5, 61. In the phonological hypothesis of GOODGLASS [5], the omission of function words is related to the fact that they are relatively unstressed under neutral intonation in English (for most sentence types), and stress is apparently highly salient in production. In the first place, it is unclear that the correlation between stress and performability is phonological and not phonetic. In speech perception, which may in relevant respects be analogous, stress is phonetically salient. In any event, as Goodglass restricts his discussion to the salience of stress in production and does not generalize that finding to other modalities, it is not necessarily to be expected that the salience effect would transfer to the clustering task. The second phonological hypothesis which Kolk considers is put forward in KEAN [6]; that hypothesis states that agrammatism involves the reduction of a string to its minimal string of phonological words, where the notion of a phonological word is defined within universal linguistic theory. Kolk states that in this version of the phonological hypothesis “stress plays a crucial role”, and that the hypothesis is that agrammatism involves the reduction of a sentence to a “simpler structure, according to criteria which are defined mainly on stress” (p. 618). While one might put forward such an hypothesis, that is not the one put forward in [6]. It has been explicitly stated and reiterated [6, 71 that stress itself is not criteria1 in the hypothesis. For English stress can be used as a defining diagnostic because phonological words contribute to the stress pattern of nonemphatic declarative sentences; as has been illustrated with examples from a variety of languages (German, Japanese, Klamath, Korean, Russian) the predictions of the hypothesis are independent of stress. Indeed, unless Broca’s aphasia is curiously restricted to speakers of stress-accent languages, any hypothesis as to the analysis of Broca’s aphasia could not rely on stress. It has long been noted by both structuralists and generative linguists that the phonological realization of a sentence is in many respects contingent on its constituent structure. This being so, a necessary component of the phonological representation of a sentence will be its constituent structure. In many instances the phonological constituent structure of a sentence is indistinguishable from its underlying or surface syntactic constituent structure. In other cases, however, there are clear distinctions between the syntactic constituent structure of a sentence and its phonological constituent structure, as is illustrated in (3) and (4). 3 (a) Syntactic Surface Structure [sthis is [&he cat that chased [&he rat that ate [&he cheese]]]]
NOTE
(b) Phonological
Constituent
359
Structure
[&this is the cat] [sthat chased the rat] [sthat ate the cheese]]. 4 (a) Syntactic Surface Structure
[sstudents h&in] 0)
Phonological
[+ollege]] sleep h&n]
Constituent
[+lasses]]]
Structure
[sstudents [rpin [,college]] sleep [ppin [Nclasses]]]. In both (3) and (4) we note a reduction, flattening out, of constituent structure representations at the phonological level. The characterization of phonological words must be stated in terms of phonological constituent structures and cannot be stated in terms of syntactic constituent structures [6, 71. Therefore, any experiment which addresses the question of the adequacy of the phonological hypothesis, must test it in terms of unequivocal phonological structure. For all the sentences which Kolk used in his study, the syntactic surface structure and the phonological representations are the same. These data cannot, in consequence, be taken as shedding any light on the hypothesis given in [6, 71. Given that for the sentences in question there is identity between the phonological and syntactic surface structures, if the data are taken as providing evidence against the phonological hypothesis, then they must also be taken as providing evidence against the syntactic hypothesis which Kolk advocates. The syntactic hypothesis which Kolk advocates is based on the plausible assumption that in processing constituent structure representations of sentences are realized. He assumes that the realization of constituent structure is necessarily syntactic in some technical sense. It should be evident that one cannot make some class of structural representations “syntactic”, “phonological”, etc., by fiat. Kolk is then left with no argument from the clustering data which supports the syntactic hypothesis over the other hypotheses.
REFERENCES 1. KOLK, H. H. J. Judgment of sentence structure in Broca’s aphasia. Neuropsychologiu 16, 617-625, 1978. 2. ZURIF, E., CARAMAZZA, A. and MEYERSON,R. Grammatical judgments of agrammatic aphasics. Neuropsychologia 10,405-417, 1972. 3. ZURIF, E. and CARAMAZZA,A. Psycholinguistic structures in aphasia: Studies in syntax and semantics. In Studies in Neurolinguistics. H. WHITAKERand H. WHITAKER(Editors). Academic Press, New York, 1976. 4. BRADLEY,D. Computational distinctions of vocabulary type. Doctoral dissertation, MIT, 1978. 5. GOODGLASS,H. Studies on the grammar of aphasics. In Psycholinguistics and Aphasia. H. G~~DGLASSand S. BLUMSTEIN (Editors). Johns Hopkins University Press, Baltimore, Maryland, 1973. 6. KEAN, M.-L. The linguistic interpretation of aphasic syndromes: Agrammatism in Broca’s aphasia, an example. Cognition 5, 9-46, 1977. 7. KEAN, M.-L. Agrammatism: A phonological deficit? Cognition 7, 69-83, 1979.
Resume
:
Les analyses par groupements hierarchiques des aphasiques agrammatiques ont conduit 3 supposer matisme provient ticale
“Adjectif”
etre alt6r8e. les Mthodes de ces
d’un
deficit
pourrait,
syntaxique, cornme les
(b) classes
du discours que : (a) l’agram-
la categoric grsmmade mats fonctionnels,
11 sefa soutenu ici que ni les hypotheses concernant d’analyses, ni les don&es produites ne sont en faveur
conclusions.
360
NOTE
Deutschsprachige
Zusammenfassung
:
Von hierachischen Cluster-Studien
zur Performanz agramma-
tischer Aphatiker wurde angenommen, dass diese Evidenz dafiir liefern dass Agrammatismus
(a) ein syntaktisches Defizit darsellt und (b)
dass die Kategorie der Adjektive, Zhnlich wie die Masse der "grammatischen" Worter, gestijrt sein kann. Hier wird jedoch argumentiert, dass weder das angewandte analytische Paradigma noch die tatsschlichen Ergebnisse Evidenz fiir die eine oder die andere Schlussfolgerung liefern.
028-3932/80/0601-0357$02.00/0
NOTE A NOTE ON KOLK’S “JUDGMENT
OF SENTENCE
STRUCTURE
MARY-LOUISE
IN BROCA’S
APHASIA”*
KEAN
School of Social Sciences, University of California, Irvine, California 92717 (Received
26 August
1979)
Abstract-Hierarchical clustering studies of the performance of agrammatic aphasics have been taken as providing evidence that agrammatism is: (a) a syntactic deficit; and (b) that the category Adjective may, like the class of function words, be impaired. It will be argued here that neither the assumptions of the analytic paradigm employed nor the actual data adduced provide evidence supporting either conclusion. KOLK [l] reports a hierarchical clustering study in which the performance on a triadic comparison task of “severe” Broca’s aphasics is compared with that of “recovered” Broca’s aphasics. Kolk used two classes of sentences as stimuli: (a) DET-N-V-DET-N (e.g. My dog chased their cut); (b) ADJ-N-V-ADJ-N (e.g. Old sailors telf sad tales). In previous clustering studies [2, 31 it has been shown that the performance of agrammatic Broca’s aphasics is distinct from that of normals for sentences of the (a) class; of particular note in those studies is that the aphasic subjects showed a neglect of the function words in the sentence, a result indicating a metalinguistic analogue to their agrammatism in production. In Kolk’s study, the “severe” group showed a neglect of function words in the (a) sentences parallel to that found in the previous studies, whereas the “recovered” group’s performance paralleled the performance which has previously been reported for normals. The striking result of Kolk’s study is that on the sentences of the (b) class the “severe” group neglected the adjectives in the same way they neglected the determiners in the (a) sentences, while the “recovered” group showed no neglect of the adjectives. On the basis of these data, Kolk draws a series of conclusions about the nature of the deficit of Broca’s aphasia; it will be argued here that Kolk’s major conclusions are not supported by the data he presents. (1) Kolk states that the “impairment of Broca’s aphasics is apparently not limited to function words alone, but is also found within adjectives, as was demonstrated by both the group data and the individual data” (p. 622). This qualified conclusion is not supported on the basis of the central assumption of the paradigm used. The assumption behind this experimental approach is that the task is sensitive to a subject’s sensitivity to the constituent structure of sentences, a sensitivity revealed through the clustering analysis of the subject’s relatedness judgments. The constituent structure of a sentence can be projected in a number of ways, e.g. with or without category specifications, with the minimal bracketings required to give the gross constituent structure of the sentence, with the maximal full bracketing of the sentence, etc. The clustering paradigm Kolk used is taken to be sensitive only to gross constituent structure; it is not sensitive to category. Consider now the non-categorically specified gross constituent structures of DET-N and ADJ-N sequences.
I (a) [-4DJ[Nll
@) IDE’WI 1
[old[sailors] ] [the[sailors] ]
As is evident from (l), DET-N and ADJ-N noun phrases Therefore, for any group of subjects, if that group treats given the assumption of the paradigm, one would have to were indeed sensitive to the parallel constituent structures
have exactly the same gross constituent structure. determiners and adjectives in a parallel fashion, conclude that the subjects were showing that they of the categorically distinct sequences.
*This work was supported in part by NIMH fellowship I-F32-MH07189-01. for his comments on an earlier version of this note. 357
My thanks to Herman Kolk
358
NOTE
In this context it is irrelevant that there was a distinction in the performance of the “severe” group from the “recovered” group; what is relevant is that each group treated both classes of sentences in exactly the same fashion. This is in no way to ignore the fact that the clusterings of the “severe” group are indeed quite different from those found for normal subjects in previous studies and for Kolk’s “recovered” group. Rather, it is simply to point out that as a matter of the logic of the situation, on the basis of these data alone the conclusion that the category adjective may be impaired is inconsistent with the central assumption of the paradigm. TO provide evidence bearing on Kolk’s suggestion that the category adjective may be compromised in Broca’s aphasia one would have to consider the full set of sentences in (2). 2 (a) DET-N-V-DET-N
My dog chases their cat
(b) ADJ-N-V-ADJ-N (c) DET-N-V-ADJ-N
Old sailors tell sad tales
(d) ADJ-N-V-DET-N
The sailors tell sad tales Big dogs chased the cat
(e) DET-ADJ-V-ADJ-N (f) ADJ-N-V-DET-ADJ
The rich pay high taxes Rich bankers cheat the poor
(g) DET-ADJ-V-DET-N (h) DET-N-V-DET-ADJ
The young ate those hamburgers Those bankers cheat the poor.
The sentences (2 C, d) are required to contrast ADJ-N with DET-N in a string, controlling for position. By Kolk’s hypothesis the parsings of (2 c, d) should be the same as the parsings of (2 a, b) both for individual data and group data. The sentences (2 e, f) contrast the category adjective in distinct constituent structures. That in (2 e, f) there are deadjectival nouns is not demonstrably relevant since lexically such items are adjectives with a clear productive morphology. As controls for (2 e, f) the sentences (2 g, h) are required. Under Kolk’s hypothesis it would be predicted that there would be an anomaly in the treatment of deadjectival nominals in (2 e-h) by Broca’s aphasics which is not found in their treatment of nouns in (2 a-d). Kolk does not provide any such necessary data. (2) Kolk considers three hypotheses for the linguistic analysis of agrammatism: the lexical hypothesis, the phonological hypothesis, and the syntactic hypothesis. The lexical hypothesis will not be considered here as it is not a hypothesis which (as far as either Kolk or I know) has been put forward in the literature, and there is independent evidence against the viability of such an hypothesis [4]. Kolk’s data have no bearing on deciding among the other hypotheses he considers. There are two phonological hypotheses which Kolk considers [5, 61. In the phonological hypothesis of GOODGLASS [5], the omission of function words is related to the fact that they are relatively unstressed under neutral intonation in English (for most sentence types), and stress is apparently highly salient in production. In the first place, it is unclear that the correlation between stress and performability is phonological and not phonetic. In speech perception, which may in relevant respects be analogous, stress is phonetically salient. In any event, as Goodglass restricts his discussion to the salience of stress in production and does not generalize that finding to other modalities, it is not necessarily to be expected that the salience effect would transfer to the clustering task. The second phonological hypothesis which Kolk considers is put forward in KEAN [6]; that hypothesis states that agrammatism involves the reduction of a string to its minimal string of phonological words, where the notion of a phonological word is defined within universal linguistic theory. Kolk states that in this version of the phonological hypothesis “stress plays a crucial role”, and that the hypothesis is that agrammatism involves the reduction of a sentence to a “simpler structure, according to criteria which are defined mainly on stress” (p. 618). While one might put forward such an hypothesis, that is not the one put forward in [6]. It has been explicitly stated and reiterated [6, 71 that stress itself is not criteria1 in the hypothesis. For English stress can be used as a defining diagnostic because phonological words contribute to the stress pattern of nonemphatic declarative sentences; as has been illustrated with examples from a variety of languages (German, Japanese, Klamath, Korean, Russian) the predictions of the hypothesis are independent of stress. Indeed, unless Broca’s aphasia is curiously restricted to speakers of stress-accent languages, any hypothesis as to the analysis of Broca’s aphasia could not rely on stress. It has long been noted by both structuralists and generative linguists that the phonological realization of a sentence is in many respects contingent on its constituent structure. This being so, a necessary component of the phonological representation of a sentence will be its constituent structure. In many instances the phonological constituent structure of a sentence is indistinguishable from its underlying or surface syntactic constituent structure. In other cases, however, there are clear distinctions between the syntactic constituent structure of a sentence and its phonological constituent structure, as is illustrated in (3) and (4). 3 (a) Syntactic Surface Structure [sthis is [&he cat that chased [&he rat that ate [&he cheese]]]]
NOTE
(b) Phonological
Constituent
359
Structure
[&this is the cat] [sthat chased the rat] [sthat ate the cheese]]. 4 (a) Syntactic Surface Structure
[sstudents h&in] 0)
Phonological
[+ollege]] sleep h&n]
Constituent
[+lasses]]]
Structure
[sstudents [rpin [,college]] sleep [ppin [Nclasses]]]. In both (3) and (4) we note a reduction, flattening out, of constituent structure representations at the phonological level. The characterization of phonological words must be stated in terms of phonological constituent structures and cannot be stated in terms of syntactic constituent structures [6, 71. Therefore, any experiment which addresses the question of the adequacy of the phonological hypothesis, must test it in terms of unequivocal phonological structure. For all the sentences which Kolk used in his study, the syntactic surface structure and the phonological representations are the same. These data cannot, in consequence, be taken as shedding any light on the hypothesis given in [6, 71. Given that for the sentences in question there is identity between the phonological and syntactic surface structures, if the data are taken as providing evidence against the phonological hypothesis, then they must also be taken as providing evidence against the syntactic hypothesis which Kolk advocates. The syntactic hypothesis which Kolk advocates is based on the plausible assumption that in processing constituent structure representations of sentences are realized. He assumes that the realization of constituent structure is necessarily syntactic in some technical sense. It should be evident that one cannot make some class of structural representations “syntactic”, “phonological”, etc., by fiat. Kolk is then left with no argument from the clustering data which supports the syntactic hypothesis over the other hypotheses.
REFERENCES 1. KOLK, H. H. J. Judgment of sentence structure in Broca’s aphasia. Neuropsychologiu 16, 617-625, 1978. 2. ZURIF, E., CARAMAZZA, A. and MEYERSON,R. Grammatical judgments of agrammatic aphasics. Neuropsychologia 10,405-417, 1972. 3. ZURIF, E. and CARAMAZZA,A. Psycholinguistic structures in aphasia: Studies in syntax and semantics. In Studies in Neurolinguistics. H. WHITAKERand H. WHITAKER(Editors). Academic Press, New York, 1976. 4. BRADLEY,D. Computational distinctions of vocabulary type. Doctoral dissertation, MIT, 1978. 5. GOODGLASS,H. Studies on the grammar of aphasics. In Psycholinguistics and Aphasia. H. G~~DGLASSand S. BLUMSTEIN (Editors). Johns Hopkins University Press, Baltimore, Maryland, 1973. 6. KEAN, M.-L. The linguistic interpretation of aphasic syndromes: Agrammatism in Broca’s aphasia, an example. Cognition 5, 9-46, 1977. 7. KEAN, M.-L. Agrammatism: A phonological deficit? Cognition 7, 69-83, 1979.
Resume
:
Les analyses par groupements hierarchiques des aphasiques agrammatiques ont conduit 3 supposer matisme provient ticale
“Adjectif”
etre alt6r8e. les Mthodes de ces
d’un
deficit
pourrait,
syntaxique, cornme les
(b) classes
du discours que : (a) l’agram-
la categoric grsmmade mats fonctionnels,
11 sefa soutenu ici que ni les hypotheses concernant d’analyses, ni les don&es produites ne sont en faveur
conclusions.
360
NOTE
Deutschsprachige
Zusammenfassung
:
Von hierachischen Cluster-Studien
zur Performanz agramma-
tischer Aphatiker wurde angenommen, dass diese Evidenz dafiir liefern dass Agrammatismus
(a) ein syntaktisches Defizit darsellt und (b)
dass die Kategorie der Adjektive, Zhnlich wie die Masse der "grammatischen" Worter, gestijrt sein kann. Hier wird jedoch argumentiert, dass weder das angewandte analytische Paradigma noch die tatsschlichen Ergebnisse Evidenz fiir die eine oder die andere Schlussfolgerung liefern.