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Aphasics' selective deficits in appreciating grammatical agreements
BRAIN
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16, 109-120 (1982)
Aphasics’ Selective Deficits in Appreciating Grammatical Agreements MURRAY GROSSMAN AND SUSANNA HABERMAN Boston University School of Medicine This study attempted to dissociate in aphasic patients different aspects of grammatical capacity. Subjects were asked to evaluate sentences containing violations of agreements between pronouns and verbs. Agreements which are considered primarily structural in nature were violated (e.g., a surface object case like “them” placed in a surface subject sentential slot) while other violated agreements seemed to involve both structural and semantic information (e.g., lack of agreement between a pronoun and a verb in terms of the number of people performing the act). These violations were couched in one of three types of sentential frames which varied in terms of syntactic complexity (e.g., active declarative vs. passive syntactic voices). The results revealed that Broca’s aphasics found agreement violations difficult to detect in complex syntactic frames. They were quite successful at detecting even violations of the largely structural “case” type of agreement, however, when couched in simpler syntactic frames. Fluent aphasics encountered more difficulty detecting violations of agreements involving both semantic and structural information than agreements which were primarily structural in nature, that is, regardless of the syntactic frame. These unique performance profiles suggest that Broca’s aphasics may be agrammatic only with respect to certain aspects of a sentence’s structure, and that fluent aphasics may also experience some selective-but different-grammatical deficits.
INTRODUCTION Grammatical relations among words in a sentence-that is, the formal structural properties that specify the manner in which words relate to (and are related to) other words in a sentence-are signaled in a number We would like to express our appreciation to Dr. Anna Pomfret and the staff of the New England Rehabilitation Hospital and to Dr. Michael P. Alexander and the staff of the Neurobehavioral Unit of the Boston Veterans Administration Medical Center for their help. We also thank Lise Menn for her valuable comments on an earlier draft of this paper. This work was supported in part by grants from NIH (NSl.5972, NS.11408,and NS06209). Portions of this study were presented at BABBLE, Niagara Falls, April, 1980. Please address reprint requests to: Murray Grossman, Psychology Research Section, Boston Veterans Administration Medical Center, 150 South Huntington Ave., Boston, MA 02130. 109
0093-934X/82/030109-12$02.00/0 Copyright 0 1982 by Academic Press, Inc. All rights of reproduction in any form reserved.
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of different ways (e.g., Morgan, 1972). For example, grammatical relations are specified in part by the sentence’s voice or syntactic frame. The syntactic frame of a sentence distinguishes between, say, an active declarative sentence and a sentence in the passive voice on the basis of the presence or absence of the verb’s auxiliary and past participle, and the introduction of the logical subject with the preposition “by” usually after the verb. This allows the logical subject and object of the sentence to be identified. Grammatical relations among words in a sentence are also reflected by the set of agreements between pronouns and verbs. There must be agreement at least between the pronoun of a sentence and the surface subject or surface object sentential slot (i.e., “case” agreement), and between the pronoun and the “number” and “person” information reflected in its verb. The pronoun must also meet the verb’s restrictions on plausible linguistic agents (e.g., that the agent of an action must be human-what we will call an “animacy” agreement). These agreements appear to reflect both structural and semantic information, and although highly intuitive, may involve differing degrees of these components. Consider “case” in this respect. Even though “case” involves a semantic component, the “case” agreement seems primarily structural in nature since it largely mirrors the assignment of phrasal structure. “Person” and “number” agreements, by comparison, may involve semantic as well as structural information since the number of people performing an act and their relationship to the speaker of the sentence reflect interpretive as well as structural aspects of the sentence. Likewise, there is an important semantic consequence vis-a-vis the “animacy” agreement. These types of agreements are outlined in Table 1. The purpose of the present study was to determine in greater detail the status of Broca’s aphasics’ and fluent aphasics’ appreciation of several structural aspects of grammar, including the syntactic and the “case, ” “number,” and “person” aspects of a sentence. Broca’s aphasics’ difficulty with complex syntactic material is well documented (e.g., Caramazza & Zurif, 1976; Goodglass, 1976; Goodglass, Blumstein, Gleason, Hyde, Green, & Statlender, 1979; Zurif, Green, Caramazza, & Goodenough, 1976). This work has suggested that Broca’s aphasics are compromised in their grasp of the meaning of sentences with noncanonical syntactic frames (i.e., non-S-V-O sentences such as passives). However, the relation between this syntactic deficit and their appreciation of other structural components of grammar-such as the ability to grasp the “case,” “number,” and “person” types of grammatical agreements-remains to be specified. Indeed, although the speech of aphasics contains pronouns like “he,” “them,” and “it” (Goodglass, Hyde, & Blumstein, 1969; Wagenaar, Snow, & Prins, 1975), it is unclear whether they fully appreciate the “case,” “number,” and “person” agreements
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TABLE
1
INVESTIGATED IN THIS STUDY, AND EXAMPLESOF VIOLATIONSOF EACH TYPE OF AGREEMENT
AN OUTLINE
OF THE TYPES OF AGREEMENTS
Type of agreement
BETWEEN PRONOUNS AND VERBS
Locus of agreement
Examples of agreement violations
Case (Primarily structural)
Reflecting the surface subject position or the surface object position of the pronoun with respect to the sentence’s verb
Them are going to the store. The ball is kicked by he.
Number (structural and semantic)
Agreement of number information between a pronoun in the surface subject position and the verb (i.e., singular vs. plural)
They is watching the birdie. Am we playing baseball?
Person (structural and semantic)
Agreement of person information between a pronoun in the surface subject position and the verb (i.e., first person vs. third person)
I is reading a newspaper. He am kissed by Jane.
Animacy (primarily semantic)
Agreement between a pronoun as an agent and the verb’s constraint of a necessarily human agent
It is praying in church. Is it marrying in the
between pronouns and their verbs. After all, the structure of their utterances is often unspecifiable due to the incorrect use (in fluent aphasics) or absence (in Broca’s aphasics) of closed class terms. A study of aphasics’ critical reading (Gardner, Denes, & Zurif, 1975) in fact has indicated some problems in appreciating agreements involving pronouns. Gardner et al. asked aphasics to judge the correctness of sentences where some of the items exhibited an incorrect pronominal adjective substituted for the correct adjective (e.g., “John sat on him chair”; “The girl raised his arm”). Broca’s aphasics and fluent aphasics both exhibited some difficulty evaluating these items. In order to determine whether Broca’s aphasics are impaired in their appreciation of all aspects of sentence form and whether fluent aphasics exhibit any selective deficits in appreciating grammatical agreements, both syntactic frame and pronoun-related agreement aspects of a sentence were manipulated systematically. Patients were then asked to judge the correctness of these sentences. Thus, the “case,” “number,” “person,” and “animacy” types of pronoun-related agreements were violated one at a time, and these violations were couched in sentences exhibiting active declarative, interrogative, and passive syntaciic frames. If Broca’s aphasics are compromised at appreciating most structural aspects of a
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sentence, then the passive syntactic frame should be the most troublesome context for the detection of pronoun-related agreement violations. Violations of the largely structural “case” agreement may also prove difficult to detect even in syntactically simpler contexts, since this type of agreement contributes primarily to the assignment of phrasal structure. Fluent aphasics, by comparison, exhibit well-documented semantic disorders (e.g., Grossman, 1981; Lhermitte, DCsrouesnC, & Lecours, 1971; Zurif, Caramazza, Myerson, & Galvin, 1974). These patients may find “number,” “person,” and “animacy” agreements most difficult to detect, then, due to their inability to bring semantic capacities to bear for the full appreciation of these grammatical agreements. METHODS Subjects Twenty-eight right-handed, high-school-educated, native English speakers between the ages of 35 and 60 years were examined. All brain-damaged patients were classified on the basis of neuroradiological information such as CT scans, performance profiles on standard neuropsychological tests such as the Boston Diagnostic Aphasia Examination (Goodglass & Kaplan, 1972) and significant portions of the frontal lobe and parietal lobe batteries in use at the Aphasia Research Center and New England Rehabilitation Hospital, and clinical examinations of neurologists. The subjects comprised nine Broca’s aphasics and eight fluent aphasics. Six patients with right-hemispheric insult were also examined as a braindamaged control group. As shown by these tests, Broca’s aphasics exhibited effortful, agrammatic speech in the context of relatively intact comprehension of single words and simple utterances, following insult to the anterior portion of the left hemisphere. Fluent aphasics presented with semantic comprehension deficits and well-intoned, somewhat empty speech with many functors and relatively few contentives, associated with temporoparietal disease in the left hemisphere. Subjects with a lesion in the anterocentral portion of the right hemisphere were not aphasic, although they did evidence some mild impairments interpreting paragraph-length material. Many of the visuospatial and auditory impairments associated with a right-hemispheric lesion were documented. All but one of the brain-damaged patients (a surgical patient who had suffered a penetrating brain wound) had experienced a stroke. Patients were tested at least 6 months after the onset of an aphasia in order to ensure, in so far as possible, a relatively stable profile of linguistic deficit. Five nonneurological control subjects were also examined. These subjects were volunteers from the general medical wards of the Boston Veterans Administration Medical Center. Interviews with family members and friends confirmed that all subjects spoke a standard dialect of English, where utterances such as “they is” and “he am” were considered poor English and were rarely produced.
Procedure Patients were presented orally with 152 sentences, one at a time, and were asked to judge if they were correct or if something was wrong with them. The sentences were read to patients in a fashion which preserved natural intonational contours, and a sentence was repeated once if requested. Sixty percent of the sentences contained an agreement violation, and these items were randomly distributed among the correct items, with all patients encountering the same random order. Four types of agreement violations were examined. Twenty percent of the incorrect items exhibited just “person” agreement violations, 20% “number” violations,
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20% “animacy” violations, and the remaining 40% of the incorrect items exhibited violations of only the “case” type of agreement. Each type of agreement violation was equally distributed over three types of syntactic frames, that is, active declarative, interrogative, and passive. Examples of agreement violations couched in these syntactic frames are provided in Table 1. It may be noted at this point that, for the “case” agreement violation, a surface subject case was replaced with a surface object case as often as a surface object case was replaced with a surface subject case. For the “person” type of violation, a first person pronoun or verb auxiliary was substituted for a third person pronoun or auxiliary, respectively, as often as a third person constituent was substituted for a first person constituent. For the “number” type of violation, a singular pronoun or auxiliary and a plural pronoun or auxiliary were replaced with the other, respectively, equally often. The nonmanipulated information represented by the pronoun and verb auxiliary was balanced in all instances (e.g., an equal number of first and third person constituents exhibited “number” violations). All items contained verbs’ auxiliaries, it may be noted, so that the presence or absence of an auxiliary would not provide clues to syntactic structure, and since these reflect more specific “person” and “number” information than morphological inflections of verbs. For example, we used something like “I am helping Jane” rather than “I help Jane” since the absence of an inflection on “help” only indicates that the subject is not third person singular, while the auxiliary “am” indicates that the subject should be both singular and first person. Interrogatives were formed by inverting the surface subject of a sentence and the auxiliary. Moreover, each type of agreement violation was concerned with a relationship between a pronoun and an auxiliary verb, so the pronoun’s coreferent did not have to appear in the sentence. Sentences were quite sparse lexically, although the major lexical constituents varied from item to item. A brief training period was administered before the set of items in order to establish the types of judgments which were required and a response mode for patients to indicate their judgments. During this session, patients were presented with sentences containing grammatical violations which were increasingly difficult to detect. An earlier item in the training period, for instance, violated three types of agreements simultaneously (e.g., “Them am kicking cans”) while a later item violated only two pronoun-related agreements.
RESULTS In order to assess patients’ ability to detect agreement violations when couched in various syntactic frames, a group (4) x type of agreement violation (5) analysis of variance-with the “syntactic frame” variable nested within the “violation type” variable-was employed. Significant main effects were found for group (F (3, 345) = 106.94; p < .OOl) and violation type (F (4, 345) = 34.31; 4,345; p < .OOl), and a significant group x violation interaction was also found (F (12, 345) = 7.45; p < .OOl). Subsequent analyses by the Scheffe method revealed that control subjects detected the agreement violations at significantly superior levels overall in comparison to each of the brain-damaged groups (each comparison at the p < .Ol level), and in fact performed at ceiling levels on all aspects of the task. Due to the possible effect of control subjects’ ceiling level of performance on the analysis of variance statistic, Kruskal-Wallis analyses of variance for ranks-a statistic less sensitive to the requirement for homogeneity of variance-were also performed on these data. An analysis of patients’ overall performance revealed H
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= 15.81 which, with three degrees of freedom, is significant at the p < .OOl level. Similarly, analyses of variance for ranks for each of the syntactic frames were significant at the p < .Ol level (declarative: H = 13.69; interrogative: H = 15.48; passive: H = 13.22). Analyses of variance for ranks were also significant at the .lO > p > .Ol level for each of the types of pronoun-related agreement violations (case: H = 6.45; person: H = 7.05; number: H = 8.29; animacy: H = 9.19). These analyses suggest, then, that the distribution of control subjects’ scores by itself fails to account for the differences among groups. With one exception, moreover, all of the differences discussed below are between groups of brain-damaged patients. Further analyses of brain-damaged patients’ overall ability to detect agreement violations also revealed differences. Broca’s aphasics performed at significantly more successful levels overall than fluent aphasics (p < .05, according to Scheffe’s procedure). In addition, right-hemispheric patients surpassed the performance of both aphasic groups in the detection of agreement violations (p < .Ol for each comparison). These differences are illustrated in Fig. 1. Closer examination of brain-damaged patients’ detection of particular agreement violations couched in specific syntactic frames revealed unique patterns of performance for each group of brain-damaged patients. Consider first the different types of syntactic frames in which the violations were couched. Between-group analyses revealed, as can be seen in Fig. 2, that Broca’s aphasics performed at superior levels in comparison to fluent aphasics in the detection of agreement violations embedded in active declarative and interrogative syntactic frames (each comparison
control
ophosic
aphasic
hemispheric
FIG 1. The mean overall level of accuracy with which patients made correct meta-
linguistic judgments of sentences which did or did not exhibit violations of agreements between pronouns and verbs.
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adult Control
I declarative
I interrogative
I passive
FIG. 2. Patients’ ability to make accurate metalinguistic judgments of sentences as a function of the syntactic frame which couched the agreement.
at the p < .05 level). Differences were not found, however, with respect to Broca’s aphasics’ and fluent aphasics’ detection of violations in passive frames. It may also be noted here that right-hemispheric patients surpassed both group of aphasics in the detection of agreement violations in all syntactic frames (each comparison at the p < .Ol level). Withingroup analyses demonstrated that Broca’s aphasics found it easier to detect agreement violations when couched in active declarative and interrogative frames in comparison to their own performance with passive syntactic frames (p < .05). In contrast, fluent aphasics did not differ, at least on this task, in terms of their own detection of violations in various syntactic frames. Analyses of individual patients’ profiles further revealed that seven of nine Broca’s aphasics encountered more difficulty with passive items than their own performance with both active and interrogative items, while this pattern of performance was observed in only three of eight fluent aphasics (.lO > p > .05, according to Fisher’s exact test). Taken together, these findings indicate that the complexity of the syntactic frame couching the agreement violations selectively influenced Broca’s aphasics’ performance. Differences were found as well with respect to patients’ ability to detect various types of agreement violations. As can be seen in Fig. 3, between-group analyses revealed that that fluent aphasics found “number” violations and “person” violations significantly more difficult to detect than Broca’s aphasics (each comparison at the p < .05 level). There were no differences, however, with respect to Broca’s aphasics’ and fluent aphasics’ ability to detect violations of the “case” type of agreement. Right-hemispheric patients surpassed both groups of aphasics at detecting these agreement violations, but differences were not found between brain-damaged patients in terms of their ability to identify cor-
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GROSSMAN AND HABERMAN loo-
80 -
602 c
$
40BrOCa’s aphasic
20-
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I Control
I case
I number
I person
animocy
3. Patients’ ability to make accurate metalinguistic judgments of sentences as a function of the specific type of pronoun-related agreement which was violated. FIG.
rect items. Further, within-group analyses showed that “number” and “person” violations were more difficult for fluent aphasics to detect than their own performance with “case” agreement violations (p < .05 for each comparison). Broca’s aphasics, by comparison, did not differ with respect to their own detection of “case,” “number,” and “person” agreement violations. Analyses of individual patients’ profiles revealed that six of eight fluent aphasics encountered more difficulty detecting both “number” and “person” agreement violations in comparison to their own performance with “case” agreement violations, while this pattern was observed in only three of nine Broca’s aphasics (.lO > p > .05, according to Fisher’s exact test). It may also be noted that Broca’s aphasics, fluent aphasics, and right-hemispheric patients encountered significantly more difficulty detecting violations of the “animacy” type of agreement than control subjects (each comparison at the p < .Ol level). These findings reveal, then, that fluent aphasics were selectively influenced by the type of pronoun-related agreement which they were asked to judge. Broca’s aphasics and right-hemispheric patients were also impaired in their ability to detect violations of the “animacy” type of agreement. An examination of the interaction between the syntactic frame and the type of pronoun-related agreement revealed one significant finding. Between-group analyses demonstrated, as can be seen in Fig. 4, that Broca’s aphasics experienced significantly less difficulty detecting the “case” type of agreement violation in active declarative and interrogative syntactic frames than fluent aphasics (each comparison at the p < .05 level). Differences between groups of aphasics were not found with respect to the detection of “case” agreement violations in passive syntactic frames. Within-group analyses revealed that Broca’s aphasics could detect vio-
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declarative
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interrogative
passive
FIG. 4. The interaction between the detection of the largely structural “case” type of agreement violation and the syntactic frame within which the “case” violation was couched.
lations of the “case” type of agreement in active and interrogative syntactic frames with significantly more success than their own performance in passive syntactic frames (p < .05). Fluent aphasics, however, did not differ in terms of their own detection of “case” violations in the various syntactic frames. Analyses of individual patients’ profiles confirmed that seven of nine Broca’s aphasics succeeded at detecting “case” agreement violations in active and interrogative syntactic frames in contrast to their own performance in passive frames, while only two of eight fluent aphasics exhibited the same pattern (p < .05, according to Fisher’s exact test). DISCUSSION Many studies have revealed deficits in aphasics’ ability to process features of sentential structure (e.g., Caramazza & Zurif, 1976; Gardner et al., 1975; Goodglass, 1976; Heeschen, 1980; Zurif & Blumstein, 1978). Aphasics also exhibit considerable difficulty in the present study at making metalinguistic judgments about grammatical information in sentences. They often accept sentences as correct even though they contain violations of agreements between pronouns and verbs. That is, aphasics appear to be insensitive to some grammatical agreements. It may be noted in this context that subjects generally accept the correct sentences as “correct.” So, aphasics may attempt to distinguish between correct items and the items which they believe contain agreement violations, but the faulty nature of their grammatical knowledge apparently results in their treatment of some violations just like correct items. The present study also attempted to characterize more precisely the nature of the grammatical deficit in Broca’s aphasics and fluent aphasics. Examinations of brain-damaged patients’ patterns of performance reveal
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that aphasics’ ability to detect agreement violations in various syntactic frames is not compromised in an “across-the-board” fashion. Rather, Broca’s aphasics and fluent aphasics each appear to be selectively insensitive to different aspects of the information which signals grammatical relations among words in a sentence. Broca’s aphasics are selectively influenced by the sentence’s syntactic frame. Specifically, they fail to detect agreement violations when they are couched in syntactically complex, passive sentential frames. It is possible that Broca’s aphasics’ inability to grasp unstressed words like the auxiliaries (e.g., Goodglass, 1968; Kean, 1978) or their difficulty appreciating the order of words in sentences (e.g. Schwartz, Saffran, & Marin, 1980) can explain this finding. However, these accounts would predict impairments with the active and interrogative frames as well. These findings reveal that Broca’s aphasics are significantly more successful at detecting agreement violations in syntactically simpler contexts, even though these sentential frames include auxiliaries and a particular ordering of words. Accordingly, it may be that Broca’s aphasics’ grammatical comprehension deficit turns especially on their inability in this task to compute relations among words in a sentence when they are not arrayed in a canonical fashion, as in passives. This is consistent with other findings demonstrating Broca’s aphasics’ disorders appreciating syntactic structure (e.g., Caramazza 8z Zurif, 1976; Goodglass, 1976; Goodglass et al., 1979; Zurif et al., 1976). It is important to note at this point that Broca’s aphasics may not be agrammatic in an “across-the-board” fashion. Rather, their impaired grasp of grammatical relations among words may be restricted to certain aspects of sentence form. Specifically, Broca’s aphasics are quite successful in the present study at detecting violations of the largely structural “case” type of agreement when embedded in a simpler syntactic frame. Thus, when a sentence’s major lexical constituents are explicitly stated in a canonical, S-V-O order, Broca’s aphasics apparently are sensitive to the violation of a grammatical agreement which reflects primarily structural information about a sentence. This is consistent with other observations that Broca’s aphasics are not agrammatic in an undifferentiated fashion. Grossman, Diller, Carey, and Zurif (1981), for example, have demonstrated that Broca’s aphasics can appreciate under certain conditions the form class distinction between a common noun and a proper noun, a distinction which turns on the presence or absence of an article. Fluent aphasics’ pattern of performance differs notably from Broca’s aphasics’ judgment profiles. Unlike Broca’s aphasics, fluent aphasics encounter greater difficulty detecting violations involving semantic as well as structural information than violations which reflect primarily structural aspects of a sentence. Several possible explanations for this,
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unrelated to grammatical facets of the task, come to mind, but these can be dismissed. Thus, the notion that they are merely responding randomly (in the face of their language comprehension deficit) cannot be maintained given that they are as successful as other patients at identifying correct items, and that they are selectively sensitive to certain agreement violations (e.g., “case”) but less so others (i.e., “number” and “person”). Similarly, it is unlikely that fluent aphasics are merely making random “false positive” errors given that they differed in their judgments depending on the particular agreement violation. It could be argued that fluent aphasics’ semantic deficit contributed to their inferior performance, and may account for their relatively impaired metalinguistic judgments in comparison to Broca’s aphasics. In fact, the “number” and “person” agreement violations prove most difficult for fluent aphasics to detect. These involve both semantic and structural information in comparison to the “case” type of agreement which involves primarily structural information and proves relatively easier for fluent aphasics to detect. It is intriguing to speculate, then, that fluent aphasics are more impaired at detecting “number” and “person” agreement violations since patients must attend to both semantic and structural elements to appreciate fully these types of agreements, that is, in contrast to just the largely structural component of the “case” type of agreement. In the context of fluent aphasics’ semantic comprehension disorders, it may not seem surprising that they encounter difficulty detecting violations of the “animacy” type of agreement. It is somewhat unexpected, however, that Broca’s aphasics and right-hemispheric patients are also impaired at detecting ‘animacy’ agreement violations. Clearly further research is necessary to establish the precise contribution of various cerebral zones to the grasp of notions like agency in sentential contexts. REFERENCES Caramazza, A., & Bemdt, R. S. 1978. Semantic and syntactic processes in aphasia: A Bulletin, 85, 898-918. review of the literature. Psychobgical Caramazza, A., & Zurif, E. B. 1976. Dissociation of algorithmic and heuristic processes in language comprehension: Evidence from aphasia. Brain and Language, 3, 572-582. Gardner, H., Denes, G., & Zurif, E. B. 1975. Critical reading at the sentence level in aphasia. Cortex, 11, 60-72. Goodglass, H. 1978. Studies in the grammar of aphasics. In S. Rosenberg & J. H. Koplin (Eds.), Developments in applied psycholinguistic research. New York: MacMillan. Goodglass, H. 1976. Agrammatism. In H. Whitaker & H. A. Whitaker (Eds.), Studies in neurolinguistics. New York: Academic Press. Goodglass, H., Blumstein, S., Gleason, J. B., Hyde, M., Green, E., & Statlender, S. 1979. The effects of syntactic encoding on sentence comprehension in aphasia. Brain and Language,
7, 201-209.
Goodglass, H., Hyde, M., & Blumstein, S. 1969. Frequency, picturability, and the availability of nouns in aphasia. Cortex, 5, 104-119. Goodglass, H., & Kaplan, E. 1972. The assessment of uphasin and related disorders. Philadelphia: Lea & Febiger.
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Grossman, M. 1981. A bird is a bird is a bird: Making reference within and without a superordinate category. Brain and Language, 12, 3 13-33 1. Grossman, M., Diller, L., Carey, S., & Zurif, E. B. 1981. A pitta class: Broca’s aphasics’ appreciation of a form class distinction which turns on the presence or absence of an article. Paper presented at the International Neuropsychological Society, Atlanta, February. Heeschen, C. 1980. Strategies of decoding actor-object relations by aphasic patients. Cortex, 16, 5-19. Kean, M.-L. 1978. The linguistic interpretation of Broca’s aphasia. Cognition, 5, 9-46. Morgan, J. L. 1972. Verb arrangement as a rule of English. Chicago Linguistic Society, 8, 278-286. Lhermitte, F., Desrouesne, J., & Lecours, A. R. 1971. Contribution a I’ttude des troubles semantiques dans I’aphasie. Revue Neurologique, 125, 81-101. Schwartz, M., Saffran, E., & Marin, 0. 1980. The word order problem in agrammatism. 1. Comprehension. Bruin and Language, 10, 249-262. Wagenaar, E., Snow, C., & Prins, R. 1975. Spontaneous speech of aphasic patients. Bruin and Language, 2, 281-303. Zurif, E. B., & Blumstein, S. 1978. Language and the brain. In M. Halle, J. Bresnan, & G. Miller (Eds.), Linguistic theory andpsychological reality. Cambridge: MIT Press. Zurif, E. B., & Caramazza, A., 1976. Psycholinguistic structures in aphasia: Studies in syntax and semantics. In H. Whitaker & H. A. Whitaker (Eds.), Studies in neurolinguistics. New York: Academic Press. Zurif, E. B., Caramazza, A., Myerson, R., & Galvin, S. 1974. Semantic feature representation in normal and aphasic language. Bruin and Language, 1, 167-187. Zurif, E. B., Green, E., Caramazza, A., & Goodenough, C. 1976. Grammatical intuitions of aphasic patients: Sensitivity to functors. Cortex, 12, 183-186.
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Aphasics’ Selective Deficits in Appreciating Grammatical Agreements MURRAY GROSSMAN AND SUSANNA HABERMAN Boston University School of Medicine This study attempted to dissociate in aphasic patients different aspects of grammatical capacity. Subjects were asked to evaluate sentences containing violations of agreements between pronouns and verbs. Agreements which are considered primarily structural in nature were violated (e.g., a surface object case like “them” placed in a surface subject sentential slot) while other violated agreements seemed to involve both structural and semantic information (e.g., lack of agreement between a pronoun and a verb in terms of the number of people performing the act). These violations were couched in one of three types of sentential frames which varied in terms of syntactic complexity (e.g., active declarative vs. passive syntactic voices). The results revealed that Broca’s aphasics found agreement violations difficult to detect in complex syntactic frames. They were quite successful at detecting even violations of the largely structural “case” type of agreement, however, when couched in simpler syntactic frames. Fluent aphasics encountered more difficulty detecting violations of agreements involving both semantic and structural information than agreements which were primarily structural in nature, that is, regardless of the syntactic frame. These unique performance profiles suggest that Broca’s aphasics may be agrammatic only with respect to certain aspects of a sentence’s structure, and that fluent aphasics may also experience some selective-but different-grammatical deficits.
INTRODUCTION Grammatical relations among words in a sentence-that is, the formal structural properties that specify the manner in which words relate to (and are related to) other words in a sentence-are signaled in a number We would like to express our appreciation to Dr. Anna Pomfret and the staff of the New England Rehabilitation Hospital and to Dr. Michael P. Alexander and the staff of the Neurobehavioral Unit of the Boston Veterans Administration Medical Center for their help. We also thank Lise Menn for her valuable comments on an earlier draft of this paper. This work was supported in part by grants from NIH (NSl.5972, NS.11408,and NS06209). Portions of this study were presented at BABBLE, Niagara Falls, April, 1980. Please address reprint requests to: Murray Grossman, Psychology Research Section, Boston Veterans Administration Medical Center, 150 South Huntington Ave., Boston, MA 02130. 109
0093-934X/82/030109-12$02.00/0 Copyright 0 1982 by Academic Press, Inc. All rights of reproduction in any form reserved.
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of different ways (e.g., Morgan, 1972). For example, grammatical relations are specified in part by the sentence’s voice or syntactic frame. The syntactic frame of a sentence distinguishes between, say, an active declarative sentence and a sentence in the passive voice on the basis of the presence or absence of the verb’s auxiliary and past participle, and the introduction of the logical subject with the preposition “by” usually after the verb. This allows the logical subject and object of the sentence to be identified. Grammatical relations among words in a sentence are also reflected by the set of agreements between pronouns and verbs. There must be agreement at least between the pronoun of a sentence and the surface subject or surface object sentential slot (i.e., “case” agreement), and between the pronoun and the “number” and “person” information reflected in its verb. The pronoun must also meet the verb’s restrictions on plausible linguistic agents (e.g., that the agent of an action must be human-what we will call an “animacy” agreement). These agreements appear to reflect both structural and semantic information, and although highly intuitive, may involve differing degrees of these components. Consider “case” in this respect. Even though “case” involves a semantic component, the “case” agreement seems primarily structural in nature since it largely mirrors the assignment of phrasal structure. “Person” and “number” agreements, by comparison, may involve semantic as well as structural information since the number of people performing an act and their relationship to the speaker of the sentence reflect interpretive as well as structural aspects of the sentence. Likewise, there is an important semantic consequence vis-a-vis the “animacy” agreement. These types of agreements are outlined in Table 1. The purpose of the present study was to determine in greater detail the status of Broca’s aphasics’ and fluent aphasics’ appreciation of several structural aspects of grammar, including the syntactic and the “case, ” “number,” and “person” aspects of a sentence. Broca’s aphasics’ difficulty with complex syntactic material is well documented (e.g., Caramazza & Zurif, 1976; Goodglass, 1976; Goodglass, Blumstein, Gleason, Hyde, Green, & Statlender, 1979; Zurif, Green, Caramazza, & Goodenough, 1976). This work has suggested that Broca’s aphasics are compromised in their grasp of the meaning of sentences with noncanonical syntactic frames (i.e., non-S-V-O sentences such as passives). However, the relation between this syntactic deficit and their appreciation of other structural components of grammar-such as the ability to grasp the “case,” “number,” and “person” types of grammatical agreements-remains to be specified. Indeed, although the speech of aphasics contains pronouns like “he,” “them,” and “it” (Goodglass, Hyde, & Blumstein, 1969; Wagenaar, Snow, & Prins, 1975), it is unclear whether they fully appreciate the “case,” “number,” and “person” agreements
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1
INVESTIGATED IN THIS STUDY, AND EXAMPLESOF VIOLATIONSOF EACH TYPE OF AGREEMENT
AN OUTLINE
OF THE TYPES OF AGREEMENTS
Type of agreement
BETWEEN PRONOUNS AND VERBS
Locus of agreement
Examples of agreement violations
Case (Primarily structural)
Reflecting the surface subject position or the surface object position of the pronoun with respect to the sentence’s verb
Them are going to the store. The ball is kicked by he.
Number (structural and semantic)
Agreement of number information between a pronoun in the surface subject position and the verb (i.e., singular vs. plural)
They is watching the birdie. Am we playing baseball?
Person (structural and semantic)
Agreement of person information between a pronoun in the surface subject position and the verb (i.e., first person vs. third person)
I is reading a newspaper. He am kissed by Jane.
Animacy (primarily semantic)
Agreement between a pronoun as an agent and the verb’s constraint of a necessarily human agent
It is praying in church. Is it marrying in the
between pronouns and their verbs. After all, the structure of their utterances is often unspecifiable due to the incorrect use (in fluent aphasics) or absence (in Broca’s aphasics) of closed class terms. A study of aphasics’ critical reading (Gardner, Denes, & Zurif, 1975) in fact has indicated some problems in appreciating agreements involving pronouns. Gardner et al. asked aphasics to judge the correctness of sentences where some of the items exhibited an incorrect pronominal adjective substituted for the correct adjective (e.g., “John sat on him chair”; “The girl raised his arm”). Broca’s aphasics and fluent aphasics both exhibited some difficulty evaluating these items. In order to determine whether Broca’s aphasics are impaired in their appreciation of all aspects of sentence form and whether fluent aphasics exhibit any selective deficits in appreciating grammatical agreements, both syntactic frame and pronoun-related agreement aspects of a sentence were manipulated systematically. Patients were then asked to judge the correctness of these sentences. Thus, the “case,” “number,” “person,” and “animacy” types of pronoun-related agreements were violated one at a time, and these violations were couched in sentences exhibiting active declarative, interrogative, and passive syntaciic frames. If Broca’s aphasics are compromised at appreciating most structural aspects of a
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sentence, then the passive syntactic frame should be the most troublesome context for the detection of pronoun-related agreement violations. Violations of the largely structural “case” agreement may also prove difficult to detect even in syntactically simpler contexts, since this type of agreement contributes primarily to the assignment of phrasal structure. Fluent aphasics, by comparison, exhibit well-documented semantic disorders (e.g., Grossman, 1981; Lhermitte, DCsrouesnC, & Lecours, 1971; Zurif, Caramazza, Myerson, & Galvin, 1974). These patients may find “number,” “person,” and “animacy” agreements most difficult to detect, then, due to their inability to bring semantic capacities to bear for the full appreciation of these grammatical agreements. METHODS Subjects Twenty-eight right-handed, high-school-educated, native English speakers between the ages of 35 and 60 years were examined. All brain-damaged patients were classified on the basis of neuroradiological information such as CT scans, performance profiles on standard neuropsychological tests such as the Boston Diagnostic Aphasia Examination (Goodglass & Kaplan, 1972) and significant portions of the frontal lobe and parietal lobe batteries in use at the Aphasia Research Center and New England Rehabilitation Hospital, and clinical examinations of neurologists. The subjects comprised nine Broca’s aphasics and eight fluent aphasics. Six patients with right-hemispheric insult were also examined as a braindamaged control group. As shown by these tests, Broca’s aphasics exhibited effortful, agrammatic speech in the context of relatively intact comprehension of single words and simple utterances, following insult to the anterior portion of the left hemisphere. Fluent aphasics presented with semantic comprehension deficits and well-intoned, somewhat empty speech with many functors and relatively few contentives, associated with temporoparietal disease in the left hemisphere. Subjects with a lesion in the anterocentral portion of the right hemisphere were not aphasic, although they did evidence some mild impairments interpreting paragraph-length material. Many of the visuospatial and auditory impairments associated with a right-hemispheric lesion were documented. All but one of the brain-damaged patients (a surgical patient who had suffered a penetrating brain wound) had experienced a stroke. Patients were tested at least 6 months after the onset of an aphasia in order to ensure, in so far as possible, a relatively stable profile of linguistic deficit. Five nonneurological control subjects were also examined. These subjects were volunteers from the general medical wards of the Boston Veterans Administration Medical Center. Interviews with family members and friends confirmed that all subjects spoke a standard dialect of English, where utterances such as “they is” and “he am” were considered poor English and were rarely produced.
Procedure Patients were presented orally with 152 sentences, one at a time, and were asked to judge if they were correct or if something was wrong with them. The sentences were read to patients in a fashion which preserved natural intonational contours, and a sentence was repeated once if requested. Sixty percent of the sentences contained an agreement violation, and these items were randomly distributed among the correct items, with all patients encountering the same random order. Four types of agreement violations were examined. Twenty percent of the incorrect items exhibited just “person” agreement violations, 20% “number” violations,
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20% “animacy” violations, and the remaining 40% of the incorrect items exhibited violations of only the “case” type of agreement. Each type of agreement violation was equally distributed over three types of syntactic frames, that is, active declarative, interrogative, and passive. Examples of agreement violations couched in these syntactic frames are provided in Table 1. It may be noted at this point that, for the “case” agreement violation, a surface subject case was replaced with a surface object case as often as a surface object case was replaced with a surface subject case. For the “person” type of violation, a first person pronoun or verb auxiliary was substituted for a third person pronoun or auxiliary, respectively, as often as a third person constituent was substituted for a first person constituent. For the “number” type of violation, a singular pronoun or auxiliary and a plural pronoun or auxiliary were replaced with the other, respectively, equally often. The nonmanipulated information represented by the pronoun and verb auxiliary was balanced in all instances (e.g., an equal number of first and third person constituents exhibited “number” violations). All items contained verbs’ auxiliaries, it may be noted, so that the presence or absence of an auxiliary would not provide clues to syntactic structure, and since these reflect more specific “person” and “number” information than morphological inflections of verbs. For example, we used something like “I am helping Jane” rather than “I help Jane” since the absence of an inflection on “help” only indicates that the subject is not third person singular, while the auxiliary “am” indicates that the subject should be both singular and first person. Interrogatives were formed by inverting the surface subject of a sentence and the auxiliary. Moreover, each type of agreement violation was concerned with a relationship between a pronoun and an auxiliary verb, so the pronoun’s coreferent did not have to appear in the sentence. Sentences were quite sparse lexically, although the major lexical constituents varied from item to item. A brief training period was administered before the set of items in order to establish the types of judgments which were required and a response mode for patients to indicate their judgments. During this session, patients were presented with sentences containing grammatical violations which were increasingly difficult to detect. An earlier item in the training period, for instance, violated three types of agreements simultaneously (e.g., “Them am kicking cans”) while a later item violated only two pronoun-related agreements.
RESULTS In order to assess patients’ ability to detect agreement violations when couched in various syntactic frames, a group (4) x type of agreement violation (5) analysis of variance-with the “syntactic frame” variable nested within the “violation type” variable-was employed. Significant main effects were found for group (F (3, 345) = 106.94; p < .OOl) and violation type (F (4, 345) = 34.31; 4,345; p < .OOl), and a significant group x violation interaction was also found (F (12, 345) = 7.45; p < .OOl). Subsequent analyses by the Scheffe method revealed that control subjects detected the agreement violations at significantly superior levels overall in comparison to each of the brain-damaged groups (each comparison at the p < .Ol level), and in fact performed at ceiling levels on all aspects of the task. Due to the possible effect of control subjects’ ceiling level of performance on the analysis of variance statistic, Kruskal-Wallis analyses of variance for ranks-a statistic less sensitive to the requirement for homogeneity of variance-were also performed on these data. An analysis of patients’ overall performance revealed H
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= 15.81 which, with three degrees of freedom, is significant at the p < .OOl level. Similarly, analyses of variance for ranks for each of the syntactic frames were significant at the p < .Ol level (declarative: H = 13.69; interrogative: H = 15.48; passive: H = 13.22). Analyses of variance for ranks were also significant at the .lO > p > .Ol level for each of the types of pronoun-related agreement violations (case: H = 6.45; person: H = 7.05; number: H = 8.29; animacy: H = 9.19). These analyses suggest, then, that the distribution of control subjects’ scores by itself fails to account for the differences among groups. With one exception, moreover, all of the differences discussed below are between groups of brain-damaged patients. Further analyses of brain-damaged patients’ overall ability to detect agreement violations also revealed differences. Broca’s aphasics performed at significantly more successful levels overall than fluent aphasics (p < .05, according to Scheffe’s procedure). In addition, right-hemispheric patients surpassed the performance of both aphasic groups in the detection of agreement violations (p < .Ol for each comparison). These differences are illustrated in Fig. 1. Closer examination of brain-damaged patients’ detection of particular agreement violations couched in specific syntactic frames revealed unique patterns of performance for each group of brain-damaged patients. Consider first the different types of syntactic frames in which the violations were couched. Between-group analyses revealed, as can be seen in Fig. 2, that Broca’s aphasics performed at superior levels in comparison to fluent aphasics in the detection of agreement violations embedded in active declarative and interrogative syntactic frames (each comparison
control
ophosic
aphasic
hemispheric
FIG 1. The mean overall level of accuracy with which patients made correct meta-
linguistic judgments of sentences which did or did not exhibit violations of agreements between pronouns and verbs.
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adult Control
I declarative
I interrogative
I passive
FIG. 2. Patients’ ability to make accurate metalinguistic judgments of sentences as a function of the syntactic frame which couched the agreement.
at the p < .05 level). Differences were not found, however, with respect to Broca’s aphasics’ and fluent aphasics’ detection of violations in passive frames. It may also be noted here that right-hemispheric patients surpassed both group of aphasics in the detection of agreement violations in all syntactic frames (each comparison at the p < .Ol level). Withingroup analyses demonstrated that Broca’s aphasics found it easier to detect agreement violations when couched in active declarative and interrogative frames in comparison to their own performance with passive syntactic frames (p < .05). In contrast, fluent aphasics did not differ, at least on this task, in terms of their own detection of violations in various syntactic frames. Analyses of individual patients’ profiles further revealed that seven of nine Broca’s aphasics encountered more difficulty with passive items than their own performance with both active and interrogative items, while this pattern of performance was observed in only three of eight fluent aphasics (.lO > p > .05, according to Fisher’s exact test). Taken together, these findings indicate that the complexity of the syntactic frame couching the agreement violations selectively influenced Broca’s aphasics’ performance. Differences were found as well with respect to patients’ ability to detect various types of agreement violations. As can be seen in Fig. 3, between-group analyses revealed that that fluent aphasics found “number” violations and “person” violations significantly more difficult to detect than Broca’s aphasics (each comparison at the p < .05 level). There were no differences, however, with respect to Broca’s aphasics’ and fluent aphasics’ ability to detect violations of the “case” type of agreement. Right-hemispheric patients surpassed both groups of aphasics at detecting these agreement violations, but differences were not found between brain-damaged patients in terms of their ability to identify cor-
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GROSSMAN AND HABERMAN loo-
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602 c
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40BrOCa’s aphasic
20-
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I Control
I case
I number
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3. Patients’ ability to make accurate metalinguistic judgments of sentences as a function of the specific type of pronoun-related agreement which was violated. FIG.
rect items. Further, within-group analyses showed that “number” and “person” violations were more difficult for fluent aphasics to detect than their own performance with “case” agreement violations (p < .05 for each comparison). Broca’s aphasics, by comparison, did not differ with respect to their own detection of “case,” “number,” and “person” agreement violations. Analyses of individual patients’ profiles revealed that six of eight fluent aphasics encountered more difficulty detecting both “number” and “person” agreement violations in comparison to their own performance with “case” agreement violations, while this pattern was observed in only three of nine Broca’s aphasics (.lO > p > .05, according to Fisher’s exact test). It may also be noted that Broca’s aphasics, fluent aphasics, and right-hemispheric patients encountered significantly more difficulty detecting violations of the “animacy” type of agreement than control subjects (each comparison at the p < .Ol level). These findings reveal, then, that fluent aphasics were selectively influenced by the type of pronoun-related agreement which they were asked to judge. Broca’s aphasics and right-hemispheric patients were also impaired in their ability to detect violations of the “animacy” type of agreement. An examination of the interaction between the syntactic frame and the type of pronoun-related agreement revealed one significant finding. Between-group analyses demonstrated, as can be seen in Fig. 4, that Broca’s aphasics experienced significantly less difficulty detecting the “case” type of agreement violation in active declarative and interrogative syntactic frames than fluent aphasics (each comparison at the p < .05 level). Differences between groups of aphasics were not found with respect to the detection of “case” agreement violations in passive syntactic frames. Within-group analyses revealed that Broca’s aphasics could detect vio-
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interrogative
passive
FIG. 4. The interaction between the detection of the largely structural “case” type of agreement violation and the syntactic frame within which the “case” violation was couched.
lations of the “case” type of agreement in active and interrogative syntactic frames with significantly more success than their own performance in passive syntactic frames (p < .05). Fluent aphasics, however, did not differ in terms of their own detection of “case” violations in the various syntactic frames. Analyses of individual patients’ profiles confirmed that seven of nine Broca’s aphasics succeeded at detecting “case” agreement violations in active and interrogative syntactic frames in contrast to their own performance in passive frames, while only two of eight fluent aphasics exhibited the same pattern (p < .05, according to Fisher’s exact test). DISCUSSION Many studies have revealed deficits in aphasics’ ability to process features of sentential structure (e.g., Caramazza & Zurif, 1976; Gardner et al., 1975; Goodglass, 1976; Heeschen, 1980; Zurif & Blumstein, 1978). Aphasics also exhibit considerable difficulty in the present study at making metalinguistic judgments about grammatical information in sentences. They often accept sentences as correct even though they contain violations of agreements between pronouns and verbs. That is, aphasics appear to be insensitive to some grammatical agreements. It may be noted in this context that subjects generally accept the correct sentences as “correct.” So, aphasics may attempt to distinguish between correct items and the items which they believe contain agreement violations, but the faulty nature of their grammatical knowledge apparently results in their treatment of some violations just like correct items. The present study also attempted to characterize more precisely the nature of the grammatical deficit in Broca’s aphasics and fluent aphasics. Examinations of brain-damaged patients’ patterns of performance reveal
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that aphasics’ ability to detect agreement violations in various syntactic frames is not compromised in an “across-the-board” fashion. Rather, Broca’s aphasics and fluent aphasics each appear to be selectively insensitive to different aspects of the information which signals grammatical relations among words in a sentence. Broca’s aphasics are selectively influenced by the sentence’s syntactic frame. Specifically, they fail to detect agreement violations when they are couched in syntactically complex, passive sentential frames. It is possible that Broca’s aphasics’ inability to grasp unstressed words like the auxiliaries (e.g., Goodglass, 1968; Kean, 1978) or their difficulty appreciating the order of words in sentences (e.g. Schwartz, Saffran, & Marin, 1980) can explain this finding. However, these accounts would predict impairments with the active and interrogative frames as well. These findings reveal that Broca’s aphasics are significantly more successful at detecting agreement violations in syntactically simpler contexts, even though these sentential frames include auxiliaries and a particular ordering of words. Accordingly, it may be that Broca’s aphasics’ grammatical comprehension deficit turns especially on their inability in this task to compute relations among words in a sentence when they are not arrayed in a canonical fashion, as in passives. This is consistent with other findings demonstrating Broca’s aphasics’ disorders appreciating syntactic structure (e.g., Caramazza 8z Zurif, 1976; Goodglass, 1976; Goodglass et al., 1979; Zurif et al., 1976). It is important to note at this point that Broca’s aphasics may not be agrammatic in an “across-the-board” fashion. Rather, their impaired grasp of grammatical relations among words may be restricted to certain aspects of sentence form. Specifically, Broca’s aphasics are quite successful in the present study at detecting violations of the largely structural “case” type of agreement when embedded in a simpler syntactic frame. Thus, when a sentence’s major lexical constituents are explicitly stated in a canonical, S-V-O order, Broca’s aphasics apparently are sensitive to the violation of a grammatical agreement which reflects primarily structural information about a sentence. This is consistent with other observations that Broca’s aphasics are not agrammatic in an undifferentiated fashion. Grossman, Diller, Carey, and Zurif (1981), for example, have demonstrated that Broca’s aphasics can appreciate under certain conditions the form class distinction between a common noun and a proper noun, a distinction which turns on the presence or absence of an article. Fluent aphasics’ pattern of performance differs notably from Broca’s aphasics’ judgment profiles. Unlike Broca’s aphasics, fluent aphasics encounter greater difficulty detecting violations involving semantic as well as structural information than violations which reflect primarily structural aspects of a sentence. Several possible explanations for this,
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unrelated to grammatical facets of the task, come to mind, but these can be dismissed. Thus, the notion that they are merely responding randomly (in the face of their language comprehension deficit) cannot be maintained given that they are as successful as other patients at identifying correct items, and that they are selectively sensitive to certain agreement violations (e.g., “case”) but less so others (i.e., “number” and “person”). Similarly, it is unlikely that fluent aphasics are merely making random “false positive” errors given that they differed in their judgments depending on the particular agreement violation. It could be argued that fluent aphasics’ semantic deficit contributed to their inferior performance, and may account for their relatively impaired metalinguistic judgments in comparison to Broca’s aphasics. In fact, the “number” and “person” agreement violations prove most difficult for fluent aphasics to detect. These involve both semantic and structural information in comparison to the “case” type of agreement which involves primarily structural information and proves relatively easier for fluent aphasics to detect. It is intriguing to speculate, then, that fluent aphasics are more impaired at detecting “number” and “person” agreement violations since patients must attend to both semantic and structural elements to appreciate fully these types of agreements, that is, in contrast to just the largely structural component of the “case” type of agreement. In the context of fluent aphasics’ semantic comprehension disorders, it may not seem surprising that they encounter difficulty detecting violations of the “animacy” type of agreement. It is somewhat unexpected, however, that Broca’s aphasics and right-hemispheric patients are also impaired at detecting ‘animacy’ agreement violations. Clearly further research is necessary to establish the precise contribution of various cerebral zones to the grasp of notions like agency in sentential contexts. REFERENCES Caramazza, A., & Bemdt, R. S. 1978. Semantic and syntactic processes in aphasia: A Bulletin, 85, 898-918. review of the literature. Psychobgical Caramazza, A., & Zurif, E. B. 1976. Dissociation of algorithmic and heuristic processes in language comprehension: Evidence from aphasia. Brain and Language, 3, 572-582. Gardner, H., Denes, G., & Zurif, E. B. 1975. Critical reading at the sentence level in aphasia. Cortex, 11, 60-72. Goodglass, H. 1978. Studies in the grammar of aphasics. In S. Rosenberg & J. H. Koplin (Eds.), Developments in applied psycholinguistic research. New York: MacMillan. Goodglass, H. 1976. Agrammatism. In H. Whitaker & H. A. Whitaker (Eds.), Studies in neurolinguistics. New York: Academic Press. Goodglass, H., Blumstein, S., Gleason, J. B., Hyde, M., Green, E., & Statlender, S. 1979. The effects of syntactic encoding on sentence comprehension in aphasia. Brain and Language,
7, 201-209.
Goodglass, H., Hyde, M., & Blumstein, S. 1969. Frequency, picturability, and the availability of nouns in aphasia. Cortex, 5, 104-119. Goodglass, H., & Kaplan, E. 1972. The assessment of uphasin and related disorders. Philadelphia: Lea & Febiger.
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Grossman, M. 1981. A bird is a bird is a bird: Making reference within and without a superordinate category. Brain and Language, 12, 3 13-33 1. Grossman, M., Diller, L., Carey, S., & Zurif, E. B. 1981. A pitta class: Broca’s aphasics’ appreciation of a form class distinction which turns on the presence or absence of an article. Paper presented at the International Neuropsychological Society, Atlanta, February. Heeschen, C. 1980. Strategies of decoding actor-object relations by aphasic patients. Cortex, 16, 5-19. Kean, M.-L. 1978. The linguistic interpretation of Broca’s aphasia. Cognition, 5, 9-46. Morgan, J. L. 1972. Verb arrangement as a rule of English. Chicago Linguistic Society, 8, 278-286. Lhermitte, F., Desrouesne, J., & Lecours, A. R. 1971. Contribution a I’ttude des troubles semantiques dans I’aphasie. Revue Neurologique, 125, 81-101. Schwartz, M., Saffran, E., & Marin, 0. 1980. The word order problem in agrammatism. 1. Comprehension. Bruin and Language, 10, 249-262. Wagenaar, E., Snow, C., & Prins, R. 1975. Spontaneous speech of aphasic patients. Bruin and Language, 2, 281-303. Zurif, E. B., & Blumstein, S. 1978. Language and the brain. In M. Halle, J. Bresnan, & G. Miller (Eds.), Linguistic theory andpsychological reality. Cambridge: MIT Press. Zurif, E. B., & Caramazza, A., 1976. Psycholinguistic structures in aphasia: Studies in syntax and semantics. In H. Whitaker & H. A. Whitaker (Eds.), Studies in neurolinguistics. New York: Academic Press. Zurif, E. B., Caramazza, A., Myerson, R., & Galvin, S. 1974. Semantic feature representation in normal and aphasic language. Bruin and Language, 1, 167-187. Zurif, E. B., Green, E., Caramazza, A., & Goodenough, C. 1976. Grammatical intuitions of aphasic patients: Sensitivity to functors. Cortex, 12, 183-186.