11
APHASICS’ ATTENTION TO GRAMMATICAL MORPHEMES* CHERYL
GOODENOUGH**, EDGAR B. ZURIF and SANDRA WEINTRAUB Boston University School ofMedicine and Boston Veterans Administration
Hospital
The widespread clinical description of Broca’s aphasics as having relatively preserved comprehension compared to their reduced production provided the focus of a study of classical aphasics’ attention to definite and indefinite articles. Aphasics of four types chose figures in response Broca’s, classical Wernicke’s, mixed anterior, and anomic to sentences in which articles were used sometimes appropriately and sometimes anomalously. Measures of response latencies and observation of response choices showed that classical Broca’s aphasics like the Wernicke’s failed to attend to the articles. Only anomic aphasics performed similarly to normals. It is suggested that agrammatism precludes attention to normally semantically empty morphemes. —
—
Despite many unresolved issues concerning the appropriate bases for classifying aphasic disorders, investigators generally agree that damage to the anterior portions of the left cerebral hemisphere leads to forms of language disruption that are very different from those caused by posterior left-hemispheric damage. a classical form of posterior language disorder Patients with Wemicke’s aphasia typically produce a &dquo;fluent&dquo; output marked by facility in articulation and many long runs of words in a variety of grammatical constructions. However, their speech is informationally empty; indefinite noun phrases are often substituted for the appropriate noun and when a noun with specific reference is chosen, it is often the wrong one. Also, the Wernicke aphasic’s comprehension of language is usually very impaired. Not all forms of posterior aphasia, however, are characterized by severe comprehension problems. Very discrete temporal or temporo-parietal lesions sometimes produce what has been termed anomic aphasia in which the principal difficulty seems to be one of finding the correct words for an utterance (Goodglass and Kaplan, 1972). Nevertheless, it should be re-emphasized that, whatever differences exist among the posterior aphasias, they all present a striking contrast to those caused by anterior damage. Anterior patients (Broca’s aphasics) typically produce a non-fluent form of speech which, unlike the posterior varieties, is relatively well-supplied with words of concrete reference. Frequently described as agrammatic, their spontaneous output is characterized by omission of grammatical morphemes and by a severe reduction in length and in grammatical variety. Also, while some anterior aphasics (mixed anteriors) clearly do not -
*This study was supported by NINDS research grants 11408 and 06209 University School ofMedicine. **Now at Département de linguistique, Université du Québec à Montréal.
-
to Boston
12
show preserved comprehension, the most common clinical impression is that agrammatism coexists with relatively intact comprehension (Goodglass and Kaplan, 1972). Recent evidence suggests, however, that intact comprehension in Broca’s aphasia might be somewhat of an illusory phenomenon. That is, it would appear that agrammatic aphasics depend on semantic constraints and contextual information, and fail when grammatical information is essential to successful comprehension of the message. One source of this evidence arises from analyses of the grammatical intuitions of agrammatic patients (Zurif, Caramazza and Myerson, 1972; Zurif and Caramazza, in press). Specifically it has been shown that agrammatic patients do not have good metalinguistic control of certain function words such as articles, but can control other function words such as prepositions which have a higher level of semantic content. This observation, which is actually not inconsistent with the clinical behaviour of Broca’s that is, with their speech and their apparent high level of awareness aphasics that such patients only attend to distinctions that make a difference. Further suggests evidence in support of this notion is provided by studies (Goodglass and Hunt, 1958; Goodglass and Berko, 1960) in which the English grammatical morpheme S is realized by agrammatic patients when it indicates plurality (as in HORSES) and thus carries semantic information, but is less often produced (and its absence less frequently noted) when it redundantly marks possession (as in THE MAN’S HAT) or agreement of the third person singular verb (JOHN RUNS). If meaningfulness is the determining factor for agrammatic aphasics, they might be expected to react differently to the same function words according to whether these words are used in a context that renders them meaningful or meaningless. In contrast, Wernicke’s aphasics, whose speech is characterised by reduced information content and also misapplication of function words, (termed &dquo;paragrammatism&dquo;) would not be expected to show this difference. The meaning of function words is a much discussed question. To the extent that these item3 are purely requirements of the structure, ’serviteurs de langue’, they are empty of meaning, according to Gleason (1961). For example it would be pointless to seek the meaning of ONE in the sentence CHOOSE THE WHITE ONE; if no other nominal is inserted following the adjective, ONE must be inserted in English (as opposed to French CHOISIR LE BLANC). However, that a choice is possible between A and THE implies that there must be some difference in message between the two. Along with Gleason, Labov (1971) suggests that linguistic motivation for such choice must be sought in discourse units that go beyond the sentence. In pragmatic terms he proposes that function words may be seen as acting to &dquo;orient the listener to one’s point of view&dquo;. Traditionally the difference between A and THE has been phrased in terms of nonspecific and specific reference. Specificity or absence of it can, however, be seen as applying to the set of alternatives from which the speaker wishes the selection to be made. The speaker uses THE to signal the existence of an implicit understanding between the listener and himself that his intended referent belongs to a set of which both have knowledge. This interpretation of the meaning of THE is consistent with a suggestion of Perlmutter’s (1~970). In arguing for the derivation of the English indefinite article from -
-
13
underlying
numeral ONE
(as distinct from the pro-form ONE used in the stimuli of Perlmutter shows the presence of the definite article, at least with experiment), to be to due For example, PARIS and JOHN SMITH do relativization. proper nouns, not occur with articles unless followed by something else, e.g., THE PARIS THAT WE KNEW, THE JOHN SMITH WHO USED TO LIVE HERE. A proper noun uniquely designates its referent. But when the speaker wishes to designate one member of a set of aspects or personalities which together constitute this referent, or to differentiate one individual from another bearing the same name, that is, belonging to the set of individuals bearing this name, as in the above examples, he uses the definite article along with a following relative clause. In the examples the implied set corresponds to all the aspects of Paris, or all the individuals named John Smith. The particular member of the set corresponding to the speaker’s intended referent is designated by the information in the relative clause. In choosing A the speaker fails to imply such an agreement. The listener is thus left to make his selection from a set he determines by means of other cues, including nonlinguistic ones. With the use of THE, the speaker implies that the selection is to be made from a particular set of which he expects his listener to be aware. Deficient perception of the article will thus have a lesser effect in causing the aphasic’s response choice to differ from the normal’s in the case of A, which simply fails to provide linguistic information, than in the case of THE, which does furnish linguistic information. Olson (1970) provides an operational definition of meaning which is appropriate to this problem of meaningfulness of function words. He suggests that speakers make their choice of lexical item on the basis of the context from which they wish to differentiate an intended referent. For example, if the speaker wants his listener to pick up a particular round, white object, he would say PICK UP THE ROUND ONE if the object were next to a square white object, while if it were in the context of a black object of the same shape he would instead say PICK UP THE WHITE ONE. In order for his instruction to be meaningful, the speaker chooses the adjective which partitions the environment: the adjective referring to shape in the context of two objects of the same colour and the adjective referring to colour in order to distinguish between two objects of the same shape. Thus if instructions are given to act upon a particular context, the words in the instruction are meaningful if they allow an unequivocal partitioning of the an
this
-
context. was made in this study to devise an experimental situation in which the words, definite (THE) and indefinite (A) articles, embedded in the same linguistic contexts, could vary in relation to the extra-linguistic context; ideally, they would vary in respect to Olson’s criteria of meaningfulness. Given the nature of the English article, however, it was not possible to achieve these conditions in as systematic a way as might be hoped. What could be systematically varied was the appropriateness of the article to the extra-linguistic environment. This was done as shown in Fig. 1. Given this pictured array of three figures, such that two are of the same shape, and two of the same colour, but no two are identical, it is possible to have descriptions exemplifying each of four combinations of ’definitiveness’ of the adjective and ’appropriateness’ of the article. In conditions 1 and 3, the adjective effectively partitions
An attempt function
same
14
Fig. the
1
Sample
array.
environment, and is thus ’definitive’. In conditions 2 and 4, the adjective fails to partition the environment unambiguously. The article is appropriate in conditions 2 and 3, and anomalous in condition 1 and particularly in condition 4. Thus, appropriate and anomalous articles are systematically combined with definitive and non-definitive adjectives. However only when the adjective fails to partition the environment unequivocally does the possibility arise of the article’s fulfilling this function, that is, of the article’s being meaningful. If A and THE function in the way that is suggested above, there should be no linguistic information added by the indefinite article A in condition 2. However, THE in condition 4, even though inappropriate, should carry the message to the listener that the round object in question belongs to a set of which he is expected to possess prior knowledge. Therefore, if the description is to be accorded a semantic interpretation as an acceptable sentence, this can be done only in relation to some set other than the total array, since the phrase is anomalous with respect to that set. That is, a set must be inferred by the listener in respect to which the phrase THE ROUND ONE is appropriate. The set of two black figures is the only candidate set available. The listener must infer, in other words, that what is meant is the round one of the two black objects. Thus, not only can the article be presented as alternately appropriate and inappropriate, it can also, in Olson’s sense, vary in meaningfulness, that is, in whether or not it acts to partition the environment. Aphasic subjects were faced with arrays of the type presented in Fig. 1 and for each array were required to press as quickly as possible what they felt was the most suitable figure signalled by each of the utterances listed in Fig. 1. In order to measure the degree to which such patients, and particularly agrammatic aphasics, were sensitive to the article’s appropriateness and inappropriateness as well as to determine whether or not they could make use of linguistic information signalled by the article, reaction times were taken in addition to noting response choice. It was assumed that if aphasics were sensitive to the definite article’s role in condition 4, they would take longer to process the material in this condition before responding.
15 METHOD
Sub jects
’.
..
Eighteen aphasic patients from the Neurology ward of the Boston VA Hospital served as subjects in this study. According to the Boston Diagnostic Examination they were of the following clinical types: Broca’s aphasics (four patients), mixed anterior aphasics (5 patients), Wernicke’s aphasics (5 patients) and anomic aphasics (4 patients). The anterior aphasics (Broca’s and mixed anteriors) all showed some agrammatism, while the speech of the Wernicke’s aphasics could be described as paragrammatic. The anomic aphasics showed no grammatical deficit. Stimulus Materials and Procedure
..
There were four different arrays, each consisting of three pictured figures. One, as shown in Fig. 1, was predominantly black and round; a second was predominantly white and round (i.e., one white circle, one black circle, and one white square); a third was predominantly black and square; and a fourth, white and square. The left-to-right order in which the three pictured figures of each array was laid out was randomized for each subject. In every case, the array presented to the subject was drawn on a strip of white cardboard which could be attached to a telegraph key. This key, when depressed, turned off a millisecond counter connected to a printout. The
activated
signal on the tape which provided the PRESS THE/A WHITE/BLACK/ ROUND/SQUARE ONE were recorded once each, with intonational emphasis placed on the adjective. The signal which activated the timer was inserted at the beginning of the sentence. The sentences were then re-recorded in five different random orders. counter was
by
a
subjects’ instructions. The eight
non-audible sentences
Subjects were tested individually. Each subject was seated at a table with the telegraph key in front of the hand ipsilateral to the side of lesion, that is, the left hand for all but one of the subjects. One random order of each of the four types of arrays was in turn affixed to the telegraph key. The subject was told he would hear sentences of the type PRESS THE BLACK ONE, and was to depress the telegraph key by pressing on the drawn object according to the instruction. A practice set of eight sentences was given, and then the subject did four test sets, each set, as mentioned, consisting of one of the six possible orders of one of the four arrays. All four arrays, were used once for each subject, the last set of sentences using an array of the same type as that given in the practice trials. Every set provided two examples of each combination of appropriateness of the article and definitiveness of the adjective (see Fig. 1 for the four conditions). Besides the automatic recording of reaction times, an experimenter observed the patient’s responses, noting which object was chosen in response to each instruction, and any comment or pertinent gesture the subject made.
16 TABLE 1
Linear comparisons reaching
*
p
APHASICS’ ATTENTION TO GRAMMATICAL MORPHEMES* CHERYL
GOODENOUGH**, EDGAR B. ZURIF and SANDRA WEINTRAUB Boston University School ofMedicine and Boston Veterans Administration
Hospital
The widespread clinical description of Broca’s aphasics as having relatively preserved comprehension compared to their reduced production provided the focus of a study of classical aphasics’ attention to definite and indefinite articles. Aphasics of four types chose figures in response Broca’s, classical Wernicke’s, mixed anterior, and anomic to sentences in which articles were used sometimes appropriately and sometimes anomalously. Measures of response latencies and observation of response choices showed that classical Broca’s aphasics like the Wernicke’s failed to attend to the articles. Only anomic aphasics performed similarly to normals. It is suggested that agrammatism precludes attention to normally semantically empty morphemes. —
—
Despite many unresolved issues concerning the appropriate bases for classifying aphasic disorders, investigators generally agree that damage to the anterior portions of the left cerebral hemisphere leads to forms of language disruption that are very different from those caused by posterior left-hemispheric damage. a classical form of posterior language disorder Patients with Wemicke’s aphasia typically produce a &dquo;fluent&dquo; output marked by facility in articulation and many long runs of words in a variety of grammatical constructions. However, their speech is informationally empty; indefinite noun phrases are often substituted for the appropriate noun and when a noun with specific reference is chosen, it is often the wrong one. Also, the Wernicke aphasic’s comprehension of language is usually very impaired. Not all forms of posterior aphasia, however, are characterized by severe comprehension problems. Very discrete temporal or temporo-parietal lesions sometimes produce what has been termed anomic aphasia in which the principal difficulty seems to be one of finding the correct words for an utterance (Goodglass and Kaplan, 1972). Nevertheless, it should be re-emphasized that, whatever differences exist among the posterior aphasias, they all present a striking contrast to those caused by anterior damage. Anterior patients (Broca’s aphasics) typically produce a non-fluent form of speech which, unlike the posterior varieties, is relatively well-supplied with words of concrete reference. Frequently described as agrammatic, their spontaneous output is characterized by omission of grammatical morphemes and by a severe reduction in length and in grammatical variety. Also, while some anterior aphasics (mixed anteriors) clearly do not -
*This study was supported by NINDS research grants 11408 and 06209 University School ofMedicine. **Now at Département de linguistique, Université du Québec à Montréal.
-
to Boston
12
show preserved comprehension, the most common clinical impression is that agrammatism coexists with relatively intact comprehension (Goodglass and Kaplan, 1972). Recent evidence suggests, however, that intact comprehension in Broca’s aphasia might be somewhat of an illusory phenomenon. That is, it would appear that agrammatic aphasics depend on semantic constraints and contextual information, and fail when grammatical information is essential to successful comprehension of the message. One source of this evidence arises from analyses of the grammatical intuitions of agrammatic patients (Zurif, Caramazza and Myerson, 1972; Zurif and Caramazza, in press). Specifically it has been shown that agrammatic patients do not have good metalinguistic control of certain function words such as articles, but can control other function words such as prepositions which have a higher level of semantic content. This observation, which is actually not inconsistent with the clinical behaviour of Broca’s that is, with their speech and their apparent high level of awareness aphasics that such patients only attend to distinctions that make a difference. Further suggests evidence in support of this notion is provided by studies (Goodglass and Hunt, 1958; Goodglass and Berko, 1960) in which the English grammatical morpheme S is realized by agrammatic patients when it indicates plurality (as in HORSES) and thus carries semantic information, but is less often produced (and its absence less frequently noted) when it redundantly marks possession (as in THE MAN’S HAT) or agreement of the third person singular verb (JOHN RUNS). If meaningfulness is the determining factor for agrammatic aphasics, they might be expected to react differently to the same function words according to whether these words are used in a context that renders them meaningful or meaningless. In contrast, Wernicke’s aphasics, whose speech is characterised by reduced information content and also misapplication of function words, (termed &dquo;paragrammatism&dquo;) would not be expected to show this difference. The meaning of function words is a much discussed question. To the extent that these item3 are purely requirements of the structure, ’serviteurs de langue’, they are empty of meaning, according to Gleason (1961). For example it would be pointless to seek the meaning of ONE in the sentence CHOOSE THE WHITE ONE; if no other nominal is inserted following the adjective, ONE must be inserted in English (as opposed to French CHOISIR LE BLANC). However, that a choice is possible between A and THE implies that there must be some difference in message between the two. Along with Gleason, Labov (1971) suggests that linguistic motivation for such choice must be sought in discourse units that go beyond the sentence. In pragmatic terms he proposes that function words may be seen as acting to &dquo;orient the listener to one’s point of view&dquo;. Traditionally the difference between A and THE has been phrased in terms of nonspecific and specific reference. Specificity or absence of it can, however, be seen as applying to the set of alternatives from which the speaker wishes the selection to be made. The speaker uses THE to signal the existence of an implicit understanding between the listener and himself that his intended referent belongs to a set of which both have knowledge. This interpretation of the meaning of THE is consistent with a suggestion of Perlmutter’s (1~970). In arguing for the derivation of the English indefinite article from -
-
13
underlying
numeral ONE
(as distinct from the pro-form ONE used in the stimuli of Perlmutter shows the presence of the definite article, at least with experiment), to be to due For example, PARIS and JOHN SMITH do relativization. proper nouns, not occur with articles unless followed by something else, e.g., THE PARIS THAT WE KNEW, THE JOHN SMITH WHO USED TO LIVE HERE. A proper noun uniquely designates its referent. But when the speaker wishes to designate one member of a set of aspects or personalities which together constitute this referent, or to differentiate one individual from another bearing the same name, that is, belonging to the set of individuals bearing this name, as in the above examples, he uses the definite article along with a following relative clause. In the examples the implied set corresponds to all the aspects of Paris, or all the individuals named John Smith. The particular member of the set corresponding to the speaker’s intended referent is designated by the information in the relative clause. In choosing A the speaker fails to imply such an agreement. The listener is thus left to make his selection from a set he determines by means of other cues, including nonlinguistic ones. With the use of THE, the speaker implies that the selection is to be made from a particular set of which he expects his listener to be aware. Deficient perception of the article will thus have a lesser effect in causing the aphasic’s response choice to differ from the normal’s in the case of A, which simply fails to provide linguistic information, than in the case of THE, which does furnish linguistic information. Olson (1970) provides an operational definition of meaning which is appropriate to this problem of meaningfulness of function words. He suggests that speakers make their choice of lexical item on the basis of the context from which they wish to differentiate an intended referent. For example, if the speaker wants his listener to pick up a particular round, white object, he would say PICK UP THE ROUND ONE if the object were next to a square white object, while if it were in the context of a black object of the same shape he would instead say PICK UP THE WHITE ONE. In order for his instruction to be meaningful, the speaker chooses the adjective which partitions the environment: the adjective referring to shape in the context of two objects of the same colour and the adjective referring to colour in order to distinguish between two objects of the same shape. Thus if instructions are given to act upon a particular context, the words in the instruction are meaningful if they allow an unequivocal partitioning of the an
this
-
context. was made in this study to devise an experimental situation in which the words, definite (THE) and indefinite (A) articles, embedded in the same linguistic contexts, could vary in relation to the extra-linguistic context; ideally, they would vary in respect to Olson’s criteria of meaningfulness. Given the nature of the English article, however, it was not possible to achieve these conditions in as systematic a way as might be hoped. What could be systematically varied was the appropriateness of the article to the extra-linguistic environment. This was done as shown in Fig. 1. Given this pictured array of three figures, such that two are of the same shape, and two of the same colour, but no two are identical, it is possible to have descriptions exemplifying each of four combinations of ’definitiveness’ of the adjective and ’appropriateness’ of the article. In conditions 1 and 3, the adjective effectively partitions
An attempt function
same
14
Fig. the
1
Sample
array.
environment, and is thus ’definitive’. In conditions 2 and 4, the adjective fails to partition the environment unambiguously. The article is appropriate in conditions 2 and 3, and anomalous in condition 1 and particularly in condition 4. Thus, appropriate and anomalous articles are systematically combined with definitive and non-definitive adjectives. However only when the adjective fails to partition the environment unequivocally does the possibility arise of the article’s fulfilling this function, that is, of the article’s being meaningful. If A and THE function in the way that is suggested above, there should be no linguistic information added by the indefinite article A in condition 2. However, THE in condition 4, even though inappropriate, should carry the message to the listener that the round object in question belongs to a set of which he is expected to possess prior knowledge. Therefore, if the description is to be accorded a semantic interpretation as an acceptable sentence, this can be done only in relation to some set other than the total array, since the phrase is anomalous with respect to that set. That is, a set must be inferred by the listener in respect to which the phrase THE ROUND ONE is appropriate. The set of two black figures is the only candidate set available. The listener must infer, in other words, that what is meant is the round one of the two black objects. Thus, not only can the article be presented as alternately appropriate and inappropriate, it can also, in Olson’s sense, vary in meaningfulness, that is, in whether or not it acts to partition the environment. Aphasic subjects were faced with arrays of the type presented in Fig. 1 and for each array were required to press as quickly as possible what they felt was the most suitable figure signalled by each of the utterances listed in Fig. 1. In order to measure the degree to which such patients, and particularly agrammatic aphasics, were sensitive to the article’s appropriateness and inappropriateness as well as to determine whether or not they could make use of linguistic information signalled by the article, reaction times were taken in addition to noting response choice. It was assumed that if aphasics were sensitive to the definite article’s role in condition 4, they would take longer to process the material in this condition before responding.
15 METHOD
Sub jects
’.
..
Eighteen aphasic patients from the Neurology ward of the Boston VA Hospital served as subjects in this study. According to the Boston Diagnostic Examination they were of the following clinical types: Broca’s aphasics (four patients), mixed anterior aphasics (5 patients), Wernicke’s aphasics (5 patients) and anomic aphasics (4 patients). The anterior aphasics (Broca’s and mixed anteriors) all showed some agrammatism, while the speech of the Wernicke’s aphasics could be described as paragrammatic. The anomic aphasics showed no grammatical deficit. Stimulus Materials and Procedure
..
There were four different arrays, each consisting of three pictured figures. One, as shown in Fig. 1, was predominantly black and round; a second was predominantly white and round (i.e., one white circle, one black circle, and one white square); a third was predominantly black and square; and a fourth, white and square. The left-to-right order in which the three pictured figures of each array was laid out was randomized for each subject. In every case, the array presented to the subject was drawn on a strip of white cardboard which could be attached to a telegraph key. This key, when depressed, turned off a millisecond counter connected to a printout. The
activated
signal on the tape which provided the PRESS THE/A WHITE/BLACK/ ROUND/SQUARE ONE were recorded once each, with intonational emphasis placed on the adjective. The signal which activated the timer was inserted at the beginning of the sentence. The sentences were then re-recorded in five different random orders. counter was
by
a
subjects’ instructions. The eight
non-audible sentences
Subjects were tested individually. Each subject was seated at a table with the telegraph key in front of the hand ipsilateral to the side of lesion, that is, the left hand for all but one of the subjects. One random order of each of the four types of arrays was in turn affixed to the telegraph key. The subject was told he would hear sentences of the type PRESS THE BLACK ONE, and was to depress the telegraph key by pressing on the drawn object according to the instruction. A practice set of eight sentences was given, and then the subject did four test sets, each set, as mentioned, consisting of one of the six possible orders of one of the four arrays. All four arrays, were used once for each subject, the last set of sentences using an array of the same type as that given in the practice trials. Every set provided two examples of each combination of appropriateness of the article and definitiveness of the adjective (see Fig. 1 for the four conditions). Besides the automatic recording of reaction times, an experimenter observed the patient’s responses, noting which object was chosen in response to each instruction, and any comment or pertinent gesture the subject made.
16 TABLE 1
Linear comparisons reaching
*
p
