Neuropsycholoyia, Vol. 32, No. 2, Pp. 193-208, 1994 Copyright 0 1994 Elsevier Saence Ltd Printed in Great Bntain. All rights reserved 0028-3932/94 ~6.00+0.00 THE ACCESSIBILITY OF PROPER NAMES JANE E. MCNEIL,* LISA CIPOLOTTI and ELIZABETH K. WARRINGTON National Hospital, London, U.K (Received 1 April 1993; accepted 13 August 1993) Abstract-In this paper we describe a patient with a severe global dysphasia who provides an example of a category specific access impairment. Using matching to sample techniques it was possible to demonstrate the selective preservation of her ability to comprehend proper nouns coupled with impaired comprehension of common nouns. It was found that for the object names category M.E.D. performed better on the first presentation of an item than she did on subsequent presentations. Her performance was also found to be affected by presentation rate and an analysis of her responses showed marked inconsistency when the same stimuli were administered more than once. This category specific access impairment suggests the relative independence of the cognitive mechanisms responsible for the access of different semantic categories. INTRODUCTION RECENT research on patients with language disorders has shown that specific semantic categories may be differentially impaired. There are now several cases on record who show a loss of knowledge for living things with relatively intact understanding of man-made objects (e.g. Refs [16] and [24]). The converse pattern has also been observed with the selective impairment of inanimate object knowledge [6, 211. There have also been a few cases described who had particular difficulties with certain grammatical classes of words. For example MCCARTHY and WARRINGTON [lo] reported the case of a patient (R.O.X.) who could retrieve low frequency common nouns but had great difficulties with any verbs. There also appears to be a more fine-grained division within the category of nouns. There are cases on record who have either the selective preservation or impairment of proper nouns relative to common nouns (e.g. Refs [2], [9], [ll], [12], [14] and [15]). An important distinction which has been made in reference to impairments within the semantic system is that between “access” and “storage” deficits. Patients with an access impairment typically show a variable pattern over time whilst those with a deficit affecting the semantic store itself show marked consistency, although this classification has recently been challenged by RAPP and CARAMAZZA [13]. The original case, A.R., described by WARRINGTON and SHALLICE [23] had an access dyslexia and showed relatively little effect of word frequency on reading. They therefore proposed that in an access deficit there will also be an absence of the usual frequency effects which are observed in aphasia and dyslexia (low frequency items being lost first). Storage deficits will show the converse pattern; consistency of performance and frequency effects. One of the first cases of an access dysphasia on record is that reported by WARRINGTON and * Present address: Jane McNeil, Psychology Department, Queen Elizabeth’s Military Hospital, Stadium Road, Woolwich, London SE18 4QH, U.K. 193
Printed in Great Bntain. All rights reserved 0028-3932/94 ~6.00+0.00
THE ACCESSIBILITY OF PROPER NAMES
JANE E. MCNEIL,* LISA CIPOLOTTI and ELIZABETH K. WARRINGTON
National Hospital, London, U.K
(Received 1 April 1993; accepted 13 August 1993)
Abstract-In this paper we describe a patient with a severe global dysphasia who provides an example of a category specific access impairment. Using matching to sample techniques it was possible to demonstrate the selective preservation of her ability to comprehend proper nouns coupled with impaired comprehension of common nouns. It was found that for the object names category M.E.D. performed better on the first presentation of an item than she did on subsequent presentations. Her performance was also found to be affected by presentation rate and an analysis of her responses showed marked inconsistency when the same stimuli were administered more than once. This category specific access impairment suggests the relative independence of the cognitive mechanisms responsible for the access of different semantic categories.
INTRODUCTION
RECENT research on patients with language disorders has shown that specific semantic categories may be differentially impaired. There are now several cases on record who show a loss of knowledge for living things with relatively intact understanding of man-made objects (e.g. Refs [16] and [24]). The converse pattern has also been observed with the selective impairment of inanimate object knowledge [6, 211. There have also been a few cases described who had particular difficulties with certain grammatical classes of words. For example MCCARTHY and WARRINGTON [lo] reported the case of a patient (R.O.X.) who could retrieve low frequency common nouns but had great difficulties with any verbs. There also appears to be a more fine-grained division within the category of nouns. There are cases on record who have either the selective preservation or impairment of proper nouns relative to common nouns (e.g. Refs [2], [9], [ll], [12], [14] and [15]).
An important distinction which has been made in reference to impairments within the semantic system is that between “access” and “storage” deficits. Patients with an access impairment typically show a variable pattern over time whilst those with a deficit affecting the semantic store itself show marked consistency, although this classification has recently been challenged by RAPP and CARAMAZZA [13]. The original case, A.R., described by WARRINGTON and SHALLICE [23] had an access dyslexia and showed relatively little effect of word frequency on reading. They therefore proposed that in an access deficit there will also be an absence of the usual frequency effects which are observed in aphasia and dyslexia (low frequency items being lost first). Storage deficits will show the converse pattern; consistency of performance and frequency effects.
One of the first cases of an access dysphasia on record is that reported by WARRINGTON and
* Present address: Jane McNeil, Psychology Department, Queen Elizabeth’s Military Hospital, Stadium Road, Woolwich, London SE18 4QH, U.K.
193
194 .I. E. MCNEIL, L. CIPOLOTTI and E. K. WARRINGTON
MCCARTHY [21]. They described a patient (V.E.R.) who had a severe global aphasia and was therefore tested using matching to sample techniques. They found that she showed marked inconsistency with multiple presentations of the same items, one of the defining criteria of an access disorder. Furthermore, they identified an additional important factor. They found that VER’s performance dramatically improved when the stimuli were presented with a relatively long interval between her response to one item and the presentation of the next stimulus. The authors suggested that this may be because the mechanism which allows access to her verbal semantic system becomes “refractory”. This may occur because several representations are activated simultaneously (decreasing the signal-to-noise ratio) or because the system becomes temporarily inactive for some other reason. The few seconds interval between items allows the damaged system to recover to its optimal level. They have therefore suggested that these rate effects may be another important defining feature of access impairments.
A further characteristic of this case was of interest. In addition to showing the features of an access impairment there was also evidence of category specificity. V.E.R. had particular difficulty comprehending object names with the relative preservation of animal and flower names. MCCARTHY and WARRINGTON [22] described a second very similar case (Y.O.T.) who appeared to have a category specific access disorder. They found that, as with V.E.R., she had significantly more difficulty with objects than with animals or foods. In addition, she made more errors when items were closely semantically related and when the presentation rate was faster. These findings along with the inconsistency of her responses led the authors to conclude that Y.O.T. also had an access impairment which was category specific. The
authors have suggested that both these cases can be explained by assuming that only certain categories within the semantic system have become “refractory”. Similarly the semantic proximity effects can be explained in terms of a gradient of “refractoriness” within particular categories.
The present case report describes a patient with a very severe global dysphasia who appeared to have a category specific access disorder affecting common nouns more than proper nouns.
CASE REPORT
M.E.D. was a 63-year-old woman who presented with a progressive dysphasia in the context of long-standing follicular lymphoma. She was admitted to the National Hospital from the Royal Marsden Hospital on 6 July 1992 for further investigation of her aphasic difficulties. A CT scan performed on 9 July 1992 showed a left posterior fronto-parietal low density lesion and 2 additional low density lesions in the left frontal lobe. This abnormality was further confirmed by an MRI which showed abnormal signal from the left posterior temporal and parietal white matter with lesser changes in the grey matter and with focal widening of the sulci. There was also a small focus of high signal in the left thalamus.
M.E.D. died unexpectedly, shortly after her discharge from hospital. Histological and neurological findings were consistent with the clinical diagnosis of progressive multi-focal leucoencephalopathy (for further details see CIPOLOTTI et al. [3]).
Neuropsychological assessment
M.E.D. was first seen in the psychology department on 7 July 1992 and then each day until her discharge on 17 July 1992. Formal assessment was difficult due to her language
THE ACCESSIBILITY OF PROPER NAMES 195
difficulties but she was still able to function at the lower end of the average range on non
verbal reasoning tests (Advanced Progressive Matrices Set, 5/12). She also obtained low average scores on two of the nonverbal subtests of the WAIS-R (Picture Arrangement Age scaled score = 8, Picture Completion Age scaled score = 7).
Her expressive language was severely compromised. She was unable to produce propositional speech and, at best, used a very small repertiore of stereotyped phrases. Her speech output was characterised by both speech production and word retrieval difficulties.
She had articulatory difficulties and made phonetic and/or phonological paraphasias in spontaneous speech and on naming and repetition tasks. She was only able to orally name 2/30 items from the Graded Naming test [12] and 5/15 items from the easier Oldfield (correctly repeating only 3/10 of the same items). Her written naming was relatively less impaired (for a full account of her category specific dysgraphia (see Ref. [3]). Her expressive language skills deteriorated rapidly until by the time of her discharge she had no useful speech and further testing was no longer feasible.
Her literacy skills were also markedly impaired. She had great difficulties reading aloud although this was considered to be secondary to her speech production problems. On the Schonell Graded Reading Test she was only able to read 3 of the first 11 words correctly but she was able to sketch many of the items and she could reliably point to written word stimuli. She performed very poorly on a graded difficulty spelling test [l] and her calculation skills were impaired (O/24, Ref. [7]). In contrast, her visuoperceptual skills appeared relatively intact. She obtained a satisfactory score of 17/20 on the Object Decision Silhouettes Test
c201.
EXPERIMENTAL INVESTIGATIONS General procedures
M.E.D.‘s expressive language skills were severely impaired. However, it appeared that both her verbal comprehension and her knowledge of visual stimuli were relatively well preserved. The following procedures were used for the series of experimental investigations. Matching-to-sample techniques were used, with arrays of either 5 or 6 items. She was asked to point to a given item from each array of stimuli and each item was tested 3 times. A pseudo random order was used so that there was one trial for each item from the array before any were repeated. This resulted in blocks consisting of a total of 15 trials for the 5 item arrays and 18 trials for the 6 item arrays. In view of some apparent variability with different presentation rates response-stimulus intervals (RSI’s) were strictly timed. It should be emphasised that the patient was under no pressure to respond quickly. By RSI we mean the time between the patient’s last response and the presentation of the next stimulus. Unless otherwise stated, RSI’s were 2 sets.
The stimuli consisted of 45 coloured pictures of very common objects belonging to 1 of 3 categories (15 objects, 15 foods and 15 animals). The pictures were arranged in arrays consisting of 5 items and there were 3 different arrays for each category (see Appendix). M.E.D. was asked to match a given spoken name to one of the array of pictures using the standard 2 set RSI and each item in each array was probed 3 times. The 3 categories were tested in a Latin square design.
Results
The number correct for each category is given in Table 1. M.E.D.‘s performance was virtually perfect for all 3 categories. There did not appear to be
any category effects with these high frequency items and her performance did not deteriorate with multiple presentations of the same stimuli.
196 J. E. MCNEIL. L. CIPOLOTTI and E. K. WARRINGTON
Table 1. Spoken-word picture matching task
Trial 1 Trial 2 Trial 3
Animals IS/l5 14115 15/15
Objects 15/15 15/15 14115 Food 15/15 14/15 14115
TOTAL 45145 43145 43145
These results suggest that, within the range of items tested, her ability to identify visual stimuli from their spoken name is relatively intact. However, the items used in this experiment were fairly loosely semantically related, for example one of the food arrays consisted of chocolate, pear, milk, soup and lettuce. Previous studies have suggested that comprehension deficits within the semantic domain are particularly sensitive to the semantic similarity of the items tested [22]. The following experiment was therefore devised using stimuli which were more closely semantically related and somewhat lower frequency than the previous experiment.
EXPERIMENT 2: SPOKEN- AND WRITTEN-WORD COMPREHENSION M.E.D.‘s ability to read single words out loud, as tested by traditional reading tests, was severely impaired (see
above). However, she appeared able to reliably match some spoken words to their written equivalent. In addition, the previous experiment had shown that M.E.D.‘s spoken-word to picture matching performance was virtually perfect with high frequency items. This experiment was therefore designed to investigate M.E.D.‘s spoken and written comprehension using arrays of items which were semantically closely related.
The test stimuli consisted of 4 arrays, one of each of the following 4 categories: clothing, personal objects, household objects and furniture (see Appendix for details of the arrays used). There were 6 semantically related items in each array. M.E.D. was presented with either a spoken name or a picture and asked to match it to an array of 6 pictures or 6 written names. Each of the 4 arrays was tested under each of the 4 conditions (spoken-word to picture, spoken-word to written-word, picture to picture and picture to written-word) using a Latin square design and each individual item was probed 3 times.
Results
The percentage correct score for each of the 4 conditions is given in Table 2.
Table 2. Spoken- and written-word comprehension
Percentage correct
Spoken word to written word Spoken word to picture Picture to picture Picture to written word
65% 14% 92% 90%
M.E.D.‘s performance on the picture/picture and picture/written-word matching tasks was fairly intact across all categories. However, a clear cut deficit has been observed on the spoken-word/picture and spoken-word/written-word matching tasks. These results taken together with the previous experiment, which failed to show a deficit in spoken-word/picture matching, suggests that her impairment may indeed be affected by either word frequency or semantic relatedness.
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EXPERIMENT 3: EFFECT OF PRESENTATION RATE ON SPOKEN/WRITTEN-WORD MATCHING
It was observed that stimulus presentation rate appeared to affect M.E.D.‘s performance. A fairly fast rate (RSI) had been used in the previous experiment and it was clearly important to establish ifher performance improved with slower rates. The following test was therefore devised to investigate the effect of stimulus presentation rate across different categories.
Procedure
The stimuli consisted of 6 arrays of 6 written words. One array for each of the following 6 types of object: household, office and small manipulable, vehicles, furniture and clothing (see Appendix for items used). M.E.D. was tested using a spoken-word/written-word matching task. There were 3 trials for each of the 36 items. Two RSI’s were used for each array, the standard 2 set rate and a slower rate of 5 sec. There was an interval of 2 min between each block of 18 trials.
Results
The percentage of correct responses for the lst, 2nd and 3rd trials (summing across all 36 objects) for each of the presentation rates is shown in Table 3.
Table 3. Spoken/written-word matching at two presentation rates
1st 2nd 3rd Total
Slow rate (5 set) Fast rate (2 set)
94% 92% 94% 94% 83% 63% 66% 71%
The results show that there was a significant error rate with the fast presentation rate. In addition, there is a serial position effect, so that her performance deteriorates after the first
trial (from 83% correct to 63% correct). However with the slower presentation rate her overall rate was very low and there was no trial effect. M.E.D. performed at a near perfect level across all 3 trials (94, 92 and 94%, respectively).
EXPERIMENT 4: SPOKEN/WRITTEN-WORD MATCHING ACROSS CATEGORIES
The 6 arrays sampled in the previous experiment were all drawn from the superordinate category of man-made objects. Nevertheless there was some suggestion that certain types of objects may have been differentially affected by the fast presentation rate. This experiment was therefore devised to maximise any category effects by using faster presentation rate on a wider range of categories.
Procedure
The stimuli consisted of 8 arrays of 6 written words. There was 1 array for each of the following categories: cutlery, clothing, boys’ names, girls’names, musical instruments, countries, famous proper names and low frequency objects (from the Graded Naming test, Ref. [ 121) (see Appendix). MEiI was tested using a spoken to written word matching procedure (RSI 2 set). The whole experiment was replicated a second time, in the same testing session, to establish the reliability of her pattern of performance.
Results
The number of correct responses for each category for each replication is shown in Table 4. The results for each replication are practically identical. Any suggestion that the category
effects are due to random fluctuations in her performance can almost certainly be discounted. As in the previous experiment there is a deterioration in her performance on successive trials. The overall percentage correct was 74% but breaking the results down into performance on
198 J. E. MCNEIL, L. CIPOLOTTI and E. K. WARRINGTON
Table 4. Matching spoken words to written words
Test Replication Total
Cutlery Girls’ names Clothing Boys’ names Musical instruments Countries Famous names proper
trial 1, 2 and 3 she scored 82, 75 and 65% respectively. However this does not hold for all categories. M.E.D. obtains a perfect (or almost perfect) performance on some categories across all trials. From the limited number of categories tested it appears that proper names and low frequency nouns appear preserved while high frequency objects are impaired.
It is worth noting that there is no systematic relationship between performance and word frequency across categories. There appears to be the normal direct relationship between word frequency and performance for countries but an inverse relationship for objects (with common objects more impaired than low frequency objects). So across all categories the
correlation between performance and word frequency is not significant (Spearman’s rho = -0.458) as the negative correlation (with objects) and the positive correlation (with countries) have effectively “cancelled” each other out. Furthermore this suggests that the category effects cannot be reduced to frequency effects as different categories are differentially affected by word frequency.
EXPERIMENT 5: EFFECT OF FREQUENCY AND SEMANTIC RELATEDNESS ON A SPOKEN/WRITTEN-WORD MATCHING TASK
The previous experiment had suggested that there may be an interaction of category with frequency. A further important variable is semantic relatedness. Our aim in this experiment was to investigate the relative roles of both frequency and semantic relatedness. Three categories were selected for further investigation. Sets of stimuli were chosen which were judged to be semantically close or semantically distant within each broad category.
Procedure
The stimuli consisted of 12 arrays, each consisting of 6 written words. There were 3 broad categories tested (objects, animals and countries) and there were 4 arrays for each category (see Appendix). The two variables being investigated were semantic relatedness (close or distant) and frequency (high or low). So each of the 4 possible combinations (close high, close low, distant high, distant low) were used for each category using a spoken- word/written-word matching task.
Results
The percentage correct for each category for each condition is shown in Table 5. In an access case such as this it is possible that any apparent category effects could be
reducible to semantic relatedness of the items used or even to inverse frequency effects. These results suggest that there is indeed a complex interaction between category, frequency and semantic relatedness. Firstly, there is an obvious category effect which cannot be reduced to semantic relatedness or word frequency. That is, objects are selectively impaired across all conditions. Secondly there is also the expected close/distant effect, with all categories being more impaired when the items are closely semantically related than when they are distantly related. In contrast however, there is not such an obvious frequency effect. As can be seen in
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Table 5. Effect of category and semantic relatedness on spoken/written-word matching
Table 6. Etrect of word frequency across categories
Frequency High Low
Objects 10136 17136 (28%) (47%)
Animals 24136 25136 (67%) (69%)
Countries 32136 19136 (89%) (53%)
Table 6 M.E.D. shows the “normal” frequency effect with countries (High frequency 89% correct, Low frequency 53%) but there is no difference in her performance on the animals and with M.E.D.‘s most impaired category, objects, if anything there appears to be an inverse frequency effect (High frequency 28% correct, low frequency 47% correct). This further confirms that the category effects observed with M.E.D. cannot be reduced to simple frequency effects and would instead appear to reflect particular difficulty accessing certain categories of words.
CONSISTENCY ANALYSIS
Serial position effect
The results from Experiments 3,4 and 5 were combined for an analysis of the consistency of M.E.D.‘s responses. It was observed that she commonly answered correctly on the first administration of a particular stimulus but on subsequent trials would make errors. This was formally tested by an analysis of all her inconsistent responses (85 in total). It was found that she was correct on the first occasion and incorrect on the second occasion 54 times but the converse pattern (incorrect on the first occasion and correct on the second occasion) only occurred 31 times. This is a significant difference (McNemar: x2 = 5.69, PcO.02).
Consistency analysis
An analysis of the consistency of M.E.D.‘s responses to individual items in Experiment 4 was carried out (using only those categories on which she made errors). Faglioni and Botti have recently criticised the usual methods used to measure consistency and have suggested some alternatives [4]. However these newer methods are not applicable in the type of word-
200 J. E. MCNEIL. L. CIFQLOTTI and E. K. WARRINGTON
picture matching tasks which have been used here (FAGLIONI, personal communication). We therefore make the assumption of independency over trials (which may not be valid because of serial position effects) and use the binomial expansion. It is then possible to generate the expected distribution of response consistency, using p = proportion correct = 0.65, and q = (1 -p). The proportion of responses with no errors, 1 error, 2 errors and 3 errors along with the number predicted by the binomial expansion is given in Table 7. The categories of
Table 7. Expected and observed distributions of correct and incorrect responses
famous proper names and low frequency objects were eliminated as her performance was perfect across all 3 trials and both administrations, so the inclusion of these categories would have yielded a falsely consistent result. It can be observed that the distribution of M.E.D.‘s correct responses is very close to that predicted by the binomial expansion. A x2 test of “goodness of fit” shows that there is no significant difference between the observed and predicted pattern of errors (x2 = 0.796, P > 0.5). This was also found for the fast rate used in Experiment 3 (x2 =0.364, P>O.5, see Table 7).
DISCUSSION
We have described the residual comprehension skills of a patient, M.E.D., with a severe aphasia. Using matching to sample techniques it was possible to show that her ability to identify visual stimuli was fairly intact and that her deficit lay within the auditory verbal domain (Experiments 1 and 2). It was also found that her responses were inconsistent with multiple administrations of the same stimuli. That is, she performed significantly better on the first presentation of an item than she did on subsequent presentations (Experiments 3 and 4). Furthermore, it has been shown that her performance is sensitive to the speed of presentation. When a slow presentation rate was used, as in Experiment 3, the number of errors she made was dramatically reduced and the serial position effect was no longer
observed. We have also described a robust category effect. This means that a primary auditory or
word perception deficit cannot explain her difficulties. Experiments 4 and 5 have shown that M.E.D. is most impaired with objects, less so with animals or country names and finally she shows a remarkably well-preserved performance with famous people’s names. In addition, M.E.D. shows a marked semantic relatedness effect. That is she performed significantly better on arrays where the items were distantly semantically related than when they were closely related (see Experiment 5). The presence of response inconsistency and presentation rate effects along with the category and semantic relatedness findings would suggest that M.E.D.‘s deficit reflects a difficulty accessing representations within the semantic store rather than a breakdown of the store itself.
THE ACCESSIBILITY OF PROPER NAMES 201
Before discussing the implications of this case for the organisation of semantic systems we would wish to draw attention to the apparent similarity between the patterns of impairment observed in M.E.D.‘s writing and comprehension. CIPOLOTTI et al. [3] have reported that, at an earlier stage in her illness, she was able to write the names of low frequency objects and proper nouns but was severely impaired writing common object names. This is a similar pattern of performance to that which later emerged with her comprehension, an impairment for everyday objects with proper nouns remaining relatively intact. The most parsimonious explanation would be that M.E.D.5 semantic representations of common objects are impaired resulting in difficulties with both comprehension and written output. However, we would suggest that M.E.D. has a double deficit affecting two different domains. It is important to emphasise that M.E.D.‘s comprehension problems only emerged at a later date, by which time her writing was no longer testable. When her category specific writing deficit was observed there was no impairment in her comprehension (see Ref. [3] for further details). In addition, M.E.D.‘s comprehension difficulties had all the hallmarks of an access impairment. We have shown that with a slow presentation rate her performance was virtually perfect even for her (otherwise) impaired categories. Furthermore, the pattern of impaired categories which has been obtained for her comprehension is slightly different from that shown with her writing. We have shown that she is more impaired with country names than with famous people’s names. In contrast her writing was almost flawless for country names and mildly impaired for famous people’s names (see Ref. [3] for further details).
The proposed characteristics of access disorders were first developed in response to the patterns of performance observed with two dyslexic patients [19,22]. The patients’ reading showed a lack of the normal frequency effects, inconsistency in performance and priming and cueing effects. These observations led Warrington and Shallice to propose that these characteristics could be seen as the hallmark of access disorders. Since these first cases were described, further cases have been reported which perform in a qualitatively similar manner but who are dysphasic rather than dyslexic [21,22]. However, it is much less clear that the characteristics applicable to the dyslexic cases would also hold for the dysphasic cases. Indeed as RAPP and CARAMAZZA [13] have pointed out these predictions have yet to be confirmed with the aphasic patients. It is equally the case that the rate effects found with the dysphasic patients have not yet been shown in an access dyslexia. There may be no justification for considering that access dysphasia and access dyslexia are the same syndrome. It is entirely possible that the aphasic patients would not show the same priming effects as the dyslexic patients and may even show negative priming. It has been shown that the access dysphasics perform more poorly with semantically related arrays than they do with distantly related arrays. If this pattern is due to the system becoming “refractory” as proposed by MCCARTHY and WARRINGTON [2] than it would be predicted that priming or cueing might actually impair performance. Similarly, the relative preservation of superordi- nate vs subordinate knowledge has not been confirmed with cases with an “access” dysphasia. At present the close/distant semantic effects are equally consistent with either “refractoriness” within the semantic system or the relative preservation of superordinate knowledge. Until a method has been developed which can tap superordinate/subordinate knowledge in these very impaired patients it is impossible to distinguish between these different competing interpretations.
Two issues merit further discussion, first the relationship of this case to other access cases and secondly the significance of access difficulties for understanding the categorical organisation of semantic systems. There is a remarkable similarity between M.E.D. and the
202 J. E. MCNEIL, L. CIPOLOTTI and E. K. WARRINGTON
access cases V.E.R. and Y.O.T., described by WARRINGTON and MCCARTHY ([21] and [22], respectively). All 3 patients were severely aphasic but using matching to sample techniques were found to have a category specific access dysphasia. They all showed inconsistencies in their responses to individual items along with rate and semantic relatedness effects. In addition, in all 3 cases a selective impairment of objects was documented. A further point of similarity between Y.O.T. and M.E.D. was that they both showed the selective preservation of proper names. A more fine grained categorical analysis showed that both patients had more difficulty with non-famous proper names (e.g. Anne or John) and country names than they did with famous people such as Mozart or Hitler. The general pattern of impairment is so similar for these three patients that it could be considered to
represent a coherent syndrome. However, whether this pattern reflects a common underlying deficit found in all patients characterised as having an access impairment will require further research.
Turning to the question of what access syndromes can tell us about the categorical organisation of semantics. We have shown that M.E.D. shows a semantic relatedness effect with closely related items giving rise to interference. Is it possible that items within some categories are more closely semantically related? This is relevant when we consider the proper names category effect in the present case. Some authors have suggested that the crucial difference between proper names and common nouns is that a proper name has a unique referent whilst a common noun refers to the all the exemplars sharing the same set of
attributes (e.g. Refs [14] and [lS]). It may be that this distinction between unique and multiple exemplars also holds for divisions within the proper nouns category itself. Non- famous proper names will be shared but a famous proper name is only linked to the semantic store for one exemplar and may therefore be less prone to semantic interference effects. It is also possible that low frequency objects differ from high frequency objects in terms of semantic distance. However, although semantic distance could plausibly explain the proper names and inverse frequency findings, it is not sufficient to account for all the category effects observed with M.E.D. It was also found that she was less impaired with animals than she was with objects (Experiment 5). It seems implausible to suggest that animals are more semantically distant and less prone to interference effects than objects.
Category effects have frequently been described in patients with semantic memory deficits where the representations themselves are thought to be damaged. However, some authors have recently suggested that these category effects may in fact be artefacts due to stimuli being insufficiently matched on variables such as word frequency, familiarity or visual complexity (e.g. Ref. [S]). We have to consider to what extent these same arguments would
be expected to apply to an access case. At present the significance offrequency effects for these cases remains unclear. It would be equally plausible to propose on a post hoc basis a rationale to expect inverse frequency effects. Indeed, in Experiment 4 we have put just such inverse frequency effects on record (see also Ref. [3]). However, the suggestion that frequency or familiarity effects alone can explain the category results we have obtained with M.E.D. is implausible. Firstly, on those experiments for which visual stimuli were used familiarity did not appear to be an important variable (it would seem to be fallacious to use measures of visual familiarity when using verbal stimuli). Secondly, although she was more impaired on low frequency countries than high frequency countries the opposite pattern of performance was found with objects (a greater impairment with high frequency objects). In addition, across all categories there was no significant correlation between word frequency and performance. The lack of any systematic relationship between frequency and performance
THE ACCESSIBILITY OF PROPER NAMES 203
across all categories suggests that, for this case at least, the category effects cannot be reduced to either “normal” or inverse frequency effects. It seems more plausible to interpret frequency and category effects as reflecting orthogonal dimensions, neither effect being reducible to the
other. In conclusion, we have reported a case whose comprehension problems are characterised
by inconsistency and rate effects, and are therefore thought to reflect a difficulty accessing semantic representations. We have also shown that she exhibits category effects which stand irrespective of frequency or semantic relatedness effects. Furthermore, she shows a remarkable similarity to the two access cases described by WARRINGTON and MCCARTHY [21,22]. We would reject the notion that category effects are an emergent property of deficits in access procedures. Rather we would suggest that these category effects are an indication that the cognitive operations which achieve access to the semantic representations are themselves categorically organised. However, the remaining issue of whether there is an inevitable association between this pattern of deficits in patients with access impairments will be clarified when further cases have been studied.
Acknowledgement-We would like to thank Dr Peter Rudge for permission to study M.E.D., a patient under his care.
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Experiment 4 stimuli
K-F freq. T-L freq.
Cutlery
Girls’ names
Countries
Knife Dish Saucer Fork
Cup Spoon MEAN Susan Mary Anne Jane Sally Elizabeth MEAN Russia Italy France Germany Canada
Boys’ names
Clothing
Peter David Tom Richard John Steve MEAN Hat Shoe Belt Glove Sock Scarf MEAN
Famous proper names Napoleon Hitler Churchill Mozart Dickens Picasso MEAN
England MEAN
Low frequency objects Corkscrew Handcuffs Bellows Chopsticks Thimble Tweezers MEAN
Musical instruments Drum Piano Trumpet Flute Violin Guitar MEAN
76 16
1 14 45
6 26.3 36 88 42 35 13 15 38.2 12 34 74 81 34
154 74.8 36 51 63 71
362 18
100.2 56 14 29
9 4 4
19.3 7 8
12 2
16 14 9.8 3 2 8
1
4.3 11 38
7 1
11 19 14.5
A A 7
31 AA 33
8 AA 23 A 28 A
A 41 AA AA 44 AA
A 46 A A
AA 18
AA AA 48 43 12 14
19 7 4 4 6
1 1 2
4 1 1.8
40 26 17 9
11 4
17.8
THE ACCESSIBILITY OF PROPER NAMES 207
Experiment 5 stimuli
CLOTHING Distant/ High
Close/ High
Close/ Low freq.
Distant/ Low freq.
ANIMALS Distant/ High
Close/ High
Close/ Low
Distant/ Low
T-L K-F frequency frequency
Hat Belt Jacket Watch Glove Shorts MEAN Boot Sock Tights Slipper Sandal Shoe MEAN Trilby Balaclava Boater Helmet Sombrero Hood MEAN Cufflinks Apron Braces Moccasin Pyjamas Mittens MEAN
Lion Duck Robin Mouse Bee Frog MEAN Horse Goat Sheep Pig cow Rabbit MEAN Giraffe Zebra Gorilla Leopard Rhino Hyena MEAN Shark Hippo Hare Panda Walrus Python MEAN
AA 48 22
AA 43
2
37 12
20 5
AA -
-
2
21
(3) -
17 4 4
-
9
A 49 48 34 A 25
AA A A 44 A 43
7 1
18 -
2 1
56 29 33 81
9 1
34.8 13 4
3 5
14 7.8
1 1
7
2 2.4
17 9 2
10 11
1 8.3
117 6
23 8
29 11 32.3
1
I 2 1 1.25 1
1
1 14 4.25
208 J. E. MCNEIL, L. CIPOLOTTI and E. K. WARRINGTON
Experiment 5 stimuli
T-L K-F frequency frequency
COUNTRIES Distant/ High
Close/ High
Close/ Low
Distant/ Low
Canada Australia India Russia Greece Japan MEAN France England Germany Spain Holland Italy MEAN Brazil Mexico Argentina Cuba Chile Peru MEAN Morocco Finland Hungary Burma Iceland Sudan MEAN
44 10 46 A 29 49
AA AA A A 26 41
13 33
6 8 9
4
4
34 11 58 72 16 38 38.2 14
154 81
8 34 59.7
8 19
41
4 12.7
5 2 4
17 4
5.5
K-F freq. refers to the KUCERA and FRANCIS (1967) word frequency count. T-L frequency refers to the THORNDIKE and LORGE (1944) word frequency
count; A refers to z 50 per million but < 100 million; AA refer to > 100 per million.
Familiarity ratings are taken from SNODGRASS and VANDERWART, 1980 (items in brackets are English equivalents of American words, e.g. trousers for pants).
