Can We Lose Memory for Music? A Case of Music in a Nonmusician

Isabelle Peretz University of Montreal, and Research Center of C6te-des-Neiges Hospital Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021

Abstract

9 A follow-up study of a patient, C.N., with a severe auditory ery was not accompanied by any signs of improvement in agnosia limited to music is reported. After bilateral temporal music recognition, which remains extremely poor. Moreover, lobe damage, C.N., whose cognitive and speech functions are the fact that she has never been able to hum tunes from otherwise normal, is totalty unable to identify or to experience memory argues for a basic memory disturbance. Thus, she was a of familiarity with musical excerpts that were once tested herc with a series of tests aiming at assessing her mem- highly familiar to her. However, she can recognize the lyrics ory for familiar and unfamiliar music.The results show that C.N. that usuaUy accompany the songs. She can also identify familiar has now recovered most perceptual skills and that despitc a sounds, such as animal cries. Thus, her agnosia appears highly transient ability to exhibit kn0wledge of familiar music under specific to music. The ftmctional nature of her de¡ has been restricted circumstances, she is markedly impaired at naming investigated through various perceptual tasks. She was initially a tune and at judging its familiarity, as well as at memorizing severely impaired in processing pitch sequential structure but familiar as well as novel music. This deficit was found to be not has always enjoyed normal processing of temporal structure. only modality-specific but music-specific as well. The findings This selective disturbance for sequential pitch information cata suggest the existence of a perceptual memory that is special- hardly account for her tune agnosia since processing of pitch ized for music and that can be selectively damaged so as to variations has dramatically improved over the years. This recov- prevent most forms of recognition ability. 9

INTRODUCTION The fact that brain damage can interfere with the ability to recognize music that was once weU-known to Recognition of familiar music is immediate and easy for the patiem has been recognized for a long time. Almost every human being. Despite its apparent effortlessness, a century ago, Bonvicini (1905, reported in Ombredane, music recognition is a complex procedure that presup- 1944) described a patient who could still process musi- poses the intcrvention of multiple processing compo- cal information adequately but who could no longer nents. At the very least, the perceptual input must be recognize well-known tunes. More precisely, he could processed along the melodic dimension (defmed by se- well detect wrong notes deliberately inserted in musical quential variations in pitch) and the temporal dimension excerpts, but could not recognize any of the musical (deflned by variations in duration) and then mapped passages, even the most familiar ones. Yet the deficit was onto a stored long-term representation that captures not "pure," since the patient was also profoundly apha- some of the invariant properties of the musical selection. sic; he could no longer understand speech. This was also Although music recognition abilities representa basic the case of Lamy's (1907) patient, who was even more and widely distributed musical competence in the popu- spectacular in being able to transc¡ his national an- lation, they have rarely been studied. The focus of re- them correctly without any feeling of knowing ir. search with normal listeners is usuaUy limited to the Both cases suggest that loss of "music memory" can processing of novel musical material (see Sloboda, 1985, occur despite intaet after damage to the leff and Dowling & Harwood, 1986, for textbooks on normal hemisphere structures. This condition does not appear music cognition). However, studying recognition of fa- to depend on musicianship, since Eustache and his col- miliar music represents a unique opportunity to better leagues (1990) reported a similar condition in a nonmu- understand the musical competence of the majority. sician. The fact that all three patients were aphasic Above aU, music rccognition can be expected to be obscured somewhat the interpretation of their defieit. associated with a fixed neural architecture, since it is a Although it has been suggested that musical abilities are basic human skill that, unlike reading and composing of autonomous functions (Fodor, 1983; Garner, 1983; Jack- music, is shared by all members of a given culture, endoff, 1987; Peretz & Morais, 1989), it is still unclcar to listeners and performers alike, from an early age. what extent they can be observed in isolation from

9 1996 Massachusetts Institute of Technology Journal of Cognitive Neuroscience 8:6, pp. 481-496

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 language disturbances (Basso, 1993). In this article, we Vecera, 1993, for reviews), C.N. may display evidence of present data from a patient, C.N., who experienced a "covert" recognition, when her memory for music is profound and selective loss of music recognition abilities tested indirectly or using forced-choice procedures. (Peretz et al., 1994), which we refer to as music agnosia. Moreover, only stored representations for remotely This patient is devoid of any special talent, be ir linguistic learned music were assessed; her potential for relearning or musical; she was a nurse who never received any or for learning music encountered since illness onset formal musical education. At the age of 35, andas a remains unknown. Assessment of aH these facets of mu- consequence of successive surgeries to repair cerebral sical memory in C.N. was the goal of the present study. aneurysms in each of her temporal lobes, she com- By examining further the specificity of the outcome to plained that she was no longer able to pick out the music processing, this new set of experiments offers a simplest ovedearned tune. She no longer recognized new avenue for the study of C.N. and thereby for the Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 excerpts from her own record collection, unless the understanding of the functional role and organization of music was accompanied by words. Yet, C.N. never en- the music recognition system. countered the least difficulty in understanding and com- The experimental situations in the first section were municating verbaUy. She also experiences no difficulty in designed to characterize the nature and severity of C.N.'s interpreting the nonverbal sounds of her environment, music recognition deficit, whereas the situations re- with the exception of music. Thus, C.N.'s recognition of ported in the second section examined her current musical patterns is disproportionally impaired relative to status with regard to musical perceptual abilities. In the the recognition of both speech and environmental final section, C.N.'s memorization of musical material is sounds. Although it has long been suspected that such a assessed in some detail. pattern exists, C.N. arguably shows the most clear-cut example of music agnosia. TESTS OF MUSIC, TITLE, AND LYRIC Assuming that music recognition is subserved by a RECOGNITION distinct neural organization, which was damaged in C.N., it is of major interest to specify the lines along which The extent of C.N.'s music recognition failures is most this breakdown occurs. This is nota straightforward task. striking. Over the past 7 years during which we have On the one hand, C.N.'s pattern of musical impairments been working with her, she has only occasionally iden- indicated a perceptual basis to her disturbance (Peretz tified a musical excerpt. Her inability to recognize music & Kolinsky, 1993; Peretz et al., 1994). C.N. was impaired is so severe that even though numerous musical ex- in d iscriminating melodic patterns (varying by their se- cerpts have been repeatedly presented to C.N., she still quential pitch pattern), but was intact in discriminating recognizes less than 10% of them. More specificaUy, 3 temporal (or rhythmic) patterns. In theory, she should years postonset (in 1990), out of 80 excerpts of well- be able to use the rhythmic charactcristics, whose proc- known folk songs and instrumental pieces that were essing is spared, for recognizing familiar tunes (Lennen- played one note at a time via a synthesizer controlled by bcrg, 1967). In practice, however, rhythm alone is a very a computer (Peretz et al., 1995), C.N. was able to name poor cue for music recognition compared to melodic only 5 of them. These poor recognition abilities were information (White, 1960; H› & Peretz, 1996). Con- replicated at the time of the present study (in 1993): sequently, C.N.'s music agnosia may be due to her failure From 57 excerpts taken from the vocal repertoire and to properly encode melodic information. By this account, 27 excerpts taken from the instrumental one, which the perceptual melodic impairment would prcvent the were all once highly familiar to C.N., she could name familiar musical passage from making contact with its only 3 of them ("Au clair de la lune," '~Ioyeux anniver- stored memory representation, which may otherwise be saire"/"Happy Birthday," and "La chanson de Lara"/ spared. "Zhivago Song"). But even these recognition hits were C.N.'s memory representations, however, do not ap- unstable, for she incorrectly attributed the same title pear intact either. C.N. is unable to sing a tune from (e.g., "Au clair de la lune') to several other excerpts. It is memory. This suggests that the stored representations of important to mention here that C.N. has always been familiar music are damaged as weU. In previous investi- able to identify music on the basis of the titles presented gations, C.N.'s memory was assessed but not studied in in isolation. For example, when cued with the title "Four detail. Prior knowledge of music was assessed by a nam- Seasons," she immediately retrieved "Vivaldi" as the com- ing task and familiarity decisions (where the subject is poser's name and evoked a specific memory associated required to judge whether or nota given musical ex- with this music (e.g., she recaHed that the first time that cerpt sounds familiar). In both tests, C.N. failed to exhibit she had heard that music was 15 years ago when work- signs of recognition. Yet, these two situations do not ing with a surgeon who usuaUy listened to 'Tour Sea- exhaust all possibilities for her manifestation of residual sons" during surgery). Only those selections of which knowledge for music. As it is the case for many prosopag- C.N. clearly identified the titles were presented and nosic patients (see Bruyer, 1991, and Farah, O'Reilly, & therefore considered as highly familiar to her.

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 Familiarity Decision with Music type of procedure was originally introduced by Sergent and Poncet (1990) to assess rcsidual knowledge of faces Identification is more demanding than recognition. Iden- in a prosopagnosic patient. In the present musical appli- tification requires not only a recognition phase, that cation of the task, 20 familiar musical excerpts (taken consists of making an appropriate contact between the from Peretz et al., 1995), including 10 exccrpts from percept and the stored previous experience with it, but vocal music and 10 from instrumental music, were audi- it also requires a successful title selection phase, fol- torily presented. None of these was previously recog- lowed by an appropriate pronunciation. Using a less nized by C.N. For each excerpt, a pair of written titles demanding task, requiring music recognition without was provided, one being the true title and the other identification, may reveal residual recognition abilities. To being untrue. The untrue title was matched to the true assess whether C.N. had access to such residual musical title in terms of familiarity and musical genre. For exam- knowledge, a familiarity decision task was devised. She Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 pie, while Ravel's "Bolero," the true title "Ravel's was presented on two different occasions with musical Bolero" and the untrue title 'q~eethoven's 5th Symphony" excerpts, half of which were familiar and hall of which appear on paperas alternative choices. Ordcr of presen- were not. Her task was to indicate whether or not each tation of the correct title was counterbalanced across musical selection sounded familiar to her. trials. The task was to decide which title corresponded As can be seen in Table 1, the mere presentation of a to the prescnted music in the first condition. In the musical excerpt does not trigger the feeling of familiarity following conditions, the same titles and the same music that normaUy precedes identification. C.N. performed at, were presentcd but incorrectly paired so as to measure or just above, chance (being 50%; with z : 1.00;p > 0.10 an eventual bias in responding; in condition 2, the titles for the first set and z = 2.83, p < 0.05 for the second did not correspond to the music presented, which was, test, by a two-tailed tesO. She clearly scores below nor- however, taken from the same repertoire (e.g., an ex- mal (X z = 27.15 and 11.92 for the first and second set, cerpt of '~Pachelbcl's Canons" was auditorily presented respectively, both p < 0.001). while 'q~,avel's Bolero" and "Beethoven's 5th Symphony" On another occasion, we again presented her with the were the written titlc choices) and, in condition 3, the second set but, this time, ir was arranged in pairs, so that music did not correspond to thc titles provided, which each familiar excerpt was paired with an unfamiliar one. were new (thus when hearing the Ravel's Boleto again, C.N. was required to say which of the two excerpts this time 'Tª EliSe" and 'The Blue Danube" werc given sounded most familiar. This procedure should have al- as titles). Finally, therc was a retest condition (condition 1). lowed C.N. to respond on the basis of the weakest Out of the 20 trials of condition 1, C.N. chose the feeling of familiarity evoked by the stimuli, following the correct title on 16 of them, which is significantly better procedure used by Young and De Haan (1988). Indeed, than chance (p < 0.05 by a two-tailed binomial teso and she did exhibir evidence of residual knowledge, as just below normal controls but not significantly so shown by her excellent performance in this task (see (mean: 18.8; range: 17-20; X 2 = 0.71). Her responscs Table 1). Thus, C.N. seems to have access to some resid- were very fast. Examination of her errors indicated that ual representations stored in memory. These traces ap- they occurred mostly for instrumental music (3 errors) pear too weak, however, to yield normal recognition. rather than vocal music (1 error). This pattern also emerged in normal controls. These findings indicate that Music-Title Verification C.N. was able to reliably associate a musical excerpt with its title when she had two alternatives to choose from. Another procedure that airas at assessing residual knowl- However, these results cannot be considered as reliable edge is a binary forced-choice title verification task. This for several reasons. First, as mentioned above, when initially presented with these excerpts, C.N. had failed Table 1. Percentages of Correct Responses for C.N. and to recognize them, further suggesting that music alone Mean Percentages of C.N.'s Five Matched Controls (with is not sufficient to activate aB the information necessary Their Lowest and Highest Scores in Parentheses) in the to achieve overt recognition. Ir was only through the Familiarity Decision Tasks simultaneous presentation of music anda title that the C.N. Controla music-title association was achieved. Second, even though C.N. succeeded in selecting the correct namc on Unfamiliar=rare most trials, she was surprised by the feedback that we Single presentation 55.0 92.5 (85.0-97.5) gave her, for she felt she had been guessing. Third, when C.N. was presented with conditions 2 and 3, where Unfamiliar=-inversions music and titles were mismatched, she curiously did as Single presentation 66.6 92.4 (86.4-97.0) before, pointing to one of the titles without trouble. None of the matched controls behaved that way; they Forced choice 90.9 all complained that we made an error in our material

Peretz 483

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 and we had to interrupt the testing procedure after a unaffected, the reverse is not true. A perceptual locus for few trials. In contrast, C.N. displayed no sign that she was the deficit implies a failure to achieve building repre- aware that the title did not correspond to the presented sentations that are necessary to either afford reliable music, much in the same way as the prosopagnosic case, contact with the stored representations or to be effec- EV., studied by Sergent and Poncet (1990). On retest, C.N. tively stored. Accordingly, the same functional impair- performed at chance with 9 correct associations out of ment--the inability to evoke memories associated with 20. Control subjects maintained the same level of perfor- music--may result from a breakdown at different stages mance as initially (with 18.0 on average; range: 17-20). of music processing. Only by disregarding perceptual Thus, the untrue pairings hada disastrous effect on disturbances can the impairment be attributed to a mem- C.N.'s ability to identify the excerpt's title. This suggests ory deficit. that in C.N. the music-title associations are abnormally At the time of testing (August 1993), C.N. was retested Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 susceptible to interference. with a battery of seven subtests described in detail elsewhere (Peretz, 1990). This battery assesses the dis- crimination of various aspects of music that are known Fam|liarity Decision for Lyrics and Tunes to contribute to music processing, while keeping the To demonstrate that C.N.'s impaired recognition abilities material as natural and identical as possible across con- are specific to the musical domain, we have used for ditions. The material is novel but respects the tonal comparison the recognition of the spoken lyrics. This has structure of the Western idiom. The tests assess abilities been previously done with C.N. (Peretz et al., 1994). In to discriminate isolated musical pitches, to detect vari- that investigation, C.N. exhibited strong evidence of a ations in musical scquences due to pitch changes, to dissociation, with recognition of lyrics being well within detect variations in musical sequences due to rhythmic the range of normal performance and recognition of the changes, and finally to recognize the musical sequences melodies at chance level. This finding was replicated in heard in prior administrations of the battery. 1993 with another set of song excerpts, comprising 32 The results are summarized in Table 2. Compared to lyrics spoken at a normal rate by a female speaker and normal controls, C.N. maintains an excellent perfor- their 32 corresponding melodies sung on la, la, la by the mance when asked to judge the relative pitch of two same speaker. C.N. obtained 28 (87.5%) on the former single tones. Interestingly, she no longer displays im- and 21 (65.6%) on the latter; the superiority effect for paired discrimination whcn the standard and compari- the lyrics over the tunes was largely significant [/(31) = son melodies differ with respect to pitch variations, and 2.963 computed per item pair, p < 0.005]. Thus, we her performance remains in the normal range when the again obtained evidence that C.N. has access to the lyrics sequences differ with respect to timing. Moreover, C.N. but not the melody of the same well-known songs, hence appears to exhibir a parallel improvement in the melody arguing for the specificity of her music recognition discrimination tests and in the delayed recognition test. deficit. However, in contrast with her scores, which now reach normal values in the melodic variation tests, her perfor- mance on the delayed memory test is still two standard TESTS OF MUSIC PERCEPTION deviations below the normal mean (mean: 83.3, SD: 5.6). One of the main issues in the study of agnosia conccrns Ir should be pointed out here that each stimulus se- the functional level at which the disturbance occurs. In quence is 4 bars long, lasts about 4 sec, and contains particular, the question is whether the deficit is primarily from 8 to 19 tones. In each melodic condition, one-third perceptual or mnesic in nature. While a memory impair- of the trials are particularly memory demanding since ment may leave the perceptual operations essentially the number of intervening pitches between the first

Table 2. Percentages of Correct Responses Obtained on the Musical Battery (Peretz, 1990) by C.N. 1 Year Postonsct (March 1988), 2 Years Postonset (December 1989), and 5 Years Postonset (August 1993), as Well as the Means of Five Normal Controls Matched to C.N.'s Sociodemographic Variables, with Their Lowest and Highest Scores in Parentheses

C.N

1988 1989 1993 Controls Isolated pitches a 87.5 100.0 100.0 94.2 (79.2-100) Melodic variations a 33.3 51.4 68.0 72.5 (63.9-83.3) Rhythmic variations b 83.9 88.2 80.4 89.2 (76.0-98.1) Delayed recognitionb 44.4 61.1 66.7 83.3 (77.8-88.9)

a Chance performance: 33.3. b Chance performance: 50.

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 tone of the target melody and the modified tone in the Aftera short pause, the test phase occurs during which comparison melody is above 22. The fact that C.N. per- the 20 target stimuli are randomly mixed with 20 lures; forms normally on these trials eliminates the possibility the subject's task is to tell for each stimulus whether or that she suffers from a short-term memory deficit for not she has heard it in the presentation set. No feedback musical material. is provided to the subject. Thus, her long-term memory difficulty now appears In two forros of the test, all stimuli consisted of musi- disproportionately impaired compared to her perceptual cal excerpts. The distinctive feature of the two forros is abilities, which appear fully recovered. This should, how- that in one test, aH musical excerpts are familiar to the ever, be considered cautiously. First, levels of perfor- subjects, and thus have preexisting stored repre- mance on the melodic discrimination tests and the sentations, whereas in the other test all stimuli are unfa- memory test are not comparable. Second, at the time of millar. The unfamiliar excerpts were taken from the Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 testing, C.N. was still experiencing difficulties with vari- musical battery described earlier. Thus, except for C.N., ous melodic discrimination tests that assessed the use of who had heard them on previous occasions, they werc tonal knowledge in the proccssing of pitch sequences completcly novel to the control subjects (who were (Steinke, Cuddy, & Peretz, 1994). This tonal competence different from those tested on the musical battery). is not assessed in the musical battery. Thus, C.N. cannot To assess the specificity of the results obtained with be considered as free from perceptual dffficulties, al- the musical material, an analog test was constructed with though she certainly recovered most of her perceptual spoken lyrics. AU lyrics were expected to be familiar for losses. they derived from familiar songs. Following the notion that C.N.'s impairment is not merely of a "nonverbal" nature but is specific to music (Peretz et al., 1994), we TESTS OF MEMORY FOR MUSIC, WORDS, added a nonmusical nonverbal recognition memory test. AND ENVIRONMENTAL SOUNDS This test involved familiar environmental sotmds. The music test battcry indicated that C.N.'s incidental The recognition data, displayed in Table 3, are parti- memorization of novel music is impaired. It then became tioned into hits ('~es" response to targets, that is, to items necessary to verify whether this holds true when inten- that had appeared in the study list) and false alarms tional as opposed to incidental learning is involved. In- ('~es" response to lures, that is, to items that had not deed, incidental encoding of music may not reflect the appeared in the study list). As can be seen, C.N.'s scores optimal performance of C.N., since she was not fully are very low for musical excerpts, both for familiar and engaged in memorizing the material. We also needed to unfamiliar musical selections; she is performing at assess whether memorization of familiar music is possi- chance. In contrast, control subjects performed success- ble. Although C.N. cannot recognize musicas familiar, she fully on the tests and exhibited a large advantage for might remember it nonetheless. For example, when pre- familiar material over nonfamiliar material [t(4) = 5.380, sented with the music of "La vie en rose," she might p < 0.005, on bit scores and t(4) = 2.041,p < 0.10, on falso recognize it as music that she had heard earlier, without alarm scores]. As expected, familiarity with the musical recognizing ir as familiar. Evaluation of these possibilities excerpts confers a clear advantage in normal memoriza- was the goal of the following experiments. tion (see analog results in the following test). The fact that C.N. performed at chance, and hence did not show any sensitivity to this familiarity factor, suggests that Recognition Memory for Music, Lyrics, and contact with stored musical representations is either Environmental Sounds absent or ineffective in supporting intentional memory. To test C.N.'s memory, we devised four forros of the In contrast to her,poor performance on musical materi- same recognition memory test. In the presentation als, C.N. performed as weU as, or even better than, nor- phase, 20 target auditory stimuli are presented one after mals with spoken lyrics as well as with environmental the other. The subject's task is to memorize each of them. sounds, clearly scoring more hits than false alarms. She

Table 3. Proportions of Hits (for Studied Items) and False Alarms (for Nonstudied Items) Obtained by C.N. and Her Matched Controls in the Four Memory Recognition Tests

C.N. Controls

Tests Studied Nonstudied Studied Nonstudied Familiar music 0.20 0.15 0.87 0.15 Unfamiliar music 0.20 0.15 0.61 0.31 Familiar lyrics 0.90 0.05 0.83 0.19 Familiar environmental sounds 1.00 0.15 0.95 0.11

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 thus exhibits convincing evidence for the selective na- previous studies employed foreign musical selections ture of her memory deficit. (e.g., Korean music in Johnson et al.'s study) in order to avoid variations in prior familiarity with the music, prior knowledge of the musical selections was here purposely Exposure Effects on Preferences for Music manipulated. The rationale was twofold. First, ir mere Direct measures of memory, such as thosc derived from exposure to music favors its liking, then already highly the music memory recognition tests used previously, do familiar excerpts 0ike the tune of ~Happy Birthday') not cover all memory manifestations. An area of memory should be preferred over unfamiliar selections o~E the research currently under active investigation is con- same gente (i.e., popular folk songs). This predicted pref- cerned with the indirect effects of memory on various erence for familiar music would provide a further index processing tasks. Prior exposure to an item has been of access to stored musical representation in C.N. Sec- Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 shown to facilitate performance on subsequent treat- ond, prior knowledge of the music may differently affect ment of that particular item in the absence of conscious preference and recognition scores, hence providing an recollection (see Schacter & Tulving, 1994, fora recent experimental variable that may help to distinguish im- review). Such indirect effects of memory, also referred plicit from explicit memorization of the music. As ob- to as repetition priming effects or implicit memory, can served in the recognition memory test used in the emerge despite severe memory disorders in direct tests previous situation, familiar music is expected to be easier (see Moscovitch, Vriezen, & Goshen-Gottstein, 1993, for to retain than novel material when explicit memory is a recent review). Thus, even if C.N.'s memory recogni- probed. By contrast, in a preference task, the musical tion is severely impaired, she might perform normally on seleetions may be so familiar or overlearned that addi- indirect tests of memory. Insofar as her perceptual re- tional exposure may not make a difference; the effect of cords of ttmes are degraded but still accessible, as sug- prior exposure should thus emerge more clearly in pref- gested by her good performance on cued-recognition erence ratings for novel musical selections. tasks, she may exhibit evidence of some sparing on Thus, in the present test, subjects were presented with indirect measures of memory. Though she cannot iden- 20 familiar musical excerpts that were mixed with 20 tify tunes or explicitly discriminate them from lures, unfamiliar ones in a study phase. They were required to stimulus information may nonetheless be stored asa decide whether or not the selection sounded familiar. perceptual record that can support priming. This task requirement permitted both verification of To test this possibility in the musical domain, we subjects' familiarity with the stimuli and encouragement exploited the notion that familiarity as a result of prior of carefuI Iistening. Subjects were not informed that this exposure is an important determinant of musical prefer- task was connected in any way with the following pref- ence. That mere repeated presentation of a musical se- erence task. After 5 ruin spent explaining the require- lection increases its liking is a well-known phenomenon ments and the purpose of the preference test, which was (see Heingarter & Hall, 1974, for a critical review of introduced as an inquiry about musical for a future earlier studies as well as convincing supporting evi- study, the subjects were presented with 80 selections. Of dence). This exposure effect on preference is best con- these, half corresponded to the studied excerpts and half ceptualized as ah implicit memory effect (Greve & Bauer, did not. The task was to tate liking of each stimulus on 1990). Preferences for musical selections build up with a 10-point scale, with 1 meaning '1 do not like it" and 10 mere repeated exposure even when subjects, by being '1 like it a lot." amnesic, cannot recognize having experienced the Asa control for the implicit aspect of the test, an stimulus before (Johnson, Kim, & Risse, 1985). In this equivalent forro of the preference test was designed to study, subjects were presented with nonwestern musical test recognition memory. The study phase was in this selections that were repeated a variable number of times condition followed by an explicit recognition test where (1, 5, or 10 times). MI subjects, amnesic and neurologi- subjects were required to judge whether or not they had cally intact subjects alike, exhibited a robust effect of heard each musical selection in the prior familiarity exposure frequency on preference ratings. Of note, the decision test on a lO-point scale (with 1 meaning "no, I preference for presented over nonpresented selections certainly haven't heard this tune," and 10 'yes, I certalnly emerged even after a single presentation. On explicit have heard that tune'5. This recognition task occurred 3 recognition, amnesic patients were, by definition, im- days affer the preference test. paired compared to normal controls. The same tech- There is a problem, however, with a within-subjects nique has also been shown to be effective in design, since mete exposure appears not only to affect demonstrating preserved implicit memory for faces in a preference ratings but to increase recognition scores as prosopagnosic patient who preferred studied to nonstu- well (Johnson et al., 1985). T•us, to arrive at a better died faces, even though the patient could not recognize understanding of the parameters under study, two or identify either (Greve & Bauer, 1990). groups of 12 university students each were tested sepa- Thus, the exposure effect on preferences appears as a rately with either the preference task or the recognition sound test of indirect memory for music. While most task.

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 Table 4. Mean Ratings on a 10-Point Scale for the Preference Task and for the Recognition Task asa Function of Prior Exposure and Familiarity with the Music a

Familiar music Unfamiliar music Presented Nonpresented Presented Nonpresented Preference Task

C.N. 5.3 4.8 4.4 4.9 Matched controls (n--5) 7.6 7.2 5.5 4.8 Young normals (n= 12) 5.7 6.0 5.1 4.1

Baseline (n=12) 5.6 4.7 Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021

Recognition Task

C.N.'s controls (n=5) 7.9 4.7 4.5 4.8 Yotmg normals (n=12) 7.8 2.9 5.5 3.6

a C.N.'s scores are presented alongside the mean scores of her matched controls as well as those of three independent groups of young univer- sity students.

Preference Task dom factors. The analyses yielded an interaction between Familiarity and Presentation [FI(1,11)-- 19.95, p < The results obtained by C.N. and her matched controls 0.001; F2(1,76) = 5.70, p < 0.02]. The effect of prior in the study phase (i.e., the familiarity decision) were presentation reached significance for the unfamiliar reported previously (see the first set in Table 1). To tunes [t(ll) = 4.919;p < 0.001] but not for the familiar statisticaUy assess whether C.N.'s pattern of preference ones [t(ll) = 1.466]. In general, familiar tunes werc scores was reliable, the data were analyzed with items preferred over unfamiliar ones [FI(1,11) = 13.00, p < as the random factor rather than subjects. Since z score 0.005 and F2(1,76) = 29.61,p < 0.001). Finally, a further transformations did not affect the results in any sig- group of 12 university students was tested on the pref- nificant way, the raw scores were kept as the dependent erence test without prior exposure in the familiarity variable. decision phase in order to provide a baseline measure of preferences. These baselinc scores are presented in Table C.N An ANOVA was performed on C.N.'s rating of each 4. When subtracted from the individual scores obtained item, with Familiarity and Presentation as between-item by the primed subjects, essentially the same results factors. This analysis yielded no reliable effect. As can be emerged; the exposure effect reached significance for seen, C.N. did not prefer familiar excerpts to unfamiliar the unfamiliar music while it did not for the familiar ones (F2 < 1), nor studied excerpts over nonstudied material. ones (F2 < 1).

C.N.'s Controls. The scorc associated with each item Preference with a Forced Choice was the average rating of the responses given by the 5 matched control subjects for that particular item. These One year later (in Septembcr 1994), C.N. was once again scores were then submitted tO a two-way analysis of presented with the same preference task. The only dif- variance taking Familiarity and Presentation as factors. ference with its prior use was that a forced-choice pro- This analysis revealed a highly significant effect of Famili- cedure was employed instead of a rating response. That arity [F2(1,96) = 87.13,p < 0.001] and an effect of prior is, after the study phase, C.N. was prcsented with one Presentation [F2(1,76) = 5.56, p < 0.05). There was no studied and one nonstudied musical excerpt, which interaction between these two factors. As can be seen in were matched in familiarity, one after the other (with Table 4, the matched controls preferred familiar over order of presentation of the studied member within a unfamiliar musical selections. They also preferred the pair being counterbalanced across trials). She was re- music previously presented to them in the study phase, quired to indicate which of the two she preferred. The independently of their own knowledge of the music. use of a forced-choice procedure was motivated by the observation that C.N. performed far better under such University Students. The same analyses were per- conditions when providing a familiarity decision (e.g., formed on the responses provided by the 12 university see Table 1). Howevcr, the forced-choice was no more subjects, considering items (F2) of subjects (F1) as ran- effective here than the single presentation in yielding

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 exposure effects. C.N. preferred the studied music in here be taken as the sole factor responsible for higher only 22 of the 40 pairs (exhibiting a slight advantage for preference ratings. The fact that C.N. did not show any the familiar over the unfamiliar music, with 12 and 10, sensitivity to this factor indicates that her prior knowl- respectively). In the study phase, C.N. succeeded a little edge of music is too weak to influence her emotional or better than a year earlier in correctly classifying 26 out aesthetic judgments. of the 40 tunes as being familiar or unfamiliar. However, Similarly, C.N.'s musical preferences for novel selec- these judgments were found to be unrelated to the tions after a single exposure were equally lacking. In preference task. general, C.N.'s preferences appear to be unaffected by prior exposure, be it in the very long term or in the short term. This stands in sharp contrast with the normal Recognition Task controls' performance. Both C.N.'s matched controls and Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 C.N. was totaUy unable to perform the task, systemati- university students were found to be highly sensitive to cally rating each excerpt as 1 ("No, I certainly have not prior exposure. As described just above, not only do they heard that music before") so that we had to interrupt prefer the music to which they have been exposed testing after half the trials. Thus, only the results of numerous times before the experiment, they also prefer normal subjects wiU be analyzed here. newly learned music over completely novel music. This As can be seen in Table 4, all subjects were able to latter effect, which is due to a single repetition, further recognize the familiar music more easily than the unfa- validates the preference task asa sotmd tool for indirect miliar music [q = 14.72 and F2(1,76) = 9.59, memory assessment of music. both p < 0.003, for the tmiversity students, and The fact that this exposure effect is probably not the F2(1,76) -- 24.48, p < 0.001, for C.N.'s matched con- product of (direct) memory recognition arises from the trols]. There was an interaction between Familiarity and results obtained on the memory recognition test. Normal Presentation [FI(1,11) -- 58.49 and F2(1,76) --34.48, controls, particularly the less educated and the older both p < 0.001, for the university students, and ones (i.e., C.N.'s matched controls), were unable to rec- F2(1,76) = 28.93, p < 0.001, for C.N.'s matched con- ognize the novel material. One could argue, however, trols]. Unlike the preference task, subjects were better that this failure may be due to their prior exposure to able to distinguish presented musical excerpts from non- the material during the preference task. This may have presented ones when presented with the familiar mate- generated a high level of interference. The university rial [t(ll)= 13.594] as opposed to the unfamiliar students, who were free of such interference effects, material [t(4) = 0.761 for C.N.'s matched controls]. Nev- nevertheiess also disptayed weak recognition memory ertheless, university students e~dlibited a significant ef- for the newly learned tunes. The fact that prior knowl- fect of prior presentation for the unfamiliar music edge of the music did not have the same impact on [t(ll) = 4.940;p < 0.001]. indirect memory (e.g., preference) and direct memory Three aspects of the results that were obtained with performance (e.g., recognition) may be taken as evi- the preference task are worth discussing: (1) the general dence for the ftmctioning of separate systems. This re- preference effect for familiar music, (2) the preference quires, however, more clear-cut data such as those that for music after a single hearing, and (3) the differential can be obtained from amnesic, nonamusic patients. effect of prior music knowledge on preference and rec- ognition. The first two points provide further evidence Exposure Effects on Word Stem Completion for C.N.'s deficient musical memory. The last effect sup- ports the implicit nature of the exposure effect observed Asa control for the normal functioning Of C.N.'s implicit in the preference judgments. memory beyond that for music, she was tested with a First, subjects generally preferred the music with standard word stem completion task. The task involves which they were familiar prior to the testing situation two main phases: one of presentation of 24 words fol- over newly heard music. This is a well-known effect, lowed by explicit recall of these words and then a phase although it has rarely been empiricaily demonstrated. To of implicit memory by way of stem completion our knowledge, the only study that has done so used (Chatelois et al., 1993; Lussier & Peretz, 1991). In the music selections that were taken from different genres latter phase, the subject is required to complete the and even cultures (with jazz, classical, and rock music stems (two-thirds of which do not correspond to the selections considered as familiar and twentieth-century studied words) with the first word that comes to mind. classical music and ethnic musicas unfamiliar; Zissman C.N. recalled explicitly 21 out of the 24 words, and she & Neimark, 1990). Thus, there might be a confound completcd 14 stems with the studied words. Both scores betwcen prior knowledge of specific musical pieces and rail within the range of 8 control subjects matched in a cultural bias for tonally structured music. This con- age (mean: 36.9; range: 34-41) and education (mean: found was eliminated here since all music selections 12.6 years; range: 11-15) to C.N. These control subjects were taken from the popular folk song repertoire. Thus, explicitly recaLled, on average, 20 words (range: 13-24) prior knowledge of the specific musical selections may and implicitly 10.6 presented words (8-14). Thus, C.N.

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 displays normal effects of implicit memory when words, of C.N.'s learning abilities, a second version, using only not music, are involved. unfamiliar tunes, was presented to C.N. in another ses- sion. The results are shown in Table 5, in temas of the Relearning of Music-Title Associations number of correct responses in associating a title with Another procedure that is now widely used to examine its corresponding music in each trial for true and untrue residual memory in aja indirect fashion is a learning task. pairings in each version. Counting the number of correct The situation, initially developed by Bruyer et al. (1983) responses in each trial for true and untrue pairings, there and since then frequently used in the domain of face were slightly more correct responses on untrue pairings recognition (e.g., de Haan et al., 1987; Sergent & Ville- (24) than on true pairings (21) for the familiar excerpts. mure, 1989; Sergent & Poncet, 1990; Etcoff, Freeman, & However, she was better at learning the familiar set than Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 Cave, 1991; McNeil & Warrington, 1993), is a repeated the unfamiliar one (with 45 vs 34 correct associations, paired-associate learning task in which hall the stimuli respectively). The advantage for the familiar material ate paired with their correct names and half with incor- over the unfamiliar one may indicate the contribution of rect names. It has been shown that some patients ate prior knowledge. Yet, it may also be due to a dffference capable of learning true pairings faster than untrue pair- in complexity that may be unrelated to familiarity. The ings, suggesting that some information about the unrec- problem here is that we do not have normal data that ognized stimulus could be accessed and thus facilitate could help us in distinguishing these two interpretations. the learning of the true pairings. Since C.N. exhibited For normal controls, relearning with the familiar set is savings in tune-title verification tasks, she might exhibit not feasible since they know most of the tune-title them in such a relearning procedure adapted to music. associations from onset. Furthermore, in a rehabilitation perspective, it is worth- In both situations, however, it is clear that C.N. does while to assess whether of not relearning is feasible with not succeed in storing reliable representations of the six C.N. musical excerpts. She succeeded only once in getting aH In the adaptation of this paradigm to music, six musi- six associations twice in a row. The success was, how- cal excerpts were presented, each one associated with a ever, ephemeral for it was disrupted by a change in title. All of these musical excerpts were initially pre- presentation order (see Table 5). Thus, unless she can use sented for identification and title matching by C.N., and external cues such as order of presentation, she experi- nonc was properly paired by her. Yet, five of the six ences great difficulty in relearning old tune-title associa- familiar titles were well recognized and evoked vivid tions or in learning new ones. Ten trials may, however, memories (e.g., she had the record of Albinoni's "Adagio" not be sufficient to create stable representations, even in at borne). Three of these titles were correctly paired with a normal brain. This was suggested by the results of one their music and three were incorrectly paired. At first, of the two matched controls who were tested wit• the the six musical excerpts were presented one at a time unfamiliar set. In the tenth trial, this control subject to C.N., and she was given the title that was to be obtained only four correct associations. Nevertheless, associated with each tune. In each subsequent trial, C.N. each control obtained 45 hits ovemll, a performance was given as much time as she wished to point to the clearly superior to C.N. (34 hits). corresponding title among the six titles displayed on Thus, in contrast with some earlier studics (e.g., paper in front of her. Each of the titles was called out Bruyer et al., 1983; de Haan, Young, & Newcombe, 1987) once in each trial. Errors were corrected affer each and in line with some others (e.g., Sergent & Villemure, response. There were 10 learning trials. The order of 1989; Etcoff et al., 1991) conducted with faces, C.N. did presentation was changed after the first four trials and not show facilitation in learning the true compared to then after the subsequent three trials. Asa further test the untrue pairings. Moreover, she encountered marked

Table 5. Number of Correct Responses per Trial in the Paired-Associate Learning Task with True and Untrue Pairings

Learning trials

1 2 3 4 5 a 6 7 8 a 9 10 Familiar excerpts True pairing 1 3 3 3 1 2 3 1 2 2 Untrue pairing 3 3 2 3 2 2 3 0 3 3

Unfamiliar excerpts 2 2 3 3 2 3 5 4 5 5

a Change of presentation order.

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 difficulties in storing such tune-title associations in alternative title was also a familiar music title, C.N. picked memory, pointing to the irreversibility of her memory up the correct title at a performance level comparable deficit. to that of her matched controls (e.g., tune-title verifica- tion test). The fact that music can be associated with its correct title, under binary forced choice, suggests that GENERAL DISCUSSION music can be processed adequately through levels of The present study was designed to assess the memory representation specifying its identity. This identity component of a music agnosic patient, C.N., in an at- verification was, however, found to be highly susceptible tempt to clarify the nature of music agnosic disturbance to interference. After having performed the same task and thereby to qualify how musical information may be but with purposely erroneous pairings between music stored in memory. The results show that C.N. has now and titles, C.N. was retested with the initial (correct) Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 recovered most perceptual skills and that despite a tran- music-title verification task. On retest, she performed at sient ability to exhibit knowledge of familiar music tm- chance. C.N. is thus able to manifest some content-spe- der restricted circumstances, she is markedly impaired at cific knowledge of the music when forced by a binary naming a ume and at judging its familiarity, as well as at choice. However, access to this knowledge appears ab- memorizing familiar and novel music. This deficit is not normally fragile. only modality-specific but music-specific. The findings One likely origin for the observed unsteady access to suggest the existence of a perceptual memory that is stored representation is a degraded input, not necessarily specialized for music and that can be selectively dam- a disrupted memory. A perceptual deficit implies a failure aged so as to prevent most forms of recognition abilities. to achieve building representations that are sufficiently The hallmark symptom of C.N.'s condition is her per- distinctive to afford reliable contact with the stored sistent music agnosia, which is in aH likelihood the result representations. On the basis of the perceptual results of her bilateral lesions located in the superior temporal presented here, on which C.N. obtained normal scores, cortices. From onset in 1987, C.N. suffered from a per- her music agnosia no longer appears to be of a percep- manent loss of music recognition abilities. She was and tual nature. However, we know from other tests (Steinke still is no longer able to experience a sense of familiarity, et al., 1994) administered to C.N. during the same period and even less one of recognition, for musical selections of time that C.N.'s perceptual abilities are still impaired. that were once highly familiar to her or that were repeat- In particular, she is still unable to use the rules of the edly presented to her over the past 7 years, during which Western tonal system to properly judge musical endings. she was regularly seen in our laboratory. Although some It is tmlikely, however, that these residual perceptual transient difficulties were noted in prosody interpreta- impairments can account for her failure to recognize and don, in voice recognition, and in musical timbre iden- memorize musical passages. Of note, her substantial re- tification, C.N. recovered most (if not all) of these covery in processing melodic information over the years auditory abilities over the years. Most notably, she never was not associated with any improvement in music rec- suffered from any other perceptual or cognitivc dysfunc- ognition abilitics, which remain extremely poor. Unless tion, for example, in speech comprehension or environ- tonal encoding of pitch proves to be critical for music mental sound recognition. recognition or any other more abstract, integrative per- Her agnosic disturbances were manifest in most rec- ceptual abilities that are not yet identified but that might ognition tasks as long as these involved musical material. still be impaired in C.N., hcr major difficulty now ap- During familiarity testing with nonmusical auditory se- pears to lie beyond the perceptual stages of proccssing. quences, such as spoken lyrics, she was always fast and One major implication of this conclusion is that C.N.'s accurate. With musical selections, she was always hesi- deficit now appears to be most consistent with a recog- tant and on most occasions performed at chance. At best, nition model that distinguishes between perceptual she could name 10% of the musical excerpts when analysis from memory representations. A traditional sub- listening to them, although all selections evoked precise division in visual, and later auditory, agnosia is drawn memories when presented by title. C.N. could barely between the perceptual analysis of the input and the decide whether or not she had known these excerpts representational system that contains the stored repre- before. She succeeded, however, in exhibiting evidence sentations of prior experience with the stimulus. This of prior knowledge of these music selections when con- two-stage model of recognition has recently been chal- fronted with a choice between one familiar selection lenged by conncctionist models. According to such mod- and one unknown piccc. Thus, C.N. has access to some els, there is no such distinction between perceptual residual representations in memory. Similarly, she ap- analysis and stored representations. Perception is con- pears to have access to some distinctive information ceived as being an intrinsic part of the process of recog- contained in the stored musical representations. She nition. The representations cannot be altered without showed remarkably good performance when required to altering the perceptual processes (see McClelland & El- match a familiar musical excerpt to its title. Although the man, 1986, for the elaboration of such a model for

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 speech recognition, and Farah, 1990, for visual object anmesic syndrome (see Vanderlinden, 1994, fora recent recognition). Recognition results from the stabilization review). It departs, however, from the amnesic syndrome of a network, in a state that is maximally consistent with in the material specificity of the deficit. First, amnesic the activation from the stimulus and the knowledge of patients, such as Korsakoff patients, are impaired in stor- previous experience encoded in the strength of connec- ing and retrieving all types of material, be it words, tions among units in the network. According to this type music, or faces. Second, amnesic patients are not agnosic of conception, the network arrives at a complete or since they normaUy recognize aH types of stimuli, words, correct interpretation of the stimulus by combining in- faces, and visual objects alike. Third, anmesic paticnts formation from the auditory input and from the stored have an intact implicit memory. Fourth, anterograde im- perceptual experience. pairments are dissociable from retrograde impairments Thus, following a two-stage model of recognition, (e.g., Goldberg et al., 1981). C.N.'s deficit does not follow Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 brain damage can, in principle, impair the memory this pattern. representations without affecting the perceptual mecha- C.N.'s recognition and is specific to nisms, and vice versa. According to connectionist mod- music. She fails to recognize music, but properly inter- eling, injury to the music recognition system would not prets aH other kinds of events or objects. Shc normally distinguish between analysis of the input and stored memorizes faces (Peretz et al., 1994), words, and envi- representations. The observed evolution of the break- ronmental sotmds. She does not exhibit any effects of down pattern in C.N. over the years tends to invalidate implicit memory for music. Again, this impairment ap- the connectionist type of model. Recognition appears pears selective, for she displayed normal implicit mcm- dissociable from perception, at lcast during the recovery ory effects in completing stems with presented words. process. However, no firm conclusion can be drawn at Thus, C.N.'s condition docs not pertain to the classic this point, for it remains unknown whether tonal encod- amnesic syndrome but should rather be conceptualized ing of pitch is a major determinant of access to stored asa domain-specific amnesic disordcr (McCarthy & War- musical representations and the available data on music rington, 1990). agnosia are scarce on this issue. Of the most significance to the current study is the Nevertheless, it is striking that C.N.'s major musical extent to which C.N.'s domain-specific disorder can be impairment now appears to concern memory. In addi- accounted for by solely invoking damage to the music tion to her impaired recognition abilities, which are recognition system. To do so, C.N.'s condition should be summarizcd above, C.N. was shown to be dramatically interpreted in light of a processing model of music impaired in aU music recognition tasks that involved a recognition. According to such a model (Peretz, 1993), memory component. She was not capable of storing built upon experimental data coUected from both nor- music representations, even for a few minutes, whether mal and brain-damaged patients, a musical selcction is the music was familiar or novel. This deficit was demon- first analyzed along two paraUel and independent sys- strated on three different recognition memory tests and tetas whose function is to specify the melodic content on two tests of music-title paired association learning. (i.e., representing the melodic contour and the tonal Although in the latter situation her performance slightly functions of the successive pitches) and the rhythmic improved across learning trials, C.N. did not manifest the content (i.e., representing the metrical organization as slightcst evidence of memorization in the recognition well as the temporal grouping of the successive dura- memory situations. tions), respectively. The repertoire (also referred to as the Indirect effects of memorization were assessed with musical lexicon, by analogy to the lexicon for words) is C.N. as well. They were indexed by two different meas- conceived asa module, available to aU listeners, which ures. One is the bias that can create preexisting associa- contains all the representations of the specific musical tions on relearning music-title associations and the pieces to which one has been exposed during his or her other is the preference bias that creates prior cxposure. lifetime. It receives its input from the musical analysis C.N. showed no sign of implicit memory. She did not systems, deflned by the melodic and rhythmic struc- learn true music-title pairings better than false ones. She tures--or perhaps a combination of the two--and, in exhibited no preference for familiar over unfamiliar mu- turn, can activate stored representations in other systems sic of higher preference ratings for previously heard for retrieval of their accompanying lyrics, if any, for music over nonpresented music. Each of these latter retrieving and pronotmcing their title and for retrieval effects was present in the responses of her matched of aU sorts of nonmusical information (such as an epi- controls. sode related to the first hearing of the music concerned). Thus, C.N.'s music agnosia involves not only an impair- The musical perceptual representations that are stored ment in identifying remotely learned music (which cor- in the repertoire are activated by exposure to the corre- responds to retrograde amnesia) but also an inability to sponding familiar music, are dependent on the auditory learn music cncountered since illness onset (i.e., antero- modality of input, and, finaUy, operatc ata nonverbal grade amnesia). Thus, her condition appears akin to the level.

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 Having discarded the contribution of perceptual fac- spect and to be restricted to a complete processing tots as the key source of C.N.'s current dif¡ and component but rather to disturb a given function in a knowing that C.N. possesses intact speech and intellec- graded fashion. It is unquestionable that the damage tual and mnesic faculties, it becomes clear that the most sustained by C.N. to her music recognition system was reasonable cause of C.N.'s condition concerns the mem- extremely severe. Nevertheless, she did exhibit residual ory component of the music recognition system. The functioning of this system under restricted circum- question is, therefore, to assess whether or not damage stances. As stated previously, she was able to manffest an to the repertoire squares with the findings. It obviously appreciable degree of recognition on some binary accounts for C.N.'s sclective disorder in music recogni- forced-choice tests. The ensuing question is, what is it tion abilities, as far as the retrograde portion of her about the forced-choice procedure that successfully en- memory is concerned. Indeed, ff contact with the stored gaged her residual recognition abilities, and that the Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 representations of most musical pieces is no longer ef- implicit memory procedures (including forced-choice fective, it entails recognition failures. Less is known procedure) did not. about how represcntations for novel music are formed. First, C.N. could discriminate between a familiar and Nevertheless, it is logical to assume that storage of new unfamiliar musical selection in a binary forced-choice musical passages will take place in the same network as situation. This task can be accomplished on the basis of that concerned with the encoding of past experience. In the faintest dffference in activation levels that can be other words, the repertoire would serve both to store obtained between a musical selection having no pre- and retrieve knowledge for specific musical selections. existing representation in the repertoire and one that If correct, then damage to the repertoire entails both an does; even ff the representation is so degraded so as to agnosic and an amnesic condition, which should be prevent the emergence of a sense of familiarity, its resid- music-specific, as observed in C.N. This account appears ual trace may support such crude familiarity discrimina- speculative at this stage for it derives mainly from the tion. C.N. was also able to match a musical excerpt to its data collected with C.N. Its appeal lies in its logical title (under opthnal conditions, without interference), grounds and its parsimony, for it dispenses with the which appears to be an even more demanding task for necessity of postulating different forms of music agnosia a damaged musical representation system. This success- that are due to different underlying causes. fui association requires that some distinctive feature con- The attribution of C.N.'s disorder to repertoire dam- tained in the music representation be activated. One age is also consistent with current models of implicit and plausible but speculative explanation is that forced explicit memory (Tulving & Schacter, 1990; Moscovitch, choice between music titles relies on some forro of 1992). Occurrence of implicit memory effects is pres- interaction between the repertoire, assumed to be musi- ently related to the integrity of perceptual records that cal in nature, and the titles/lyrics representation systems allow the patient to represent the surface characteristics that are assumed to be distinct, although highly imercon- that uniquely describe the word or object presented. If nected (Peretz, 1993). In the presence of a damaged building or access to such perceptual records is no repertoirc but an intact verbal associative memory, as is longer possible, as is the case after damage to the music the case with C.N., the music-title verification task may recognition system, then these representations can no tap the interaction between the two systems, which may longer support implicit memory effects. The absence of be less disrupted than the music system. However, C.N. implicit memory effects in C.N. may thus result from her was found to be tmable to build upon thcse residual inability to build up or to access a faithful musical rep- music-title associations when performing the paired as- resentation rather than from lack of memory per se. sociation relearning task, which is one of the implicit Furthermorc, implicit and explicit memory are con- memory measures. One possibility is that this relearning ceived as sequential phenomena. If in~plicit memory is task, by also presenting untrue pairings between the impaired, explicit memory is necessa¡ compromised, music and the title, creates too much interference for for the latter recruits and elaborates on the same percep- C.N. to rely on her residual knowledge for true associa- tual representations. This explains why implica memory tions. That C.N.'s performance is highly susceptible to can function normally in the presence of a severely interference was indeed demonstrated in the music-title impaired explicit memory, but not rice versa. Damage to verification task. One solution to this problem would be the perceptual stored representations for music would to present only true pairings in one learning session and thus prevent both implicit and explicit memory manifes- only untrue pairings in another session. This should be tations, as is the case of C.N. done in future inquiries. Until now, the functioning of the repertoire was con- The other task in which C.N. could have exhibited sidered as ah all or none phenomenon. Either the reper- residual functioning of her degraded music perceptual toire is fully functional, as is the case for normal subjects, representations, but did not, is the preference task. Given or it is abolished by brain damage. Obviously, this is an her ability to discriminate between a familiar passage oversimplification. Brain damage is not expected to re- and an unfamiliar one, C.N. was expected to prefer famil-

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 iar cxcerpts over unfamiliar ones. Again, this judgment patient has been published elsewhere (Peretz et al., does not require contact with fully intact stored repre- 1994). sentations. On the basis of even a weak memory trace, Several CT scans, taken scveral years apart, converged such a bias would be expected. Indeed, normal subjects in revealing bilateral lesions of rostral auditory associa- do prefer a musical selection even after a single hearing, tion cortex with sparing of the primary and caudal which can hardly be conceived of as being stored in a association arcas. Thus, the preservation of C.N.'s speech resistant format. C.N. did not rate familiar music any and language functions is likely attributable to preserva- higher than novel music. Moreover, in a forced-choice tion of the left primary auditory area and putative lan- procedure, she did not exhibit the normal exposure guage area of Wernicke. effect. That is, she did not prefer those selections that When we first tested C.N. in March 1988, 1 year after were presented to her in a prior study phase, and thus her second operation, she again scored in the normal may be conceptualized as having become more salient range on the BDAE. Her Full Scale IQ was 97 and her Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 (or more activated), to the musical selections that were Wechsler memory MQ was 115, indicating normal intel- not presentcd previously. Ir should be mentioned that lectual and memory abilities for her age and education. this failure cannot be attributed to an emotional dis- Over the years, C.N. manifcsted persistent auditory turbance preventing her from judging attractiveness for deficits that included the processing of music out of music. C.N. is fully able to judge the emotional content proportion to the processing of speech and environ- of music (as yet unpublished data). Again, it can be mental sounds. To summarize the main findings, she argued that thcse conditions were not optimal for C.N. exhibited (1) impaired recognition of familiar umes, because of the presence of highly interfering material. (2) impaired discrimination of unfamiliar tunes on the There were 80 musical excerpts, each associated with a basis of melody (i.e., pitch patterns), (3) preserved dis- variable degree of prior exposure. Nevertheless, it re- crimination of unfamiliar tunes on the basis of rhythmic mains to better specify both the nature and the mode of patterns, (4) normal recognition of environmental operation of the repertoire in a normal brain before sounds, (5) impaired perception of lhlguistic information providing a full account of C.N.'s residual and impaired but not affective information conveyed by speech pros- recognition abilities. The prescnt results at least offer ody, (6) impaired recognition of familiar voices, and new avenues for exploring the functioning of this (7) impaired recognition of musical instrument sounds. largely neglected component of the music processing Sincc that time, we have been able to study her quite system. regularly, allowing us to collect longitudinal data. The In conclusion, the neuropsychological dissociation re- data presented in the current study were mostly col- vealed by C.N. between deficient recognition abilities for lected during the summer of 1993 when C.N. came from music and normal recognition abilities for nonmusical Brussels to Montreal to be tested in our laboratory. C.N. but auditory information gives strong support to a theo- served as subject in aH the experiments reported. Her retical framework that distUlguishes multiple forros of performance was compared to that of tire female sub- perceptual memory, each mediated by the functional jects with no history of neurological or psychiatric dis- activation of a distinct code stored in a distinct mate¡ case, who thus served as normal controls; they were atl specific memory system. of the same age (mean: 39.6 years; range: 38-45), musical background, and education (all nurses working in hospi- tals) as C.N. METHODS Case Description FamUiarity Decision with Music Material C.N. is a 40-year-old, right-handed nurse who underwent two successive surgical operations for repair of mirror The first set contained 80 trials, half of which were aneurysms on the left and right middle cerebral arteries, unfamiliar excerpts that corresponded to real but rarely 7 years prior to the present investigation. Two weeks played music matched in genre to the familiar ones, for after her second craniotomy, C.N.'s performance on the they were taken from the same repertoire (Berthier, French version of the Boston Diagnostic Exami- 1979). The second set compriscd 66 trials, in wbich the nation (BDAE, Goodglass & Kaplan, 1972) showed no unfamiliar excerpts corresponded to the familiar ones evidence of aphasia. Her only complaint concerned but were played in reverse (from the last note to the music-related activities. C.N. received 15 years of educa- firsO. tion, but had no formal training in music. As her father was a professional cellist who played regularly at home, Apparatus and Procedure she was raised in a musical environment. Prior to her illness, C.N. was an avid listener of music and sang to Unless stated otherwise, in all experimental situations, her child every day. A thorough case history of the the musical material was produced one note ata time

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 on an 81Z Yamaha synthesizer controlled by an IBM Memory Recognition for Music, Lyrics, and compatible computcr. All stimuli were recorded onto Environmental Sounds tape and presented in free field at a loudness level that Material was comfortable and customary for the listener. In the familiar music test, all lures were matched to the targets in familiarity. The mean ratings for the targets and Investigation of Music Perception lures were both 4.5, on a 5-point scale, where 1 meant Control Subjects totally unfamiliar and 5 highly familiar. They werc also The control data were provided by five normal subjects, matched in length, with a mean of 8.8 and 9.2 sec for tested in our previous study (Peretz & Kolinsky, 1993), the targets and lures, respectively [t (38) = 0.355]. All whose ages and socioeconomic backgrounds closely were taken from the same pool of normalized data matched that of C.N. (age mean: 33.6 years; range: 29-40; (Peretz et al., 1995). In the unfamiliar music test, targets Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 education mean: 14.6 years; range: 13-15). Al1 were right- and lures were strictly matched in duration, with a mean handed and most were nurses working in hospitals like of 9.1 sec. In the spoken lyrics test, all lyrics were expected to be familiar, for they derived from familiar C.N. songs whose musical components were rated on average 4.4 and 4.7 for 14 targets and 14 lures, respectively Material and Procedure (Peretz et al., 1995). For the remaining lyrics, no norms were available. Targets and lures were matched in dura- The material consisted of a pool of 24 novel but tonal tion with a mean length of 1.1 sec. The environmental musical sequences, arranged in different conditions. sounds test involved 20 target events, of which 10 were These were played on a piano by a professional and noises from human artifact (e.g., train displacement recorded on audio tapes. In the "isolated pitch" condi- noise), 7 were animal cries (e.g., wolf cry), 2 were musi- tion, two piano tones were presented successively and cal instruments (e.g., trumpet sound), and 1 was a natu- the task was to judge whether their pitches were iden- ral sound (e.g., wind blowing). To each target was tical or not. When different, the pitch distance varied matched a distractor of the same category (e.g., 'Tire" for from 3 to 10 semitones. This test included 24 trials, with '~r in the natural sound category) and of the same 8 trials involving the same pitches and the resta dfffering duration. Targets lasted 13.4 sec on average and lures pitch. In the melodic variation tests, pa]rs of melodies lasted 12.3 sec [t(38) = 0.003]. Al1 sounds were takcn had to be classified as "same" or "different." When dfffer- from a coUection of prerecorded digital sounds. 1 ent, a pitch change was inserted in the comparison melody. This pitch change modified the contour--that is, the pitch direction--of the original melody in one con- Exposure Effects on Preferences for Music dition and respccted the contour in another condition. Material In the third condition, the comparison melody in each trial involved the same type of pitch changes as in the There were two sets of stimuli. In set A, 20 familiar tunes previous two conditions, but this time the whole melody with a mean familiarity rating of 4.5 (Peretz et al., 1995) was transposed to a dffferent key to prevent the subject were mixed with 20 unfamiliar tunes taken from the from using absolute pitch asa discrimination cue. Each same repertoire (Berthier, 1979). In set B, another series condition involved 24 trials, of which one-third consisted of 20 fan~iliar tunes, having a mean rating of 4.3 in of identical melodies. In the present study, only the familiarity, were mixed with 20 unfamiliar ones along the average scores obtained across the three conditions are same criteria. Set A was presented in the study phase presented. Among the rhythmic variation tests, there is a preceding the preferenee task, whereas set B was pre- temporal grouping test, where the taped versions of the sented before the recognition task. Set A and set B were melodies presentcd in the melodic conditions are pre- randomly mixed to ser-ve as stimuli in both the prefer- sented in a "same-different" classification task (24 trials). ence and the recogniª tasks but in a different order. When a rhythmic difference occurred, it modified the size and the number of temporal groups in the compari- Exposure Effects on Word Stem Completion son sequence. The other rhythmic test was a metric test, where subjects were required to classify each of the 24 Material melodies presented in the previous tests asa waltz ora The study list is made up of 24 imageable, concrete march. The results reported here are averaged scores words, which were selected from Freibergs' (1970) word across these two "rhythmic" tests. Further details about free association norms for French. All words contained the test material can be found in Peretz (1990), and either two or three syllables and had a mean frequency further information about C.N.'s results on these tests as of 30 (from 1 to 75 occurrences per miUion) for written well as on other similar conditions can be found in French (Baudot, 1970). The first syUable was used asa Peretz and Kolinsky (1993). cuc for stem completion. Each selected word had to

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Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/jocn.1996.8.6.481 by guest on 26 September 2021 begin with a syUable that had at least five different tion without awareness. Cognitive Neuropsychology, 4, entries in the dictionary. The syllables differed across 385-415. Dowling, W., & Harwood, D. (1986). Music cognition. Series words. Presentation of test material and recording of in cognition and perception. New York: Academic Press. responses were done using a Macintosh computer. Fodor, J. (1983). The modular#y of mind. Cambridge,MA: MIT Press. Etcoff, N., Freenhan, R., & Cave, K. (1991). Can we lose mem- Relearning Music-Title Associations ories of faces? Content speciticity and awareness in a prosopagnosic.Journal of Cognitive Neuroscience, 3, 25- Given C.N.'s excellent performance in tune-title match- 41. ing, several attempts wcre made before arriving at the Eustache, E, Lechevalier, B., Viader, E, & Lambert, J. (1990). following solution, which involved only excerpts from ldentification and discrimination disorders in auditory per- familiar instrumental pieces. Three excerpts were given ception: A report on two cases. Neuropsychologia, 28, 257-270. Downloaded from http://mitprc.silverchair.com/jocn/article-pdf/8/6/481/1755407/jocn.1996.8.6.481.pdf by guest on 18 May 2021 their true titles ("French Cancan," 'Tª Elise," "Green- Farah, M. (1990). Visual agnosia. Disorders of object recogni- sleeves') and three had their titles interchanged ("Albi- tion and what they tell us about normal vision. A Brad- noni's Adagio," "Mozart's 40th Symphony," '~31eeping ford book. Cambridge: MIT Press. Beauty'). Farah, M., O'Reilly, R., & Vecera, S. (1993). Dissociated overt and covert recognition as an emergent property of a le- sioned neural network. Psychological Review, 100, 571- Acknowledgments 588. Freibergs, V. (1970). Normes d'association libre attx cinq I am grateful to C.N. and her family for their active cooperation, premi~res r› aux 100 mots de Kent-Rosanoff, and to Myriam Baba'i, Lise Gagnon, Sylvie H› V› › des r› associatifs. Montr› Universit› de Reich, and Bernard Bouchard for their help with the material Montr› and controls' testing. I also thank Maryse Lassonde, Martial Gardner, H. (1983). Frames of mind. The theory of multiple Vanderlinden, and Robert Zatorre for their insightful comments intelligences. New York: Basic Books. made on an earlier draft. While writing this paper, I learned that Goldberg, E., Antin, S., Bilder, R., Hugues, J., & Mattis, S. C.N. died from the sequelae of the rupture of a new aneurysm; (1981). Retrograde amnesia: Possible role of me- I wish to dedicate this papcr to her. This research was sup- sencephalic reticular activation in long4erm memory. Sci- ported by a feUowship and research grant from the Natural ence, 213, 1392-1394. Sciences and Engineering Research Council of Canada. Goodglass, H., & Kaplan, E. (1972). The assessment ofapha- sia and related disorders. Philadelphia: Lea & Febiger. Reprint requests should be sent to Isabelle Peretz, D› Greve, K. W., & Bauer, R. M. (1990) Implicit learning of new ment de Psychologie, Universit› de Montr› C.P. 6128, succ. faces in prosopagnosia: An application of the mere expo- Centre-viUe, Montr› (Qu› H3C 3J7, Canada. E-mail: sure paradigm. Neuropsychologia, 28, 1035-1041. [email protected] H› S., & Peretz, I. (1996). Recognition of music in long- term memory: &re melodic and temporal patterns equal partners? Memory & Cognition, in press. Note Heingarter, A., &Hall, J. (1974). Affective consequences in 1. Prerecorded sounds from the environment were obtained adults and children of repeated exposure to auditory stim- from Lucasfilm Ltd. 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