Accounting for delusional misidentifications. H D Ellis and A W Young BJP 1990, 157:239-248. Access the most recent version at DOI: 10.1192/bjp.157.2.239

References Reprints/ permissions You can respond to this article at Downloaded from

This article cites 0 articles, 0 of which you can access for free at: http://bjp.rcpsych.org/content/157/2/239#BIBL To obtain reprints or permission to reproduce material from this paper, please write to [email protected] http://bjp.rcpsych.org/cgi/eletter-submit/157/2/239 http://bjp.rcpsych.org/ on November 11, 2012 Published by The Royal College of Psychiatrists

To subscribe to The British Journal of Psychiatry go to: http://bjp.rcpsych.org/site/subscriptions/

BritishJournalof Psychiatry(1990),157,239—248

Accounting for Delusional Misidentifications HADYN D. ELLISand ANDREWW. YOUNG Accountsof the majorDMSsaregivenusingtheoreticalmodelsof the functionalcomponents underlying recognition of familiar people. Thus, Capgras' syndrome is suggested to involve impairment of processes that can support ‘¿covert' recognition of familiar faces in

prosopagnosia.It thereforeforms a potential ‘¿mirror image' of the impairmentsunderlying prosopagnosia, and earlier attempts to link the two conditions directly are questioned. Frégoli

syndrome and intermetamorphosisare explained as defects at difterent stages of an information-processingchain. Not only arethese accountsconsistentwith the association of different DMSswith different braininjuries,but they alsooffer both suggestionsfor new inquiriesand predictionsabout possiblepreservedand impairedabilities.

The delusional misidentification syndromes (DMSs)

impact on the traditionally

are psychiatric disorders distinguished by the fact thattheyallinvolvesome deviation from normal

DMS.

processesof recognisingpeople. A recentcollection of papers on DMS (Christodoulou, 1986)gives a good coverageof the history, fmdingsandissues,and

psychiatric

field of

Before discussingthree of the most prominent DMS disorders (Capgras', Frégoliand intermetamorphosis),

we first describethe model of face recognition by

for the waypeopleprocessphysiognomicinformation. As yet, however,the theoreticalinsightsgainedfrom

Bruce & Young (1986), which extends that by Hay & Young (1982) and is the bestsummary of available data. More extensive discussions of such models are available elsewhere (e.g. Bruce, 1988; Young & Ellis,

psychological and neurological studies have had little

1989a;Effis, 1989).Here, we simply focus on those

Young & Ellis (1989a) discusstheoretical explanations

1. These reprasent the ob@ct as it Is actually seen 2. Malysls of facial movement aspects of speech 3. AnalysIs for age, sex, race, etc. 4. These can also be accessed by voice, ga@e@ @, 1969) Independent of the first two stages FIG. 1.

The information-processing

model of familiar face recognition (Bruce & Young, 1986).

239

240

ELLIS AND YOUNG

parts of the model that are relevant for our attempts

modulesfor analysingother aspectsof facesthan

to provide theoretical explanations for DMS.

identity (categorical definitions of age, sex, race, etc.

Following this, we consider the neurological con dition of prosopagnosia in order both to underline

and facialexpression)arealsosupportedby latency data (seeBruce, 1986;Younget a!, 1986;Bruceet a!, 1988). Much of the strongestevidencefor this model however,comesfrom neurologicalcasehistoriesof patientssufferingfrom prosopagnosia, the inability to recognisepreviouslyfamiliar faces(Bodamer, 1947) which usually follows bilateral occipital inferotemporal damage (Meadows, 1974). This conditionproducesa more or lesscompletebreak down of overt face recognitionability in which even the most familiar faces—¿ friends, relatives, family, and the patient'sown face whenseenin a mirror - are not consciouslyrecognised.(For a historyof the disorder,seeEffis, 1989.)Typically, prosopagnosicpatients fall into one of two or moregroupsdependingon whethertheirsymptoms are primarily perceptual, whereby they see faces as blobs, caricatures, all alike, etc., or more memorybased,wherebyfaceslook normalenough but evoke no senseof familiarity (Hécaen, 1981; De Renzi, 1986). The majority of prosopagnosics have suffered

the conclusionsof the face-recognitionmodeland to providethe specifichypothesisfor our analysis of Capgras' syndrome. A model of face recognition It is possibleto attempt a theoretical explanation of DMSs within the kind of information-processing

modelof facerecognitionput forward by Bruce& Young(l986a). Accordingto thismodel(Fig. 1)the recognition of a familiar

face involves sequential

stages.Firstly, there is a stage(I) in which the informationconcerningthestructureof theseenface isencodedusing‘¿descriptions' whichareview-centred (i.e. representtheobjectasit isactuallyseen)and/or independent of expression. These descriptions provide

raw data which are then analysedfor expression, facialspeechand informationaboutage,sex,race, etc. Marr's (1982)modelof visionwasadaptedfor this stage. The secondstage (II) is where the familiarityor otherwiseof a faceis signalledby the FaceRecognitionUnits(FRUs). Familiarfacesthen stimulateinformation held at the PersonIdentity Node (PIN) level (III), where semanticor bio graphicalinformationisstored.Thisthirdstagemay alsobe accessed by voiceor gait or othermeansof signallingidentity. According to Hay & Young (1982), Bruce& Young (l986a), and Effis(1986a), other aspectsof face processing,such as the perceptionof facial expression,are accomplished independently fromandin parallelwiththedetermin

strokes and are middle-aged to elderly men (Mazzuchi

& Biber, 1985).Usually,bilateralareasof occipito temporal cortex are involved (Meadows, 1974; Damasio eta!, 1982), but in some casesneuroimaging

techniqueshave revealedoccipito-temporal lesions involvingonly the right cerebralhemisphere(De Renzi,1986;Landiseta!, 1986).Mostprosopagnosic patientsmanageto identify familiar peopleon the basisof voice,gait andclothingwhichsuggests that the damageoccursbefore the PIN stageof pro ation of individual identity. Furthermore, information cessing.Somedisplayproblemsin identifyingfacial about the person'sname is stored and retrieved expression(Shuttleworth et a!, 1982) but most independentof his or her biographicaldetails. prosopagnosics can interpretthe moodsof others Supportfor the Bruce& Young(1986a)modelof baseduponphysiognomiccues(Bruyereta!, 1983). face recognition comes from a diary study of Face recognition and expressioninterpretation, everydayerrorsof identification(Youngeta!, 1985). however,aredoublydissociable,implyingseparate Thisrevealedproblemsincludingdiaristsrecognising mechanisms (Kurucz& Feidmar,1979).Bythesame a faceasbeingfamiliar but beingunableto access token, facerecognitionand the ability to makeuse biographicalinformation concerningthe person, of lip-readingto aid normal communicationalso and, more often, them knowingnot only that the showdoubledissociation(Campbelleta!, 1986).As face is familiar but also all sortsof biographical Effis(1986b)hasargued,thesedifferent caseslend details,yet not beingableto locatethe individual's supportto thevariousstagesof themodelshownin name.Suchexperiences areconsistentwith theidea Fig. 1. that the recognitionprocesscan become‘¿blocked' at eachof the successive stagesshownin Fig. 1. Otherexperimentsusingreaction-timetechniques Theoretical approach to understanding DMS havealsoproduceddataconsistentwith a sequential seriesof decisionstageseachof whichtakesa finite Our aim in this paper is to advanceexplanations for time to completein a prescribedorder (seeBruce, the major DMSs basedon the current understanding 1988;Sergent,1986).The existenceof independent of normal face-recognition processesand the ways

ACCOUNTING FOR DELUSIONALMISIDENTIFICATIONS in which they can be impaired. In doing this, our explicit intention is to extend the cognitive neuropsychological approach to the study of conditions that have been traditionally defined as being psychiatric in nature. Recent

developments

in

cognitive

neuro

psychology have leant heavily on the view that complex mental functions involve the interaction of a number of modular subcomponents (Fodor, 1983; Ellis & Young, 1988; Shallice, 1988). The

241

The major DMSs Capgras'syndrome In 1923 Capgras & Reboul-Lachaux reported the case of a 53-year-old woman who displayed what

they called “¿l'illusion dessosies―, a delusionalbelief that people who she knew had been replaced by identical doubles (seeBerson, 1983, for an explana

tion of ‘¿sosies' and Christodoulou, 1986, for the historical/mythological background). In addition to neurological and neurophysiological literature now believingthat her husbandand childrenhad been provides abundant evidence for such modular replacedby doubles,the womanlater claimedthat organisation, which would make sensein terms of police and neighbourshad beensimilarly duplicated. the important ‘¿design principles' of keepingessential She also believed that there existed doubles of neural interconnections as short as possible and herself. allowing part of a complex systemto be modified Berson (1983) reports a computer search which by experience or evolution without adversely affecting the performance of the rest of the system

located 133 similar case reports in English, as well

as reports in French, Italian, Russian, Dutch, German, Spanishand Japanese;and Signer(1987) found reports of 315 patients in the English and French literature. In most casesthe diagnosis was of schizophrenia. Many cases also appeared to involve organicdisorders,but, regardlessof the cause of Capgras' syndrome, the symptoms of most patients are dominated by a marked paranoid component(Berson,1983).It is alsoworth noting that the peoplebelievedto havebeenduplicated are generally those closeto the patients. Theseare the kind of people for whom the patient has strongly positive or negativeaffective responses.Sometimes which has been successful in understanding the patientsbelievethat there is more than a single breakdown of normal performance, both in terms impersonator(Todd et a!, 1981). of everydayslips and errors and the deleterious Capgras'patientstendto beparanoid,or, at least, effects of brain injury, can also be of benefit in rather suspicious by nature, and the doubles are understanding delusional misidentifications. Indoing invariably thought of as evil or dangerousin some so, we do not entirely take a leapinto the dark, since way. Capgras' patients also tend to suffer from much recent evidence has begun to suggestsome depersonalisation-derealisation.Patientssometimes organic involvement in DMS, and parallels to report that everything looks strange, for example,

(Marr, 1982;Cowey, 1985). Studies of the different types of breakdown that can affect performance of any complex cog nitive capacity can thus provide insight into the underlying organisation of the responsible func tionalcomponents.More importantly,an adequate theoretical model should be able to account for the types of impairment that can occur and in turn, shoulditself be modified if inconsistentforms of impairmentare actuallyobserved(Ellis & Young, 1988). Here we try to demonstrate that this approach

neurological conditions have already been drawn.

Furthermore, such an approach, carried out syste matically, has advantages in allowing a more

things may look painted or not natural and faces may

look like masksor waxmodelsor seemto havebeen changedbyplasticsurgery.Interestingly, theinstance of Capgras' among femalesis generally thought to suggestingaspectsworthy of further investigation be rather higher than it is among males(Sims& and in predicting certain patterns of co-occurring White, 1973). symptoms. The last point leadsus to an important caveat. It Organicv. functional aetiology is traditional to refer to delusionalmisidentification of Capgras' syndrome syndromes, but in fact, unlike when they were first introduced, eachof theseis now actually defmed by Although labelling Capgras' syndrome as a manifest a singleparticular symptom, rather than a symptom ation of paranoid schizophrenia has constituted constellation. We would thus prefer to speak of an explanationof the disorderfor somecommen Capgrassymptom, and soon, but haveretained the tators, it is a rather unsatisfactoryand incomplete conventional‘¿syndrome' terminologyherebecause one. Merrin & Silberfarb(1976), whoseideaswere it has become so thoroughly entrenched in the more impressive,saw a connectionbetweende literature. personalisation-derealisation andCapgras'syndrome theoretical

understanding

of the conditions,

in

242

ELLIS AND YOUNG

casesbegan with reduced feelings of unreality or depersonalisation,(were)followed by indiscriminate

et a!(1974)showedCapgras-likesymptomsfollowing electroconvulsive therapy (ECT). All of these instancescast doubt on Enoch's (1963) suggestion

misidentification and finally by the establishmentof

that the title ‘¿Capgras' syndrome' shouldbe reserved

the Capgras' delusion―. However, as Todd et a! (1981)pointout, thisin itselfdoesnot fully explain the development of Capgras' syndrome, because patients afflicted by feelingsof depersonalisationor derealisationhaveinsightandappreciatetheillusory nature of the phenomenon, whereas those with Capgras' delusion generally don't. In the main, Capgras' syndromehasbeentreated as a functional disorder. A number of investigators have noted, however, that Capgras' patients often haveassociatedbrain lesions,or that their symptoms may have resulted from someform of poisoning or other exogenous factor. In his review of focal abnormalities of the central nervous system in patients with a DMS, Joseph(1986)discoveredthat the majority of patients have clear computerised

for thedelusionalmisidentificationandreplacement for an identicaldoublein a clearsensorium,andthis withoutorganicbasis(i.e. in a settingof functional illness with a psychodynamic interpretation).

symptoms

when

they

wrote

“¿a number

of

tomography (CT) scanevidenceof brain abnormalities.

Explaining Capgras' syndrome

As we haveindicatedearlier, a numberof researchers now take the viewthat Capgras'syndromemay be the result of underlying organic brain damage. Although the evidencefor this is not yet conclusive, modernbrain-imagingtechniqueshaveshownthat in a large numberof casesof Capgras'syndrome thereisclearevidenceof brainlesions.Nonetheless, somecommentators,suchas Bersen(1983), argue that “¿organic factorsin themselves,however,seem neither necessary nor sufficient to explain the particular andpeculiarcontentof the delusion―. This

Of the 23 patients studied by him, approximately two-thirds had signsof cortical atrophy. In all cases view is perhaps overstated. the signs were bilateral: in some they were largely One of the most interesting suggestions put frontal; in othersparietalor temporal.Unfortunately, forward by thosewho favour an organicbasisfor Joseph did not break down his group by specific Capgras' syndrome is that the condition is related DMS so there is no way of attributing specific sites

of brain damageto particular typesof DMS. It may be noted that Kiriakos & Aranth (1980) found obvious evidenceof organic damagein only four out of 13 Capgras' patients, but they employed X-ray and electroencephalography (EEG) measures- rather

gross forms of imaging - whereas many lesions require CT scan or magnetic resonance imaging (MRI) to become evident. Joseph (personal com munication, 1989)claimsthat all DMS patientsgiven full evaluation have revealed some CNS abnormality. Fishbain et a! (1986) reported the caseof someone

displayingCapgras'syndromefollowing metrizanide myelography.The patient,a 67-year-oldmale, had beenadmitted to hospital following pain in his left calf. Twenty hours after myelography, the patient developedthe following symptoms:severevomiting, severeheadache,confusion, disorientation to time

to one long recognised in the neurological literature, known as reduplicative paramnesia (Alexander eta!, 1979). Such paramnesias often involve reduplication

of places,with the patient maintaining that he/she is in a place which is an almost exact copy of the

actual location. There is a clear parallel with the Capgras'delusion,whichinvolvesreduplicationof people, and Alexander eta! (1979) demonstrated that

a combinationof bilateral frontal and right hemi spheredamageseemedto be presentfor patientsof both types. The link betweenthe two conditions is supported by Anderson (1988), who drew attention

to a number of casesin which Capgras'patientswere observed to reduplicate more than just people. Interestingly,Kapur et a! (1988) reportedthe case of a 71-year-old man who developed reduplicative paramnesiafor placesbut not facesfollowing right frontal vascularlesion, indicatingthe dissociable and place (he thought he was in his son's home) and nature of reduplicativeparamnesia. a delusionalbelief that his doctor wasa duplicate A link between prosopagnosiaand Capgras' of theoriginal. After treatmentwith prochlorperazine, syndrome has also been suggested,but never symptoms gradually remitted. successfully forged. Lewis(1987) in his studyof a MacCallum (1973) also reported Capgras' syn single case of transient Capgras' syndrome, for drome followingmedicalintervention;in this case example, provided MRI data demonstrating the it appeared to be due to the patient inhaling an presence of bilateraloccipito-teinporal lesionsaswell overdoseof a bronchialdilatorcontainingadrenaline assmallerbilateralfrontallesions.The frontallesions and adropinemethonitrate. In another of MacCallum's are consistentwith the fmdingsof Alexanderet a! cases,Capgras' syndromeappearedto be related to (1979) but occipito-temporallesionsare the usual the patient's diabetes. A patient describedby Hay anatomicalcorrelateof prosopagnosia(Meadows,

ACCOUNTING FOR DELUSIONAL MISIDENTIFICATIONS

1974; Damasioet a!, 1982). As we havesaid, the occipito-temporal

lesions underlying prosopagnosia

are often bilateral, but in somecases(basedonly on evidence from brain imaging) are apparently located

exclusivelyin the right cerebral hemisphere(De Renal, 1986;Landiset a!, 1986). The patient studied by Lewis (1987)had actually shownsignsof mild prosopagnosiaduring child hood, and this prompted him to suggestsome sort of connectionbetweenthe two syndromes.According to Lewis there seemsto be a parallel between prosopagnosiaand Capgras' syndrome.In the latter case there would appear to be a disconnection betweenthe perceptof a faceand its evocationof affective memories. Joseph (1986) also posited a disconnection ex planation. “¿It may be that in misidentification syndromes in particular and reduplicative phenomena

243

claimed was particularly sensitiveto prosopagnosia. Finding that their Capgras' patients also performed

poorly on thistestthey thenarguedthat a parallel existed between the two syndromes. However, as Benton(1980)hasemphasised, theface-matching test is not sensitiveto prosopagnosia:many, if not most,

prosopagnosicscan adequatelyperform the test (Bauer, 1984;Young& Ellis, l989b), althoughthey may rely on unusualstrategies(Newcombe,1979). Instead, it is patients with right parietal lesionswho

perform suchtasksespeciallypoorly; yet theseare not prosopagnosic (i.e. theyremainableto recognise familiarfaces).In the same way, itshould be emphasisedthat patients who experience the Capgras'

delusion are not prosopagnosic: they continue to recognisewithout apparent difficulty the dummies and imposters that have replaced their relatives. So if there is any connectionbetweenDMS and

in general, brain diseasecauses a disconnection betweenthe right and left hemispherecortical areas, that decode afferent sensory information and maintain the normal functionsof orientation to person,place,time and objectrelationshipthat we describe as ‘¿orientation'.― In Joseph's view each

prosopagnosia it is unlikely to be a direct one.

hemisphere forms

necessary to show a clear cause and effect relation

a representation

of

a face

Other misconceptionsof the nature of proso pagnosiahavealsobeenintroducedinto the literature on Capgras' syndrome.For example,Todd et a! (1981)maintainthatin orderfor anorganicaetiology for Capgras' syndrometo be established,it is

separately. Normally, these images are ‘¿fused' by ship between prosopagnosia and Capgras' syndrome. interhemispheric transfer, and thus are presented on They evenadd that the associationis particularly a conscious levelasa fully integratedrepresentation doubtful in view of the fact that there are usually no signsof any visual field defectsin Capgras' of the external world. “¿In patients with mis identification syndromes . . . each hemispheric patients.Here theyappearto believe,erroneously, ‘¿image' is presented separately leading to an that visual field defectsarea necessaryconcomitant awarenessof theconsciouslevelof two simultaneously of prosopagnosia. Thisisnotthecase.Prosopagnosia separatebut physically identifiable or similar persons, can exist in the absenceof visual field defects, places, objects, times or object relationships. although they frequently accompany the condition Depending upon which hemispheric connections are but not, it would seem,in any causallyconnected most impaired, the clinical syndromes of mis way (Meadows, 1974). If thereisa connection betweenprosopagnosia and identification, reduplication, or disorientation will result―.Although there is as yet no very compelling Capgras'syndrome,thenit operatesin a rathermore empirical evidence to support Joseph's view, it merits subtleway. In orderto developthisargument,it is further investigation and is not necessarily in necessaryto consider evidencefor different recognition consistentwith the theoreticalideaswhich we present routes, derived from the phenomenaof ‘¿covert shortly. recognition' of faces by prosopagnosics.Bauer (1984) studied a prosopagnosic patient, LF, who had

Face-processing impairmentsin Capgras'patients

sufferedbilateral occipito-temporalbrain damage following a motorcycle accident. He was profoundly

Thereseemslittledoubtthat face-processing impair prosopagnosic,and yet when shown picturesof mentscanbe found in Capgras'patients.Tzavaras previously familiar faces (famous or personally et a! (1986) found that on face-matchingtests known), along with five names drawn from the same semanticcategory, which were read out to him, LF (Tzavaras et a!, 1970) DMS patients were signifi candypoorer than pathologicaland normal controls. displayed significantly greaterautonomic responses They deemedthis “¿an infra-cinical prosopagnosic to thecorrectnamecomparedwiththefourincorrect symptom― whichmayimplysomeorganicfactorin names. This technique, known as the Guilty DMS. Shraberg & Weitzel (1979) studied two Knowledge Test, is widely used by American police Capgras' patients by giving them the Benton face forces as a method for detecting lying by criminal matching test (Benton et a!, 1983) which they suspects. Bauer's data mainly concern the skin

244

ELLIS AND YOUNG

engendered non-recognition of faces:at onelevelthe patient recognisesthe face but at anotherlevelhe well above any chancelevel of performance(i.e. or shedoesnot recogniseit. More recently(andalso 20%). Tranel & Damasio(1985)confirmedBauer's independently)Anderson (1988) made a similar observationsusinga modifiedtechniquein whicha suggestionwhen he argued “¿that the Capgras' seriesof randomly arranged known and unknown delusionresultsfrom lesionsof the pathway for faceswere presentedto two prosopagnosicpatients. visualrecognitionat a stagewherevisualimagesare They alsoshowedincreasedautonomicreactionsto imbuedwithaffectivefamiliarity―. Anderson'sideas the previously known faces. (and thoseof Derombies)are similar to the ones Bauer(1984, 1986)advancedthe viewthat there presentedabovealthoughhe(1988)isnot ableto be aretwo routesto facialrecognition.The mainroute more specific about the mechanismby which runs from visualcortexto temporallobesvia the “¿affective familiarity―may operate. Indeed, one inferior longitudinal fasciculus. Following Bear difference is that our hypothesis rests on the (1983), he termed this the ‘¿ventral route': it view that more than one recognition pathway correspondsto the systemresponsiblefor overt or is involved, and makes the clear predictionthat conscious recognition, and it is the route which Capgras' patients will not show the normally typically is damaged in casesof prosopagnosia. The appropriateskinconductanceresponses to familiar other, describedasthe ‘¿dorsal route', runs between faces, despite the fact that these will be overtly the visual cortex and the limbic system, via the recognised. inferior parietal lobule, and is sometimesintact in The explanation, however, is still incomplete. prosopagnosicpatients. It is this latter route which, Bersen(1983)pointedoutthatin Capgras'syndrome, Bauer claims, gives the face its emotional significance not all facesseemto be duplicated,only thoseof conductance response (SCR). LF showed a dis criminating SCR to some 62.5% of the known faces -

and hence, when the ventral route is selectively

people close to the patient. A possible answer to this

damaged, can give rise to covert recognition (i.e. recognition at an unconscious level). If we acceptBauer's dual recognition route (and from the work of Dc Haan et a!, 1987,it may be thatweshouldbelookingfor morethantworoutes), we can try to apply the notion towardsan under standing of Capgras' syndrome.Young & Ellis (l989a) havebegunto explorethe phenomenonof Capgras'syndromeby suggesting that it isa mirror image of prosopagnosia. In other words, patients with Capgras' syndromeseemto have an intact

is that it is only in theseinstancesthat one expects morethanthebasicinformationabouta face.Only certainfacesnormallyhaveassociatedwith them a particularlystrongaffectivecomponent,and there fore only theseare vulnerablein the caseof any disconnectionbetween the visual areas and the cerebral structures involved in Bauer's dorsal recognitionpathway. One may extend this argument to other re duplicativeparamnesias. Places,objects,etc.arenot affectively neutral and so the absenceof an emotionallychargedinputcouldproducethefeeling of recognition,but it not beingquite right. Again this would be particularly true for those placesand objectswith which the patient is most familiar.

primary or ventral route to face recognition, but may

have a disconnectionalong or damagewithin the secondary or dorsal route. This would mean that they

receivea veridical image of the personthey are lookingat,whichstimulates alltheappropriate overt

semanticdataheldaboutthat person,but theylack another, possibly confirming, set of information which, as Lewis (1987) and Bauer (1986) have independentlysuggested,may carry somesort of affectivetone.Whenpatientsfmdthemselves in such a conflict(thatis, receivingsomeinformationwhich indicatesthe facein front of thembelongsto X, but not receivingconfirmation of this), they may adopt some sort of rationalisation strategy in which the individualbeforethemisdeemedto bean imposter, a dummy, a robot, or whateverextanttechnology may suggest. Derombies (1935)also attachedgreat importance to the affective state of Capgras' patients. He suggestedthat Capgras' syndromeresultsfrom a simultaneous intellectualrecognitionandaffectively

Frégoli syndrome In 1927Courbon& Fail reportedanotherform of DMS. Their patient was a 27-year-oldlabourer's daughterwho had workedvariouslyas a domestic servant,in a factory, in a restaurant,etc. Shewas paid by the day and sleptin SalvationArmy type refuges.Her abidingpassionwas the theatre; she preferredto go without food in order to attend a performance.Admitted to hospital following an attackon an employer,shereportedto Courbon& Fail that shewasthe victim of enemies:in particular of theactresses RobineandSarahBernhardtwhom shehad often seenin the theatre. She insisted that these actresseshad followed her about for many

ACCOUNTING

FOR DELUSIONAL

245

MISIDENT1FICATIONS

years, taking the form of people she knew or

the other hand, such inconsistencies are also noted, but attributed to the effects of disguise. The syndrome can thus be characterised as involving impaired this instead of that and stroking her or forcing decision mechanisms. In Bruce & Young's terms, the her to masturbate. The patient reported often being interfered with or attacked by people who impairment is in the cognitive system itself, which places an inappropriate evaluation on the evidence particularly took the form of Robine. it receives. Such decision mechanisms can also mal Courbon & Fail adopted the term ‘¿Frégoli function for normal people, as other everyday errors syndrome' after the Italian actor and mimic, collected by Young et a! (1985) showed. Leopoldo Frégoli,famous for his ability to im The PIN stage and associated cognitive system personatepeople on the stage.The hallmark of the Frégoli syndromeis the delusionalmisidentification would therefore be the likely site for malfunction of familiar personsdisguisedasothers. De Pauw et leading to Frégolisyndrome (seeFig. 2). Specifically, either the PIN system becomes driven by a deranged a! (1987) classified the illusion of Frégolias hyper cognitive system or hyperexcitable nodes representing identification. They contrast this with Capgras' syndrome,whichwasclassifiedashypo-identification. particular people appear to become engaged, some times almost regardless of whatever output from the They reported the case of Mrs C, a 66-year-old widow, who believed that she was being persecuted previous FRU stage occurs, and impaired decision mechanisms accept this evidence. Since strangers' faces by her cousin and his female friend. She described in detail how the couple disguised themselves with make-up, wigs, dark glasses, false beards and different clothes, and repeatedly accosted her when Face she was out. She confronted strangers in public demanding that they reveal their true identity; she took complicated routes on her way home to shake off her persecutors; and she often reported their activities to the local police. “¿They keep changing their clothes and their hairstyles, but I know it's met, overpowering

her thoughts, making her do

1

them. He can look like an old man. They want a medal for doing that. It's like an actor and actress preparing for different scenes,―she said. Mrs C had a history of brain damage: she suffered haematoma over the left frontal area after a fall in 1982. A CT scan also showed right-sided posterior temporo-parietal infarct together with general cortical atrophy. She had earlier been treated for hyper tension and she had also been diagnosed as having right-sided temporal arteritis. Although she recovered from her initial symptoms of speechslurring and memory problems as well as her orientation diffi culties, she then developed the delusional belief just described. Her Frégolisyndrome seemed to be

controllable with trifluoperazine. As in cases of Capgras' syndrome, Frégolimay be associated with some degree of objective face

Voices1 etc.

processingimpairment. Dc Pauw et a! (1987)found that Mrs C scoredpoorly on the Warrington face recognition test. More detailed investigation of such impairments would be worthwhile. Frégolisyndrome bears some relation to a type of

error that all of us make in everydaylife (Young et a!, 1985).When we expectto meet a particular person, occasionally and transiently we will mis 1. Not shown in originai model. identify a stranger as that person. However, we usually quickly correct this mistake when inconsistent Fio. 2. Simplified face-recognition model indicating the level at evidence is picked up. In the Frégolisyndrome, on which it is proposed the illusion of Frégolioccurs.

246

ELLIS AND YOUNG

are often the source of the patients' delusions it is clear that it would be of interest to study whether any degreeof resemblance to the misidentified person

Face

I

is necessary. Intermetamorphosis First described by Courbon & Tusques (1932), intermetamorphosis refers to cases where, for the patient, the physical appearance of some people may change radically to correspond with the appearance of someone else. Courbon & Tusques described a 49-year-old depressive patient who reported that animals and objects she owned took the form of

another animal or object. She also experienced changesin her husband'sappearance,whichcould be comeexactlylike that of a neighbouror could rapidly transform to look larger or smaller or younger. Various people in rapid succession also took on the guise of her son, but she used the particularly large size of his feet to discount these delusions. Courbon & Tusques (1932) pointed out that intermetamorphosis involves a false recognition of both appearance and associated identity, whereas in the illusion of Frégolithe patient is not confused about physical appearance. Intermetamorphosis is relatively rare: Bick (1986) reviewed two cases reported after Courbon & Tusques' (Chnstodoulou, 1975; Malliaros et a!, 1978) and presented another, a 42-year-old woman who had had a long history of epilepsy and paranoid schizophrenia. During a period in hospital, she became suddenly agitated and declared that her doctor was her dead uncle. According to Bick (1986), three of the four cases reviewed by him had temporal lobe epilepsy. Joseph (1987) has subsequently described a 49-year-old patient who displayed both Capgras' syndrome (believing her husband had been replaced by an identical imposter) and intermetamorphosis (stating

that severalother patientslooked like her father and that her son's physical appearance had altered). In

etc.

1. Nc* shown in original modeL Fio. 3. Simplified face recognition model indicating the level at which it is proposed intermetamorphosis occurs.

the particular person. The FRUs then signal familiarity and, in turn, communicate with appropriate PINs in the semantic memory system where the person's biographical details are stored.

this casea CT scanwasgivenand it revealedmild

Intermetamorphosis may be construed as an

atrophy of the frontal lobe, severebilateral atrophy of the temporal lobe, moderate atrophy of the occipital lobe and a mildly enlarged ventricular system. The prima facie evidence for a possible

inappropriate excitation of an FRU which could

organic component in intermetamorphosis, as for other DMS disorders, is thus quite strong.

In order to establish an explanation for inter metamorphosis within the Bruce & Young (1986) model of normal face recognitionprocesses,it is necessaryto focuson the secondstage,the FRU stage, highlightedin Fig. 3. Representationsfor known faces are posited to exist, each of which is somehow excited or triggered by the appearance of

occur, for example, if the particular FRU had a considerably lowered triggering threshold. A corollary to this suggestionis that it is more likely that faces

similar to the misidentified personwill causethe unit to fire inappropriately, and, as with the Frégoli symptom, more systematic investigation of the resemblancebetweenthe appearanceof the actual and delusionally substitutedpeoplewould be useful. A clear prediction from our account of thesecon ditions is that physicalresemblancewill beimportant in triggering episodes of intermetamorphosis but much less important to the Frégolidelusion.

ACCOUNTING

FOR DELUSIONAL

247

MISIDENTIFICATIONS

At this stageit is not possibleto establishwhy and

mistakenly perceived in intermetamorphosis and wrongly categorisedin Frégoli syndromewould also be of theoretical benefit. The final pointwewishto stressisthat discussing comeexcited.Unfortunately,noneof thecasehistories DMS in relation to prosopagnosiareinforcesthe of patients' behaviour during such an instance of suggestionsmade by Joseph(1986)and others that misidentification has reported how the patients DMS may originateprimarily from organicbases. respondedto voices.According to the model shown The nextstepmustsurelybe to deriveroutinelyin in Fig. 3, voicesinput from a different recognition casesof DMS high-quality brain images that should systembut employthe samePINs. Joseph& O'Leary assistin classification.In time it shouldbe possible (1987) indeedreporteda Frégoli casewho claimed to correlateparticularDMSswithdamageto specific that a Mr B had beenreplacedby another acquaint brain areas. ance. While the physicalappearanceof Mr B was unchangedhe appearedto have the other person's Acknowledgements voice.Thus, whereasFrégoli patientsmay misperceive

how suchthresholdshiftsoccur, but noticethat once an FRU has fired it will automatically then causethe corresponding and equally inappropriate PIN to be

voices, those with intermetamorphosis

syndrome

could make an incorrectfacial identificationbut shouldnotproducethesameerroronthevoice.This shouldproducediscrepancies at timeswhichwould,

The authors are funded by an Economic and Social Research Council Programme:RecognisingFaces(XC15250004).They would like to thank Drs Szulecka and De Pauw for their help and encouragement.

perhaps, be resolved becauseof the primacy of visual

over aural perception but could, nonetheless,be elicited during clinical interview.

References ALEXANDER, M. P., STUSS, D. T. & BENSON, D. F. (1979) Capgras

syndrome: a reduplicative phenomenon. Neurology, 29,334-339. ANDERSON, D.

Conclusion The advantages in attempting to explain various DMS stateswithin the theoretical constructsderived from studies of normal and pathological face recognition are numerous. Chief among them, of course, is the hope that it may lead both to a completeunderstandingof DMSs and, in turn, assist clinicians in diagnosis and treatment. Secondly, the opportunity to bring together a seemingly disparate set of phenomena, for some time

N.

(1988)

The

delusion

of

inanimate

doubles:

implications for understanding the Capgras phenomenon. British Journal of Psychiatry, 153, 694-699. BAUER, R. M. (1984)

Autonomic

recognition

of names

and

faces:

a neuropsychologicalapplication of the Guilty KnowledgeTest. Neuropsychologia, 22, 457-469. —¿

(1986)

The

cognitive

psychophysiology

of

prosopagnosia.

In

Aspects of Face Processing (eds H. Ellis, M. Jeeves, F. Newcombe.

ci a!). Dordrecht:

Martinus

Nijhoff.

Ba@a,D. M. (1983) Hemispheric specialization and the neurology of emotion. Archives of Neurology, 40, 195-202. BENTON, A. L. (1980)

The neuropsychology

of facial

recognition.

American Psychologist, 35. 176-186. —¿,

H4u.isssu,

K.,

[email protected],

N.

R.,

ci

al

(1983)

Contributions

to Neurological Assessment. New York: Oxford University Press. BERSON, R. J. (1983) Capgras' syndrome. American Journal of PsychIatry, 140,8. Biat, P. A. (1986)The syndrome of intermetamorphosis. Bibliotheca Psychiatrka, 164, 131—135.

effectivelydealtwith asbeinglargelyunrelated,carries with it many advantages.For example,the ideasthat havebeenpositedregardingCapgras'syndromeallow us to perceive a very obvious deficit in the model outlined in Fig. 1, that is, it only depictsthe ‘¿overt'BODAMER,3. (1947) Die Prosop-Agnosie. Archly fürPsychiatric und Nervenkrankheiten, 179, 6-54. route to facerecognition. Experimentson prosopag V. (1986) Recognlsing familiar faces. In Aspects of Face nosic patients, togetherwith the theoretical ideaswe BRUCE, Processing (eds H. Ellis, M. Jeeves, F. Newcombe, ci al). havepresentedhere,strongly suggestthat the model Dordrecht: Martinus Nijhoff. is incompletein that it only displaysa singleroute to recognitionand fails to accommodatewhat, perhaps, Journal of Psychology, 77, 305—327. may turn out to bea sort of emotional recognitionof faces (and indeed other routes, as well). sex and familiarity of faces. Canadian Journal of Psychology. 41, 510—520. The third aspectof our endeavoursto which we wish to draw attention is its potential value in BRUYER,R., LATERRE,C., SERON,X., ci a! (1983) A case of prosopagnosia with some preserved covert remembrance of organisingclinical observationsof DMS patients.We familiar faces. Brain and Cognition, 2, 257-284. havesuggestedvarious typesof evidencethat should CAMPBEU., R., LANDIS,T. & REGARD,M. (1986) Face recognition becollectedroutinely in suchcases.it is, for instance, and lip reading: a neurological dissociation. Bluin, 109, 509—521. clearlyimportant to notepatients' responsesto voices CAPORAS,J. & REB0uL-LAcuAux, J. (1923) L'illusion des ‘¿sosies' dans un déliresystésnatise chronique. Bulletin de Ia Socidié aswell as faces,becauseby doing so we may refine Clinique de Mddecine Mentale, 2, 6—16. our ideasconcerningthe level of impairment. Some CmusroDouLou, G. W. (1978) Syndrome of subjective doubles. American Journal of Psychiatry, 135, 249-251. assessment of the similarity between people —¿

(1988)

—¿

&

—¿,

Recognising

YouNG,

Ews,

A.

H.,

Faces.

(1986)

GIBUNO,

Hillsdale,

Understanding

F.,

ci

a!

(1988)

NJ:

Lawrence

face

recognition.

Parallel

processing

Erlbaum.

BritIsh

of

the

248

ELLIS AND YOUNG

CHRIsTocouwu, G. N. (1975) Reported in Bick (1986). —¿

(1986)

The

delusional

misidentification

syndrome.

Bibliotheca

Psychiatrica, 164. CouRsoN,

P. & FAIL, 0. (1927) Illusion

schizophrenia. —¿

&

of Frégoli syndrome

and

Societe Clinique de Mddecine Mentale.

TusQuEs,

3.

(1932)

Illusions

d'intermetamorphose

et

Ku@ucz, 3. & FELDMAR,0. (1979) Proso-affective agnosia as a symptom of cerebral organic disease. Journal ofthe American Geriatrics Society, 27, 225-230. LANDIs,T., CUMMINGs, J. 0., CERIsT@,L., ci al (1986) Are unilateral right posterior cerebral lesions sufficient to cause prosopagnosia?

de

charme. Annales Medico-Psychologiques, 14, 401—406. Coway, A. (1985) Aspects of cortical organization related to selectiveattentionand selectiveimpairmentsof visualperception:

A tutorialreview.In AttentionandPerformance, XI (edsM. Prosopagnosia: anatomical basis and behavioral mechanisms.

Neurology,32, 331—341. E., YOuNG, A. & NEWCOMER,F. (1987) Face recognition

without awareness. Cognitive Neuropsychology, 4, 385—415. DEPAUW,K. W., SZULECKA, T. K. & P0LTocK,T. L. (1987) Single case study. Frégoli syndrome after cerebral infarction. Journal of Nervous and Mental Disease, 175, 1—6. DE RENZI,E. (1986) Current issues in prosopagnosia. In Aspects of Face Processing (eds H. Ellis, M. Jeeves, F. Newcombe, ci al). Dordrecht: Martinus Nijhoff. DER0MBIas,M. (1935) L'illusion de sosie, forme particuliers de la

British Journal ofPsychiatry,

W.

&

YOuNG,

A.

0.

(1988)

Human

Cognitive

R. Bruyen). Hillsdale, NJ: Lawrence Erlbaum. of

face

recognition.

In

Neurology

(eds

K.

Pock, H. J. Freund & H. Ganshirt). Heidelberg: Springer Verlag. —¿

(1989)

Past

and

recent

studies

of

prosopagnosia.

In

(eds 3. R. Crawford & D. M. Parker). New York: Plenum. ENGcI@, M. (1963) The Capgras syndrome. Acta Psychiatrica

NEWCOMER,

A.

&

RosoMon',

(1986)

Capgras

and Pathology in Cognitive Functions (ed. A. Ellis). New York: Academic Press. HAY, 0.0., JOLLEY,D. 3. & JoNSs, R. 0. (l974)A case of Capgras'

syndrome in association with pseudo-hypoparathyroidism.Acta Psychiatrica Scandinavica, 50, 73-77. HECAEN,H. (1981) The neuropsychology

of face recognition.

central

nervous

in patients with misidentification (1987)

Delusional

system

&

0'L@y,

D.

H.

information

in

versus

in Psychology

Methodological

constraints

on

and

neuropsych

to Mental Structure.

SHRABERO,D. & WEITZEL,W. D. (1979) Prosopagnosia

and the

Capgras syndrome. Journal of Clinical Psychiatry, 40,313-316. SHuTr1@wOkm,

E. C.,

observations

on the

SYRING, V. & ALLEN,

nature

N. (1982)

of prosopagnosia.

Further

Brain

and

of

the

Capgras

and

Anterior

cortical

in

Frégoli

syndrome. Journal of Clinical Psychiatry, 4$, 409-411. KAPUR, N., TuENER, A. & KING, C. (1988) Reduplicative

paramnesia

possible anatomical and neuropsychological mechanisms. Journal of Neurology, Neurosurgery and Psychiatry, 51, 579-581. KIRI@os, R. & A@&r@im, 3. (1980) Review of 13 cases of Capgras syndrome. American Journal of Psychiatry, 137, 1605-1607.

of the Capgras and de

Clerambault syndromes. A case history. British Journal of Psychiatry, 123,635—637. ToDD, 3., DEWHuRSr,K. & WAuI5, D. (1981) The syndrome of

Capgras. British Journal of Psychiatry, 139, 319-327. Tw@L, D. & D@sIo, A. R. (1985) Knowledge without aware ness: an autonomic index of facial recognition by prosopagnosics. Science, 228, 1453—1454. TzAvARAs,A., HEc@, H. & LEBRAS,H. (1970) Le problIme de Ia specificitédu deficit de Ia reconnaissancedu

visage humain

lorsdes

lésionshemisphériquesunilatérales Neuropcychologia,8,403-418. —¿.

LuATE,

3.

&

BIDAULT,

E.

(1986)

Face

recognition

dysfunction

and delusional misidentification syndromes. In Aspects of Face Processing (eds H. Ellis, M. Jeeves, F. Newcombe, ci a!). Dordrecht: Martinus Nijhoff. YOUNG,A. W. & ELLIS,H. D. (1989a) Handbook of Research on

Face Processing. Amsterdam: North Holland. —¿

atrophy

the delusion of sub

stitution.Journal of Clinical Psychiatry, 48, 4. SIMS, A. & WHITE. (1973) Coexistence

types responding to clorazepate. Ada (1987)

of visual

dyslexia: Functional

In Research

Cambridge: Cambridge University Press.

abnormalities

PsychiatricaScandinavica,75, 330—332. —¿

processing

SHALLICE,T. (1988) From Neuropsychology

syndromes. Bibliotheca

misidentification

intermetamorphosis

The Capgras

ological studies of face perception in normals. In The Neuro psychology of Face Perception and Facial Expression (ed. R. Bruyer). Hillsdale, NJ: Erlbaum.

Psychiatrica,164,68—79. —¿

The

and acquired interpretation.

SERGENT, 3. (1986)

In

Perceiving and Remembering Faces (eds 0. Davies, H. Ellis & 3. Shepherd). London: Academic Press. Focal

(1979)

physiological

SIGNER, S. F. (1987) Capgras syndrome:

syndrome

HAY, D. C. & YouNG, A. W. (1982) The human face. In Normality

A. B. (1986)

0. N.

Cognition, 1,307-322. H.

associated with metnizamidemyelography.InternationalJournal of Psychiatry in Medicine, 16, 131-136. FocoR, 3. (1983) TheModularityof Mind. Cambridge,Mass: MJT Press.

JosEpH,

F.

prosopagnosia

Scandinavica, 39, 437—462. D.

with an organic

phenomenon. Archives of General Psychiatry, 33, 965—968.

Developments in Clinical and Experimental Neuropsychology

FISHBAIN,

symptoms

Medicinel(eds D. Osborne, M. Gruneberg& 3. Eiser). London: Academic Press.

Neuropsychologyof FacePerceptionandFacialExpression(ed. Disorders

six

150, 117-121.

(1973)Capgras

MERRIN, E. L. & SILSERFARB,P. M. (1976)

Neuro

ELLIS,H. D. (1986a) Processes underlying face recognition. In The

(1986b)

in

(1978)Organic contributors to the intermetamorphosis syndrome. AmericanJournal of Psychiatry, 135,8. MARk,D. (1982) Vision. San Francisco: Freeman. MAzzIJcnI, A. & BIRER,C. (1983) Is prosopagnosia more frequent in males than females? Cortex, 19,509-516. MEMows, 3. C. (1974) The anatomical basis of prosopagnosia. Journalof Neurology,Neurosurgery and Psychiatry, 37, 489-501.

psychology. London: Erlbaum.

—¿

findings

MALLIARAS,D. E., Kossovrrs,@, Y. T. & CHRIsrocouwu,

reconnaissance systematique (these de Paris quoted by A. Brochado). Annales Medico-Psychologiques, 94, 706—717). A.

radiological

basis. British Journal of Psychiatry, 123, 639-642.

D@sio, A. R., D@sIo, H. & V@ HOESEN, 0. W. (1982)

ELLIS,

and

LEWIS,S. W. (1987) Brain imaging in a case of Capgras' syndrome. MACCALLUM, W. A. 0.

Posner & 0. Mann). New Jersey: Eribaum.

DE H@,

Clinical

additional patients. Cortex, 22, 243-252.

&

—¿

(1989b)

Childhood

prosopagnosia.

Brain

and

Cognition,9, 16—47. —¿,

HAY,

D.

C.

&

ELLis,

A.

W.

(1985)

The

faces

that

launched

a thousand slips: everyday difficulties and errors in recognizing people. British Journal of Psychology, 76, 495-523. YouNG, A. W., MCWEENY,H*y, D. C., ci a! (1986) Matching familiar and unfamiliar faces on identity and expression. Psychological Research, 48, 63-68.

*Hadyn D. Ellis, BA,PhD,DSc,CPsychol, FBPsS, SchoolofPsychology, University of WalesCollegeof Cardiff

Cardiff CFJ 3YG; AndrewW. Young,BSc,PhD,DSc,CPsychol, FBPsS, Departmentof PsychologyUniversity of Durham, Durham DHE 3LJ Correspondence