Social Cognition, Vol. 20, No. 5, 2002, pp. 353-379 MEMKLEIN ORY ET ANDAL. T EMPORAL EXPERIENCE MEMORYAND TEMPORAL EXPERIENCE: THE EFFECTS OF EPISODIC MEMORYLOSS ON AN AMNESIC PATIENT’S ABILITYTO REMEMBER THE PAST AND IMAGINE THE FUTURE Stanley B. Klein and Judith Loftus University of California, Santa Barbara John F.Kihlstrom University of California, Berkeley This articleexamines the effects of memoryloss on apatient’s abilityto remember thepast and imaginethe future. We presentthe case of D.B.,who, asa resultof hypoxicbrain damage, suffered severe amnesia for the personally experienced past.By contrast, his knowledge of thenonpersonal pastwas relatively preserved. Asimilarpattern was evidenced in hisability to anticipatefuture events. Although D.B. had greatdifficulty imagining what his experiences might be like in thefuture, hiscapacity to anticipateissues and eventsin thepublic domain wascomparable to thatof neurologicallyhealthy, age-matched controls. These findings suggest that neuropsychologicaldissociations between episodic and semanticmemory for the past also may extend to the ability to anticipate the future. Ourexperience of personalidentity depends, in afundamentalway, on ourcapacity to represent the self asa psychologicallycoherent entity persistingthrough time, whose past experiences areremembered asbe- longing toits present self (e.g., Klein, 2001). The experience ofself-conti- nuity, in turn,provides the mentalscaffolding from which we can imagine possible futures statesin which wemightbe involved(for re - view,see Moore& Lemmon,2001). Perhaps the best waytoconvey the Thiswork was supported byan Academic SenateResearch Grant to StanleyB. Klein fromthe University of California,Santa Barbara, and by National Institute of Mental HealthGrant MH-35956 to JohnF. Kihlstrom. Wewould like to thankMark Wheeler and GianfrancoDalla Barbafor their extremely helpful comments onearlier versions ofthis ar- ticle. Address correspondence to StanleyB. Klein, Department of Psychology,University of California, Santa Barbara, CA 93106; E-mail:[email protected]. 353 354 KLEIN ET AL. importanceof timeand memory in ourexperience of self isto quote Tulving (2002). ...we can,if we wish, close oureyes and think aboutwhat wedid ten min- utes ago,or how wecelebrated ourlast birthday. And we canthink about what we might bedoing tomorrow, or next year. This kind ofsense oftime makes ahuge difference towhat we are and how we live. Ifwe retained all ourother mental capacities,but lost the awareness oftime in which ourlives are played out,we might still beuniquely different from allother animals but we would no longer be human as we understand it. (pp. 311) Thus,understanding the humanexperience ofpersonal identity re- quires recognizing the memorialand temporal basis of thatexperience. In thisarticle, we present atheoreticalanalysis and empirical investiga- tionof the roleplayed bymemoryin enabling the experience ofself as temporally extended, as an entity spanning past, present, and future. MEMORY AND TIME Memory andtime have a specialrelationship. On the one hand,the actof remembering logicallypresupposes asense oftime(for reviews,see Fur- long,1951; Howe & Courage,1997; James, 1890; McCormack & Hoerl, 1999). Onthe otherhand, our subjective experience oftimeis held tobe a constructionof memory(for reviews,see Fraisse,1963; Friedman, 1993; Larsen,Thompson, & Hansen,1996; Ornstein, 1969 ). The conceptsof memoryand time are thus interdependent, neither completely separa- ble fromthe other(e.g., Rosenfield,1992; Sorabji, 1972). In thisarticle we explore thisinterdependence by examining whathappens when the re - lationbetween memoryand time breaks down. In particular,we de- scribe effects wroughtby catastrophicmemory loss on an amnesic patient’s ability to remember the past and imagine the future. Analysesof the effects of amnesiaon temporalexperience havetended tofocuson the roleof memoryin enabling reconstructionof one’s past (e.g., Barbarotto,Laiacona, & Cocchini,1996; Dalla Barba, 1993; Hodges &McCarthy,1995; Markowitsch, Fink, Thone,Kessler, & Heiss,1997; Reinvang,Nielson, Gjerstad, & Bakke, 2000;Russell,1971; Tulving, 1989; Wilson& Wearing,1995 ).However,memory also serves a prospective function,enabling itsowner to plan future actionsand anticipate future events (for reviews,see Brandimonte,Einstein, & McDaniel, 1996; Ingvar,1985; Suddendorf &Corballis,1997; Tulving, 1985;Tulving & MEMORY AND TEMPORAL EXPERIENCE 355 Lepage, 2000). Indeed, acasecan be madethat information storage is in- trinsicallyprospective, used tosupportfuture decisionsand judgments thatcannot be knownin advancewith certainty (e.g., Dawkins,1976; Klein, Cosmides,Tooby, & Chance,2002; Tulving &Lepage, 2000). Yet, despite itsimportance, the roleof memoryin imaging the future largely hasbeen neglected ininvestigationsof the amnesicsyndrome (for ex- ceptions,see DallaBarba, Cappelletti, Signorini, &Denes, 1997;Talland, 1965;Tulving, 1985). Weattemptto address this oversight by examining the effects ofmemoryloss on bothretrospective and prospective compo - nents of temporal experience. TYPES OF MEMORY, TYPES OF TEMPORAL EXPERIENCE Toappreciatethe relationbetween memoryand time, it is necessary to considerthe types of temporalexperience madepossible by different formsof memory.Tulving (1983,1993a, 1993b, 1995, 2000 )hasargued thatit is useful todistinguish between twoforms of long-term memory: episodicand semantic (see alsoCermak, 1984; Markowitsch, 1995; Moscovitch,Y aschyshyn,Ziegler,&Nadel,2000;Viskontas, McAndrews,& Moscovitch,2000; Wheeler &McMillan,2001; Wood, Ebert,& Kinsbourne, 1982). Akey distinctionbetween episodicand se- manticmemory is the natureof subjective temporalexperience thatac- companiestheir retrieval(e.g., McCormack& Hoerl,1999; Tulving, 1993b,1995; Tulving &Lepage, 2000;Wheeler &McMillan,2001; Wheeler, Stuss, & Tulving, 1997). Episodicretrieval is held toconsist in knowledge ofapreviously expe- rienced event alongwith an awarenessthat the event occurredin one’s past.For example, recalling the occasionwhen Iarrivedlate for an ap- pointmentrequires thatI havea mentalstate representing the particular event of being latealong with an additionalrepresentation of thatevent assomething that happened ata previoustime in my life (see also Gennaro,1992; Kihlstro m,1997; Klein, 2001;Levine et al.,1998; McCormack& Hoerl,1999; Perner, 1991;Suddendorf &Corballis,1997 ). Episodicrecollection thus enables apersonto mentally travel back in timeto relive previously experienced personalevents (for reviews,see Tulving 1993b;Suddendorf &Corballis,1997; Wheeler et al.,1997 ). Itfol- lowsthat impairments in episodicrecollection should compromise one’s abilityto reexperience apersonalpast, and, as is well known,a considerablebody of researchshows that this indeed occurs(e.g., 356 KLEIN ET AL. Cermak& O’Connor,1983; De Renzi,Lucchelli, Muggia, &Spinnler, 1995;Kitchener, Hodges,& McCarthy,1998; Klein, Loftus,& Kihlstrom, 1996;Levine et al.,1998; Markowitsch et al.,1993; Talland, 1970; Tulving, 1989; Viskontas et al., 2000; Wheeler et al., 1997). In additionto enabling mentaltime travel into one’ s past,episodic memoryalso is hypothesized toprovide afoundationfor imagining whatone’ s experiences mightbe like in the future (e.g., DallaBarba, 2000;Suddendorf, 1994;Suddendorf &Corballis,1997; Tulving, 1985, 1993b;Tulving &Lepage, 2000;Wheeler et al.,1997 ). Although few stud - ies haveexamined the proposedrelation between episodicmemory and awarenessof apersonalfuture, thosethat have are generally supportive. Forexample, DallaBarba et al.(1997 )reportthe caseof patientG.A., who developed anamnesic-confabulatorysyndrome following arupture of her anteriorcommunicating artery. Testing revealed thatG.A.’ s confab- ulationswere confined primarilyto tasksrequiring her toaccessher per - sonalpast or plan her personalfuture. Forexample, in responseto the question“ Whatare you going todotomorrow?”she replied “Iwill go outshopping aloneby car”(Dalla Barba et al.,1997, p. 430), despite the factthat since her diseaseshe hadnever gone shopping aloneand cer- tainlywould not have been allowedto doso given her medicalcondi- tion. Anothersource of evidence comesfrom observations of patientK.C., who,as aresultof a severe braininjury, losthis entire fund ofepisodic memory,rendering him unable tobring tomind asingle personalexpe- rience fromany point in hispast (e.g., Tulving, 1985,1989, 1993b; Tulving, Hayman,& MacDonald,1991 ).When informallyinterviewed concerning hisplans for the future, K.C.was unable toimagine anything he was likely to do on any subsequent occasion (Tulving, 1985). Although the temporalexperiences attributedto patients G.A. and K.C.differ incertainrespects— G.A. has some awareness of her future (albeit one comprisingevents incongruous with her personalhistory andpresent situation),whereas for K.C. the future hasceased to ex- ist—they aresimilar in suggesting thatdisruption of episodicmemory can compromise the ability to project one’s existence into the future. In contrastto episodic recollection, retrieval from semantic memory doesnot entail awareness that one isin amentalstate that represents somethingin one’s past.Rather, it is experienced asgeneric knowledge aboutthe world(e.g., facts,people, events)withoutan accompanying thoughtthat this information is known because ithas been experienced MEMORY AND TEMPORAL EXPERIENCE 357 before (e.g., Klein, Chan,& Loftus,1999; Perner &Ruffman,1994; Tulving 1993a,1993b, 1995; Tulving &Lepage, 2000;Wheeler, 2000; Wheeler et al.,1997