Social Cognition, Vol. 17, No. 3, 1999, pp. 273-297
CONTEXTS OF CRYPTOMNESIA:
MAY THE SOURCE BE WITH YOU
C. NEIL MACRAE
University of Bristol
GALEN V. BODENHAUSEN
Northwestern University
GUGLIELMOCALVINI
University of Bristol
Cryptomnesia represents an intriguing type of mental illusion in which people mis
takenly believe that they have produced a new idea when in fact they have simply
unwittingly retrieved an old, previously encountered idea from memory. Drawingon recent research on this form of inadvertent plagiarism, we hypothesized that
perceivers' susceptibility to the illusion that other people's responses were actually
self-generated would be influenced by contextual variables that impact upon the
efficiency of source monitoring. The results of three studies, examining different
contextual factors (i.e., Experiment 1, perceptual similarity; Experiment 2, cognitive distraction; Experiment 3, retrieval context), confirmed this prediction. We
consider how difficulties in source monitoring may inform our understanding of the
process and consequences of cryptomnesia in everyday life.
One of the most disheartening experiences of old age is discovering that a
point you have just made so significant, so beautifully expressed was
made by you in something you published a long time ago.Skmncr (1983, p. 242)
Information is only as reliable as the source from which it springs, so it is
perhaps not too surprising that social impressions, judgments, and eval
uations are calibrated in terms of the credibility of their original source.
When a given source's credibility is low, information issuing from that
source tends to have little impact on perceivers' judgments (e.g.,
The authors thank John Skowronski, Rich Marsh, and an anonymous reviewer for his or
her helpful comments on this work.
Address correspondence to C. Neil Macrae, Department of Experimental Psychology,
University of Bristol, 8 Woodland Road, Bristol BS8 1TN, UK. E-mail: c.n.macrae@bris-
tol.ac.uk.
273
274 MACRAE, BODENHAUSEN, AND CALVINI
Hovland & Weiss, 1951; Macrae, Shepherd, & Milne, 1992; Pratkanis &
Aronson, 1992). Of course, our own ideas, perceptions, and evaluations
are likely to be seen as highly credible. So, on average, items that we generate ourselves are likely to exert greater influence on our judgmentsand behavior than information we receive from sources whose reliabil
ity and credibility is less certain (e.g., Pyszczynski & Greenberg, 1987).
Given, therefore, their privileged status within the processes of social
perception and judgment, it is obviously important to have a memory
system capable of distinguishing these self-generated products from in
formation we acquire from external, potentially questionable sources.
Fortunately for the social perceiver, our memory system is
well-equipped to keep track of the sources of stored information (John
son, Hashtroudi, & Lindsay, 1993; Raye, Johnson, & Taylor, 1980). Nev
ertheless, on occasion, memory can play some mischievous tricks on
unsuspecting social perceivers, prompting a variety of troublesome ef
fects. For example, we may tell a friend an hysterical anecdote, failing to
appreciate that either we told her the same story on a previous occasion,
or worse still that she was actually the originator of the tale. Of all our
memory lapses, this latter oversight is particularly troubling, as it im
plies that we may periodically take credit for other people's creative out
puts (e.g., research ideas, recipes, jokes), erroneously believing that theyare in fact our own. Such instances of unintentional plagiarism, or
cryptomnesia as it is termed, occur when consciousness is populated bymemories, but perceivers do not explicitly recognize the items as such
(Taylor, 1965). Instead, they are taken to be the original products of cur
rent cognitive processing. As Brown and Murphy (1989) put it;
"Cryptomnesia refers to generating a word, an idea, a song, or a solutionto a problem, with the belief that it is either totally original, or at least
original within the present context. In actuality, the item is not original,but one which has been produced by someone else (or even oneself) atsome earlier time" (p. 432).As it turns out, cryptomnesia extends beyond the theft of witty anec
dotes from their owners indeed, science, literature, and the music in
dustry are littered with cases of inadvertent plagiarism. From Freud to
GeorgeHarrison to the makers of the recentmovie The FullMonty (1997),
many have been castigated for allegedly stealing other people's creative
products. Even for we lesser mortals, however, cryptomnesic episodescan shape our behavioral outputs. In discussion with a friend, for exam
ple, we may unwittingly repeat a phrase (e.g., "over the hill") or word
(e.g., "decrepit") she has just uttered, yet be quite unaware that this du
plication has occurred (Jacoby & Kelley, 1987). As these mundane in
stances of inadvertent plagiarism are rarely detected, there are typicallyno costs associated with the theft of other people's behavioral products.
CONTEXTS OF CRYPTOMNESIA 275
In other contexts (e.g., literature, music), however, cryptomnesia can
have decidedly worrisome implications for perceivers, ranging from
private embarrassment to public censure. Plagiarize unintentionally, it
would appear, at one's potential peril.If, then, perceivers have a propensity to steal other people's behavioral
products, it is obviously useful to know exactly why and when this theft
occurs. For example, is it possible to identify processing conditions under
which perceivers are particularly likely to plagiarize others? If indeed it
is, then what are these conditions and how frequently do they occur in
daily life? Simply stated, is cryptomnesia something we should worry
about in our everyday interactions with others? In a related vein, when
duplication occurs, are perceivers more likely to plagiarize Self or others?
While both types of plagiarism are undeniably problematic, clearly the
latter variety has more troubling implications for perceivers. Finally, can
cryptomnesia be understood in terms of existingmodels ofmemory func
tion or must new theoretical frameworks be advanced to accommodate
the emerging empirical evidence? In the research reported here, we de
scribe three experiments that attempt to widen our understanding of the
process and consequences of unintentional plagiarism.
SOURCE MONITORING AND CRYPTOMNESIA
Inadvertent plagiarism is believed to derive from the failure of some basic
memory operations specifically, perceivers' capacity to enlist the source
monitoring processes that enable them to identify the origin of their recol
lections (Brown & Halliday, 1991; Brown & Murphy, 1989; Johnson et al.,
1993; Johnson & Raye, 1981; Landau &Marsh, 1997;Marsh & Bower, 1993;
Marsh & Landau, 1995; Marsh, Landau, & Hicks, 1997). Put simply, unin
tentional plagiarism occurs when perceivers misconstrue their memories
as original thoughts. Given this attributional failing, cryptomnesia is
clearly a variant of source forgetting, a phenomenon whereby perceiversdemonstrate an impaired ability to identify the origin (i.e., when, where) of
their recollections (Johnson et al., 1993; Schacter, Harbluk, & McLachlan,
1984). This memory lapse has some all too familiar consequences. For ex
ample, perceivers may be unable to discern whether an event was experienced or imagined (e.g., visiting the zoo as a small child), to statewhich of
multiple targets produced a particular behavior (e.g., was it Uncle John or
Aunt Jean who broke the bathroom window?), or to report the setting or
time frame inwhich a specific event occurred (e.g., eating anchovies for the
first time). In each of these cases, the problem is the same; although
perceivers are capable of retrieving and scrutinizing fragments of a particular memory, they are singularly unable to recollect the context in which
the memory was acquired. As a result, errant source attributions occur
276 MACRAE, BODENHAUSEN, AND CALVINI
(Jacoby & Kelley, 1987; Johnson et al., 1993; Johnson & Raye, 1981). In
cryptomnesia, of course, the attribution process is complicated still further
as perceivers have no idea that the contents of consciousness are memo
ries; instead, they are taken to be original thoughts. Little wonder, there
fore, that perceivers periodically purloin the research ideas, anecdotes,
and melodies of others. So why then does source forgetting (hence
cryptomnesia) occur?
According to the influential framework proposed by Johnson and her
colleagues (Johnson, 1988; Johnson et al., 1993; Johnson & Raye, 1981),
successful source monitoring depends upon two factors: (1) the charac
teristics of stored memorial representations; and (2) the decision pro
cesses that are employed when perceivers attempt to establish the originof their recollections. Memories differ enormously in content, varyingboth in terms of the amount and quality of information they convey.
Generally speaking, whenever the characteristics of stored representations are plentiful and highly differentiated, perceivers are unlikely to
make source-monitoring errors. Instead, these errors tend to occurwhen
memories have overlapping or common properties (Johnson et al., 1993;
Johnson & Raye, 1981). The accuracy of source monitoring is also af
fected by the decision processes that perceivers recruit when they at
tempt to resolve problems of source identification. In this respect, two
general information-processing strategies are available (Chaiken,
Lieberman, & Eagly, 1989; Johnson et al., 1993). First, the determination
of source can rely on heuristic processes that inspect only the quality (i.e.,amount of information, clarity of detail) of stored representations. These
processes are relatively automatic in character (i.e., effortless, precon-scious, fast), prompting the rapid, although fallible, computation of
source judgments (Chaiken et al., 1989; Johnson et al., 1993). Second,
source can also be determined by systematic processes that are generallyslower, more accurate, and more attentionally demanding than their
heuristic counterparts (Johnson et al., 1993). Responsive to perceivers'goal states, these processes are susceptible to disruption and interfer
ence from competing mental activities. Operating in tandem, heuristic
and systematic processes combine to resolve problems of source identi
fication, with the relative contribution of each process determined byperceivers' goal states and the characteristics of the task at hand (Johnson et al., 1993).
Accepting the proposition that cryptomnesia is a variant of source for
getting, it is possible to advance the following empirical prediction.Under contexts in which source monitoring is problematic (Johnson et
al., 1993; Johnson & Raye, 1981 ), onemight expect levels of unintentional
plagiarism to be elevated. The reasoning here is quite straightforward: If
perceivers find it difficult to establish the identity of an item in con-
CONTEXTS OF CRYPTOMNESIA 277
sciousness, then they may be particularly inclined to conclude that the
item is an original product of their current thought processes. As such, in
contexts that reliably promote source confusion, perceivers may displaya pronounced tendency to plagiarize others, or perhaps even them
selves. In the present article, we investigate this intriguing possibility(see also Landau & Marsh, 1997). Prior to describing our experiments,however, we first detail how cryptomnesia can be elicited in the labora
tory; we then speculate on why at least certain forms of inadvertent pla
giarism may be moderated by difficulties in source monitoring.
ELICITING CRYPTOMNESIA
Despite its potentially troublesome implications for perceivers, it is onlywithin the last decade or so that cryptomnesia has attracted serious em
pirical attention. Previous attempts to investigate this topic were ham
pered by the daunting task of eliciting inadvertent plagiarism under
controlled conditions. Thanks to the development of two experimental
analogues of cryptomnesia, however, it is now possible to investigatethis fascinating phenomenon in the laboratory. In the original experimental procedure, Brown and Murphy (1989) had groups of partici
pants take turns in orally generating exemplars from various semantic
or orthographic categories (e.g., sports, musical instruments, words be
ginning with the letters TH). Crucially, prior to the commencement of
this task (i.e.,generate items), participantswere admonished not to repeat
any of the items. As such, instances of unintentional plagiarism occurred
whenever participants duplicated their own or another person's re
sponses. Quite remarkably, despite the instruction not to repeat any of
the items, participants displayedmodest levels of plagiarism during this
task. More alarmingly, however, on other indices of cryptomnesia, con
siderably higher levels of duplication were detected. Following the
item-generation task, Brown and Murphy (1989) required participantsto perform two additional activities: first, to reproduce their earlier re
sponses (i.e., recall own); and second, to generate additional exemplars
(i.e., generate new) that had not been offered (by either Self or others) in
the generation task. In the recall-own task, plagiarism occurred when
ever participants duplicated another person's response. In the gener
ate-new task, it was apparent whenever participants produced an item
that had been offered before. The results were revealing: Elevated levels
of cryptomnesia were observed on both measures, although partici
pants generally preferred to steal the products of others than to plagiarize their own previous efforts. Summarizing their findings, Brown and
Murphy (1989) concluded that "recently experienced information can be
inadvertently plagiarized shortly after the initial experience" (p. 439).
278 MACRAE, BODENHAUSEN, AND CALVINI
In the second experimental analog of cryptomnesia,Marsh and Bower
(1993) investigated inadvertent plagiarism using a word puzzle task
called Boggle. Adapting the essential features of the Brown and Murphy
(1989) procedure, Marsh and Bower required participants to form English words by stringing together adjacent items in a 4 x 4 matrix of let
ters. Participants performed this task against a computer partner and
were instructed not to reproduce either their own or the computer's so
lutions to the puzzle. As in the original Brown andMurphy (1989) procedure, in the course of the experiment, participants performed three
tasks: generate-items; recall-own; and generate-new. Importantly, on all
threemeasures of cryptomnesia,Marsh and Bower replicated the effects
observed by Brown and Murphy (1989). Indeed, if anything, the inci
dence of inadvertent plagiarism was greater on the Boggle puzzle than
Brown and Murphy's category-exemplar generation task. Taken to
gether, then, these two ingenious procedures provide converging evi
dence for the existence of inadvertent plagiarism that is amenable to
experimental investigation.But is there any reason to believe that cryptomnesia is moderated by
difficulties in source monitoring (Johnson et al., 1993)? Four years ago,Marsh and Landau (1995) were skeptical about this relationship and
concluded that, "There appears to be very little evidence that the factors
shown to influence source monitoring alter the incidence of
cryptomnesia" (p. 1580). In a recent publication, however, these authors
have modified their position somewhat, arguing instead that source
confusion can exacerbate cryptomnesia, but only certain types of inad
vertent plagiarism (Landau &Marsh, 1997). So why this change of view
point?Motivating Landau and Marsh's (1997) revised position was their
observation that quite different decision processes are associated with
the tasks used to measure cryptomnesia in the laboratory. Specifically,in the two generative tasks (i.e., generate-items; generate-new)
perceivers need only implement an elementary decision process that enables them to identify whether an item in consciousness is old or new.
For example, the familiarity of an item can serve just such a purpose
(Jacoby & Kelley, 1987; Johnson et al., 1993). Given that recognition judgments are generally not affected by source confusion (Johnson et al,
1993), it is therefore unlikely that difficulties in source monitoringshould increase the frequency of generative cryptomnesic errors. In therecall-own task, however, matters are considerably more complicated,as perceivers must supplement a basic recognition (i.e., old-new) judgment with a secondary assessment of whether the item was
self-generated or provided by a partner (Marsh et al., 1997). Critically,this additional decision process (i.e., was the item yours or mine?) de-
CONTEXTS OF CRYPTOMNESIA 279
mands an extended reasoning typical of source-monitoring tasks,where
perceivers must distinguish between classes of formerly encountered
items Qohnson et al., 1993; Johnson & Raye, 1981). Thus, of the three
tasks used to measure cryptomnesia, only the recall-own task demands
the cognitive operations needed in source monitoring. As such, only
performance on this task should be affected by standard manipulationsof source confusion. But is this really the case?
Inspection of the available literature provides only limited support for
the contention that source confusion can increase the incidence of at least
certain forms of cryptomnesia (Landau & Marsh, 1997; Marsh et al.,
1997). Perhaps the most compelling evidence comes from a recent study
by Landau and Marsh (1997). Modifying the basic Boggle procedure,Landau and Marsh created task conditions where Self- and
Other-generated solutions to the word puzzle were highly confusing.This confusionwas achieved by requiring some participants to guess the
computer's solutions during the item-generation task, an activity be
lieved to increase the cognitive similarity between the computer's re
sponses and self-generated solutions. Based on an application of
Johnson et al.'s (1993) source-monitoring framework, it was anticipatedthat when the two sources (i.e., Self and computer) were highly similar,
levels of inadvertent plagiarism would increase, but only in the re
call-own task. Interestingly, this is exactly what Landau and Marsh
found. Thus, at least where the theft of puzzle solutions from a computer
is concerned, source confusion appears to increase the incidence of
cryptomnesia. But just how widespread are these cryptomnesic effects?
Under conditions of source confusion, do perceivers reliably steal other
people's behavioral products? In the present research, we consider this
important empirical question.
THE PRESENT RESEARCH
Given the noted perils of inadvertent plagiarism, in the presentwork we
reconsider the contention that source confusion increases the incidence
of cryptomnesia, but only certain types of unintentional duplication (i.e.,
recall-own errors). As this prediction gains only limited support in the
available literature (Landau & Marsh, 1997), we deemed it appropriateto undertake a detailed investigation of the effects of source confusion
on cryptomnesia. In so doing, we made a number of modifications to
previous research on this topic. First, we employed a different
item-generation task. Second, and more important, to establish the gen
erality of cryptomnesic effects across task contexts, we considered
whether different manipulations of source confusion would prompt
280 MACRAE, BODENHAUSEN, AND CALVINI
comparable outbreaks of inadvertent plagiarism. This latter issue is
noteworthy, of course, as it is only by explicating the task conditions
under which inadvertent plagiarism reliably occurs that one can beginto anticipate social settings in which perceivers may be particularly sus
ceptible to this type of memorial lapse.To elicit cryptomnesia in the laboratory, we utilized Brown and
Murphy's (1989) category-exemplar generation task. Participantswere required to offer, in a round-robin fashion, six exemplars from
each of four orthographic categories, while under the general admoni
tion not to repeat any of the previous responses. Having generated the
items, participants were then requested to reproduce their earlier ef
forts (i.e., recall-own) and to provide a number of additional exem
plars (i.e., generate-new) from each orthographic category. In
adopting this paradigm, we made one important modification to the
original procedure. Although Brown and Murphy (1989) had partici
pants perform the item-generation task in groups of four, it turned out
that the most likely source of a plagiarized item was the person speak
ing immediately before each participant. As such, recognizing that
this individual is the most likely source of a plagiarized response, in
the present procedure participants were required to perform the
item-generation task in pairs.Our assumption, following Landau and Marsh (1997), was that source
confusion would increase the incidence of cryptomnesia, but only in the
recall-own task. We did not anticipate that standard manipulations of
source confusion would increase the incidence of generative
cryptomnesic errors. To provide a comprehensive investigation of the
effects of source confusion on unintentional plagiarism, in each of the re
ported experiments the difficulty of source monitoring was manipulated in a different manner (i.e., Experiment 1, perceptual similarity;
Experiment 2, cognitive distraction; Experiment 3, retrieval context).We
varied the basis of source confusion for three reasons: First, we wanted
to establish the generality of the finding that source confusion increases
the incidence of inadvertent plagiarism, at least with respect to
perceivers' tendency to take credit for other people's efforts. Second, we
hoped to identify the type of processing conditions that may exacerbate
cryptomnesia outside the laboratory. Third, we wanted to establish the
extent towhich Johnson et al.'s (1993) source-monitoring framework can
inform our theoretical understanding of cryptomnesia. To realize this fi
nal objective, we therefore employed experimental manipulations that
obstructed the encoding (i.e., Experiments 1 & 2) and post-encoding (i.e.,
Experiment 2) operations believed to underlie successful source moni
toring (see Johnson et al., 1993).
CONTEXTS OF CRYPTOMNESIA 281
EXPERIMENT 1
PERCEPTUAL SIMILARITY AND CRYPTOMNESIA
When the perceptual or semantic similarity of two sources is increased,
perceivers typically experience difficulty recollecting exactly who saidwhat (Ferguson, Hashtroudi, & Johnson, 1992; Lindsay, 1990; Lindsay,Johnson, & Kwon, 1991). For example, perceivers are more likely to
misattribute statements made by one speaker to another when the two
sources describe the same event than when they describe different
events (Lindsay et al., 1991). Similarly, one is more likely to confuse the
source of a recollection when the potential candidates are two women
than when they are a man and a woman (Johnson, Nolde, & De
Leonardis, 1996; Lindsay et al., 1991). This latter effect is corroborated byan extensive literature in social psychology, which demonstrates that
perceivers make more within-group (e.g., female-female) than be-
tween-group (e.g., female-male) confusions when recollecting the be
havior of others (see Taylor, Fiske, Etcoff, & Ruderman, 1978).
Extrapolating these findings to the investigation of cryptomnesia, an in
teresting empirical prediction emerges. Specifically, when participants
generate items in same-sex (e.g., female-female) rather than mixed-sex
dyads (e.g., female-male), difficulties in source monitoring may in
crease the incidence of cryptomnesia, at least with respect to partici
pants' tendency to believe that their partner's responses were in fact
self-generated. In our first experiment, we investigated this prediction.
METHOD
Participants and Design. Twenty-eight undergraduates (21 women and
7men) were paid2 ($3.20) for their participation in the experiment. The
experiment had a single factor (group: same-sex or mixed-sex) be-
tween-participants design.Stimulus Material and Procedure. Participants arrived at the laboratory
in pairs (i.e., female-female or female-male) and were greeted by a fe
male experimenter who explained that the experimentwas an investigation of people's word-production skills. Following Brown and Murphy(1989), the experimental procedure was divided into three phases: item
generation; written recall of own responses; and written retrieval of new
exemplars. In the item-generation task, participants were told that theywould take turns in orally generating exemplars from four different or
thographic categories (i.e., words beginning with the letter pairs BE, FO,
MA, and TH), and that each categorywould be completed in turn. Partic
ipants were instructed to produce a new exemplar each time and not to
282 MACRAE, BODENHAUSEN, AND CALVINI
TABLE 1. Percentage of Incorrect Responses as a Function of Task, Error Type, and
Group Composition (Experiment 1)
Task
Genera te-Items Recall-Own Generate-New
Self-
Plagiarism(%)
Partner-
Plagiarism
(%)
Partner-
Plagiarism(%)
New-
Errors
(%)
Self-
Plagiarism(%)
Partner-
Plagiarism(%)
GroupSame-Sex
Mixed-Sex
0
0
0
0.8
24.4
14.5
6.7
8.2
2.6
2.6
4.6
6.2
duplicate any of the previous responses. The order of presentation of the
orthographic categories was counterbalanced and participants pro
vided six exemplars for each category. The experimenter wrote down
items as they were produced and also tape recorded the session as a
backup. Following the item-generation phase and a 3-minLite distractor
task (i.e., counting backwards in 3s from 2000), participantswere given a
recall sheet listing the four orthographic categories with six blank spacesbeneath each letter pair. The experimenter instructed participants to
write down the six examples they had provided during the generationtask (i.e., recall-own).When this taskwas completed, the recall sheetwas
removed and replaced with a second sheet that listed the four ortho
graphic categories with six blank spaces beneath each letter pair. On this
sheet, participants were instructed to provide six completely new exam
ples for each orthographic category (i.e., generate-new). It was emphasized that all the blank spaces on the sheets must be completed. Upon
completion of the experiment, participants were debriefed, paid,thanked, and dismissed.
RESULTS AND DISCUSSION
As is conventional in research of this kind (Brown & Murphy, 1989), the
proportion of errors produced on each task were analyzed separately in aseries of 2 (group) x 2 (error type) analyses of variance (ANOVAs), the results of which are summarized below (see Table 1 for treatment means).Generate-items. During the item-generation task, plagiarized re
sponses can come from two sources: Specifically, participants can duplicate either their own responses (i.e., self-plagiarism) or the responses oftheir partner (i.e., partner-plagiarism). As can be seen in Table 1, how
ever, errors on this taskwere extremely uncommon and did not vary as afunction of dyad composition or error type.Recall-Own. Again, two types of error can be committed on this task.
When instructed to recollect their own responses, participants can either
CONTEXTS OF CRYPTOMNESIA 283
produce items previously provided by their partner (i.e., part
ner-plagiarism), or else they can produce entirely new items that they er
roneously believe to be old (i.e., new-errors). A 2 (group: same-sex or
mixed-sex) x 2 (error type: partner-plagiarism or new-error)
mixed-model ANOVA revealed a main effect of error type on participants' task performance, F(l, 26) = 49.84, p < .0001. As expected, how
ever, this effect was qualified by a significant group x error typeinteraction, F(l, 26) = 11.24, p < .003. An analysis of simple effects confirmed the predicted pattern of results. Whereas new-errors (i.e., intru
sions) were not affected by the composition of the dyad [F(l, 44) < 1, ns],
dyad composition did affect participants' tendency to take credit for
their partner's responses, with higher rates of plagiarism emerging in
the same-sex than the mixed-sex groups, F(l, 44)= 9.77, p < .003. In addi
tion, partner plagiarisms were more abundant than intrusion errors in
both groups [same-sex, F(l, 26) = 53.95, p < .0001; mixed-sex, F(l, 26) =
6.77, p < .02]. Closer inspection of the reproductive errors in the
mixed-sex dyads revealed no difference in men and women's tendencyto steal items from a partner of the opposite sex (respective Ms: male =
15%, female = 14%). As expected, however, women in the same-sex
dyads (M = 24.4%) were more likely than women in themixed-dyads (M= 14.8%) to steal an item from their partner, F(l,19)
= 6.18, p < .03.
Generate-New. In this task, participants could err either by plagiarizingtheir partner's efforts (i.e., partner-plagiarism) or by duplicating their
own previous responses (i.e., self-plagiarism). A 2 (group: same-sex or
mixed-sex) x 2 (error type: self-plagiarism or partner-plagiarism)mixed-model ANOVA revealed only a main effect of error type on performance on this task [F(l, 26) = 5.49, p < .03], with participants more
likely to plagiarize their partner's responses than to indulge in
self-plagiarism (respective Ms: 5.4% vs. 2.6%). Sex composition of the
dyad did not exert a reliable effect on performance of this task (p > .55).
These results, then, support the prediction that source confusion in
creases the incidence of cryptomnesia, but only with respect to certain
forms of inadvertent plagiarism (Landau & Marsh, 1997). On the two
generative tasks (i.e., generate items; generate new), the composition of
the groups had little impact on the incidence of cryptomnesia. As ex
pected, however, quite different effects emerged on the reproductivetask (i.e., recall-own) where participants were required to produce their
previous responses. As predicted by Johnson et al.'s (1993)
source-monitoring framework, levels of cryptomnesia were elevated
when participants performed the initial generation task in same-sex
rather than mixed-sex groups (Lindsay et al., 1991). The results con
firmed that female participantsweremore likely to plagiarize a responseif it was previously provided by a woman than by a man, thereby con-
284 MACRAE, BODENHAUSEN, AND CALVINI
firming that source confusion exacerbates perceivers' tendency to take
credit for other people's efforts. But just how robust is this finding?Would other manipulations of source confusion prompt comparable
cryptomnesic effects? In our second experiment, we addressed this
question.
EXPERIMENT 2
DISTRACTION AND CRYPTOMNESIA
In Experiment 1, source confusion was elicited by manipulating the gender composition of the groups that performed the category-exemplar
generation task (Lindsay et al., 1991). As an expansive literature testifies,
however, target confusion could also have been induced by means of a
variety of other manipulations (Johnson et al., 1993; Johnson & Raye,1981). Because source monitoring depends upon the quality of stored
memorial representations, anything that prevents perceivers from bind
ing memory details to one another, and to the memory trace itself,
should promote source confusion (Chalfonte & Johnson, 1996), hence er
rant source attributions. Thus, factors such as stress, distraction, and al
coholic inebriation, to name but a few, should all attenuate perceivers'
source-monitoring performance. As Johnson et al. report, "anything that
prevents a person from fully contextualizing information at acquisition(i.e., creating an event) will reduce encoding of potentially relevant
source-information" (1993, p. 5). By implication, of course, these factors
should also have a significant impact on perceivers' propensity to plagiarize others. Thus, if distraction prompts source confusion, then it
should also increase the likelihood that perceivers will erroneously believe that other people's effortswere in fact self-generated. In our second
experiment, we investigated this prediction.
METHOD
Participants and Design. Twenty-eight undergraduates (14 women and14 men) were paid 2 ($3.20) for their participation in the experiment.The experiment had a single factor (distraction: present or absent) be-
tween-participants design.StimulusMaterial and Procedure. Participants arrived at the laboratory in
mixed-sex pairs, were greeted by a female experimenter, and randomlyassigned to one of the treatment conditions. The experimentwas identicalto Experiment 1, except for two procedural modifications: First, all participants performed the category-exemplar generation task in mixed-sex
pairs. Second, the manipulation of source confusion was introduced
CONTEXTS OF CRYPTOMNESIA 285
TABLE 2. Percentage of Incorrect Responses as a Function of Task, Error Type, and
Distraction (Experiment 2)
Task
Genera te-Items Recall-Ovvn Genera te-New
Self-
Plagiarism(%)
Partner-
Plagiarism(%)
Partner-
Plagiarism(%)
New-
Errors
(%)
Self-
Plagiarism(%)
Partner-
Plagiarism(%)
Distraction
Present
Absent
0.6
0.8
0.8
0.8
23.5
12.7
9.1
9.7
2.3
2.0
5.2
3.5
while participants performed the item-generation task. Specifically, for
half of the participants (i.e., distraction condition) a radio was ostensibly
playing in the laboratory during the task. In reality, however, it was a
tape-recorded excerpt from a radio show featuring a series of topicalnews items. This excerptwas selected becausewe believed itwould be in
teresting (hence distracting) to undergraduates. The radio was already
playing when participants arrived at the laboratory and it was switched
off by the experimenter when the generation task was completed. In all
other respects, this experiment was identical to Experiment 1.
RESULTS AND DISCUSSION
As in Experiment 1,the proportion of errors produced on each taskwere
calculated and analyzed separately in a series of 2 (distraction) x 2 (error
type) mixed-model ANOVAs (see Table 2 for treatment means).
Generate-items. As in the previous experiment, errors on this taskwere
extremely uncommon and the error rate was not affected by the experimental manipulations.Recall-Own. There were reliable main effects of both factors on partici
pants' recall-own task performance [distraction, F(l, 26)= 5.47, p < .03;
error type, F(l , 26) = 15.42, p < .0006]. As expected, however, these effects
were qualified by a significant distraction x error type interaction, F(l,
26) = 5.27, p < .03. Simple effects analyses confirmed our experimental
predictions. Whereas new errors were not affected by cognitive distrac
tion [F(l, 52) < 1, ns], this manipulation did affect participants' tendencyto take credit for their partner's responses, with higher rates of plagiarism emerging when participants were distracted during the generation
task, F(l, 52) = 10.73, p < .002.! In addition, under conditions of cognitive
1 None of the plagiarized items in the distraction-present conditionwerewords that ap
peared in the radio segment.
286 MACRAE, BODENHAUSEN, AND CALVINI
distraction partner-plagiarisms were more abundant than new-errors,
F(l, 26) = 19.35, p<.0001.
Generate-New. The ANOVA revealed a significant effect of error type on
task performance [F(l, 26)= 4.43, p < .05], with participants more likely to
plagiarize their partner's responses than to engage in self-plagiarism (re
spective Ms: 4.4% vs. 2.2%). However, distraction did not produce a reli
able effect on error rates in this generate-new task (p > .29).
Replicating the results of Experiment 1, these findings provide further
evidence that source confusion exerts quite specific effects on the inci
dence of cryptomnesia (Landau & Marsh, 1997). Under conditions
where source monitoring was compromised through cognitive distrac
tion, although an increase in cryptomnesia was observed, this was only
apparent for reproduction errors (i.e., recall-own task). That is, whilst
distraction increased the likelihood that participants would take credit
for their partner's previous efforts, it did not affect any of the generativeerrors also symptomatic of inadvertent plagiarism.
EXPERIMENT 3
RETRIEVAL CONTEXT AND CRYPTOMNESIA
Corroborating Landau and Marsh's (1997) findings, the results of Experiments 1 and 2 confirmed that source confusion can increase the inci
dence of cryptomnesia, at least with respect to perceivers' tendency to
believe that other people's efforts were in fact self-generated. Of generaltheoretical interest, in each of these experiments, source confusion was
induced by a manipulation that compromised the encoding of
source-relevant material during the item-generation task. Thus, when
the protagonists were both women (i.e., Experiment 1 ) or the generationtask was performed under distracting conditions (i.e., Experiment 2),source confusion exacerbated participants' propensity to take credit for
their partner's efforts. As it happens, however, source monitoring can
also be impaired by manipulations that obstruct a variety of
post-encoding operations (Johnson et al., 1993; Johnson & Raye, 1981).As Johnson et al. note, "because source monitoring depends not only on
the quality of the information as encoded but also on the quality of the
decision processes when source-monitoring judgments are made, any
thing limiting these decision processes at test should also disrupt source
monitoring" (1993, p. 6). Thus, stress, distraction, and attentional depletion are all test factors that reliably impair source-monitoring performance (Johnson et al., 1993). To this list, one can also append the
characteristics of the retrieval context, as this is also known to play a
prominent role in source monitoring (Jacoby & Kelley, 1987; Johnson et
CONTEXTS OF CRYPTOMNESIA 287
al., 1993). But what impact might this factor have on perceivers' propensity to plagiarize others?
One intriguing possibility is that levels of cryptomnesia may be ele
vated when the context in which information was generated is rein
stated at a later date. As a graphic illustration of this possibility, consider
Jacoby, Kelley, Brown, and Jasechko's (1989) cautionary observation:
Many of us have had the experience of presenting an idea to a colleague onlyto have the colleague thoroughly reject the idea. In a later conversation,
however, the colleague reintroduces the earlier rejected idea as an insightthat he or she just had. ...Nature may be so perverse as to make it likely that
we will present a stolen idea as being our own to the very person from
whom we stole it. The cues offered by his or her appearance and the content
of a current conversation may be similar to those present during the priorconversation and serve as excellent cues for the unconscious retrieval of the
idea. (p. 41)
If operating, such a process would have a considerable impact on the
incidence of cryptomnesia, as participants typically generate and retrieve
items in the company of their partner.When present, one's partnerwould
obviously cue many responses that he or she produced during the initial
generation task (Jacoby et al, 1989). If, of course, these items are accompanied by source-specifying information, then there is little cause for con
cern, as the items will be construed as recollections and attributed to the
appropriate source (i.e., Self or partner). When this information is less ac
cessible, however, problems may begin to emerge. Specifically, when
faced with the puzzle of establishing the status and origin of an item in
consciousness, one may be duped into believing that either it is the original product of one's current cognitive processing (i.e., is a novel item), or
alternatively that it was formerly self-generated. Either way, an
attributional error would occur. When, however, one's partner is absent
during the retrieval process, source confusion should be less pro
nounced, as fewer partner-cued items would be expected to pop into con
sciousness. Somewhat ironically, therefore, the presence of one's partner
during the recall-own taskmay actually increase one's propensity to pla
giarize his or her previous responses (Jacoby et al., 1989).
Given the structure of the retrieval context in experimental investigations of cryptomnesia, however, it is also possible that the presence of
one's partner could have precisely the opposite effect on task performance that is, it could reduce levels of inadvertent plagiarism. If an
item is produced in the initial generation task (by either Self or other),
then through its enhanced accessibility in memory (Marsh & Landau,
1995) this will increase the likelihood that the item will appear in con-
288 MACRAE, BODENHAUSEN, AND CALVINI
TABLE 3. Percentage of Incorrect Responses as a Function of Task, Error Type, and
Retrieval Context (Experiment 3)
Task
Generate-items Recall-C>wn Generate-New
Self- Partner-
Plagiarism Plagiarism(%) (%)
Partner-
Plagiarism(%)
New-
Errors
(%)
Self-
Plagiarism(%)
Partner-
Plagiarism
(%)
Retrieval Context
Partner Present 0.8 0.3
Partner Absent 0.6 0.3
9.7
21.4
8.1
7.9
1.1
2.3
3.8
3.1
sciousness during the recall-own task. If so, then again one would be
confronted with a tricky attributional dilemma; specifically, from where
did the item originate? If one's partner is present, however, it is conceiv
able that he or she may function as something of an aide-de-memoire, pro
viding valuable source-related cues to the origin of the item (Johnson et
al., 1993). Thus, on generating a particular exemplar, the presence of
one's partner may remind one that she previously produced the item.
When one's partner is absent, however, these source-specifying cues
would be unavailable, hence one might expect levels of cryptomnesia to
be elevated under these conditions. The question of interest, then, is as
follows: does the presence of one's partner during the recall-own task in
crease or decrease the incidence of cryptomnesia (Jacoby et al., 1989)? In
our third experiment, we investigated this issue.
METHOD
Participants and Design. Twenty-eight undergraduates (14 women and14 men) were paid 2 ($3.20) for their participation in the experiment.The experiment had a single factor (retrieval context: partner-present or
partner-absent) between-participants design.StimulusMaterials and Procedure. Participants arrived at the laboratory
in pairs (female-male), were greeted by two female experimenters, and
randomly assigned to one of the treatment conditions. The experimentwas identical to Experiment 2, apart from the manipulation of source
confusion. On this occasion, rather than varying the difficulty of the en
coding process, we manipulated the retrieval conditions under which
participants performed the final two cryptomnesic tasks (i.e., re
call-own, generate-new). Specifically, whereas half of the participantsperformed the recall-own and generate-new tasks in the company of
their partner, the others performed these tasks while their partner was
absent. Following the item-generation task, to minimize the impact of
CONTEXTS OF CRYPTOMNESIA 289
contextual cues on task performance, all participants were taken to a different room (or rooms) to complete the experiment. In each condition
(i.e., partner-present vs. partner-absent), two people remained in the
room during the recall-own and generate-new tasks (i.e., participant +
partner or participant + new experimenter). In all other respects, this ex
periment was identical to Experiment 2.
RESULTS AND DISCUSSION
As in Experiments 1 and 2, the proportion of errors produced on each
task were calculated and analyzed separately in a series of 2 (retrieval
condition) x 2 (error type) mixed-model ANOVAs (see Table 3 for treat
ment means).
Generate-items. As in each of the previous experiments, error rates on
this task were uniformly low and were not influenced by experimentalcondition.
Recall-Own. Therewere reliablemain effects of both experimental fac
tors on participants' recall performance [retrieval condition, F(l,26) =
13.16, p < .002; error type, F(l,26)= 15.43, p < .0006]. These effects were
qualified, however, by a significant retrieval condition x error type in
teraction, F(l,26) = 9.62, p < .005. Simple effects analyses revealed the
following results. Whereas new-errors were not affected by retrieval
condition [F(l,50) < 1, ns], partner-plagiarism was influenced by this
manipulation [F(l,50) = 22.05, p < .002], with higher rates of plagiarism
emerging in the partner-absent than the partner-present condition. In
addition, partner plagiarisms were more abundant than intrusion er
rors in the partner-absent condition, F(l,26) = 24.71, p < .0001.
Generate-New. There was a marginal effect of error type on task performance [F(l,26) = 3.57, p < .07], with participants more likely to plagiarizetheir partner's responses than to indulge in self plagiarism (respectiveMs: 3.4% vs. 1.7%). Retrieval context did not have an effect on error rates
in this task (p > .75).
Although employing a different manipulation of source confusion,
these results directly replicate those observed in Experiments 1 and 2.
Whereas source confusion had no effect whatsoever on the incidence of
cryptomnesia in the two generative tasks (i.e., generate items; gener
ate-new), quite different effects emerged on the reproductive task (i.e.,
recall-own) where participants were required to produce previous re
sponses. Specifically, levels of cryptomnesia were elevated when the retrieval context did not contain any source-related cues (i.e.,
partner-absent condition). That is, participants were more likely to steal
290 MACRAE, BODENHAUSEN, AND CALVINI
their partner's responses when he or shewas absent, rather than present,
during the recall-own task.- Of course, it remains possible that levels of
cryptomnesia could be elevated when one's partner is present duringthe retrieval task (Jacoby et al., 1989). The deciding factor, we suspect,
may be how many items one's partner has previously generated. In the
present paradigm, the production ofmultiple items may have rendered
one's partner a valuable source-specifying cue. That is, through the re
peated production of items, strong associative links may have been
forged in memory between one's partner and his or her responses (Johnson et al., 1993). As such, when present, one's partner may have func
tioned as a useful source-specifying retrieval cue. If, however, only a
single item had been produced in the generation task, it is unlikely that
such associative links would have been formed, hence under these con
ditions the presence of one's partner may actually elicit bouts of
cryptomnesia (see Jacoby et al., 1989). One useful task for future research
will be to investigate this possibility.
GENERAL DISCUSSION
Taken together, the results of the present studies support the notion that
impairments in source monitoring can increase the incidence of at least
certain forms of inadvertent plagiarism (Johnson et al., 1993; Landau &
Marsh, 1997; Marsh et al., 1997). In the context of a category-exemplar
generation task (Brown & Murphy, 1989), when: (1) the exemplars were
generated by similar targets (i.e., Experiment 1); (2) the generation task
was executed under distracting conditions (i.e., Experiment 2); or (3)source-related cues were not present at the time of retrieval (i.e., Experiment 3), source confusion exacerbated participants' tendency to believe
that other people's efforts were in fact their own. In the discussion that
follows, we consider the theoretical and practical implications of these
findings.
2. Another possible explanation can be offered for the low levels of plagiarism that were
observed in the partner-present condition. When participants in the partner-present con
dition were completing the recall tasks, it is possible that they may have believed that their
responses would later be shared with the other person, thereby prompting them to use
more stringent decision criteria than their colleagues in the partner-absent condition
(Johnson et al., 1993). If operating, such an effect would reduce levels of cryptomnesia in
the partner-present condition. Whilst such an explanation is possible, it is worth notingthat during the debriefing session no participant expressed the belief that his or her re
sponses would be seen by the other person. Thus, it is unlikely that the present effects origi-nated via this route.
CONTEXTS OF CRYPTOMNESIA 291
ON DUPLICATION: YOUR IDEA OR MINE?
Given the documented existence of unintentional plagiarism, it is obvi
ously important to delineate the task conditions under which this worri
some phenomenon is likely to occur. For example, if one has the
potential to steal a colleague's latest research idea, it is useful to identifyfactors that may precipitate this heinous action. Following others, we
speculated that cryptomnesia may reflect a basic malfunction of source
memory specifically, perceivers' capacity to reconnect a recollection
with its rightful owner (Johnson et al., 1993; Landau & Marsh, 1997).
Thus, when unable to discern the identity of an item in consciousness,
perceivers may be inclined to believe that the item was self-generatedwhen, in fact, it was produced by someone else. Our findings confirmed
this prediction.Moreover, whether source confusionwas elicited byma
nipulations that impaired the encoding (i.e. Experiments 1 & 2) or re
trieval (i.e., Experiment 3) of source-related information, a reliable effect
emerged source confusion exacerbated perceivers' tendency to take
credit for other people's efforts (Johnson et al., 1993; Landau & Marsh,
1997;Marsh et al., 1997). As expected, however, source confusion did not
increase the incidence of other types of cryptomnesia. Specifically, generative errors were not affected by manipulations of source confusion.
This finding confirms Landau and Marsh's (1997) observation that the
recall-own task differs from the two generative activities (i.e., gener
ate-items, generate-new) in terms of the decision processes it requires.Whereas the recall-own task demands extended source-monitoring (i.e.,
was it your response or mine?), the two generative activities simply re
quire that participants establish the novelty of each exemplar generated
(i.e., is the item old or new?). Given these processing differences, onlythe recall-own task is affected by standard manipulations that increase
the difficulty of source monitoring (Johnson et al., 1993). It remains possible, however, that in other experimental paradigms even the two generative activities may be disrupted by manipulations of source
confusion. One task for future research on this topic will be to consider
this possibility.
Despite using the same generative task (i.e., category-exemplar gener
ation), the present findings diverged from those observed by Brown and
Murphy (1989) in a couple of interesting ways. First,whereas Brown and
Murphy observed significant rates of plagiarism in the generation task,
such errors were almost entirely absent in the present research. Second,
in the experiments reported herein, plagiarism rates in the recall-own
task were apparently much higher than those reported by Brown and
Murphy (1989). Our intuition is that these differences may be due to the
292 MACRAE, BODENHAUSEN, AND CALVINI
procedural alterations we made to the original paradigm in the present
research. Specifically, whereas Brown and Murphy had participants
perform the item-generation task in groups of four, in the present work
participants completed this task in pairs. One consequence of this modi
fication was that fewer items were elicited during the generation task
(i.e., 48 vs. 64 items). This difference, we suspect, may account for the
elimination of cryptomnesia in the initial generation task. The reduction
in size of the experimental groups would also be expected to influence
task performance on the recall tasks, as the decision criteria that partici
pants recruitwould be different in groups of four than in dyads (Johnsonet al., 1993). As for the increased rate of inadvertent plagiarism observed
on the recall-own task, this we believe is a function of the manipulationsof source confusion employed. In the control conditions (i.e., no confu
sion), rates of cryptomnesia were comparable to those reported byBrown and Murphy (1989).
Although performance on the two generative activities was unaf
fected by manipulations of source confusion, these tasks nonetheless
help to elucidate another important aspect of cryptomnesia namely,what exactly is it that perceivers plagiarize? For example, do perceivers
engage in bouts of self-duplication, unwittingly repeating their own
previous responses (Skinner, 1983), or do they prefer instead to steal
other people's efforts (Jacoby & Kelley, 1987)? This turns out to be an im
portant question, as clearly these two varieties of cryptomnesia have
quite different implications for perceivers.Whereas self-plagiarism typ
ically elicits nothing more sinister than feelings of embarrassment or re
gret, copying other people's outputs (e.g., ideas, songs, poems) can have
decidedly disturbing consequences for perceivers, such as an appear
ance in court. So which form of inadvertent plagiarism ismost prevalent,
partner plagiarism or self-duplication? At least with respect to performance on the generate-new task, the present findings tell a pretty consistent tale. Across all three experiments, participants were more likely to
plagiarize their partner's responses than they were to engage in bouts of
self-duplication. So why might this be so? Why do perceivers prefer tosteal their partner's responses?To answer the previous question, one must consider the dynamics of
the initial item-generation task. In furnishing items on this task, not onlydo participants represent their articulated responses in memory, but so,
too, they store a record of the cognitive operations associated with the
generation of each item (Johnson et al., 1993; Johnson & Raye, 1981). For
example, if an item was particularly difficult to generate, was affectivelysalient, orwas personally relevant in someway or another (e.g., it cued a
plethora of autobiographical recollections), then this information is also
stored in memory together with a record of the item itself. The same can
not be said, of course, for partner-generated responses, as obviously one
CONTEXTS OF CRYPTOMNESIA 293
has no idea how these items were generated or what associations they
may have evoked (see Marsh & Hicks, 1998). Thus, because
self-generated items are highly differentiated in memory, one is less
likely to plagiarize them at a later date (Johnson et al., 1993). The representational similarity of partner-generated items, however, make them
likely candidates for appropriation. Somewhat disturbingly, therefore,in demonstrating a predilection for partner plagiarism rather than
self-duplication, perceivers display the variety of cryptomnesia that is
ultimately most damaging.But from the plethora of partner-generated items that reside in mem
ory, which ones get stolen? According to Marsh and Landau (1995), the
answer lies in the post-generational accessibility of items in memory.
Following their initial generation, items are believed to retain different
activation strengths, and it is these differences that are thought to deter
mine which responses are likely candidates for theft. To evaluate this
prediction,Marsh and Landau made a simple modification to the Boggle
procedure. Following the item-generation task, participants performeda lexical-decision task (LDT), where they were required to reportwhether a series of letter stringswere legal "English" words. During this
task, participants were presented, among other things, with the solu
tions that had previously been provided to the Boggle puzzle. On com
pletion of the LDT, participants then performed the conventional
recall-own and generate-new tasks. The question of theoretical interest
was as follows: Would the relative accessibility of items in the LDT de
termine the extent to which they were plagiarized by participants, with
highly accessible items comprising the most likely candidates for theft?
As it turned out, this is exactly what Marsh and Landau found, prompt
ing them to conclude that, "Items with greater strength are more likely to
be later plagiarized" (1995, p. 1575). Much like other memory illusions,
therefore, basic cognitive principles appear to determine both the condi
tions under which cryptomnesia is likely to occur and items that are
probable candidates for theft (Jacoby & Kelley, 1987; Johnson et al., 1993;Landau & Marsh, 1997; Marsh & Landau, 1995). In this respect, the
source-monitoring framework advanced by Johnson and her colleagues
(Johnson, 1988; Johnson et al., 1993; Johnson & Raye, 1981) provides a
useful theoretical framework for understanding cryptomnesia and its
associated effects in mental life.
CRYPTOMNESIA AND EVERYDAY LIFE
The existence of inadvertent plagiarism poses some potentially anxi
ety-provoking questions for social perceivers. When we bask in the pridethat derives from ourmost recent creative product be it a research idea, a
new recipe for cheesecake, or a romanticaria can we be sure that our feel-
294 MACRAE, BODENHAUSEN, AND CALVINI
ing is justified? After all, perhaps the glory belongs elsewhere, as we have
been the unwitting victim of cryptomnesia. This sudden realization that
one's cherished ideas are actually someone else's is an experience that has
troubled some of psychology's leading thinkers. In describing how he de
veloped his theory of original bisexuality, for example, Freud (1901/1960)noted that a colleague, Fliess, claimed to have furnished him with the idea
several years earlier. Although, Freud completely rejected this claim, he
subsequently remembered their original encounter and correctly traced
the origin of the idea to his colleague. But just how ubiquitous is this typeof source error? Dowe plagiarize others on a regrettably regular basis, or is
inadvertent duplication a relatively infrequent affair? Is cryptomnesia
something we should worry about?
Inspection of the modest literature on this topic confirms the potential
perils of cryptomnesic thinking (Betz, Skowronski, & Ostrom, 1996;
Bink, Marsh, Hicks, & Howard, in press; Wicklund, 1989; Wicklund,
Reuter, & Schiffmann, 1988). Betz et al. (1996), for example, provide a
provocative demonstration of what happens when a memory and its
source become dissociated (Johnson et al., 1993). Following the presentation of a story, participants were required to complete a multiple-choice
recognition test assessing their memory for the piece. After respondingto some of the questions, however, participants were shown other peo
ple's bogus responses to the same test items. Later, participants' recol
lections of the story were reassessed, this time with a cued-recall task.
The question of interest was as follows: To what extent would partici
pants' memories be shaped by other people's bogus recollections? The
results were intriguing. Participants frequently appropriated other people's recollections, particularly when these memories were seemingly
highly credible. Similar effects have also been reported in a recent studyby Bink et al. (in press). When asked to produce novel ways to reduce
traffic accidents, participants were more likely to plagiarize an idea if itwas previously produced by a high- than a low-credibility source (i.e.,traffic planner vs. college student). Thus, not only do perceivers have a
worrying propensity to purloin other people's behavioral products, butit would appear that they prefer to steal items from the most reliable,
trustworthy, and prestigious of sources.
Although source-monitoring errors are by no means an inevitable
consequence of memory function (Johnson et al., 1993), the characteris
tics of everyday interaction may ironically serve to promote unwantedbouts of cryptomnesia. Of relevance in this regard are the decision criteria and processing strategies that perceivers routinely employ duringsource monitoring (Chaiken et al., 1989; Johnson et al., 1993). In a rangeof social settings, it is probable that perceivers will employ stringent
source-monitoring criteria, thus preventing the occurrence of
cryptomnesia. Take, for example, task contexts where perceivers believe
CONTEXTS OF CRYPTOMNESIA 295
their outputs will be scrutinized or evaluated by others. Under condi
tions such as these, cryptomnesia is unlikely to emerge as perceivers will
be highly motivated to avoid source-monitoring errors (Johnson et al.,
1993; Johnson & Raye, 1981). Generally speaking, whenever perceiversare encouraged to pay close attention to their behavioral products, inad
vertent plagiarism is unlikely to occur (see Marsh et al., 1997). Unfortu
nately, these conditions may be the exception rather than the rule in
daily life. As Marsh et al. argue, "In the generation of ideas, and perhapsin many other real-world situations of interest...people's decision crite
ria may be quite different. Most likely, people fail to apply sufficiently
stringent criteria to avoid source-monitoring errors" (1997, p. 895). This
failure to scrutinize source-relevant informationmay be due to a varietyof factors, although most bouts of cryptomnesia can probably be traced
to the fact that in many task contexts perceiversmay simply lack the mo
tivation or cognitive capacity to employ the systematic processing strat
egies that would ensure source-monitoring success (Johnson et al.,
1993). In others words, the characteristics of everyday task environ
ments may serve to promote unwanted bouts of cryptomnesia.
Notwithstanding the previous discussion, unconscious plagiarism is
not necessarily an undesirable mental phenomenon. Rather, inadvertent
plagiarism simply reflects the intermittent failure of a source-monitor
ing system that typically serves us well (Johnson et al., 1993). The same
processes that enable us to keep track of the origin of our recollections
also periodically persuade us that an insight or thought is original,when
in fact itwas generated by someone else. Sometimes, of course, these fail
ures in source monitoring can have rather unpleasant consequences,such aswhen one steals amelody ormovie plot from its creator. On other
occasions, however, it is possible that perceivers may accrue tangiblebenefits through cryptomnesic thinking, such as creative insights, con
versational fluency, and facilitated learning.What is certain, however, is
that perceivers lack the self-monitoring skills needed to detect the some
times subtle influences of inadvertent plagiarism. As such, it is probablethat cryptomnesic effects shape a variety of our behavioral products, we
are simply unaware that these unconscious forces are operating. Indeed,
given people's propensity to plunder other people's efforts, perhaps
kleptomnesia3 is a more appropriate label for this particular memory
lapse.Of course, where some of our behavioral outputs are concerned, we
would be well advised to consider the possibility of "cryptomnesic con
tamination." Consider, for example, academic life, where the intellec-
3. Thanks to Dan Gilbert for coining this term and to DanWegner for suggesting that we
(intentionally) steal it.
296 MACRAE, BODENHAUSEN, AND CALVINI
tual ownership of ideas is a cornerstone of the scientific enterprise. Here,
too, implicit cryptomnesic forces may operate. As Marsh et al. speculate,"As we repeat the ideas of our colleagues each day in teaching our
courses and in our casual conversations often without properly credit
ing the source do these failures to engage source-monitoring processescombined with these repeated exposures lead to a greater level of inad
vertent appropriation than many of us would ever imagine (1997, p.
896)?" Our suspicion is that they probably do, and in the present re
search we have attempted to demonstrate how standard manipulationsof source confusion (Johnson et al., 1993) can exacerbate people's pro
pensity to plagiarize others. Given that these manipulations simulate
processing contexts routinely encountered in life outside the laboratory
(e.g., target similarity, cognitive distraction), one may reasonably sur
mise that cryptomnesia is a potent force in shaping our behavioral products. To avoid such an influence, of course, the recommended course of
action is straightforward,monitor the origin of one's recollections (Johnson etal., 1993; Johnson & Raye, 1981). Or as Obi-Wan Kenobi should per
haps have said "may the source be with you."
REFERENCES
Betz, A. L, Skowronski, J. J., & Ostrom, T. M. (1996). Shared realities: Social influence and
stimulus memory. Social Cognition, 14, 113-140.
Bink, M. L., Marsh, R. L, Hicks, J. L.,& Howard, J. D. (in press). The credibility of a source
influences the rate of unconscious plagiarism. Memory.
Broun, A. S., & Halliday, H. E. (1991). Cryptomnesia and source memory difficulties.
American journal of Psychology, 104, 475190.
Brown, A. S., & Murphy, D. R. (1989). Cryptomnesia: Delineating inadvertent plagiarism.Journal of Experimental Psychology: Learning, Memory, and Cognition, 15, 432-442.
Chaiken, S., Lieberman, A., & Eagly, A. H. (1989). Heuristic and systematic information
processing within and beyond the persuasion context. In J. S. Uleman & J. A. Bargh(Eds), Unintended thought (pp. 212-252). New York: Guilford.
Chalfonte, B. L., & Johnson, M. (1996). Feature memory and binding in young and older
adults. Memory and Cognition, 24, 403-416.
Ferguson, S., Hashtroudi, S., & Johnson, M. K. (1992). Age differences in usingsource-relevant cues. Psychology and Aging, 7, 443-452.
Freud, S. (1960). The psychopathology of everyday life. In J. Strachey (Ed. and Trans.), Thestandard edition of the complete works of Sigmund Freud (Vol. 6). London: HogarthPress. (Original work published in 1901).
Hovland, C, & Weiss, W. (1951 ). The influence of source credibility on communication ef
fectiveness. Public Opinion Quarterly, 15, 635-650.
Jacoby, L. L., & Kelley, C. M. (1987). Unconscious influences of memory for a prior event.
Personality and Social Psychology Bulletin, 13, 314-336.
Jacoby, L. L, Kelley, C. M Brown, J., & Jasechko, J. (1989). Becoming famous overnight:Limits on the ability to avoid unconscious influences of the past. Journal ofPersonal
ity and Social Psychology, 56, 326-338.
Johnson, M. K. (1988). Reality monitoring: An experiential phenomenological approach.Journal of Experimental Psychology: General, 117, 390-394.
CONTEXTS OF CRYPTOMNESIA 297
Johnson, M. K., Hashtroudi, S., & Lindsay, D. S. (1993). Source monitoring. PsychologicalBulletin, 114,3-28.
Johnson, M. K., Nolde, S. F., & De Leonardis, D. M. (1996). Emotional focus and source
monitoring. Journal ofMemory and Language, 35, 135-156.
Johnson, M. K., & Raye, C. L. (1981). Reality monitoring. Psychological Review, 88, 67-85.
Landau, J. D.,& Marsh, R. L. (1997). Monitoring source in an unconscious plagiarism para
digm. Psychonomic Bulletin and Review, 4, 265-270.
Lindsay, D. S. (1990). Misleading suggestions can impair eyewitnesses' ability to remem
ber event details, journal ofExperimental Psychology: Learning,Memory, and Cognition,16, 1077-1083.
Lindsay, D. S., Johnson, M. K., & Kwon, P. (1991). Developmental changes in memory
source monitoring. Journal of Experimental Child Psychology, 52, 297-318.
Macrae, C. N., Shepherd, J. W., &Milne, A. B. (1992). The effects of source credibility on the
dilution of stereotype-based judgments. Personality and Social Psychology Bulletin,
IS, 765-775.
Marsh, R. L., & Bower, G. H. (1993). Eliciting cryptomnesia: Unconscious plagiarism in a
puzzle task, journal of Experimental Psychology: Learning, Memory, and Cognition, 19,
673-688.
Marsh, R. L., & Hicks, J. L. (1998). Test formats change source-monitoring decision pro
cesses, journal of Experimental Psychology: Learning, Memory, and Cognition, 24,
1137-1151.
Marsh, R. L., & Landau, J. D. (1995). Availability in cryptomnesia: Assessing its role in two
paradigms of unconscious plagiarism, journal of Experimental Psychology: Learning,
Memory, and Cognition, 21, 1568-1582.
Marsh, R. L., Landau, J. D., & Hicks, J. L. (1997). Contributions of inadequate source moni
toring to unconscious plagiarism during idea generation, journal of Experimental
Psychology: Learning, Memory, and Cognition, 23, 886-897.
Pratkanis, A., & Aronson, E. (1992). Age ofpropaganda: The everyday use and abuse ofpersuasion. New York: Freeman.
Pyszczynski, T., & Greenberg, J. (1987). Toward an integration of cognitive and motiva
tional perspectives on social inference: A biased hypothesis-testing model. In L.
Berkowitz (Ed.), Advances in experimental social psychology (Vol. 20, pp. 297-340). San
Diego, CA: Academic Press.
Raye,C. L., Johnson, M. K.,& Taylor, T. H.(1980). Is there something special aboutmemoryfor internally generated information? Memory & Cognition, S, 141-148.
Schacter, D. L., HarblukJ. L, & McLachlan, D. R. (1984). Retrieval without recollection: An
experimental analysis of source amnesia, journal ofVerbal Learning and Verbal Behav
ior, 23, 593-611.
Skinner, B. F. (1983). Intellectual self-management in old age. American Psychologist, 38,239-244.
Taylor, F. K. (1965). Cryptomnesia and plagiarism. British journal of Psychiatry, 111,
1111-1118.
Taylor, S. E., Fiske, S. T., Etcoff, N. L., & Ruderman, A. J. (1978). Categorical and contextual
bases of person memory and stereotyping. Journal of Personality and Social Psychol
ogy, 36, 778-793.
Wicklund, R. A. (1989). The appropriation of ideas. In P. Paulus (Ed.), Psychology ofgroupinfluence (2nd ed pp. 393-423). Hillsdale, NJ:
Erlbaum.
Wicklund, R. A., Reuter, T., & Schiffmann, R. (1988). Acting on ideas: Appropriation to
one's self. Basic and Applied Social Psychology, 9, 13-31.
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