PSYC 575 Cognitive Psychology

COMP R E H EN S I V E R E V I EW

Induction of false beliefs and false memories in laboratory studies—A systematic review

Beate Muschalla | Fabian Schönborn

Institute of Psychology, Technische Universität

Braunschweig, Braunschweig, Germany

Correspondence

Prof. Dr. Beate Muschalla, Technische

Universität Braunschweig, Institute of

Psychology, Humboldtstraße 33, 38106

Braunschweig, Germany.

Email: [email protected]

Abstract

Psychological interventions often use guided discovery and other techniques for

diagnostic exploration and intervention planning. This way, memories may arise in

the person, which may be true or false. False memories of earlier events can be harm-

ful and result in real suffering, similar to actual traumatic memories. Based on cogni-

tive psychological and psycho-traumatological findings, there is pronounced dissent

in the academic disciplines regarding the conceptualization, relevance and research

of false memories. This review contributes to the basic question of how often false

beliefs and false memories may be induced within the frame of different interactional

techniques. A systematic review has been conducted of 59 articles from (quasi-)

experimental studies and two qualitative sources from 30 data bases. Three main

methods of memory induction provide the basis for reporting: imagination inflation,

false feedback, and memory implantation. Due to the conceptual and methodological

diversity of the studies, the results appear to be heterogeneous. Free and guided

imagery, as well as suggestive statements, could induce false beliefs or false memo-

ries in, on average, 20%–50% of the participants who underwent experimental

manipulation concerning false past events. A false belief induction may occur after

dream interpretation or hypnosis in more than 50% of participants. Personalized sug-

gestion is more effective in inducing memory than the general plausibility of the

suggested events. Further research questions are which therapeutic actions seem

appropriate in cases of harmful false memories. This depends not only on whether

there are veridical elements in the false memory but also on the quality and meaning

of the memory for the person's life and ability to cope with burdens.

K E YWORD S

false beliefs, false memories, guided imagery, memory induction, side effects, suggestion

1 | INTRODUCTION

False belief is present when an individual is erroneously convinced that

an event has happened to or with them earlier in their life, even if

they previously had no idea that this event had happened and also

had no pre-existing memories in terms of pictures, sensations, or

details of the event. False memories can be defined as false beliefs

about such past events which are experienced not only as facts but

Received: 5 January 2021 Revised: 23 January 2021 Accepted: 25 January 2021

DOI: 10.1002/cpp.2567

This is an open access article under the terms of the Creative Commons Attribution?NonCommercial?NoDerivs License, which permits use and distribution in any

medium, provided the original work is properly cited, the use is non?commercial and no modifications or adaptations are made.

© 2020 The Authors. Clinical Psychology & Psychotherapy published by John Wiley & Sons Ltd

1194 Clin Psychol Psychother. 2021;28:1194–1209.wileyonlinelibrary.com/journal/cpp

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

also as memories (Lampinen, Neuschatz, & Payne, 1998), that is, with

details of the people involved, sensations, process of the event, and

so on.

False beliefs and false memories concerning earlier events (which

did not happen) can be mainly understood as phenomena of memory

disorders. They may appear as phenomena of confabulation or param-

nesia, to use the psychopathological nomenclature. Because cognitive

interventions, such as those used in coaching, training, or psychother-

apy, are basically understood as the modification of memories by

means of specific talk (motivational interviewing, cognitive reframing,

cognitive rescripting, and guided imagery), false beliefs and false mem-

ories play an important role in psychological interventions.

Psychological interventions are well-established ways of improv-

ing mental health or changing behaviour; they are able to achieve pos-

itive effects on mental health or behaviour. There is still a widespread

assumption that this type of intervention, characterized by “talking,” does not lead to undesired or negative side effects because “talking” is noninvasive and cannot cause damage. However, current findings

show that both expected side effects and undesired effects can occur

in coaching and psychotherapeutic treatment, due to correct

(Linden & Schermuly-Haupt, 2014; Schermuly & Graßmann, 2019) or

incorrect interventions.

One type of undesirable effect relates to the development of

false beliefs or false memories of events. These events did not happen

but are sometimes used as an explanation for current psychological

problems people experience. People with induced false memories

become aware of memories of events that they did not experience, by

mixing various influences. Meanwhile, memories of past experiences

can reactivate the emotions originally experienced (Pohl, 2007). This

may result in potentially harmful consequences, for example, disliking

or avoiding people or situations associated with the (false) memories.

False memories might be accompanied by emotions that are strongly

compelling (McNally et al., 2004). Lieberei and Linden (2008) pres-

ented a case in which a patient developed a false memory and a fully

fledged posttraumatic stress disorder with intrusions, vivid memory

pictures, and avoidance behaviour, after having participated in a

follow-up course in which her colleagues' fatal accident was dis-

cussed. Brainerd and Reyna (2005) reported further cases in which

intrafamily abuse in early childhood was suggested to patients under-

going psychotherapy, which caused the patients to break off contact

with their families and assume the roles of abuse victims.

Because there has been little systematic synthesis of what is

known about the induction of false memories, the present review

study tries to systematize how and with what frequency, false beliefs,

and false memories can be induced.

An earlier systematic review on false memories (Brewin &

Andrews, 2017) reports relevant research paradigms for inducing false

memories of early childhood events in adults in an experimental situa-

tion. The mechanisms by which false memories could be induced in

laboratory studies, relate to (i) imagination inflation (the repeated imag-

ination of events that did not actually happen), (ii) false feedback (con-

veying suggestive misinformation in a talk), and (iii) memory

implantation (through manipulated photographs or false statements by

relevant caregivers, Scoboria et al., 2017). It was possible to identify

characteristics for assessing the quality of induced memory. According

to these, the quality of induced memory can be evaluated in ascend-

ing order, as follows: (i) the conviction that an event occurred, (ii) the

subjective re-experience of a (false) memory in such a way that it is

believed to be true, and (iii) the belief that the memory is true. The last

two points must be fulfilled for an induced memory to be qualitatively

similar to a “real” memory (Brewer, 1986; Brewin & Andrews, 2017).

The research question in this present review is as follows:

In how many people do different memory induction techniques

(imagination inflation, false feedback, memory implantation) lead to a

successful induction of false beliefs and false memories?

Investigations using the imagination inflation paradigm are essen-

tially based on the induction of false memories or false beliefs, which

are primarily caused by the test person or patient's imagination. These

imaginations are guided and supported by the person conducting the

experiment. In the misinformation paradigm, the induction and thus

suggestive potential is even more under the influence of the

researchers. Accordingly, Loftus and Mazzoni (1998) even called it an

expert-personalized suggestion paradigm. The induction is essentially

based on the authority and the supposed knowledge attributed by the

respondent to himself. In the case of implantation, the induction takes

place using similar mechanisms as in the case of misinformation. How-

ever, here the authority and suggestive potential usually lies less with

the leader of the experiment than with the subject's parents (who

report true and false events before the experiment) or with the valid-

ity of manipulated childhood photographs.

An earlier and so far, first, attempt to summarize the effectiveness

and extent of false memory induction can be found in Brewin and

Andrews (2017). They state that the paradigms of imagination infla-

tion, false feedback, and implantation, mentioned above, are most likely

to simulate the clinical context, allow replication in the laboratory, and

can also be justified in respect to ethical considerations. Brewin and

Andrews (2017) found that in the majority of research participants,

these mentioned research paradigms do not elicit false memories. The

authors concluded: “On the one hand, it has provided a valuable

Key Practitioner Message

• It is the trainer or therapist's duty to help clients to

change, reframe, and form their memories, as clients'

complaints often pertain to autobiographical memories.

• However, different exploratory techniques (guided imag-

ery, suggestive statements, hypnosis, and dream interpre-

tation) can increase the probability of potentially harmful

false beliefs or false memories being induced in on aver-

age 20%–50% of those exposed to false event induction.

• Any memory work and reframing during coaching, train-

ing, and psychotherapy should be done in a way that

enables the client to cope better with life and avoid the

induction of harmful false beliefs or false memories.

MUSCHALLA AND SCHÖNBORN 1195

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

demonstration that compelling false memories can sometimes be cre-

ated even with the restrictions imposed by laboratory research. […]

On the other hand, we believe it cannot be concluded that false mem-

ories of childhood events possessing these characteristics are com-

mon, that they are easy to suggest or implant or that the majority of

individuals are susceptible to them.” (p. 20). However, the methodological procedure in Brewin and

Andrews (2017) does not correspond fully to the standard of a sys-

tematic review, as they did not explicitly apply the PRISMA reporting

guidelines and did not report the precise search strategy. Thus, the

procedure of this present analysis is intended to adopt the memory

induction paradigms introduced above (Brewin & Andrews, 2017) and

identify and synthesize the relevant literature on the current princi-

ples and standards of a systematic review, using English and German

language sources.

2 | METHOD

A systematic literature search was conducted in 30 data bases. Arti-

cles in the English and German languages, from 1970 to 2019, were

included. The data bases and the search terms used are reported in

supporting information Table S1. In accordance with the PICO search

scheme (Person, Phenomenon of interest, context; Nordhausen &

Hirt, 2018), the search terms listed in the supporting information

Table S2 were used.

All the articles from the literature search of which the topics were

in any way associated with psychotherapeutic settings or action and

were included as valid search results. This includes theoretical and

empirical articles, both in the context of experimental laboratory

research and of clinical practice. Furthermore, the false beliefs and

false memories investigated were categorized according to the con-

cepts of false belief, false memory, and autobiographical memory con-

tent. Only primary sources in the German or English language have

been considered (Figure 1).

Articles referring to neurophysiological measurements, neurologi-

cal diseases (e.g. dementia) or developmental disorders (e.g. autism)

have been excluded. Articles discussing false memories in the context

of substance-induced disorders or schizophrenic forms of disorder

have also been excluded, together with all articles referring to forensic

work as an expert witness in legal proceedings, for example, in

assessing the credibility of statements. Forensic articles were only

included if the forensic methods were used or discussed in a thera-

peutic context. The articles were also excluded if the false memories

were related to false recognition or generally to semantic memory

content. Furthermore, findings related to investigations of traumatic

F IGURE 1 Outcome of systematic literature search for false memories according to the defined search terms in 30 international databases

1196 MUSCHALLA AND SCHÖNBORN

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

false memories were excluded if they were discussed in the context

of childhood development. Finally, all articles with anonymous authors

were excluded, as were those for which no abstract was available,

unless the article's title suggested an inclusion criterion.

3 | RESULTS

3.1 | Induction of false memories

The question of the induction of false memories is the area that has

been most intensively researched and probably has the highest level

of evidence. There were 59 articles involving 75 separate studies and

a total N of 7,062 participants from randomized experiments or quasi-

experiments (Figure 1). Of the total 59 sources, 21 were based on the

imagination inflation research paradigm; a further 18 refer to the

misinformation paradigm and 20 to the implantation paradigm.

3.2 | Imagination inflation paradigm

Making a synthesis from research using the imagination inflation para-

digm (Table 3) is challenging. Although all the investigations refer to

the same research approach and predominantly simulate the same

interactional techniques, there is enormous variability in the

approaches: It was only possible to highlight three sources in which

an experiment and an appropriate differentiation of false beliefs and

false memories were performed (Paddock et al., 2000; Paddock &

Terranova, 2001; Mazzoni & Memon, 2003).

The sample size-weighted average percentage of research partici-

pants who developed false beliefs was 55.3% over three studies

(Heaps & Nash, 1999; Horselenberg et al., 2000; Sharman, Garry, &

Hunt, 2005, Table 1), and the sample size-weighted average percent-

age for falsely believed events (stimuli) was 33.3% over 10 studies

(Bays, Foley, & Zabrucky, 2013; Bays, Zabrucky, & Gagne, 2012;

Clancy, McNally, & Schacter, 1999; Garry, Manning, Loftus, &

Sherman, 1996; Paddock et al., 1998, 1999; Pezdek, Blandon-Gitlin, &

Gabbay, 2006; Pezdek & Eddy, 2001).

It can be assumed from the sources included in this analysis that

free and guided imagination can lead to the adoption of false memo-

ries or false beliefs by up to 33%–55% of the manipulated partici-

pants. On the other hand, some studies have also shown that

induction is not possible or even that deflation of the presented mate-

rial must be assumed. Based on the idea that there is normally a cer-

tain overlap between a belief in the truth of an event and an

individual memory (nested model proposed by Scoboria, Mazzoni,

Kirsch, & Relyea, 2004), it can still be assumed that an induction rate

about 33%–55% may be the upper limit, but we do not know the pre-

cise prevalence. According to the original studies, rates do also vary

between about 20% and 47% of participants. Furthermore, tech-

niques that use both free and guided imagery in combination with

journaling (writing about the event and the associated feelings and

thoughts) appear to exhibit greater inductive effects. The imagination

of an episode from the observer's perspective also has a stronger

effect than imagining it from the ego perspective (Table 1).

3.3 | False feedback

On the basis of the available data, false memory induction by using

dream interpretations and suggestive statements (Table 2) to increase

the plausibility of events varies from 18% to >80%. Some studies

report induction rates of more than 50% of participants, while this

effect is not apparent at all in others. The problem here is that the

methods used to induce false memories were not identical across the

studies and are also not always clearly recognizable. However, the fact

that the simulated therapeutic methods lead to a change in conviction,

even though a low level of conviction was assumed initially, is well-

replicated in the original studies. The adoption of a changed convic-

tion can persist over a longer period of time. The plausibility of events

is also important, so that it is less the knowledge of specific events that

leads to a change and more the probability that an event might have

happened to one personally. There is a tendency for general plausibility

to be less effective than personalized suggestion. This in accordance

with the model of related convictions and memories (Scoboria

et al., 2004).

In sum, the sample size-weighted average percentage of

research participants who developed false beliefs was 32.5% over

13 studies (Berkowitz, Laney, Morris, Garry, & Loftus, 2008;

Bernstein, Laney, Morris, & Loftus, 2005; Clifasefi, Bernstein,

Mantonakis, & Loftus, 2013; Geraerts et al., 2008; Hart &

Schooler, 2006; Laney, Fowler, Nelson, Bernstein, & Loftus, 2008;

Mazzoni, Loftus, & Kirsch, 2001; Mazzoni, Loftus, Seitz, &

Lynn, 1999; Scoboria, Lynn, Hessen, & Fisico, 2007, 2012a,b).

The sample size-weighted average percentage of research

participants who developed false memories was 11.28% over six

studies (Geraerts et al., 2008; Hart & Schooler, 2006; Laney &

Loftus, 2008; Laney, Morris, Bernstein, Wakefield, &

Loftus, 2008; Scoboria et al., 2007; Scoboria, Mazzoni, Jarry, &

Bernstein, 2012).

3.4 | Memory implantation

There is a partially varying understanding of false memory. This makes

it difficult to make a coherent statement about whether and to what

extent the induction of a false memory can arise through the tech-

niques used. Additionally, some authors relate the percentage results

to the participating subjects, while others relate their results to the

number of falsely remembered items. This means that even the odds

presented cannot be compared. However, on the basis of the avail-

able data (Table 3), it can at least be claimed that a change was mea-

sured in each study, which, if the results are interpreted

conservatively, can only be interpreted as a change in the belief that

an event had happened. Suggested content has a greater effect if it

contains personal material and thus has a higher self-reference. The

MUSCHALLA AND SCHÖNBORN 1197

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

TABLE 1 False belief or false memory induction by imagination inflation

Author (year) Type of study Sample

Simulated memory induction

technique Results

Paddock et al. (1998) Experiment Study 1: 98 undergraduate

psychology students, average

age 19 years, 76% women

Study 2: 106 volunteers from a

manufacturing plant, aged

13–47 years, 63% women

Guided imagery Study 1: False beliefs increased

in up to 38% of imagined

events on life events

inventory (LEI)

Study 2: No increase of false

beliefs after imagined events

(no percentages reported)

Clancy et al. (1999) Experiment Sample 1: 12 women from

general population who

reported being abused as a

child and

Sample 2: 12 women who

reported not being abused,

average age 37 years

Guided imagery Sample 1: False beliefs

increased in 20% of events

Sample 2: False beliefs

increased in up to 25% of

events

Heaps and Nash (1999) Experiment 55 psychology students, aged

22 years, 61.8% women

Hypnosis and guided imagery 44% of participants had positive

changes in the sense of false

beliefs after intervention,

42% had no change

Paddock et al. (1999) Experiment 94 undergraduate psychology

students, aged 21 years, 56%

men

Guided imagery False beliefs increased in 47%

of imagined events on life

events inventory (LEI)

Spanos, Burgess,

Burgess, Samuels, and

Blois (1999)

Experiment 117 undergraduate psychology

students, 65% women

Hypnosis with and without

regression

79% of the hypnotic

participants and 95% of the

nonhypnotic induction

participants reported rich and

detailed false infancy

memories, such as seeing

bright lights, bars on their

crips, and doctors and nurses

wearing masks

Horselenberg

et al. (2000)

Experiment Study 1: 34 undergraduate

psychology students, 85%

women

Study 2: 45 students, 66%

women, aged 16–20 years

Free imagery and journaling Study 1: Percentage of

participants with increased

probability ratings for

imagined event items: 38%

Study 2: Journaling with free

imagery had tendentially

greater effects than imagery

without journaling. Journaling

effects were independent of

personality.

Paddock, Terranova,

Kwok, and

Halpern (2000)

Experiment Experiment 1: 125

undergraduate students from

an engineering school, aged

21 years, 51% men

Experiment2:143students from

thesameengineeringschool,

aged20 years,94men

Guided imagery Experiment 1: Guided imagery

lead participants to rate

known childhood events

closer to events for which

they had memories.

Experiment 2: Known-to-

remember-shift were

stronger in case of higher

extraversion, external locus

of control, a memory than

conveyed fear, overall

affective content

Paddock and

Terranova (2001)

Experiment 359 undergraduate students,

48% men, aged 20 years

Guided imagery Guided imagery lead on average

to change of beliefs into false

memory; this effect was

stronger in conditions where

the imagery intervention was

done by an authority/expert

person

1198 MUSCHALLA AND SCHÖNBORN

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

TABLE 1 (Continued)

Author (year) Type of study Sample

Simulated memory induction

technique Results

Mazzoni and

Memon (2003)

Experiment 82 students, 35% men, aged

21 years

Free imagery False memories of impossible

childhood events occurred in

up to 25%–50% of

participants after imagery

Von Glahn et al. (2012) Experiment Experiment 1: 59

undergraduate psychology

students, aged 19 years, 42%

men

Experiment 2: 60 participants

(out of the experiment 1

group)

Repeated interviews, free

imagery and journaling

Repeated interviews (5 times

being asked a list of events

that might have happened)

did not lead to induction of

false beliefs.

Journaling lead to significant

increase in confidence of

certain events (false beliefs)

dependent on the amount of

memory details which had to

be written down (3 or 6

details)

Garry et al. (1996) Quasi-

experiment

46 undergraduate psychology

students

Guided imagery False beliefs increased in 32%

of imagined events on life

events inventory (LEI)

Pezdek and Eddy (2001) Quasi-

experiment

75 persons, consisting of older

(76 years) and younger

(21 years) adults

Free imagery False beliefs increased in 39%

of imagined events on life

events inventory (LEI). No

age differences in inflation

rates

Sharman et al. (2005) Quasi-

experiment

128 undergraduate psychology

students

Suggestive expressions and

guided imagery (ego

perspective and observer

perspective)

In 65% of participants,

confidence increased for

imagined events from the live

events inventory

False beliefs appear stronger

when an observer

perspective is used during

imagery, as compared to ego

perspective

Pezdek, Blandon-Gitlin,

and Gabbay (2006)

Quasi-

experiment

145 undergraduate students,

aged 22 years, 69% females

Guided imagery and journaling False beliefs rather appears

when highly plausible events

are used for induction (38%

of events increased) in

comparison to low plausible

events (21% of events

increased)

Bays et al. (2013) Quasi-

experiment

151 undergraduate students,

74% women

Guided imagery and journaling 26.7% increased belief ratings

of specific events, 15%

decreased belief rating of

specific events

Sharman and

Powell (2013)

Quasi-

experiment

126 university members, aged

18–64 years, 69% women

Cognitive interview No significant induction of false

belief or false memory,

independent from the fact if

an event was rated as highly

or low plausible

Sharman, Garry, and

Beuke (2004)

Quasi-

experiment

(several

groups)

67 undergraduate psychology

students

Free imagery and paraphrasing Participants became more

confident that the fictitious

events had happened in

childhood (regardless of

whether imagined or

paraphrased). No repetition

effect was found beyond that

of a single exposure

(Continues)

MUSCHALLA AND SCHÖNBORN 1199

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

effect of an induction is also stronger if the suggestion is based on

plausible statements made by significant reference persons. Manipu-

lated photographs may also induce false beliefs but these false beliefs

appear to be less pronounced. Finally, contrary to the nested model

proposed by Scoboria et al. (2004), false memories can also arise of

events for which there was no pre-existing belief and which the sub-

jects had previously assessed as unlikely.

Summarized, the sample size-weighted average percentage of

research participants who developed false beliefs was 37% over

11 studies (French, Sutherland, & Garry, 2006; Hyman, Husband, &

Billings, 1995; Ost, Foster, Costall, & Bull, 2005; Otgaar, Scoboria, &

Smeets, 2013; Pezdek, Finger, & Hodge, 1997; Shaw & Porter, 2015;

Short & Bodner, 2011; Wade, Garry, Nash, & Harper, 2010; Wade,

Garry, Read, & Lindsay, 2002) and 26.6% over 12 studies for false

memories induction (Desjardins & Scoboria, 2007; French et al., 2006;

Garry & Wade, 2005; Heaps & Nash, 2001; Hessen-Kayfitz &

Scoboria, 2012; Lindsay, Hagen, Read, Wade, & Garry, 2004; Ost

et al., 2005; Otgaar et al., 2013; Pezdek et al., 1997; Porter, Yuille, &

Lehman, 1999; Qin, Ogle, & Goodman, 2008; Short & Bodner, 2011).

The sample size-weighted average percentage for falsely believed

events was 35% over two studies (Hyman & Pentland, 1996; Qin

et al., 2008).

4 | DISCUSSION

On the basis of the studies analysed, it can be assumed that an induc-

tion of false memories is favoured by various conditions which vary

widely in each case. Furthermore, it is unlikely that the interventions

mentioned above act as a single causative agent in producing false

memories. Instead, it is the coincidence of several conditions: A spe-

cific type or technique, the interviewer, trainer or therapist, the set-

ting, and the person. In addition, the constructive nature of (flexible

and changeable) memory must be considered to be a basic human

characteristic that favours or even makes possible all types of associ-

ated memory phenomena.

Imagination techniques, journaling, hypnosis, dream interpreta-

tions, as well as general suggestive conditions, all have the potential

to induce false beliefs or even false memories. In particular, imagina-

tion techniques, which use visualizations of episodes from the

observer's perspective, carry a risk of confusing remembered and

presented material. It is apparent that combining several techniques

increases the risk of induction (Horselenberg et al., 2000; Scoboria

et al., 2007; Scoboria, Mazzoni, Jarry, & Shapero, 2012; Von Glahn,

Otani, Migita, Langford, & Hillard, 2012). In addition, the higher the

level of self-reference or the more personalized the induction

TABLE 1 (Continued)

Author (year) Type of study Sample

Simulated memory induction

technique Results

Sharman and

Barnier (2008)

Quasi-

experiment

(several

groups)

78 undergraduate students,

aged 22 years, 68% women

Guided imagery False convictions are stronger

when positive events are

used as induction material

Sharman and

Scoboria (2009)

Quasi-

experiment

(several

groups)

60 undergraduate psychology

students, 22 years, 81%

women

Suggestive expressions and

guided imagery

Imagination inflation regardless

of event plausibility.

Plausibility did not affect

participants' belief, but it did

affect their memories. In

dependence on the

plausibility of the event, false

memories are much more

often induced than

convictions

Bays et al. (2012) Quasi-

experiment

(several

groups)

135 undergraduate psychology

students, 82% women

Free imagery and journaling Inflation of false beliefs occurs

with similar frequency like

deflation in all conditions.

40% of events did not change

post manipulation. When

changes occurred, they were

similarly likely to increase

(31%) or decrease (29%)

Marsh, Pezdek, and

Lam (2014)

Quasi-

experiment

(several

groups)

Study 1: 47 college psychology

students, age 20 years, 55%

women

Study 2: 64 students, 72%

women

Guided imagery (ego

perspective and observer

perspective) and journaling

False belief could be induced by

reports from an observer

perspective but not from ego

perspective

Note: Articles are ordered chronologically according to year of publication and to method (experiment and quasi-experiment). Studies reported the percentages

of events that have been rated as believed being true after the imagination, or percentages of participants who increased in belief or memory after the

intervention, or (in case no percentages are reported) dimensional measures of degree of belief or intensity of memory.

1200 MUSCHALLA AND SCHÖNBORN

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

TABLE 2 False belief or false memory induction by false feedback

Author (year) Type of study Sample

Simulated memory induction

technique Results

Mazzoni, Loftus,

et al. (1999)

Experiment 72 undergraduate students Interpretation of dreams 30% of the dream

interpretation group

increased their beliefs and

reported memories. Increase

of false beliefs occurred in

50% of events (decrease in

4.5%).

Mazzoni, Lombardo,

et al. (1999)

Experiment 44 undergraduate students,

age 21 years, 64% women

Interpretation of dreams For two critical events, about

80% of the belief scores

increased, that is, 80% of

participants were convinced

to have experienced the

event

Mazzoni et al. (2001) Experiment Three studies with 65 + 71

+ 57 undergraduate

students

Suggestive statements and

statements expanding

plausibility

Increase in beliefs of

implausible traumatic events

in 18% of participants

Bernstein et al. (2005) Experiment 228 undergraduate students Suggestive interpretations Significant induction of false

belief (having felt sick after

eating a specific ice cream

as a child) in 20% of

participants (experiment 1)

and in 41% of cases

(experiment 2). 4% of the

believers even remembered

the event, 96% just believed

it had happened.

Berkowitz et al. (2008) Experiment 404 undergraduate students Suggestive statements and

statements expanding

plausibility

False beliefs were induced in

up to 30% of participants.

76% of written memory

details were neutral (not

positive or negative affect)

Geraerts et al. (2008) Experiment 180 undergraduate students,

aged 21 years, 75% women

Suggestive statements False belief was induced in

39% of participants, 7%

reported memories. After

three suggestive sessions,

behavioural consequences

were observed: The

believers (believing having

got sick after eating egg

salad as a child) ate

significantly less often egg

salad than controls or

nonbelievers

Laney and Loftus (2008) Experiment 301 undergraduate students,

aged 20 years, 75% women

Suggestive statements 20.6% of those manipulated

developed false memories

for their critical events:

They believed falsely that

they had these events and

were emotional.

Laney, Morris,

et al. (2008)

Experiment 368 undergraduate students,

aged 20 years, 80% women

Suggestive statements and

free imagery

False beliefs developed in up

to 44% of participants

(positive event) and 49%

(negative event). False

memories occurred in 5%

and 12%.

(Continues)

MUSCHALLA AND SCHÖNBORN 1201

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

TABLE 2 (Continued)

Author (year) Type of study Sample

Simulated memory induction

technique Results

Scoboria, Mazzoni, Jarry,

and Shapero (2012)

Experiment 42 undergraduate students,

aged 19 years, 85% women

116 undergraduate students,

age 20 years, 79% women

Suggestive statements and

guided imagery

False beliefs were induced in

40% of participants (who

had low plausibility rating in

the beginning). A nonlinear

relation between the

estimation before

suggestion and false

autobiographical beliefs

after suggestion has been

found

Clifasefi et al. (2013) Experiment 147 undergraduate

psychology students, aged

19 years, 70% women

Suggestive statements Significant induction of false

belief (having been sick from

alcohol) in 20% of

participants (believers), 80%

remained nonbelievers.

From the believers, 40%

reported memories.

Loftus and

Mazzoni (1998)

Quasi-

experiment

24 undergraduate students Interpretation of dreams For two of presented critical

events, no participants

decreased, but 82%–100% went into the direction of

becoming more confident

that the event had

happened to them.

Hart and Schooler (2006) Quasi-

experiment

112 students Suggestive statements False beliefs increasing in

11%–20% of participants,

decreasing in 13%, no false

memories. Participants

responded with greater

confidence that they had

experienced an enigma

when given plausibility

information, it did not

increase their memory for

the event, and schematicity

decreased reported memory

of the event.

Scoboria et al. (2007) Quasi-

experiment

Study 1: 62 undergraduate

students, aged 20 years,

77% women

Study 2: 164 undergraduates,

aged 22 years, 88% women

Suggestive statements and

statements expanding

plausibility

Study 1: False beliefs under

conditions of plausible

events in 50% of

participants, but no false

memories

Study 2: 45% of participants

increased in false belief

Scoboria, Mazzoni, and

Jarry (2008)

Quasi-

experiment

21 women aged 20 years Suggestive statements and

statements expanding

plausibility

Results show that a subtle

suggestion about the

personal past can modify

behaviour. Specifically, food

preferences and eating

behaviour were both

reduced in a manner

consistent with the

suggestion provided.

Pezdek, Blandon-Gitlin,

Lam, Hart, and

Schooler (2006)

Quasi-

experiment

(several

groups)

Study 1: 296 undergraduate

students in psychology

classes, aged 22 years, 198

women

Study 2: 125 students, aged

24 years, 56 women

Suggestive statements and

statements expanding

plausibility

Study 1: Providing background

knowledge can increase

beliefs about personal

events, but that its impact is

limited by the extent of the

individual's familiarity with

1202 MUSCHALLA AND SCHÖNBORN

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

techniques applied, the more the risk of false belief induction

increases (Scoboria, Mazzoni, Jarry, & Bernstein, 2012). A review

by Otgaar, Muris, Howe, and Merckelbach (2017) which focused

on clinical studies—false memory effects in participants with PTSD,

or a history of trauma, or depression—found similar phenomena of

false memories being increased by induction: If the material pres-

ented was emotional, the clinical participants' levels of false mem-

ory increased relative to those of the comparison groups. This

difference was not observed when nonemotional material was

presented. People with PTSD, a history of trauma, or depression

were at risk for producing false memories when they were

exposed to information related to their knowledge base with the

potential to activate associations.

Because most techniques in training, coaching, and psychother-

apy will use personalized material, images, and exploration strategies,

it can be assumed that findings from the experimental laboratory

studies reviewed here are relevant to these practice settings. The

subjectively perceived authority or professionalism of a trainer,

coach, or psychotherapist can also lead to an induction. It is impossi-

ble to eliminate the risk of this condition, which makes the practi-

tioner's reflective ability and their interaction approach indispensable.

This results in the need for supervision, the use of evaluated

methods to ensure the quality of the practitioner's own work, and

their knowledge of the intervention's possible side effects. Psycho-

therapy research shows the relevance of reciprocity and the interac-

tion between the patient and psychotherapist (Langhoff, Baer,

Zubraegel, & Linden, 2008). This is also crucial in the induction of

nonexperiential material.

However, the induction of false memories is a general factor

which does not stem exclusively from the context of psychotherapy.

Empirical findings have shown that a control group may develop false

memories or a change in conviction (Berkowitz et al., 2008). Similarly,

it has been shown that subjects might not develop false memories but

instead remember less or report less information after an imagination

exercise (Bays et al., 2013).

Finally, the fundamental problem is that in both practice and the

experimental context, there is often no clear distinction between

induced false beliefs or their associated vivid, false memories. It

should be borne in mind that even the belief in a trauma (not only full,

vivid, false memories) can bring about serious consequences for those

involved.

In the case of false memories in psychotherapy, it must be deter-

mined whether this is a side effect of an indicated intervention, a mal-

practice, an incorrect intervention in the presence of an existing

contraindication (Linden & Schermuly-Haupt, 2014), or the effect of

any experiences outside the intervention setting. Usually, the trainer/

coach/therapist as the producer of the intervention focuses their

attention on the positive rather than the negative effects of the inter-

vention (Hatfield, McCullough, Frantz, & Krieger, 2010). However,

false memories in the context of psychological interventions can have

strong negative consequences (Linden & Schermuly-Haupt, 2014) and

professionals should be aware of this risk. There is also a discrepancy

TABLE 2 (Continued)

Author (year) Type of study Sample

Simulated memory induction

technique Results

the context of the

suggested target event.

Study 2: False beliefs occurred

under condition of plausible

and familiar events, but

there was no change in

belief in 70% of participants

Sharman and

Calacouris (2010)

Quasi-

experiment

(several

groups)

46 undergraduate students,

aged 20 years, 78% women

Free imagery Childhood events containing

achievements and affiliation

were used as experimental

stimuli. For achievement

events, participants' explicit

motives (subjective need for

success) predicted their

false beliefs and memories.

Scoboria, Mazzoni, Jarry,

and Bernstein (2012)

Quasi-

experiment

(several

groups)

125 undergraduate students,

aged 20 years, 77% women

Suggestive statements and

statements expanding

plausibility and guided

imagery

Generalized suggestions had

hardly any effect on

increased beliefs that events

had happened. Personalized

suggestions lead to false

memories in 19% of

manipulated participants

and false beliefs in 24% of

manipulated participants

Note: Articles are ordered chronologically according to year of publication, and to method (experiment and quasi-experiment).

MUSCHALLA AND SCHÖNBORN 1203

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

TABLE 3 False belief or false memory induction by implantation

Author (year) Type of study Sample Simulated (therapy) technique Results

Hyman and

Pentland (1996)

Experiment 65 undergraduate students, 75%

women

Repeated interviews, suggestive

statements and imagery

Recall of true events: 85%– 100% (one to three sessions);

false belief in 15%–35% (one

to three sessions) of false

events

Desjardins and

Scoboria (2007)

Experiment 44 undergraduate students,

aged 22 years, 89% women

Repeated interviews and guided

imagery

68% of participants exposed to

self- relevant story details

were judged as having created

memories or images about the

false event, as compared with

36.4% exposed to nonself-

relevant stories. Subjective

ratings of memory intensity

were higher for self- relevant

groups, and self- relevant

participants were less likely to

correctly guess the false

events

Qin et al. (2008) Experiment Study 1: 119 participants:

Community and students,

aged 27 years

Study 2: 132 undergraduates

Suggestive statements,

plausibility expanding

statements, guided imagery

and repeated interviews

Study 1: 10% full false

memories, 16% partially false

memories in the participants

Study 2: Adults' abilities to

distinguish true from false

memories and the criteria they

used to make such

judgements were examined.

Participants distinguished true

and false memories to a

certain extent. However, error

rates were high:

Approximately 40% of the

time, participants mistakenly

identified false memories as

true.

Wade et al. (2010) Experiment 53 family members of students,

aged 21 years, 59% female

Free imagery and repeated

interviews

37% of the participants had false

belief after first interview,

42%–68% after the second

interview. False beliefs were

less induced by means of

visual information in

comparison to verbal

information

Garry and

Wade (2005)

Experiment 44 undergraduate students,

aged 21 years

Guided imagery Recall of true events was 97%.

False memories occurred in up

to 82% under condition of

narration and 50% under

condition of visual information

(photo). Narratives produce

more false memories than

photos do

Strange, Wade,

and

Hayne (2008)

Experiment 105 participants, aged 20 years,

70% women

Free imagery and repeated

interviews

False beliefs and false memories

occur more often under

conditions of events before

infantile amnesia (events at

age 2 years), as compared to

later (event at age 10). False

memories occurred in up to

38% (event age 2) and 19%

(event at age 10) participants

1204 MUSCHALLA AND SCHÖNBORN

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

TABLE 3 (Continued)

Author (year) Type of study Sample Simulated (therapy) technique Results

Scoboria,

Wysman, and

Otgaar (2012)

Experiment 61 undergraduate students,

aged 21 years, 82% women

101 students, aged 21 years,

78% women

Suggestive statements, guided

imagery and repeated

interviews

False beliefs were induced under

conditions of absolute or

relative suggestive

statements. The more

absolute a statement was (e.g.

all events were named by the

parents), the higher was the

probability of false belief

induction

Hyman

et al. (1995)

Quasi-experiment Study 1: 20 and Study 2: 51

psychology students, 75%

women

Repeated interviews and

suggestive questions

Study 1: 20% of false events

were falsely recalled (84% of

true events)

Study 2: Replication and

extension of study 1: 25% of

false events were falsely

recalled (95% of true events)

Pezdek

et al. (1997)

Quasi-experiment Study 1: 29 catholic students

from women high school

Study 2: 20 graduate students,

aged 28 years

Suggestive statements and

plausibility expanding

statements

Study 1: False beliefs in 14%

(Jews) and 35% (Catholics) of

participants, false memories in

7.5%. Only plausible events

have been falsely

remembered: Catholics

remembered the false catholic

events, Jews remembered the

false jewish event.

Study 2: 15% of participants

reported false beliefs

Hyman and

Billings (1998)

Quasi-experiment 66 undergraduate students, 56%

women

Free imagery 85% of true events were

recalled. Clear false memories

on false events occurred in

15% of participants, partly

false memories by 12%, trying

but no memory response by

27%, no memory in 30% of

participants

Porter et al. (1999) Quasi-experiment 77 undergraduate students,

aged 19 years, 79% women

Guided imagery and repeated

interviews

26% of participants “recovered” a complete false memory for

the false experience and

another 30% recalled aspects

of the false experience.

Heaps and

Nash (2001)

Quasi-experiment 63 undergraduate students Plausibility expanding

statements

37% of participants reported

false memories after

imagination (narrative recall of

false memories)

Wade et al. (2002) Quasi-experiment 20 nonpsychology students,

aged 20 years, 50% women

Gudied imagery False beliefs or partial false

memories in up to 50% of

participants after exposition

to a fake photograph and 3

interviews with imagery

instructions

Ost et al. (2005) Quasi-experiment 31 undergraduate psychology

students, aged 20 years, 77%

women

Free imagination and repeated

interviews

False beliefs about childhood

events induced in 22% of

participants; false memories in

only one participant

French

et al. (2006)

Quasi-experiment 29 pairs of adult siblings, aged

22 years

Suggestive statements,

plausibility expanding

statements, and

peer-discussion of

the topics between

participants

Before the discussion, false

memories were induced in 5%

and false beliefs in 19%. After

the discussion, the rate was

reduced in both false beliefs

(3%) and false memories (2%).

(Continues)

MUSCHALLA AND SCHÖNBORN 1205

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

in terms of knowledge and approaches, between researchers and pro-

fessionals, which has led to a lively debate on recovering memory

therapies (Stocks, 1998; Ulatowska & Sawicka, 2017).

4.1 | Limitations and further research

A major limitation of the research in this field is that many studies

involved healthy, mostly 20-year old, female undergraduate

(psychology) students. Therefore, the results cannot be generalized to

the general population. However, studies have shown that memory

processes such as activation spreading are independent of age with

similar mechanisms being observed in 25 year olds and in 70 year olds

(Balota & Duchek, 1989) and that age was not systematically associ-

ated with rates of false belief inflation (Pezdek & Eddy, 2001).

Also, many of the studies only focus on short-term effects. Meth-

odologically, the false beliefs or false memories in these experiments

often pertained to mundane events (e.g. having eaten rotten egg

salad; Geraerts et al., 2008) rather than to the type of traumatic

events that may be the topic in psychotherapy. However, there is the

general issue that really life threatening or otherwise traumatic events

cannot be induced for ethical reasons. This generally limits the possi-

bilities for experimental research on traumatic memories.

Research on false memories is also prone to bias due to interpre-

tation: As an example, the de Rivera studies (de Rivera, 1997, 2000)

are introduced as research on people who falsely recalled having

been the victims of abuse; however, strictly speaking, the facts do

not support this conclusion: The subjects were people who first

recovered memories of abuse during psychotherapy and later, after

therapy, retracted these memories. The fact that they retracted their

memories does not of itself necessarily imply that the memories

were wrong.

Our review also reiterates that clearer definitions of false memo-

ries and false beliefs are necessary, as they offer the potential to

TABLE 3 (Continued)

Author (year) Type of study Sample Simulated (therapy) technique Results

Short and

Bodner (2011)

Quasi-experiment 34 undergraduate students,

aged 20 years, 82% women

Cognitive interview False beliefs on having

experienced the suggested

event were induced in 41% of

participants, false memories in

21%

Otgaar

et al. (2013)

Quasi-experiment 89 undergraduate students,

aged 22 years, 80% women

Suggestive statements, repeated

interviews, and guided

imagery

False memories have been

induced in 36% of

participants. From those, 23%

have later withdrawn their

memories. In 13% of the

participants false memories

remained after debriefing,

even though the persons did

no more believe that the

memory is experience-based

(“nonbeliefed memory”).

Shaw and

Porter (2015)

Quasi-experiment 60 undergraduate students,

aged 20 years, 72% women

Suggestive statements, repeated

interviews, and guided

imagery

False beliefs or false memories

were induced in 70% of

participants within scenarios

of criminal events, within

noncriminal events in 76% of

participants

Lindsay

et al. (2004)

Quasi-experiment

(several groups)

45 undergraduate students, 80%

women

Guided imagery False memories were induced by

true photographs and guided

imagery (on two true and one

false childhood events) in 65%

of participants

Hessen-Kayfitz

and

Scoboria (2012)

Quasi-experiment

(several groups)

82 undergraduate students,

aged 20 years, 77% women

Suggestive statements, repeated

interviews, and guided

imagery

False memories were induced in

5% (not self-relevant event) to

19% (self-relevant event) of

participants. Induction was

strongest in scenarios with

ego-related information. For

true events 60% of

participants had memories.

Note: Articles are ordered chronologically according to year of publication, and to method (experiment and quasi-experiment).

1206 MUSCHALLA AND SCHÖNBORN

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

investigate false memories with a more uniform conceptual under-

standing. A more selective use of the concepts of false belief and false

memory in future research could make it easier to generalize results

and improve communication within the debate on false memories

(Pezdek & Lam, 2007). Elaborated instruments are needed to make

the differentiability and measurement of the intensity of a memory

change clear. Laboratory investigations in which the presence of an

induction is assessed by a subsequent debriefing or the evaluation of

a transcript should be made as transparent as possible. Experimental

studies of false memories should no longer be conducted with homog-

enous (psychology) student samples but include more heterogeneous

participants from the general population or from other specific groups

(e.g. different age groups, professional groups).

5 | CONCLUSION

False memories of false events can be regarded as phenomena which

can only be adequately researched in the laboratory and are only

rarely established with absolute certainty in practice but can never-

theless lead to harmful consequences for those involved. In the pre-

sent review, it was found that false memories can be researched in

the laboratory and that it can be assumed that various methods and

techniques increase the probability of false beliefs or false memories

being induced in, on average, 20%–50% of participants.

In the context of psychological interventions, the challenge arises

on the one hand, of recognizing a (potentially harmful) false memory

as such and therefore not carrying out a nonindicated intervention,

which could possibly lead to undesirable effects. On the other hand,

the professional is himself the person who can confirm or even create

false belief or false memory phenomena through his actions.

Finally, whether the consequence of a false memory is harmful or

helpful for the person who does not depend on whether it is a valid

memory or a false memory. In any case, it is the professional's duty to

help the person change, reframe, and form their memory, as clients'

complaints often pertain to autobiographical memories. Any reframing

should be done in a way that enables the person to cope with life bet-

ter. Reframing is oriented forward, is done in the here and now, and as

such, the reframing process and outcome is independent of any past

events which induced and formed the earlier memories and beliefs.

ACKNOWLEDGMENTS

The manuscript was proofread for English language by Kelly GmbH.

This research did not receive funding.

DATA AVAILABILITY STATEMENT

Data are the 59 original articles on which this review is based

on. They are accessible via public databases or from the authors upon

request.

STATEMENT OF ETHICS

Ethical approval was not obtained, because no human beings have

been investigated directly.

CONFLICT OF INTEREST

The authors have no conflicts of interest to declare.

AUTHOR CONTRIBUTIONS

B.M. designed the research question, supervised the research process,

prepared the tables, wrote the manuscript, and carried out the revi-

sion. F.S. conducted literature search and literature analysis and pre-

pared the tables.

ORCID

Beate Muschalla https://orcid.org/0000-0001-5285-6618

REFERENCES

Balota, D. A., & Duchek, J. M. (1989). Spreading activation in episodic

memory: Further evidence for age independence. Quarterly Journal of

Experimental Psychology, 41, 849–876. https://doi.org/10.1080/

14640748908402396

Bays, R. B., Foley, M. A., & Zabrucky, K. M. (2013). Timing does matter:

Examining imagery's impact on the temporal origins of false beliefs.

Acta Psychologica, 142(1), 30–37. https://doi.org/10.1016/j.actpsy.

2012.10.004

Bays, R. B., Zabrucky, K. M., & Gagne, P. (2012). When plausibility manipu-

lations work: An examination of their role in the development of false

beliefs and memories. Memory, 20(6), 638–644. https://doi.org/10.

1080/09658211.2012.692797

Berkowitz, S. R., Laney, C., Morris, E. K., Garry, M., & Loftus, E. F. (2008).

Pluto behaving badly: False beliefs and their consequences. American

Journal of Psychology, 121(4), 643–660. https://www.jstor.org/stable/

20445490

Bernstein, D. M., Laney, C., Morris, E. K., & Loftus, E. F. (2005). False

beliefs about fattening foods can have healthy consequences.

Proceeding of the National Academy of Science of the United States of

America, 102(39), 13,724–13,731. https://doi.org/10.1073/pnas.0504 869102

Brainerd, C. J., & Reyna, V. F. (2005). The Science of False Memory. Oxford:

Oxford University Press. https://doi.org/10.1093/acprof:oso/

9780195154054.001.0001

Brewer, W. F. (1986). What is autobiographical memory? In D. C. Rubin

(Ed.), Autobiographical Memory (pp. 25–49). Cambridge: Cambridge

University Press.

Brewin, C. R., & Andrews, B. (2017). Creating memories for false autobio-

graphical events in childhood: A systematic review. Applied Cognitive

Psychology, 31(1), 2–23. https://doi.org/10.1002/acp.3220 Clancy, S. A., McNally, R. J., & Schacter, D. L. (1999). Effects of guided

imagery on memory distortion in women reporting recovered memo-

ries of childhood sexual abuse. Journal of Traumatic Stress, 12(4),

559–569. https://doi.org/10.1023/A:1024704815234 Clifasefi, S. L., Bernstein, D. M., Mantonakis, A., & Loftus, E. F. (2013).

“Queasy does it”: False alcohol beliefs and memories may lead to

diminished alcohol preferences. Acta Psychologica, 143(1), 14–19. https://doi.org/10.1016/j.actpsy.2013.01.017

de Rivera, J. (1997). The construction of false memory syndrome: The

experience of retractors. Psychological Inquiry, 8(4), 271–292. https:// doi.org/10.1207/s15327965pli0804_1

de Rivera, J. (2000). Understandings persons who repudiate memories

recover in therapy. Professional Psychology: Research and Practice,

31(4), 378–386. https://doi.org/10.1037/0735-7028.31.4.378 Desjardins, T., & Scoboria, A. (2007). “You and your best friend Suzy put

slime in Ms. Smollett's desk”: Producing false memories with self-

relevant details. Psychonomic Bulletin & Review, 14(6), 1090–1095. https://doi.org/10.3758/BF03193096

MUSCHALLA AND SCHÖNBORN 1207

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

French, L., Sutherland, R., & Garry, M. (2006). Discussion affects memory

for true and false childhood events. Applied Cognitive Psychology,

20(5), 671–680. https://doi.org/10.1002/acp.1219 Garry, M., Manning, C. G., Loftus, E. F., & Sherman, S. J. (1996). Imagina-

tion inflation: Imagining a childhood event inflates confidence that it

occurred. Psychonomic Bulletin & Review, 3(2), 208–214. https://doi. org/10.3758/BF03212420

Garry, M., & Wade, K. A. (2005). Actually, a picture is worth less than

45 words: Narratives produce more false memories than photographs

do. Psychonomic Bulletin & Review, 12(2), 359–366. https://doi.org/10. 3758/BF03196385

Geraerts, E., Bernstein, D. M., Merckelbach, H., Linders, C.,

Raymaekers, L., & Loftus, E. F. (2008). Lasting false beliefs and their

behavioral consequences. Psychological Science, 19(8), 749–753. https://doi.org/10.1111/j.1467-9280.2008.02151.x

Hart, R. E., & Schooler, J. W. (2006). Increasing belief in the experience of

an invasive procedure that never happened: The role of plausibility

and schematicity. Applied Cognitive Psychology, 20(5), 661–669. https://doi.org/10.1002/acp.1218

Hatfield, D., McCullough, L., Frantz, S. H. B., & Krieger, K. (2010). Do we

know when our clients get worse? An investigation of therapists' abil-

ity to detect negative client change. Clinical Psychology &

Psychotherapy, 17(1), 25–32. https://doi.org/10.1002/cpp.656 Heaps, C., & Nash, M. (1999). Individual differences in imagination infla-

tion. Psychonomic Bulletin & Review, 6(2), 313–318. https://doi.org/10. 3758/BF03214120

Heaps, C., & Nash, M. (2001). Comparing recollective experience in true

and false autobiographical memories. Journal of Experimental Psychol-

ogy: Learning, Memory, and Cognition, 27(4), 920–930. https://psycnet. apa.org/doi/10.1037/0278-7393.27.4.920

Hessen-Kayfitz, J. K., & Scoboria, A. (2012). False memory is in the details:

Photographic details differentially predict memory formation. Applied

Cognitive Psychology, 26(3), 333–341. https://doi.org/10.1002/acp.

1839

Horselenberg, R., Merckelbach, H., Muris, P., Rassin, E., Sijsenaar, M., &

Spaan, V. (2000). Imagining fictitious childhood events: The role of

individual differences in imagination inflation. Clinical Psychology &

Psychotherapy, 7(2), 128–137. https://doi.org/10.1002/(SICI)1099-

0879(200005)7:2<128::AID-CPP238>3.0.CO;2-Q

Hyman, I. E., & Billings, F. J. (1998). Individual differences and the creation

of false childhood memories. Memory, 6(1), 1–20. https://doi.org/10. 1080/741941598

Hyman, I. E., Husband, T. H., & Billings, F. J. (1995). False memories of

childhood experiences. Applied Cognitive Psychology, 9(3), 181–197. https://doi.org/10.1002/acp.2350090302

Hyman, I. E., & Pentland, J. (1996). The role of mental imagery in the

creation of false childhood memories. Journal of Memory and Language,

35(6), 101–117. https://doi.org/10.1006/jmla.1996.0006

Lampinen, J. M., Neuschatz, J. S., & Payne, D. G. (1998). Memory illusions

and contiousness: Examining the phenomenology of true and false

memories. Current Psychology: Development, Learning, Personality,

Social, 16, 181–224. Laney, C., Fowler, N. B., Nelson, K. J., Bernstein, D. M., & Loftus, E. F.

(2008). The persistence of false beliefs. Acta Psychologica, 129(1),

190–197. https://doi.org/10.1016/j.actpsy.2008.05.010 Laney, C., & Loftus, E. F. (2008). Emotional content of true and false

memories. Memory, 16(5), 500–516. https://doi.org/10.1080/

09658210802065939

Laney, C., Morris, E. K., Bernstein, D. M., Wakefield, B. M., & Loftus, E. F.

(2008). Asparagus, a love story healthier eating could be just a false

memory away. Experimental Psychology, 55(5), 291–300. https://doi. org/10.1027/1618-3169.55.5.291

Langhoff, C., Baer, T., Zubraegel, D., & Linden, M. (2008). Therapist– patient alliance, patient–therapist alliance, mutual therapeutic alliance,

therapist–patient concordance, and outcome of CBT in GAD. Journal

of Cognitive Psychotherapy, 22, 68–79. https://doi.org/10.1891/0889. 8391.22.1.68

Lieberei, B., & Linden, M. (2008). Unerwünschte Effekte, Nebenwirkungen

und Behandlungsfehler in der Psychotherapie. Zeitschrift für Evidenz,

Fortbildung Und Qualität Im Gesundheitswesen, 102(9), 558–562. https://doi.org/10.1016/j.zefq.2008.09.017

Linden, M., & Schermuly-Haupt, M.-L. (2014). Definition, assessment and

rate of psychotherapy side effects. World Psychiatry, 13(3), 306–309. https://doi.org/10.1002/wps.20153

Lindsay, D. S., Hagen, L., Read, J. D., Wade, K. A., & Garry, M. (2004). True

photographs and false memories. Psychological Science, 15(3),

149–154. https://doi.org/10.1111/j.0956-7976.2004.01503002.x Loftus, E. F., & Mazzoni, G. A. L. (1998). Using imagination and personal-

ized suggestion to change people. Behavior Therapy, 29(4), 691–706. https://doi.org/10.1016/S0005-7894(98)80026-9

Marsh, B. U., Pezdek, K., & Lam, S. T. (2014). Imagination perspective

affects ratings of the likelihood of occurrence of autobiographical

memories. Acta Psychologica, 150, 114–119. https://doi.org/10.1016/ j.actpsy.2014.05.006

Mazzoni, G. A. L., Loftus, E. F., & Kirsch, I. (2001). Change beliefs about

implausible autobiographical events: A little plausibility goes a long

way. Journal of Experimental Psychology: Applied, 7(1), 51–59. https:// psycnet.apa.org/doi/10.1037/1076-898X.7.1.51

Mazzoni, G. A. L., Loftus, E. F., Seitz, A., & Lynn, S. J. (1999). Changing

beliefs and memories through dream interpretation. Applied Cognitive

Psychology, 13(2), 125–144. https://doi.org/10.1002/(SICI)1099-0720 (199904)13:2<125::AID-ACP560>3.0.CO;2-5

Mazzoni, G. A. L., Lombardo, P., Malvagia, S., & Loftus, E. F. (1999).

Dream interpretation and false beliefs. Professional Psychology:

Research and Practice, 30(1), 45–50. https://doi.org/10.1037/0735-

7028.30.1.45

Mazzoni, G. A. L., & Memon, A. (2003). Imagination can create false

autobiographical memories. Psychological Science, 14(2), 186–188. https://doi.org/10.1046/2Fj.1432-1327.1999.00020.x

McNally, R. J., Lasko, N. B., Clancy, S. A., Macklin, M. L., Pitman, R. K., &

Orr, S. P. (2004). Psychophysiological responding during script-driven

imagery in people reporting abduction by space aliens. Psychological

Science, 15, 493–497. https://doi.org/10.1111/j.0956-7976.2004.

00707.x

Nordhausen, T., & Hirt, J. (2018). RefHunter. Manual Zur Literaturrecherche

in Fachdatenbanken Version 1.0 (Martin-Luther-Universität Halle-

Wittenberg & FHS St. Gallen, Hrsg.), Halle (Saale). Verfügbar unter

Ost, J., Foster, S., Costall, A., & Bull, R. (2005). False reports of childhood

events in appropriate interviews. Memory, 13(7), 700–710. https://doi. org/10.1080/09658210444000340

Otgaar, H., Muris, P., Howe, M. L., & Merckelbach, H. (2017). What drives

false memories in psychopathology? A case for associative activation.

Clinical Psychological Science, 5, 1048–1069. https://doi.org/10.1177/ 2167702617724424

Otgaar, H., Scoboria, A., & Smeets, T. (2013). Experimentally evoking

nonbelieved memories for childhood events. Journal of Experimental

Psychology: Learning, Memory, and Cognition, 39(3), 717–730. https:// psycnet.apa.org/doi/10.1037/a0029668

Paddock, J. R., Joseph, A. L., Chan, F. M., Terranova, S., Manning, C., &

Loftus, E. F. (1998). When guided visualization procedures bay

backfire: Imagination inflation and predicting individual differences in

suggestibility. Applied Cognitive Psychology, 12(7), 63–75. Paddock, J. R., & Terranova, S. (2001). Guided visualization and suggestibil-

ity: Effect of perceived authority on recall of autobiographical

memories. The Journal of Genetic Psychology, 162(3), 347–356. https:// doi.org/10.1080/00221320109597488

Paddock, J. R., Terranova, S., Kwok, R., & Halpern, D. V. (2000). When

knowing becomes remembering: Individual differences in susceptibility

to suggestion. The Journal of Genetic Psychology, 161(4), 453–468. https://doi.org/10.1080/00221320009596724

1208 MUSCHALLA AND SCHÖNBORN

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense

Paddock, J. R., Terranova, S., Noel, M., Eber, H. W., Manning, C., &

Loftus, E. F. (1999). Imagination inflation and the perils of guided

visualization. The Journal of Psychology, 133(6), 581–595. https://doi. org/10.1080/00223989909599764

Pezdek, K., Blandon-Gitlin, I., & Gabbay, P. (2006). Imagination and mem-

ory: Does imagining implausible events lead to false autobiographical

memories? Psychonomic Bulletin & Review, 13(5), 764–769. https://doi. org/10.3758/BF03193994

Pezdek, K., Blandon-Gitlin, I., Lam, S., Hart, R. E., & Schooler, J. W. (2006).

Is knowing believing? The role of event plausibility and background

knowledge in planting false beliefs about the personal past. Memory &

Cognition, 34(8), 1628–1635. https://doi.org/10.3758/BF03195925 Pezdek, K., & Eddy, R. M. (2001). Imagination inflation: A statistical artifact

of regression toward the mean. Memory & Cognition, 29(5), 707–718. https://doi.org/10.3758/BF03200473

Pezdek, K., Finger, K., & Hodge, D. (1997). Planting false childhood memo-

ries: The role of event plausibility. Psychological Science, 8(6), 437–441. https://doi.org/10.1111/2Fj.1467-9280.1997.tb00457.x

Pezdek, K., & Lam, S. (2007). What research paradigms have cognitive psy-

chologists used to study “false memory,” and what are the implications

of these choices? Consciousness and Cognition, 16(1), 2–17. https://doi. org/10.1016/j.concog.2005.06.006

Pohl, R. (2007). Das Autobiographische Gedächtnis. Die Psychologie unserer

Lebensgeschichte. Stuttgart: Kohlhammer.

Porter, S., Yuille, J. C., & Lehman, D. R. (1999). The nature of real,

implanted, and fabricated memories for emotional childhood events:

Implications for the recovered memory debate. Law and Human Behav-

ior, 23(5), 517–537. https://doi.org/10.1023/A:1022344128649 Qin, J., Ogle, C. M., & Goodman, G. S. (2008). Adults' memories of

childhood: True and false reports. Journal of Experimental Psychology,

14(4), 373–391. https://psycnet.apa.org/doi/10.1037/a0014309 Schermuly, C. C., & Graßmann, C. (2019). A literature review on negative

effects of coaching—What we know and what we need to know,

coaching: An international journal of theory. Research and Practice,

12(1), 39–66. https://doi.org/10.1080/17521882.2018.1528621 Scoboria, A., Lynn, S. J., Hessen, J., & Fisico, S. (2007). So that's why I don't

remember: Normalising forgetting of childhood events influences false

autobiographical beliefs but not memories. Memory, 15(8), 801–813. https://doi.org/10.1080/09658210701685266

Scoboria, A., Mazzoni, G., & Jarry, J. L. (2008). Suggesting childhood food

illness results in reduced eating behavior. Acta Psychologica, 128(2),

304–309. https://doi.org/10.1016/j.actpsy.2008.03.002 Scoboria, A., Mazzoni, G., Jarry, J. L., & Bernstein, D. M. (2012). Personal-

ized and not general suggestion produces false autobiographical

memories and suggestion-consistent behavior. Acta Psychologica,

139(1), 225–232. https://doi.org/10.1016/j.actpsy.2011.10.008 Scoboria, A., Mazzoni, G., Jarry, J. L., & Shapero, D. (2012). Implausibility

inhibits but does not eliminate false autobiographical beliefs. Canadian

Journal of Experimental Psychology, 66(4), 259–267. https://doi.org/10. 1037/a0030017

Scoboria, A., Mazzoni, G., Kirsch, I., & Relyea, M. (2004). Plausibility and

belief in autobiographical memory. Applied Cognitive Psychology, 18(7),

791–801. https://onlinelibrary.wiley.com/doi/abs/10.1002/acp.1062

Scoboria, A., Wade, K. A., Lindsay, D. S., Azad, T., Strange, D., Ost, J., &

Hyman, I. E. (2017). A mega-analysis of memory reports from eight

peer-reviewed false memory implantation studies. Memory, 25(2),

146–163. https://doi.org/10.1080/09658211.2016.1260747 Scoboria, A., Wysman, L., & Otgaar, H. (2012). Credible suggestions affect

false autobiographical beliefs. Memory, 20(5), 429–442. https://doi. org/10.1080/09658211.2012.677449

Sharman, S. J., & Barnier, A. J. (2008). Imagining nice and nasty events in

childhood or adulthood: Recent positive events show the most imagi-

nation inflation. Acta Psychologica, 129(2), 228–233. https://doi.org/ 10.1016/j.actpsy.2008.06.003

Sharman, S. J., & Calacouris, S. (2010). Do people's motives influence their

susceptibility to imagination inflation? Experimental Psychology, 57(1),

77–82. https://doi.org/10.1027/1618-3169/a000010 Sharman, S. J., Garry, M., & Beuke, C. J. (2004). Imagination or exposure

causes imagination inflation. The American Journal of Psychology,

117(2), 157–168. https://www.jstor.org/stable/4149020, https://doi.

org/10.2307/4149020

Sharman, S. J., Garry, M., & Hunt, M. (2005). Using source cues and famil-

iarity cues to resist imagination inflation. Acta Psychologica, 120(3),

227–242. https://doi.org/10.1016/j.actpsy.2005.04.002 Sharman, S. J., & Powell, M. B. (2013). Do cognitive interview instructions

contribute to false beliefs and memories? Journal of Investigative

Psychology and Offender Profiling, 10(1), 114–124. https://doi.org/10. 1002/jip.1371

Sharman, S. J., & Scoboria, A. (2009). Imagination equally influences false

memories of high and low plausibility events. Applied Cognitive Psychol-

ogy, 23(6), 813–827. https://doi.org/10.1002/acp.1515 Shaw, J., & Porter, S. (2015). Constructing rich false memories of commit-

ting crime. Psychological Science, 26(3), 291–301. https://doi.org/10. 1177/0956797614562862

Short, J. L., & Bodner, G. E. (2011). Differentiating accounts of actual,

suggested and fabricated childhood events using the judgment of

memory characteristics questionnaire. Applied Cognitive Psychology,

25(5), 775–781. https://doi.org/10.1002/acp.1756 Spanos, N. P., Burgess, C. A., Burgess, M. F., Samuels, C., & Blois, W. O.

(1999). Creating false memories of infancy with hypnotic and non-

hypnotic procedures. Applied Cognitive Psychology, 13(3), 201–218. https://doi.org/10.1002/(SICI)1099-0720(199906)13:3<201::AID-

ACP565>3.0.CO;2-X

Stocks, J. T. (1998). Recovered memory therapy: A dubious practice

technique. Social Work, 43, 423–436. https://doi.org/10.1093/sw/43.

5.423

Strange, D., Wade, K., & Hayne, H. (2008). Creating false memories for

events that occurred before versus after the offset of childhood

amnesia. Memory, 16(5), 475–484. https://doi.org/10.1080/

09658210802059049

Ulatowska, J., & Sawicka, M. (2017). Recovered memories in clinical

practice—A research review. Psychiatr. Pol., 51, 609–618. https://doi. org/10.12740/PP/62770

Von Glahn, N. R., Otani, H., Migita, M., Langford, S. J., & Hillard, E. E.

(2012). What is the cause of confidence inflation in the life events

inventory (LEI) paradigm? The Journal of General Psychology, 139(3),

134–154. https://doi.org/10.1080/00221309.2012.672938 Wade, K. A., Garry, M., Nash, R. A., & Harper, D. N. (2010). Anchoring

effects in the development of false childhood memories. Psychonomic

Bulletin & Review, 17(1), 66–72. https://doi.org/10.3758/PBR.17.1.66 Wade, K. A., Garry, M., Read, J. D., & Lindsay, D. S. (2002). A picture is

worth a thousand lies: Using false photographs to create false

childhood memories. Psychonomic Bulletin & Review, 9(3), 597–603. https://doi.org/10.3758/BF03196318

SUPPORTING INFORMATION

Additional supporting information may be found online in the

Supporting Information section at the end of this article.

How to cite this article: Muschalla, B., & Schönborn, F. (2021).

Induction of false beliefs and false memories in laboratory

studies—A systematic review. Clinical Psychology &

Psychotherapy, 28(5), 1194–1209. https://doi.org/10.1002/

cpp.2567

MUSCHALLA AND SCHÖNBORN 1209

10990879, 2021, 5, D ow

nloaded from https://onlinelibrary.w

iley.com /doi/10.1002/cpp.2567 by L

iberty U niversity, W

iley O nline L

ibrary on [27/02/2023]. See the T erm

s and C onditions (https://onlinelibrary.w

iley.com /term

s-and-conditions) on W iley O

nline L ibrary for rules of use; O

A articles are governed by the applicable C

reative C om

m ons L

icense