A plethora of research has shown that false memories can be elicited using various suggestive manipulations. Such false memories can be particularly dangerous in legal settings. And indeed: There are numerous cases in which innocent people were wrongfully convicted based on erroneous memories. But what is happening now? In a recent paper, Chris Brewin and Bernice Andrews want to make the case that “susceptibility to false memories of childhood events appears more limited than has been suggested”. Strong message, but we disagree. We were invited to write two commentaries on this review. They will soon be published but here they are already.
Commentary 1: (Authors: Henry Otgaar, Harald Merckelbach, Marko Jelicic, and Tom Smeets)
The Potential for False Memories is Bigger than Brewin and Andrews Suggest
Brewin and Andrews (in press; B&A) have taken up the challenge to provide a review on false memory susceptibility for childhood events. This is a daunting task as the psychological literature is replete with studies on false memories using different paradigms, different populations, and different ways of defining false memory. Although B&A are to be commended with executing such an arduous exercise, we disagree with their central message that “susceptibility to false memories of childhood events appears more limited than has been suggested” (p.1).
First, B&A’s review is selective in that it only focusses on a subset of studies employing imagination inflation, false feedback, and memory implantation to elicit false childhood memories. Moreover, B&A did not include literature on other false memory paradigms (e.g., misinformation, doctored video) that relate to autobiographical false memories and that have been informative regarding false memory propensity for childhood events. A case in point is their omission of several important imagination inflation studies; studies that have, for instance, looked at imagination inflation for action events (e.g., Goff & Roediger, 1998; Otgaar, Scoboria, Howe, Moldoveanu, & Smeets, in press). In contrast to what B&A argue, these studies did find that false memories were accompanied by high confidence. For example, Goff and Roediger (1998) stated “[t]he more errors [false memories] the subjects made, the higher their mean confidence ratings” (p.29).
One could argue that these studies did not tap into childhood events. However, imagination inflation studies on memory for actions typically involve multiple events that the participant either has to perform or imagine and these self-generated actions are – like childhood events –autobiographical in nature. If B&A had solely wanted to focus on studies concerning false memories for childhood events, then why did they include literature on the crashing memory paradigm (e.g., Smeets, Telgen, Ost, Jelicic, & Merckelbach, 2009)? This paradigm focuses on false memories for highly media-exposed, public events rather than childhood events. Likewise, B&A did not address studies on evidently wrong childhood memories, such as those of past lives (Peters, Horselenberg, Jelicic, & Merckelbach, 2007). Thus, it appears that B&A were rather selective in their inclusion of the extant literature, which makes their estimate of false memory vulnerability for childhood events provisional.
Second, a problematic selectivity also invaded B&A’s evaluation of studies that were included in their review. B&A argued that a full false memory is a memory that encompasses a belief in the occurrence of the event, recollective details, and high confidence that these details are accurate. They correctly showed that many false memory implantation studies did not measure confidence but then omitted such studies when they calculated their percentage of full false memory (15%). It would have been more balanced to explain to the reader – and potential judges and juries – that depending on the criteria that one uses, full false memory creation can range from 15% up to 46%. Clearly, this range provides a more reliable estimate of the potential to implant false memories for entire events than the lower bound percentage.
Third, it is remarkable that B&A did not examine false memories induced by misinformation (Loftus, 2005); a type of false memory that has also been regarded as an implanted false memory (Brainerd, Reyna, & Ceci, 2008). Of course, false memories induced by misinformation are often about small details and do not pertain to entire events. Yet, and in contrast to B&A’s central message, the general picture seems to be that these implanted false memories are articulated with high confidence. Some researchers even observed that people are more confident in these implanted false memories than in true memories (Takarangi, Parker, & Garry, 2006).
To examine whether implanted false memories induced by misinformation are, indeed, reported with high confidence, we conducted a small-scale review on misinformation studies that measured confidence (see Table 1). A search was performed on the Web of Science database using the search terms “misinformation”, “false memory”, and “confidence”. To be included in the review, studies were required to have used the misinformation paradigm and to have measured confidence in false memories. Of the 36 potential articles, nine papers (=12 studies) fulfilled our criteria. When reading the papers, an additional two papers (= three studies; total = 15 studies) were identified that met our criteria (i.e., Assefi & Garry, 2003; Loftus, Donders, Hoffman, & Schooler, 1989).
Although our review is by no means exhaustive, it does give a rough estimate of the relation between implanted false memories and confidence. Thus, in 93% (n =14) of the studies, implanted false memories were associated with confidence ratings exceeding the midpoint of the scale. A weighted percentage of the data revealed a mean confidence rating of 74% (unweighted 95% CI [0.66, 0.78]. Clearly then, confidence is often high in implanted false memories resulting from misinformation, a finding that runs counter to B&A’s idea that participants are often not very sure about their implanted false memories.
Thus, the picture is much more complex than B&A want the reader to believe on the basis of their selective review of the extant literature. Another issue is that B&A ignore courtroom realities, a point that we address in Smeets, Merckelbach, Jelicic, and Otgaar (2016).
Implanted False Memories Studies Elicited by the Misinformation Paradigm Measuring Confidence
|Authors||Participants (adults)||Confidence||Rating Scale|
|Loftus et al. (1989); Exp. 1||204||3.5||1 to 5|
|Loftus et al. (1989); Exp. 2||338||4.1||1 to 5|
|Pickel (1999)||86||5.13||1 to 10|
|Assefi & Garry (2003)||148||3.3 and 3.6||1 to 5|
|Mitchell et al. (2003)||51||1.49 and 2.20 (from Figure)||1 to 3|
|Takarangi et al. (2006); Exp. 1||40||4.04||1 to 5|
|Takarangi et al. (2006); Exp. 2||40||3.74||1 to 5|
|Paz-Alonso & Goodman (2008)||232||3.76||1 to 5|
|Foster et al. (2012); Exp. 1||64||3.81||1 to 5|
|Foster et al. (2012); Exp. 2||96||3.80 and 4.40||1 to 5|
|Van Damme & Seynaeve (2013)||300||3.49||1 to 5|
|Fenn et al. (2014)||107||3.61||1 to 8|
|Jack et al. (2014)||48||3.9 (from Figure)||1 to 5|
|Dodson et al. (2015); Exp. 1||59||76% and 84%||50% to 100%|
|Dodson et al. (2015); Exp. 2||96||75.3% and 76.3||50% to 100%|
Assefi, S.L., & Garry, M. (2003). Absolut® memory distortions: Alcohol placebos influence the misinformation effect. Psychological Science, 14, 77-80.*
Brainerd, C.J., Reyna, V.F., & Ceci, S.J. (2008). Developmental reversals in false memory: A review of data and theory. Psychological Bulletin, 134, 343-382.
Brewin, C., & Andrews, B. (in press). Creating memories for false autobiographical memories in childhood: A systematic review. Applied Cognitive Psychology.
Dodson, C.S., Powers, E., & Lytell, M. (2015). Aging, confidence, and misinformation: Recalling information with the cognitive interview. Psychology and Aging, 30, 46-61.*
Fenn, K.M., Griffin, N.R., Uitvlugt, M.G., & Ravizza, S.M. (2014). The effect of Twitter exposure on false memory formation. Psychonomic Bulletin & Review, 21, 1551-1556.*
Foster, J.L., Huthwaite, T., Yesberg, J.A., Garry, M., & Loftus, E.F. (2012). Repetition, not number of sources, increases both susceptibility to misinformation and confidence in the accuracy of eyewitnesses. Acta Psychologica, 139, 320-326.*
Goff, L.M., & Roediger, H.L. (1998). Imagination inflation for action events: Repeated imaginings lead to illusory recollections. Memory & Cognition, 26, 20-33.
Jack, F., Zydervelt, S., & Zajac, R. (2014). Are co-witnesses special? Comparing the influence of co-witness and interviewer misinformation on eyewitness reports. Memory, 22, 243-255.*
Loftus, E. F. (2005). Planting misinformation in the human mind: A 30-year investigation of the malleability of memory. Learning & Memory, 12, 361–366.
Loftus, E.F., Donders, K., Hoffman, H.G., & Schooler, J.W. (1989). Creating new memories that are quickly accessed and confidently held. Memory & Cognition, 17, 607-616.*
Mitchell, K.J., Johnson, M.K., & Mather, M. (2003). Source monitoring and suggestibility to misinformation: Adult age-related differences. Applied Cognitive Psychology, 17, 107-119.*
Otgaar, H., Scoboria, A., Howe, M.L., Moldoveanu, G., & Smeets, T. (in press). Challenging memories in children and adults using an imagination inflation procedure. Psychology of Consciousness: Theory, Research, and Practice.
Paz-Alonso, P.M., & Goodman, G.S. (2008). Trauma and memory: Effects of post-event misinformation, retrieval order, and retention interval. Memory, 16, 58-75.*
Peters, M.J.V., Horselenberg, R., Jelicic, M., & Merckelbach, H. (2007). The false fame illusion in people with memories about a previous life. Consciousness and Cognition, 16, 162-169.
Pickel, K.L. (1999). Distinguishing eyewitness descriptions of perceived objects from descriptions of imagined objects. Applied Cognitive Psychology, 13, 399-413.*
Smeets, T., Telgen, S., Ost, J., Jelicic, M., & Merckelbach, H. (2009). What’s behind crashing memories? Plausibility, belief and memory in reports of having seen non-existent images. Applied Cognitive Psychology, 23, 1333-1341.
Takarangi, M.K.T., Parker, S., & Garry, M. (2006). Modernising the misinformation effect: The development of a new stimulus set. Applied Cognitive Psychology, 20, 583-590.*
Van Damme, I., & Seynaeve, L. (2013). The effect of mood on confidence in false memories. Journal of Cognitive Psychology, 25, 309-318.*
*: papers included in the review
Commentary 2: (Authors: Tom Smeets, Harald Merckelbach, Marko Jelicic, & Henry Otgaar)
Dangerously Neglecting Courtroom Realities
When looking at false memory phenomena, there are two perspectives. One could go from the lab to the court, assuming that researchers first became interested in false memories and then generalized the conclusions that could be drawn from the gathered empirical evidence to court cases in which memory accuracy of an eyewitness or victim was crucially important for justice to be served. Alternatively, one could go from the court to the lab. Evidently, many researchers in the field of false memory have taken this second route. They are familiar with cases in which innocent people were convicted based on false memories and it was this tragedy that inspired and informed their lab research (e.g., Loftus, 2002, McNally, 2012). The statistics of the Innocence Project show that in a considerable proportion of miscarriages of justice, mistaken eyewitness testimonies and false confessions play a prominent role (http://www.innocenceproject.org; e.g., Scheck, Neufeld, & Dwyer, 2001). At minimum, this suggests that the problem of false memories in courts should not be trivialized. In the U.K., a topical dissertation regarding cases brought to the Criminal Cases Review Commission (CCRC) revealed that in many of these cases, the applicant argued that a key witness (or witnesses) had been mistaken at trial (Heaton, 2013).
Many memory researchers have been inspired by legal cases featuring erroneous memory – ranging from minor (albeit non-trivial) memory distortions to full-blown false memories – to examine potential causes of false memories in eyewitnesses, victims, and defendants. These memory researchers never aspired to provide the courts with precise risk taxations but rather aimed to inform the legal arena of why and when memory errors tend to occur. To be sure, one of the problems in generalizing from the lab to the court has to do with limited research relying on clinical samples. Indeed, research on how false memories may be elicited in the laboratory by and large employed non-clinical samples of clever undergraduate students whose memory, verbal skills, and motivation may not at all be representative of individuals who end up in a court case as witnesses, victims or defendants. Consider the prototypical person taking legal actions based on recovering memories of childhood sexual abuse. Such a person is routinely in search of an explanation for current complaints such as a depression, anxiety, or an eating disorder, and it is this very need for an explanation that may render this person vulnerable to accepting seemingly plausible reasons such as childhood sexual abuse (i.e., “motivated cognition”; see Loftus & Davis, 2006; Merckelbach, 2003). It was not until studies regarding genuine and false memories in undergraduate samples had provided clues about potential causes underlying recovered memories that research started focusing on people actually reporting memories of childhood sexual abuse (McNally, 2012).
B&A’s practical message seems to be that expert witnesses should be wary when informing the legal arena about the scale on which full false memories might be induced. We would argue that this message is naïve: even if one accepts 15% as an accurate higher bound estimate of the false memory base rate induced by mildly suggestive techniques in intelligent undergraduates, this percentage is alarmingly high. B&A stress that most paradigms elicit false beliefs rather than memories and that, hence, the base rate of full false memories is lower than previously assumed. However, even if techniques such as the false feedback paradigm are more likely to elicit false beliefs than false memories, this is still perilous for legal settings. Evidence is accumulating that behavioural consequences are driven by beliefs and less by recollections (Bernstein, Scoboria, & Arnold, 2015). This suggests that a false belief of child sexual abuse might be sufficient to start a legal proceeding.
One other issue that should be considered is that expert witnesses may not be very good in determining whether a childhood memory that forms the basis for an allegation is false or accurate. After all, in terms of accompanying emotions and bodily signs false memories might appear as genuine as true memories (e.g., McNally, Lasko, Clancy, Macklin, Pitman, & Orr, 2004). Thus, all that expert witnesses can do is point at the base rates of false memories in lab studies that used mild interventions and then compare these to the interventions that might have contributed to the memory of the event that is the focus of the court case. And while there is an extensive literature on false memories in the lab – as the review by B&A nicely demonstrates –, studies on the false memory potential of routine clinical interventions are conspicuously absent. What happens if – as is done in Eye Movement Desensitization and Reprocessing (EMDR) – patients are encouraged to retrieve memories by providing them with the metaphor of memory as a perfectly recorded movie? What happens if – as is done in schema-focused therapy – patients learn that their sense of who they are (their “self”) consists of early maladaptive schema’s containing buried childhood memories? What happens when patients’ aversive memories undergo positive reinstatements? We do not know, simply because there is almost no scientific literature addressing these issues. Brewin (2015, p.21) recently advanced the idea that “psychotherapy creates new memories.” If true, legitimate follow-up questions would be whether and on what scale interventions create new memories that are false. What we do know is that therapeutic interventions sometimes harm people (Crawford, Thana, Farquharson, Palmer, Hancock, Bassett, Clarke, & Parry, 2016; Lilienfeld, 2007) and that unlike pharmacological trials, psychotherapeutic trials seldomly record adverse side effects (Parry, Crawford, & Duggan, 2016). It is this absence of vital information that should be noted as an important limitation in court reports. Indeed, future studies in this field focusing on the false memory potential of routine clinical interventions in symptomatic individuals are urgently needed.
In sum, we argue that B&A’s review is selective in the studies and in the topics it addressed and in doing so, sketches a picture that could lead researchers to incorrectly assume that outside the psychological lab, false memories have a low probability. That would be unfortunate, if only because it would neglect the realities of the courtroom in which false memories may wreak havoc in the lives of innocent people.
Bernstein, D.M., Scoboria, A., & Arnold, R. (2015). The consequences of suggesting false childhood food events. Acta Psychologica, 156, 1-7.
Brewin, C.R. (2015). Reconsolidation versus retrieval competition: Rival hypotheses to explain memory change in psychotherapy. Behavioral and Brain Sciences, 38, e4.
Brewin, C., & Andrews, B. (in press). Creating memories for false autobiographical memories in childhood: A systematic review. Applied Cognitive Psychology.
Crawford, M.J., Thana, L., Farquharson, L., Palmer, L., Hancock, E., Bassett, P., Clarke, J., & Parry, G.D. (2016). Patient experience of negative effects of psychological treatment: Results of a national survey. British Journal of Psychiatry, 208, 260-265.
Heaton, S.J. (2013). A critical evaluation of the utility of using innocence as a criterion in the post conviction process. Doctoral thesis, University of East Anglia.
Lilienfeld, S.O. (2007). Psychological treatments that cause harm. Perspectives on Psychological Science, 2, 53-70.
Loftus, E. F. (2002). Memory faults and fixes. Issues in Science and Technology, 18, 41.
Loftus, E.F. & Davis, D. (2006). Recovered memories. Annual Review of Clinical Psychology, 2, 469-498.
Merckelbach, H. (2003). Taking recovered memories to court. In P. J. van Koppen (Ed.), Adversarial versus inquisitorial justice: Psychological perspectives on criminal justice systems. Perspectives in law & psychology, Vol. 17 (pp. 119-130). New York: Kluwer Academic/Plenum Publishers.
McNally, R.J. (2012). Searching for repressed memory. In R. F. Belli (Ed.), True and false recovered memories: Toward a reconciliation of the debate (pp. 121-147). Vol. 58: Nebraska Symposium on Motivation. New York: Springer.
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.
Parry, G.D., Crawford, M.J., & Duggan, C. (2016). Iatrogenic harm from psychological therapies – Time to move on. British Journal of Psychiatry, 208, 210-212.
Scheck, B., Neufeld, P., & Dwyer, J. (2001). Actual innocence: When justice goes wrong and how to make it right. New York: Signet Books.
Note: The published commentaries will also include abstracts and might slightly differ from the current versions.