Ethics and Behavior, 9(1) 39-50 Copyright ~ 1999. Lawrence Erlbaum Associates, Inc
Martha C. Dean, Sydney, Australia
The "lost in a shopping mall" study has been cited to support claims that psychotherapists can implant memories of false autobiographical information of childhood trauma in their patients. The mall study originated in 1991 as 5 pilot experiments involving 3 children and 2 adult participants. The University of Washington Human Subjects Committee granted approval for the mall study on August 10.1992. The preliminary results with the 5 pilot subjects were announced 4 days later. An analysis of the mall study shows that beyond the external misrepresentations, internal scientific methodological errors cast doubt on the validity of the claims that have been attributed to the mall study within scholarly and legal arenas. The minimal involvement--or, in some cases, negative impact --of collegial consultation, academic supervision, and peer review throughout the evolution of the mall study are reviewed.
Key words: research ethics, false memories, mall study, autobiographical memory
The "lost in a shopping mall" study (Loftus & Pickrell, 1995) originated as five single-participant "pilot" experiments conducted at the direction of University of Washington researcher Elizabeth Loftus. Loftus (Loftus & Ketcham, 1994) described the study in terms that suggest that proper research guidelines were not followed in these pilot experiments. The results of the mall study continue to be misrepresented in the media, in sworn testimony, and in scholarly publications. The roles of mechanisms currently in place to ensure the integrity of such research are reviewed here.
Loftus (Loftus & Ketcham, 1994) provided a revealing account of the evolution of the mall study. In August 1991, Loftus attended a talk (Ganaway, 1991) that' blamed recovered memories of sexual abuse on media exposure and psychotherapists' expectations (Loftus & Ketcham, 1994, p.89). After this talk, Loftus wondered if she "could provide a theoretical framework... showing that it is possible to create an entire memory for a traumatic event that never happened" (Loftus & Ketcham, 1994, p. 90). As Loftus explained: "I wanted to 'scar' the brain with something that never happened, creating a vivid but wholly imagined impression. I just couldn't quite figure out how to do it" (Loftus & Ketcham, 1994, p.92).
Loftus described her dilemma to a group of University of Washington graduate students and psychology majors:
The trick was to design a study powerful enough to prove that it is possible to implant a false memory while also winning the approval of the university's Human Subjects Committee, which reviews proposed research projects to ensure that they wilt not be harmful to participants. (Loftus & Ketcham, 1994, p. 91)
In October of the same year, Loftus discussed the memory-implantation hypothesis with a colleague from the University of Georgia during a drive to the Atlanta airport. During this discussion, Loftus decided to base her study on getting lost in a shopping mall. Still, Loftus wondered if "we could get the idea through the Human Subjects Committee. Maybe" (Loftus & Ketcham, 1994, p. 94).
Pilot Subject 1
Shortly after the University of Georgia trip, Loftus attended a party where she participated in the creation of the first false mall memory (Pilot Subject 1). Although not a pilot study in the strictest sense, the results of this interaction were included in what has been referred to as a "pilot study" (Goleman, 1992) and as "pilot subjects" (Loftus, 1992). At this party, Loftus asked a friend: "Do you think it might be possible to convince [his daughter] that she was lost in a shopping mall when she was five years old?" (Loftus & Ketcham, 1994, p.95). Loftus' friend initiated this experiment by introducing his 8-year-old daughter, Jenny, to Loftus. After hearing a third set of corroborating details from her father, Jenny replied that she remembered "looking all over for you, and I couldn't find you" (Loftus & Ketcham, 1994, p.95). Loftus asked: "Were you scared, Jenny?" (Loftus & Ketcham, 1994, p.95). Jenny shook her head. Loftus' friend told his daughter that he had been scared, and his daughter replied: "Not as scared as I was" (Loftus & Ketcham, 1994, p.95). Loftus concluded:
I couldn't believe what I had just witnessed. In five minutes, with a few suggestions and minor prods from her father [and Loftus], Jenny had accepted a false memory and embellished it with details of her own. She remembered being lost, she remembered looking all over for her father, and she remembered being scared. In less time than it took to cook a hard-boiled egg, we [italics added] had created a false memory. (Loftus & Ketcham, 1994, pp.95-96)
Pilot Subjects 2 to 5
The second and third pilot subjects were the result of an extra credit assignment that Loftus offered to her undergraduate cognitive psychology class in late 1991:
I've been thinking a lot lately about whether it is possible to inject into someone's mind a whole memory for a fictitious event. For example, would it be possible to make someone believe that they were lost in a shopping mall as a child when, in fact, they had never been lost in a shopping mail? (Loftus & Ketcham, 1994, p.96)
Three weeks later, 2 of Loftus' approximately 120 undergraduate cognitive psychology students turned in assignments (Pilot Subjects 2 and 3) with results indicating that they had successfully convinced their 8- and 14-year-old family members of a false "lost" memory. Two further single-participant experiments (Pilot Subjects 4 and 5) were conducted by unspecified persons to determine if adults could be convinced of a similar false memory (see Table 1).
Human Subjects Committee (HSC) Approval
Jim Coan, the brother of Chris (Pilot Subject 3), was assigned as chief co-investigator for the mall study. In this role, Coan prepared the HSC application. Loftus described the HSC's reaction to the mall study proposal:
The Human Subjects Committee tore our proposed study apart. "What if your subjects are under emotional stress and became upset at the deception inherent in the experimental situation?"... "How do you plan to screen out vulnerable subjects? What will you do if someone becomes seriously distressed when informed of the deception? What if a subject finds the false memory disturbingly similar to an event that actually happened? Will your subjects experience a sense of betrayal at being manipulated?" (Loftus & Ketcham, 1994, p.100)
Summary of the Five Pilot Subjects
Experimenter/Experimentier's Relationship to Loftus
False Lost Memory/Age
Sporting goods store/5-6
These issues were resolved and permission to implement the mall study was granted by the HSC on August 10, 1992 (HSC Application No. 22-175-C, 1992) *1
Four days later, Loftus made a startling announcement at the American Psycho-logical Association's (APA) annual convention:
Well, we' re just beginning a program of research where we essentially try to simulate what goes on in this Piaget anecdote. Could you inject an entire memory into the mind of someone for something that never existed? A childhood memory, even something that was mildly traumatic? I'm sorry I don't have more data to tell you about here today, but it took several months for the Human Subjects Committee to officially approve this idea.... I'll talk about just a couple of pilot subjects now. Our preliminary study involves injecting memories of getting lost in a shopping mall. (Loftus, 1992)
Loftus (1992) proceeded to describe the experience of Chris, the 14-year-old pilot subject in whom a false lost memory was "implanted" in 1991 without HSC approval.
It appears that Loftus was presenting these data as if they were developed during a properly controlled pilot research study rather than during a classroom exercise. In addition, Loftus implied during this presentation to the APA that she had refrained from experimenting with human participants until after the HSC approved the proposal.
*1. Mall study chief co-investigator Jim Coan (1997) stated: "The same month we received Human Subjects [sic] approval, July 1992, the 'Chris Study' appeared in the New York Times, in an article by Daniel Goleman titled 'Childhood Trauma: Memory or Invention?"' (p.276). That statement is inaccurate; HSC approval was granted on August 10,1992 (HSC Application No. 22-175-C, 1992).
Participants were recruited by University of Washington students who provided both a participant and a relative of the participant (Loftus & Pickerell, 1995, p.721). Twenty-four participants (3 men, 21 women) ranging in age from 18 to 53 completed the study (Loftus & Pickerell, 1995, p.721). Each participant was provided with a booklet containing brief accounts of three true childhood incidents which were provided by the relative. Relatives also provided "information about a plausible [italics added] shopping trip to a mall or large department store" (Loftus & Pickrell, 1995, p. 721) so that a fourth false incident that supposedly occurred when the participant and close family member were together could be included in the booklet in the third position (Loftus & Pickrell, 1995, p.721). Participants were told that they
were participating in a study on childhood memories, and that [the researchers] were interested in how and why people remembered some things and not others. They were asked to complete the booklets by reading what their relative had told [the researchers] about each event, and then writing what they remembered about each event. If they did not remember the event, they were told to write "I do not remember this." (Loftus & Pickrell, 1995. p.722)
When the study booklets were completed by the participants, "7 (29.2%) of the 24 subjects 'remembered' the false event, either fully or partially" (Loftus & Pickrell, 1995, p.722). During the first interviews conducted I to 2 weeks after completion of the booklets, the participants were told that the researchers were "interested in examining how much detail they could remember, and how their memories compared with those of their relative" (Loftus & Pickrell, 1995, p.722). At the beginning of the first interview, participants were again asked to recall as much as they could about each of the four events; then they were asked to rate their clarity and confidence for each memory (Loftus & Pickrell, 1995, p.722). At some unspecified point during the first interview, 1 of the 7 participants who had previously "remembered" the false event revealed that she had changed her mind, leaving 6 (25.0%) participants who still believed at the conclusion of the first interview that the false memory was true (Loftus & Pickrell, 1995, p.722). According to Loftus: "This same percentage held for the second interview" (Loftus & Pickrell, 1995. p.722).
The second interviews were conducted 1 to 2 weeks later. Participants were again asked for further detail and to rate their clarity and confidence levels. At the end of the second interviews the participants were told that the study had attempted "to create a memory for something that had not happened" (Loftus & Pickrell, 1995, p.722). The participants were asked to select the false memory: "Of the 24 total, 19 subjects correctly chose the getting-lost memory as the false one, while the remaining five [20.8%] incorrectly thought that one of the true events was the false one" (Loftus & Pickrell, 1995, p.723).
The authors stated that they "make no claims about the percentage of people who might be able to be misled in this way" (Loftus & Pickrell, 1995, p.723) and that they are "providing an'existence proof' for the phenomenon of false memory formation" (Loftus & Pickrell, 1995, p.724).
Although the mall study has been cited to support claims that psychotherapists can implant memories of false autobiographical information of childhood trauma in their patients, the therapeutic implications of the study appear to be limited to a narrowly defined and perhaps even unlikely situation. The mall study results suggest that if a psychotherapist were to devise a plausible false memory of childhood trauma and tell a client, "I was given this information by your relative who was present at the time," then the client may accept this false account as fully or partially true. Notably, a similar study (Pezdek, 1995) found that although 3 (15%) of 20 participants recalled a plausible false memory of getting lost in a shopping mall, none of the participants accepted an implausible false memory that they had received a painful enema as a child from their parent.
Precedent and practice at the University of Washington have established that certain types of research with human participants do not require review by the HSC. The University of Washington defines those categories that do not require review:
(a) accepted and established service relationships between professionals and clients where the activity is designed solely to meet the needs of the client; (b) research using only publicly accessible materials; (c) research using only historical documents; (d) research using only archaeological materials or other historical or prehistorical artifacts; (e) research based on data tapes or other records which lack all personal identificr5; (f) research based on surveys or interviews with elected or appointed public officials or candidates for public office; and (g) research based on pathological or diagnostic specimens which lack all personal identifiers. (Secretary of the University of Washington Faculty, 1970, vol. Iv, chap. I, section 2)
Under these provisions, an attempt to implant a false memory in a human participant as described in Loftus' published and publicly presented work would require HSC approval. Loftus subsequently explained why she did not obtain HSC approval prior to assigning students to implant a false memory. "Well I didn't think I needed [HSC approval]. Because as far as I knew class observations wasn't [sic] research; it was a class demonstration" (Vickie Turner and Michael Turner v. Linda Honker, MEd; Art C. Aarauzo, MD; Charter Behaviorial Health System of Dallas, Inc.; Maryanne Watson, PhD, and Lee Smith, PhD, 1996). However, this sworn testimony that these activities were a class demonstration rather than research appears to contradict Loftus' (1992) statement that these activities constituted a "preliminary study."
Were Students Informed of Ethical Guidelines Specific to Their Assignment?
There is no evidence to indicate that Loftus' students were informed that deceiving study participants might be problematic. As Coan (1997) reported: "I hadn't realized that deceiving participants as a part of psychological research was anything other than business as usual ... I hadn't considered most of their concerns at all, let alone how to address them" (p. 275).
There is no evidence to indicate that Loftus' students were informed of ethical guidelines regarding the use of children as research participants. For example, the University of Washington's HSC requires that prior assent must be obtained from all child participants, and a Committee-approved form is provided for this purpose (University of Washington HSC staff, personal communication, June 2, 1997). Because the experiments on Brittany and Chris were conducted by Loftus' students without a Committee-approved form, they appear to have been conducted in violation of University of Washington HSC requirements.
According to Loftus' account, the pilot subjects reacted "with good-natured amazement to the news that experimenters had successfully tampered with their memories" (Loftus & Ketcham, 1994, p.100). Although trusted family members do tell socially sanctioned "white lies" to children regarding Santa Claus, the Tooth Fairy, and the Easter Bunny, an experiment that involves "tampering" with a child's memory by a trusted family member may open the possibility for potential risk to the child.
Should Student-Generated Data Be Disseminated as Research?
It is yet to be determined if unapproved student-generated data can be disseminated outside the classroom as preliminary research with the inference that HSC approval has been granted.
The results of the mall study have been pervasively misrepresented in the media, in scholarly journals, and in courtroom testimony to suggest that therapists can implant false memories of sexual abuse in their clients. Although researchers are not responsible for media inaccuracies regarding their research, they are ethically required to attempt to correct inaccuracies to the extent that this is possible. We are not aware of any efforts by Loftus to correct these inaccuracies, and we welcome any published evidence to the contrary.
The first media report of the mall study (Goleman, 1992) appeared in the New York Times on July 21, 1992, 3 weeks prior to HSC approval. In this initial report, readers were erroneously led to believe that Coan participated in all of the experiments and that the five participants experienced the same protocol:
With Jim Coan, a graduate [sic] student, Dr. Loftus had a close relative of her experimental subjects describe three events from the subject's childhood, and offer specifics for the setting of a fictitious fourth event, the time the person supposedly got lost. "We told the subjects we were studying childhood memories, and asked them to write everything they could remember about each of these incidents," said Dr. Loftus. In the pilot study, the subjects, two [sic] children and three [sic] adults, proceeded to supply details of the fictitious incident, apparently not realizing it was not true. (p. Cl)
Four days after HSC approval was granted, the Associated Press (1992) inaccurately reported that the five case studies were the "first five subjects" in a study, implying that a study had been properly initiated:
To prove that memories can be planted, Loftus and colleague Jim Coan have launched a study in which they try to convince subjects they were lost in a shopping mall at age 5. They often start by having a parent or other trusted authority figure suggest to the study subject that such an event occurred. "Not only have the first five subjects developed a memory of the false incident," Loftus said, "but they also often elaborate the story with their own details." (p. A5)
As previously noted, 20.8% of the participants remained fully or partially convinced of the false memory by the end of the second interview. The following statements indicate that by 1995 the results of the mall study were inflated to 25% (or more) in interviews with Loftus, in sworn testimony, and in scholarly publications.
Loftus: In one experiment, it was shown that the memory of being lost in a mall at the age of five and being rescued by an elderly person can be implanted by pressured suggestion. More than 25% [italics added] of the subjects "remembered" this happening. (Klein, 1995, p.193)
I [Loftus] would say in roughly a quarter that we succeeded in getting them to remember all or part of the experience of getting lost that we suggested to them. (Turner V. Honker, 1996, p.160)
Of the 24 subjects in whom we suggest three true events and one false one, 75% said they couldn't remember the false events. The remaining subjects developed a complete false memory or a partial one. (Loftus, Feldman, & Dashiell, 1995)
Seven of 24 subjects "remembered" the false event-cither fully or partially-in the initial booklet, but in the follow-up interviews only 6 subjects (25%) remembered the event. (Loftus, Coat', & Pickrell, 1996)
More recent accounts suggest that it was easy to implant a false memory. These reports overlook the 19 participants who did not accept the false memory, as well as the fact that not all 5 participants fully accepted the false memory: "In one famous study, 'Lost in a Shopping Mall,' [Loftus] proved that false memories of childhood could be implanted in 25 percent of research subjects merely by suggestion" (Morrison, 1996, p.52).
Haney (1997) quoted Loftus' February 2, 1997, presentation to the American Association for the Advancement of Science: "With just a little gentle coaxing," Loftus said, "about one-quarter of study subjects agree this happened to them."
These statements illustrate the tendency of secondary sources (journalists, scholars, and indeed Loftus herself) to overestimate both the ease with which participants in the original mall study were made to be!ieve a false autobiographical event and the extent to which the experimental manipulation was successful.
The Role of Scientific Standards in Ensuring Scholarly Integrity
The scientific community has established such mechanisms as peer consultation,2 faculty supervision, and peer review to ensure that human participants are not harmed. In the next section, we examine how faculty supervision and peer review functioned throughout the mall study.
2. As previously noted, Loftus' peer consultation was limited to a group of University of Washington graduate students and psychology majors, as well as one colleague at the University of Georgia.
The University of Washington provided this description of its research environment:
The University creates an environment in which research flourishes, and depends on individuals to exercise their integrity in carrying out their scientific and scholarly activities. Senior faculty, principal investigators, and others in positions of responsibility for the conduct of research are expected to exercise reasonable supervision of those under their direction to ensure the integrity of the research being conducted. (Secretary of the University of Washington Faculty, 1970, vol. IV, chap. 1 ,section 1)
Therefore, as a senior faculty member at the University of Washington, Loftus was responsible for supervising students to whom she had provided an assignment that would require them to experiment on human participants. However, Loftus apparently gave her students an assignment for which she appeared to be aware would require HSC approval (Loftus & Ketcham, 1994, pp.91, 94). Furthermore, there is no indication that Loftus informed her students of this requirement.
The "lost in a shopping mall" study was published in Psychiatric Annals (Loftus & Pickerell, 1995), a peer-reviewed journal. However, noting the following criticisms, this review might best be described as cursory.
First, a factual ambiguity appears on page 722 (Loftus & Pickrell, 1995): Six participants claimed to remember the false incident during the first interview, and "this same percentage held for the second interview." As previously noted, this same percentage (25%) did not hold for the second interview because only 5 participants claimed to remember the false incident by the end of the second interview (p.723).
Second, Loftus and Pickrell (1995) claimed that they are providing an "'existence proof' for the phenomenon of false memory formation" (p.724). This use of the term existence proof is misleading. Behavioral research provides "evidence," not the more absolute mathematical "proof" of any construct. An existence proof is the process by which a scientist attempts to prove the existence of an unobservable entity or phenomenon by describing this entity in a manner that allows for or explains what is observable. Although memories are not observable, the written responses (booklets) and oral behavior (interviews) were observable. These self-reports are open to multiple interpretations regarding their causes, including (but not limited to) the assumption that they are more or less correlated with the participants' perceptions of their memories as real. Therefore, we suggest that the authors would have more accurately represented their results if they had simply claimed to provide an example of behavior consistent with false memory formation, rather than existence proof for such a phenomenon.
Third, the Method section is incomplete. This section does not include the criteria used to differentiate between participants who fully accepted the false memory and those who partially accepted the false memory. The section does not indicate whether those participants who wrote "1 do not remember this" and then continued on to speculate as to "how and when it might have happened" (Loftus & Pickrell, 1995), were then classified as partially remembering the false event.3
3. There are other important deficiencies in the published description of the Method, such as whether or not a double blind technique was used to minimize interviewer or experimenter bias as an extraneous variable. However, those methodological deficiencies are beyond the scope of this article.
Finally, the study results are incomplete. There are no data on relative success rates-that is' how many participants were "fully" convinced and how many were only "partially" convinced of the false memory.
At several points in the conduct and reporting of this mall study research, some members of the scientific community have apparently overlooked opportunities to ensure that the research would be properly conducted and accurately reported. Remarkably, few within the scientific community have commented on the lapses in proper research practices that Loftus displayed in The Myth of Repressed Memory (Loftus & Ketcham, 1994). We suggest that fewer still have compared the primary research results of the original mall study to the many inaccuracies reported in subsequent or secondary sources.
Many within the scientific community may be continuing to overlook similar opportunities. Secondary reports about a subsequent study (Garry, Manning, Loftus, & Sherman, 1996) provide a case in point, demonstrating both selectivity and inaccuracy. This research was conducted to determine whether imagining a childhood event would increase participants' confidence that this event occurred. The results of this study show that of the eight imagined events, imagining cutting one's hand on a broken window showed the greatest increase in confidence (24% (imagined) vs. 12% (not imagined)). Overall, confidence levels increased 8.2% and "all but (italics added) the 'Lifeguard' item" (p. 216) showed an increase in confidence.
The following articles selectively reported only the results of the cut hand event. Neither article reported the overall results of the original research, and Loftus (1996) incorrectly stated that all items showed an increase in confidence:
In the case of the cut hand, about 25 percent of the volunteers who had been asked to imagine the accident now were more likely to believe that it actually happened to them. About 12 percent of those in a control group that had not been asked to imagine the accident also changed their minds and on the second time seeing the list said they had some recollection of breaking a window with their hand in childhood. (Russell, 1997)
After engaging in this act of imagination (cut hand, 24% of subjects increased their subjective confidence that something like this actually happened to them. For those who had not imagined the event, only 12% showed a corresponding increase. The other seven critical items (italics added) used in this study similarly showed increased subjective confidence after imagination. (Loftus, 1996)
We have attempted to present what might very well be the first rigorous examination of the "lost in a shopping mall" study and its citations in subsequent sources. We suggest that similar studies on such controversial topics as implanting false memories deserve rigorous scrutiny as well. It remains to be seen whether the scientific community can ensure that such research will be properly conducted and accurately quoted in the future.
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