Research is revealing how people can develop memories of things that never really happened.

The most common cause of wrongful convictions in the judicial system is mistaken identification
— US Department of Justice

Jennifer Thompson’s nightmare began when she woke up. It was three in the morning when a man jumped on her, forced her arms down and held a knife to her throat. He warned her to be quiet or he would kill her. First she thought he was a prankster, then she thought he was a burglar. And then she realised he was a rapist.

In a documentary on the US public television network PBS (Frontline: What Jennifer Saw), Jennifer describes that she knew she would get away, and she knew she would make him pay. “My first plan was to try to get information, and to try to look at him so that if there was any type of mark or a tattoo or a scar that I would have a better idea of how to identify him. My second plan was to just try to get out.” With amazing presence of mind, Jennifer was determined to commit his face to memory.

I was trying to see as much of him as I could to see if there was any tattoos or any scars or unusual jewelry or a part in the hair, anything that I could use for information to identify him. And so once my eyes became adjusted to the darkness, I was able to use light sources such as coming through my, my blinds and my bedroom window. A night light that I had. At one point he bent down and turned on my stereo and a blue light came off of the stereo and it shined right up to his face. And I was able to look at that. When I went into the bathroom I shut the light on, and he immediately told me to shut it off, and again in the kitchen, I was able to turn that light on and there were lights coming off from the back of my apartment. So there were really several sources of light that I used and tried to manoeuvre him in different positions to where I could use that light. I also made sure I stood near him when I got up, knowing that I’m five foot one, so to assess how tall he was, how big he was. Noticing his clothes, just anything that I could to use.

Eventually, Jennifer escaped. Shortly afterwards, she was able to use all the information she collected about her rapist to identify Ronald Cotton in a lineup. She recognised his mannerisms, his build, and his voice. Ronald Cotton was convicted.

But Ronald Cotton was innocent. After more than ten years in prison, Cotton was later exonerated by DNA testing carried out by the Innocence Project at the Cordozo Law School in New York. The real perpetrator, Bobby Poole, was convicted on the basis of a new DNA test. And what does Jennifer Thompson say about who she “sees” when she remembers the incident?

Q: And when you think of the rapist – who do you see?

A: I still see Ronald Cotton. And I am not saying that to point a finger. I am just saying that is who I see. And I would love to erase that face out of my mind. I would do anything to erase that face out of my mind, but I can’t. It is just in my head. Sometimes it is more fuzzy than others because my mind now says “Well, it’s Bobby Poole,” but it is still the face I see.

Jennifer Thompson was so careful, so confident, and so wrong.1 But Jennifer is not alone: as many as 8,500 people a year may be wrongfully convicted in the US (Rattner, 1988). Surely this figure stems from inherent flaws in the US criminal justice system, you say? Probably not as much as you’d think: Rattner also found that in half the cases in which convicted people were later exonerated, inaccurate eyewitness identification was the major reason for the conviction.

Memories Untrustworthy

Thus, it should not be surprising when we learn that David Dougherty may have been wrongfully identified by a neighbour. Or that Guy Wallace, the Marlborough Sounds water taxi driver, swears he dropped Ben Smart and Olivia Hope off at a 12 metre blue and white ketch with portholes. That couldn’t have been Scott Watson’s boat — it was brown at the time — but a Carterton man later came forward and said that he owns a 15-metre two-masted scow with portholes, which was in the Sounds.

The fact is, our personal experiences aren’t accurately and permanently laid down on some mental videotape we call “memory”. Although that’s the prevailing belief about human memory, it’s a myth. We tend to remember the gist of experiences. We distill out the basic essence of an event, and what we extract doesn’t stay pure for long. With every retelling we toss in more contaminants: we make inferences, confuse imagination with reality, shade the truth, or even exaggerate for the sake of the punch line.

Since the mid-1970s, hundreds of experiments around the world, including here in New Zealand, have led psychological scientists to conclude that memory can be moulded into a shape that bears little resemblance to its source. And sometimes memories can be moulded out of nothing at all.

A hypothetical example will make my assertions clearer. Suppose that when you finish reading this article, you decide to go for a walk. When you get to a main intersection, you see a car speed past a stop sign, hit a parked car, and take off. Let us skip over the complicated process of how event information gets inside the head, and just assume that you’ve extracted information about this unsettling experience. You call the police, and wait for them to arrive so that you can tell them what you’ve witnessed.

As you wait, the decay process has already begun. Information about what you’ve seen fades away quite rapidly. As it fades, your memory becomes increasingly susceptible to suggestions. Perhaps another eyewitness says to you, “Wow, did you see that? I can’t believe that guy just took off like that! I have to admit, he was pretty scary looking, with that big beard and moustache. Perhaps then you realise that you didn’t actually notice whether the driver had any facial hair, but perhaps you don’t.

By the time the police show up, you do remember the beard and the moustache –at least you believe you do, and you tell the police about them. Your memory is changed now, the visual images altered by verbal suggestions. Mental pictures changed by words.

Leading Questions

In one of the earliest studies of the impact of misleading information on event recall, Loftus and Palmer (1974) showed films of car accidents to experimental subjects who later answered a series of questions about them. Embedded in the stem of a particular question was a word designed to lead the subject into a certain type of response.

For example, when they were asked “About how fast were the cars going when they smashed into each other?” subjects reported greater speeds than did subjects who were asked the same question when “hit” or “collided” took the place of “smashed”. Additionally, subjects asked the “smashed” question were more likely to claim they had seen broken glass in the accident scene, although none existed.

A similar study, also using a filmed automobile accident, presupposed the existence of certain plausible items in questions designed to mislead subjects (Loftus, 1975). For instance, some subjects were asked “How fast was the white sports car going when it passed the barn while travelling along the country road?” when there was no barn at all.

For the other subjects, a similar question served as a control: “How fast was the white sports car going while travelling along the country road?” Whether in the misleading or the control form, the subject’s estimation of speed was unimportant; the question was basically designed as a vehicle for misinformation. Later, all the participants were asked whether they had seen a barn in the film. Those who had received the misleading information in the earlier question were more likely to say they had seen a barn.

These examples are only some of the many experiments providing empirical support for the idea that we can be wrong about what we have witnessed, even when those events are unusual or stressful. But what about events we have participated in, and not merely observed? These kinds of memories are what cognitive psychologists call autobiographical memories. Can people come to have false autobiographical memories, even for stressful, unusual or unpleasant experiences? Again, scientific research suggests the answer is yes.

Take Loftus and Pickrell’s (1995) study as one example. They used close relatives as the source of both true and false suggestions, and asked subjects to recall events described by the relative. Three of the events were true, but one was false.

The gist of the false event was the same for all subjects: they got lost in a shopping mall when they were five years old, an elderly lady found them crying, and helped reunite them with their families. The sibling provided the experimenters with idiosyncratic detail, such as what mall, why the child might have wandered away, and what the parent’s reaction was once the child was returned safely. The subjects read the suggested events in booklets, wrote down what they remembered, and were interviewed twice over a couple of weeks. About a quarter of the subjects (29%) remembered at least some of the suggested false event.

Here is what one woman remembered about being lost at the Hillsdale Shopping mall. During the second interview, she said:

I vaguely, vague, I mean this is very vague, remember the lady helping me and Tim and my mom doing something else, but I don’t remember crying. I mean I can remember a hundred times crying…I just remember bits and pieces of it. I remember being with the lady. I remember going shopping. I don’t think I, I don’t remember the sunglasses part.

Even after she was debriefed, she still had the memory. “….I totally remember walking around in those dressing rooms and my mom not being in the section she said she’d be in. You know what I mean?”

The Power of Suggestion

More recently, my colleagues and I have developed a much less labour-intensive method for creating what is probably the germ of a full blown false memory (Garry, Manning, Loftus & Sherman, 1996). It takes only a few minutes, not a few weeks, and instead of relying on older siblings and parents, we simply rely on the power of imagination.

First, we ask subjects how confident they were that they experienced various childhood events such as “broke a window with your hand” or “got in trouble for cutting a playmate’s hair” before the age of 10. Second, in a seemingly unrelated experiment weeks later, we ask them to imagine some of those events, but not others. For instance, one event subjects might be asked to imagine is accidentally breaking a window.

Imagine that it’s after school and you are playing in the house. You hear a strange noise outside, so you run to the window to see what made the noise. As you are running, your feet catch on something and you trip and fall. As you’re falling you reach out to catch yourself and your hand goes through the window. As the window breaks you get cut and there’s some blood.

Sometimes we ask subjects to write down what they imagine, and sometimes they merely imagine. In the third stage, we obtain new confidence reports from our subjects. The typical result? Depending on experimental variations, we find anywhere from 45% to 70% of subjects become more confident that at least one imagined event actually happened to them before age 10. This confidence-boosting effect of imagination is called “imagination inflation,” and we suspect it is one way to plant a seed that can grow into a fully-developed false memory.

Here at my lab at Victoria University, my graduate students and I have found imagination inflation effects in some unusual instances. Recently, my graduate student Seema Assefi and I collaborated with Charles Manning and Elizabeth Loftus of the University of Washington, and found that even when we ask people to imagine the event happening to other people, they become more confident that the event happened to them, not to the other person. The other doesn’t have to be a person with whom subjects identify; chosen protagonists range from a child aged Bruce Willis (a small ray of hope for this country that no subject identified with him) all the way to the Muppet Miss Piggy.

In other research, Julia Hayes and I have discovered that the timing of the hypothetical event is important: adults experience imagination inflation for childhood events, but not for events from five years ago. Children show similar timing effects. Eight to 10-year-old children experience imagination inflation for events from when they were aged 3 to 5, but not for events from as recently as yesterday. The results of these timing experiments lead us to wonder if there is something about the relatively weak quality of long-ago memories that makes them more confusable with imagined long-ago experiences.

Consider now the application of imagination inflation research: the potential memory-distorting influence of imagination in some real life situations. You don’t have to be in one of these experiments to imagine what could happen if a well-meaning but uninformed therapist asks a client to use imagery in an attempt to recover long-buried memories of childhood sexual abuse.

This paper is a quick survey of a vast experimental literature. I have tried to provide some empirical evidence that we can come to have false memories of little details, big buildings, and whole events, whether we simply witness those events or actually take part in them, and whether those events are from long ago or more recently.

But the study of human memory — especially false memories — is a complicated, contentious issue. Psychological scientists like me often find ourselves defending the politics of our research. We are accused of being clueless academics whose work in laboratories (read out loud in scathing tone: not real life) helps rapists and child molesters go free.

In a March 2, 1991 hypnosis workshop at Parkwood Hospital, Atlanta, the infamous psychologist Cory Hammond charged that scientists who are skeptical of those with memories of, for instance, satanic cult abuse, are untrained, naive, or intellectualising — or cult members themselves.

A few years later, apparently unsatisfied with his failure to halt the progress of science, Hammond discarded his McCarthy era allusions and tried out this hunting one:

In closing, I want to say that I’m an academic, and a clinician. I’m a full professor. But you know, it’s been open season on clinicians with the false memory movement. I think it’s time somebody called for an open season on academicians and researchers. In the United States and Canada in particular, things have become so extreme with academics supporting extreme false memory positions, so I think it’s time for clinicians to begin bringing ethics charges for scientific malpractice against researchers, and journal editors — most of whom, I would point out, don’t have malpractice coverage — when they grossly over-generalise, overstate, and selectively review research.

Hammond closes with this:

You know, this week I’ve actually heard an academic make what I consider a very extreme statement: that all clinicians using hypnosis should videotape and save all their hypnosis sessions to document and control for bias. Well then, I think we ought to ask all researchers to videotape every experimental session, every pre- and post-hypnotic experimental session with every one of their subjects and save them for seven years to document the kind of uncontrolled bias that is occurring in the laboratory. Thank you. (June, 1997)

I bet Ronald Cotton wishes he had been in one of Corey Hammond’s hypnosis sessions, or one of my experiments, or even at an ATM the night Jennifer Thompson was raped. Any place that had a video camera.


This paper is based on a talk at the new The New Zealand Skeptic Society conference in Wellington, August, 1998. Additional material is based on a chapter from the upcoming book Mind Myths, by Wiley Books, expected out in February. For more information on this paper, or related research, contact:

Full references are available from the editor.

1 For more information on this fascinating case, visit the PBS Frontline web site at
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