The Misinformation Effect
In a review of the literature on the misinformation effect, Elizabeth Loftus reports that four questions have occupied the
attention of researchers:
1.
When are people susceptible to misinformation? People are particularly prone to misinformation when
the passage of time allows the original memory to fade. This finding leads to the discrepancy detection
principle, which states that recollections are more likely to change if a person does not immediately
detect discrepancies between post event information and memory for the original event. Consistent
with this principle is the finding that people are more likely to be influenced if they are exposed to
misinformation that is subtle. For example, the question, “Was the mustache worn by the tall intruder
light or dark brown?” is less subtle in suggesting the existence of a mustache than is the question, “Did
the intruder who was tall and had a mustache say anything to the professor?” People are more likely to
falsely claim they saw a mustache when exposed to the latter.
Also consistent with the discrepancy detection principle is the finding that forewarning people that a
post event narrative may be misleading enables them to better resist its influence. They are more likely
to scrutinize the information and thus detect a discrepancy.
2. Who is susceptible to misinformation? Young children are particularly susceptible to the
misinformation effect. The largest study examining individual differences involved the nearly 2000 people
who attended a science museum in San Francisco. All participants watched a short film clip and later
answered a series of questions about it. Some were exposed to misleading questions. Memory
performance rose as a function of age up to the twenties, leveled off, and then fell sharply for people
over 65. Moreover, the youngest and oldest groups (participants varied from 5 to 75 years of age)
showed large misinformation effects.
3. What happens to the original memory? Some have
argued that the original memory traces are changed by post event
information. For example, new information may update the
previously formed memory. Others have argued that misinformation does not affect memory at all but
merely influences the reports of research participants who did not encode the original event in the first
place. Or, if they have encoded the event, they select the misleading information because they conclude
it must be correct. Several lines of research indicate that misinformation does impair the ability to
remember original details. One line of evidence involves studies using tests that do not permit the
misinformation option. For example, participants see a stop sign that is later referred to as a yield sign.
They are now given a test that does not permit the selection of the yield sign (e.g., the choice is between
a stop sign and a no-parking sign). If the misinformation has impaired memory for the stop sign, then the
misinformed participants would be less likely to remember the stop sign than the controls. If there has
been no memory impairment, then misled participants would be expected to be as accurate as control
participants. Several published studies show that the misled participants do perform more poorly!
4. Do people genuinely believe the misinformation? One reason to think that research participants believe
in their misinformation memories is that they often express these memories with great confidence. However, it
seems possible that participants report misinformation memories merely to prove that they are “good” research
participants. To test for this possibility, participants in one study were told that the information contained in a post
event narrative was wrong and should not be reported on the test. It seems reasonable that if participants still
showed evidence of the misinformation effect, then they truly believed they saw the details suggested in the post
event narrative at the time of the original event. This is in fact what the research has found.
Loftus concludes that misleading information can turn a lie into memory’s truth. It can cause people to
believe that they saw things that never really existed or that they saw things differently from the way things actually were. Writing with a colleague she
states, “Give us a dozen healthy memories . . . and our own specified world to handle them in. And we’ll guarantee to take any one at random and train it
to become any type of memory that we might select . . . regardless of its origin or the brain that holds it.”
Henry Roediger and his colleagues demonstrated the subtle way in which social influence may shape recall, a process they called the social
contagion of memory. Their findings reinforce Loftus’s important conclusion that “misleading information can turn a lie into memory’s truth.”
In the Roediger study, a research participant (an undergraduate) and a confederate spent either 15 or 60 seconds viewing each of six common
household scenes (e.g., a kitchen) containing many objects. In a subsequent collaborative recall test, the two each recalled six items from each scene. On
occasion, the confederate reported items not in the original scene. Some of the erroneous items were highly consistent with the scene schema (e.g., a
toaster) while other were less so (e.g., oven mitts). After a short delay, the naive subject tried to recall as many items as possible from the six scenes. The
misinformation effect was evident as the student reported more erroneous items than students in a control condition who did not hear a confederate
reporting erroneous items. Social contagion was greater when the scenes were presented for less time (i.e., for 15 rather than 60 seconds) and when the
intruded items were more schema consistent (i.e., toaster rather than oven mitts).
Loftus, E. (1992). When a lie becomes memory’s truth: Memory distortion after exposure to misinformation. Current Directions in Psychological Science, 1, 121–123.
Roediger, H. L., Meade, M. L., & Bergman, E. T. (2001). Social contagion of memory. Psychonomic Bulletin & Review, 8, 365–371.
The Misinformation Effect and False Confessions
Constructive memory can lead to false confessions as well as false accusations. Saul Kassin provides an excellent review of
research on the psychology of false confessions. He observes that despite the conventional wisdom that people do not
confess to crimes they never committed, 20 to 25 percent of all DNA exonerations involve innocent prisoners who
confessed. Why might people confess to a heinous crime they did not commit? Kassin distinguishes among three types of
false confessions: voluntary, compliant, and internalized.
In voluntary confessions, people may have a pathological need for attention, feelings of guilt, the perception of
tangible gain, or the desire to protect someone. Such confessions often occur in high-profile cases. For example, in 2006,
John Mark Kerr falsely confessed to the murder of JonBenet Ramsey.
In compliant confessions, people are sometimes induced to confess through the police interrogation process. The
suspect acquiesces in order to escape from a stressful situation, avoid punishment, or gain a promised reward. In 1989,
after lengthy interrogations, five New York City teenagers confessed in the famous Central Park jogger case. Each suspect
claimed that he expected to go home afterward. All the boys were convicted only to be exonerated in 2002, when the real
rapist was confirmed by DNA evidence.
Internalized false confessions are those in which innocent but vulnerable suspects are exposed to highly suggestive
questioning. They confess because they come to believe that they committed the crime in question, a vivid example of the
misinformation effect. Michael Crowe, a 14-year-old, actually came to believe he had stabbed his sister to death. In the
course of lengthy interrogations, Michael was misled into think-ing that there was substantial physical evidence of his guilt.
He finally concluded that he was indeed the killer. He said, “I’m not sure how I did it. All I know is I did it.” Eventually, he
became convinced that he had multiple personality—that “bad Michael” acted out of jealous rage while “good Michael”
blocked the incident from consciousness. The claims against Crowe were dropped when a drifter from the neighborhood
was found with the victim’s blood on his clothing.
Kassin notes that certain interrogation techniques can exert too much influence. One tactic is the presentation of false
evidence. Police in the United States are allowed to lie, for example, telling suspects that there is incontrovertible evidence
of their guilt (e.g., a hair sample, a failed polygraph test, or eyewitness identification), even though no such evidence exists.
Such deception, notes Kassin, can trick people into believing that they indeed committed the crime.
Kassin’s laboratory studies illustrate his views. In one study, students typed on a keyboard in what they thought was a
reaction time experiment. In the course of the study, the participants were accused of causing the computer to crash by
pressing a key they had been forewarned to avoid. They were asked to sign a confession. All the students were truly
innocent and all initially denied the charge. Nonetheless a significant minority eventually signed the confession. In some
sessions but not others, a confederate said she witnessed the participant hit the forbidden key. This false evidence doubled
the number of students who signed the confession from 48 percent to 94 percent. As assessed moments later, this
manipulation also increased the number of participants who actually believed they were guilty. Subsequent studies have
replicated this misinformation effect even when the negative consequences of confession are highlighted.
Kassin, S. M. (2008). False confessions: Causes, consequences, and implications for reform. Current Directions in Psychological Science, 17, 249–253.