top of page

The Effect of False Memories on the Legal System

Eyewitness testimony is one of the most convincing types of evidence in criminal cases, but it can be hard to accurately assess their importance. Nonetheless, in the absence of physical evidence, memory reports are often used as key evidence to establish guilt or innocence. However, recent psychological research shows that what we remember is not wholly accurate. We may have an inaccurate or entirely fabricated recollection of an event, known as a false memory. These are a major concern for the legal world as they can lead to some being falsely convicted or exonerated.

In truth, our minds are susceptible to misremembering and forgetting details, and even creating new memories (known as memory illusions). These memory illusions can arise spontaneously or be influenced by other people.

A 1974 experiment run by American psychologists Elizabeth Lofter and John Palmer found that specific language in questions about an event significantly affect the answer. Participants were shown videos of a car collision happening at 20mph, 30mph, and 40mph, and then asked questions about what speed the car was going. The questions asked were identical except for the verb used. Some verbs, such as ‘collided’, suggested a minor collision. Others, such as ‘smashed’, implied a serious crash. Lofter and Palmer found that the language used had more impact on the participant’s answer than the actual speed of the cars.

This and further experiments shows that our memory cannot be relied on for fine details of events and can be manipulated by interview tactics and question wording. Leading questions, which prompt or encourage the desired answers, are often used by police and in courtrooms. Moreover, Loftus and Palmer propose that what we learn about an event after it happened becomes integrated with the actual memory of the event, which means that one cannot distinguish between sources of information. Consequently, when assessing the importance of eyewitness testimony, it becomes very difficult to discern between reality and what is implied.

From a legal standpoint, this finding is important because manipulation of an accused’s memory could lead to a false confession, one of the leading causes of wrong convictions.

There are many reasons why a false confession may occur, but they are largely police-induced. Intensive police questioning has been shown in a review of 125 wrongful conviction cases to result in 84% of the false confessions which occurred. This happens because interrogation tactics may lead an accused person to believe their guilt, despite having no recollection of the crime.

Additionally, in at least 75% of DNA exoneration cases, the initial conviction is caused by faulty eyewitness testimony. A notable case is that of Stefan Kiszko, a 24-year-old man who spent sixteen years in prison because he was wrongly convicted of the rape and murder of an 11-year-old girl. The true perpetrator was found through DNA testing more than thirty years after the crime took place.

Faulty eyewitness testimonies are not uncommon, and do not mean that a witness is lying. Memory is a reconstructive process. When we retrieve memories, what we remember becomes integrated with previously encoded memories and information, and therefore may lead to unintended errors. These errors can have serious consequences in a courtroom.

Kiszko’s case demonstrates that eyewitness testimony should not be relied on for conviction, and that physical evidence is needed to support such claims.

Despite all this research, the unreliability of memories is not well known, and many believe memory to be highly accurate. A 2011 survey of the U.S population found that 63% of participants in a study agreed that “human memory works like a video camera, accurately recording the events we see and hear so that we can review and inspect them later.” However, all 16 memory experts disagreed. There is a significant discrepancy between public general knowledge of how memory works, and the scientific reality.

Thus, one can infer that these misunderstandings extend to jurors, who are likely to wrongly assess eyewitness testimonies, or other evidence which involves memories.

Since experiences cannot be remembered with complete accuracy, they should not be used as hard evidence. Instead, physical evidence is needed to support eyewitness testimonies. Also, measures must be taken to avoid altering memories, and evidence based on memory reports should be flagged accordingly.


bottom of page