The Eyewitness Is Lying – And Doesn’t Even Know It

The whole concept of justice is based on one weak assumption: that human memory functions as a camera does. If you aim it at a crime scene, it will record what took place and then be ready to “play back” in a courtroom months later. Two recent studies have quietly refuted that assumption – and the consequences are disturbing.

Memory Doesn’t Fail at Random – It Fails in a Person

The initial study, carried out at the University of Portsmouth, didn’t simply pose the question “dose alcohol harm memory?” since that’s obvious. Rather, the researcher put a more specific question to the test: which features of a face does a drunk brain forget?

The response is rather specific. Intoxicated witnesses were still able to remember external features – such as hair, face shape, and the overall outline of a person. However, they forgot the internal features like the eyes, nose, and mouth – the details which actually enable one face to be distinguished from another. This phenomenon is known as alcohol myopia: A psychological theory stating that alcohol narrows a person’s attention and mental capacity, causing them to focus only on immediate, obvious cues while ignoring long-term consequences.

The reason this is genuinely different from the common advice that “you shouldn’t trust drunk witnesses” is that it is the least helpful feature for identification that ends up surviving. Hair can be dyed, cut, or covered by a hood, and face shape is rather vague – but it is the eyes and mouth that actually allow one suspect to be distinguished from a hundred others who look similar in a lineup. Therefore, alcohol is not only impairing memory but is also selectively erasing the past of it most useful for forensic identification, while at the same time leaving witnesses confident that they remember “enough”.

The Room Full of Witnesses Problem

A different myth is challenged by research carried out at the University of Liverpool: the idea that a larger number of witnesses leads to more reliable evidence. In fact, witnesses influence one another and thus contaminate each other’s memories. If one person incorrectly remembers a particular detail and then states it out loud, the other people often pick up that mistake and include it in their own version of events – this is known as memory conformity: a psychological phenomenon where an individual alters their own memory report of an event to match the incorrect or differing report of another person.

“What is so disturbing is the question of who is most at risk. It is not the witnesses who are least confident who are most easily influenced – rather, it is the comparison of confidence levels between witnesses that matters.“