How reliable is our memory under conditions of stress?

In an earlier entry about false confessions, I briefly touched upon the topic of how memory works. The way it works barely resembles the way artificial memory systems work. Rather than accurately retrieving information, we reconstruct our memories every time we recall them.

The topic of memory, just like many other Psychology topics, is subjected to a lot of misconceptions and myths. The way we collect, store and recall memories is extremely complex with different factors like emotional activation or information type playing an important role.

How do emotions affect our memories?

It is a widespread idea that emotions have a strong effect on memory. As early as the inception of psychoanalysis, its proponents theorized that memories of traumatic experiences or emotionally disturbing events tended to be repressed. Despite the fact that repressed memories are still a popular concept, the actual incidence of repressed memories is very small. So much so, that many psychologists believe they should not be considered a real phenomenon.

Oddly enough, the belief that emotionally charged events are more memorable is also a common idea. So, what truth is there to these popular assumptions?


There is considerable scientific evidence that proves that information with emotional content is remembered more vividly than neutral information. [1] This happens not only with autobiographical memories – important events in our lives- but also with information provided in a lab in the course of an experiment.

Emotional information is remembered more accurately because of two special features that make its initial encoding more effective; valence and arousal. Emotional information, as opposed to neutral one, is evaluated by us as either positive or negative (valence). Emotional information also provides some type of physiological and psychological activation; having a soothing or agitating effect on us (arousal). Information is more effectively encoded when processed in this context of activation and interpretation as it helps us to combine new information with already existing memories.

Unreliable accounts

If emotionally charged memories seem to be remembered better than neutral ones, why are people so unreliable when retelling an emotional story?

Even though emotional events are generally remembered better than neutral ones, very intense emotional activation can make people forget details. Intense activation leads to attention narrowing which makes us focus on the central aspects of an event, ignoring the secondary details.

The Yerkes–Dodson curve; a classic, empirical law that dictates that performance increases with physiological or mental arousal, but only up to a point, can explain the difference in accuracy of memories on subjects under stress. When a certain point of activation is reached, performance decreases.

Yerkes-Dodson curve

The case of eyewitness testimony

The study of memory accuracy is of extreme importance to the field of Forensic Psychology. Eyewitness testimony plays a vital role in countless criminal investigations and court proceedings but the question that I get often times is; how reliable is eyewitness testimony?

Regarding eyewitnesses to a crime or accident, we should understand that they can vividly remember a given event and its most important features but; depending on their physiological activation, they won’t be able to give specific details about secondary aspects. Collateral information like the physical appearance of an aggressor or the color and size of certain objects won’t be stored accurately.

It seems to be the case that right after experiencing a traumatic event, only essential information is remembered. In the hours or days following the event, some secondary details and collateral information can be recovered and remembered.

The problem comes when an overzealous investigator questions a witness, providing details with their questions, which the subject can then incorporate into their own recollection, leading to inaccurate testimonies.

So in short, the accuracy of memories in the context of stressful events depends on:

  • The level of activation of the subject.
  • The amount of time that has elapsed since the event.
  • How the person is being questioned.

What could be done about this?

Interrogation techniques need to be refined. Not only police investigators need to formulate neutral and simple questions that don’t provide any information or opinion regarding the case. Also, the questioning by lawyers and prosecutors can alter a testimony, so they should be conducted carefully as well. When it comes to recognizing suspects, police lineups should be conducted similarly to how a scientific investigation, making use of double blinds and preventing anyone from giving any hints to the person doing the identification.

[1] Remembering emotional events. A. Burke (1992)


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