Memory Distortion: What Really Happened in the Past?

What is Memory Distortion?

When we refer back to some of our best memories, we tend to think we remember every detail extremely clearly. However, when we describe these memories to others, we find that they remember certain aspects differently. In this case, what really happened in the past?

Over time, memories can become distorted, while the individual continues to believe with great confidence that their version of the memory is accurate. More specifically, memory distortion refers to the phenomena in which a memory is recalled incorrectly than what really occurred. This can be due to multiple things, such as the amount of attention the person was paying to the event when it originally took place. While such examples seem a bit obvious, others may not necessarily be so clear. For example, if we imagine storing memories of personal life experiences as a videotape stored away in a drawer for years, we also intuitively imagine that even after years of storage the videotape will play the exact same clip. Unfortunately, this is not the case when it comes to our own memories because over time our memories can change and become less like the original event.

What Do We Know So Far?

Scientists have been trying to understand memory distortions for many years now in hopes of discovering how reliable eyewitness testimonies are. If a bystander can confidently claim that they remember the exact events which they witness at a crime scene, then the court will rule their claims as sufficient evidence against the person being accused. However, current research findings show that memory distortions happen unconsciously which is why the bystander can recall the event confidently even when their story is untrue. Inaccurate eyewitness testimonies can have serious consequences such as the court ruling an innocent person as guilty. More recently a study including two large experiments wanted to investigate how memories reported for eyewitness testimonies can become distorted (Cochran et al., 2016). In the first experiment, researchers gathered 186 college students who were asked to write a memory report of a given event. The researchers then created falsified versions of their written reports that were similar for the most part but also included inaccurate details. The results indicated that the participants who were given inaccurate versions of their own reported memories later also altered their memory to suit the falsified version the researchers created. In short, providing false information about an event that is seemingly believable can cause memory distortions. These findings further support the notion that memories in eyewitness testimonies can change, especially after the court presents other possible claims that are similar, yet inaccurate to what really happened at the crime scene. In the second experiment, researchers asked 392 students to participate in a similar set of tasks. In the end, they found that the participants who did not realize their memories were falsified, were the same participants who experienced memory distortion. However, the participants who noticed the manipulation did not experience such significant memory distortion. In other words, awareness plays an important role in memory distortions such that being unaware that falsified information is being presented is what causes memories to change. A much earlier study where participants watched a video of a crime scene, or a car crash, later found that memories become distorted most when the participants were not able to detect that details of the events were manipulated when they were asked to recall the event again (Loftus, 1992). This experiment further supported the idea that the lack of awareness in memory distortion leads to further changes in memories over time.

Memories can also be at a higher risk of becoming distorted depending on the individual’s emotional and physical state. A three-experiment study presented participants with a series of 48 words where half the words caused negative emotional arousal and the other half were neutral terms. At the end of the study, researchers found that participants were able to recall the words that caused negative arousal more than the words that were neutral and therefore had no emotional impact (Kensinger & Schacter, 2006). Moreover, these findings suggest that memories which cause negative emotional responses may be less likely to become significantly distorted. Referring back to the eyewitness testimony example, according to this study bystanders of crime scenes should be able to recall the events they saw relatively well if contradicting information is not presented. The physical state of individuals has also been found to impact the amount of distortion that can take place. More specifically, in a study with 32 participants, 16 individuals experiencing chronic pain and 16 individuals being completely healthy, researchers presented the participants with a list of 20 words and later asked them to remember a personal event from their past that was somehow related to the word list. Near the end of the study, scientists found that the participants who experienced chronic pain also experienced more memory distortion when they attempted to remember an event from their own past (Meyer et al., 2015). This ultimately means that the physical state of experiencing chronic pain can also lead to memory distortions even when the participants were not presented with any misinformation. Both studies are critical points necessarily for understanding how and why memories become distorted. As time goes by, changes in emotional and physical states may also cause our memories to become altered without our knowledge (Schacter et al., 2011). In short, recent research has also found that being presented with falsified versions of the event and being unaware of the deception greatly increases the amount of distortion within the given memory.

How does this Impact Society?

Understanding memory distortions will also allow us to understand how the mind functions overall. Once a solid foundation of knowledge for memory becomes formed, then we can apply our findings to major aspects within our society such as the courtroom. For instance, the weight of eyewitness testimonies will not have such a strong impact on a judge’s decision to rule an accused person as guilty. By making this change within our society, the rate of falsely accused criminals being sentenced to punishments which they do not deserve will decline greatly. Such research could even save lives in the case that a falsely accused criminal is sentenced to the death penalty.

Ultimately, a great deal of scientific findings all point to the same direction, that memories can become altered without our knowledge, even memories of our own personal experiences. Now try to remember a personal event which you feel you can recall confidently in detail. How can you be sure that this memory is also not distorted?


Cochran, K. J., Greenspan, R. L., Bogart, D. F., & Loftus, E. F. (2016). Memory blindness: Altered memory reports lead to distortion in eyewitness memory. 717-726. doi:

Kensinger, E. A., & Schacter, D. L. (2006). Reality monitoring and memory distortion: Effects of negative, arousing content. Memory & Cognition, 34 Current Directions in Psychological Science, 1 Pain Medicine, 16 Memory & Cognition, 44(5), (2), 251-260. Retrieved from

Loftus, E. F. (1992). When a lie becomes memory’s truth: Memory distortion after exposure to misinformation. doi: autobiographical memory. (4), 121-123.

Meyer, P., Karl, A., & Flor, H. (2015). Pain can produce systematic distortions of (5), 905-910. doi:

Schacter, D. L., Guerin, S. A., & St. Jacques, P. L. (2011). Memory distortion: An adaptive perspective. Trends in Cognitive Sciences, 15(10), 467-474.