Beyond stressful: why sexual assault can cause poor memory recall


The lack of appropriate memory recall about an event that happened in the past is often labeled as grounds for suspicion about whether that event actually occurred. However, in the case of highly stressful and traumatic events, lack of recall isn’t an abnormality; it’s the norm.

Before getting into why it shouldn’t be expected that someone going through a traumatic experience would remember everything clearly, it is important to set up how the process of memory works. There are three parts to this process: encoding, storage and recall.

Encoding, the first part of memory, refers to the short-term intake of information from the outside world. It is very selective because the brain does not want to process everything that happens around it. For example, you do not have to encode the details of what a person was wearing if they simply gave you directions to a bathroom. The details being encoded, known as central details, are a function of what is being paid attention to and what is emotionally significant. Meanwhile, the details that fail to be encoded are considered peripheral details.

What’s important to note about central details is that what one may consider a significant detail may not necessarily be considered such by the person experiencing the event.

For example, under the stress and trauma induced by witnessing the suicide of a family member, one may only remember the blaring of the sirens as the ambulances approached afterward.

The next stage of the memory process is storage. From this phase, the difference between central and peripheral details is revealed. If peripheral details are not reinforced and encoded once again, they begin to lose their spot in the brain. This erosion of the peripheral details eventually only leaves central details. There are many factors that affect whether the memories encoded in the first phase stay in the storage phase over time.

One of those factors is sleep. As people sleep, their brain determines whether the information encoded is actually necessary, thus throwing away the memories that are no longer needed and reinforcing the memories that seem significant. This is the same reason why performing a task that requires memory without appropriate sleep isn’t productive.

Another factor is whether the emotional significance attached to the memory is positive or negative. Specifically, negative memories show a more distinct differentiation between central and peripheral memories. This can be seen in post-traumatic stress disorder and what is often described as the tunnel vision associated with the memories a person with PTSD can have.

Evolutionarily speaking, it makes sense to strongly differentiate between positive and negative experiences because doing so allows people to react appropriately to situations that call to mind the experience that initiated the memory in the first place.

The final aspect of memory is retrieval, which also comes with its own slew of issues. Memory is a tricky subject, especially when dealing with events that occurred decades in the past. Memories tend to change over time and can be manipulated relatively easily. They tend to be reconstructed as people change in their worldview and personality. Suggestions by people who are perceived to be close enough to an incident also tend to have a great impact on past memories.

Meanwhile, the fact that the experience was highly stressful and traumatic somewhat protects the memory from deterioration and makes the central details of the incident very clear. In this case, it is no longer about fighting the deterioration of the memory, it’s about fighting the repression of the memory.

If a veteran were asked if they killed anyone in Iraq, the brain’s focus would be to make sure the visceral emotions related to the event did not surface because of a particularly vivid memory. The veteran might keep the recollection of having to kill someone simple, refusing to describe the look on the face of the person that the veteran so clearly remembers but does not want anyone to know.

Most importantly, veterans themselves do not want to remember the horrible events that happened while they were deployed.

In an article for Scientific American, Dr. Jim Hopper, a teaching associate at Harvard Medical School and an expert in sexual assault and its effects on the brain, pointed to these factors when describing the memory loss faced by Christine Blasey Ford when she provided a testimony against current Supreme Court nominee Brett Kavanaugh. An editor’s note states that Hopper’s article would have been his expert testimony on Kavanaugh’s Sept. 27 confirmation hearing, had he been allowed to testify.

In the specific case of Ford’s testimony, Hopper brings to national attention that she seemed to shift throughout the testimony between the psychologist she is now and the 15-year-old girl who experienced the event firsthand.

He noted that she used “technical language in real abstractions in order to distance [herself] from the emotions that are associated with it or the sensations, visual images and things like that that could come back.”

Thus, she seems to fit in the same category as the veteran who does not describe the look on the face of the man he killed because he cannot face the emotional consequences he would have to come to terms with if he looked straight into the memory.

Hopper also speaks to the idea that the hearing itself resulted in a 147 percent spike in calls to the National Sexual Assault Hotline, according to RAINN, the anti-sexual violence organization that administers the hotline.

He mentions that people “are encountering all these reminders of their own trauma. And it’s activating their brain, their body. And then, again, those sensations and emotions can start flooding in.” Thus, the hearing could have resulted in many more people who have been through trauma coming to terms with their unresolved memories and emotions regarding their experiences.