People often assume and expect that we will be able to remember major events in our lives with clear and steady accuracy and that this determines the “truth” of what happened. However, traumatic events like sexual assault are encoded differently from regular, more routine experiences.
All of our experiences are encoded in the brain, stored to the short-term memory, and then the long-term memory, by the hippocampus. In the event of high stress such as sexual assault, a surge of hormones is released in order to aid the response system to deal with the situation (read how the brain is affected during trauma). During this intense neural activity, normal brain function is altered – this includes the way events are encoded by the hippocampus.
During traumatic events like sexual assault, encoding surrounding details (Peripheral Information) and the chronology of the incident (Time Sequencing Information) is difficult, and therefore you may find yourself only remembering some parts of the incident.
“Memories of traumatic events are laid down differently to everyday memories. Usually we encode what we see, hear, smell, taste and physically sense, as well as how that all slots together and what it means to us […] This enables us to recall events as a coherent story. But during traumatic events our bodies are flooded with stress hormones. These encourage the brain to focus on the here and now, at the expense of the bigger picture”
Linda Geddes, BBC
On the other hand, the neural activity in the brain can also divert attention from the assault, to other details (ex. Colour of the curtains). This information is then encoded into the short- and long-term memories, creating associations between small details and the trauma. This can result in intensified memories, which means that you are able to vividly remember these details possibly with little to no context about them.
The nature of the traumatic memory can be described as followed: fragmented, associated with intense arousal, readily primed and triggered, and poorly contextualized into memory. As a result, memories of traumatic events such as a sexual assault can be fragmentary or incomplete. It can be difficult to recall many details of a sexual assault in a complete or linear way. This is also why, after a stressful situation, people have trouble remembering some specific details, and say things like, “It was all a blur.”
At the end of the day, it isn’t realistic or rational to be to able to recall all aspects of a traumatic experience with detailed accuracy from start to finish. This is simply not how the brain works.
Learn more about how memory is effected by trauma here: https://time.com/3625414/rape-trauma-brain-memory/
and here: https://link.springer.com/chapter/10.1007/978-3-030-23645-8_20