A recent study by psychologists at the Beckman Institute for Advanced Science and Technology reveals that we remember the seconds immediately following an upsetting incident more vividly than the ones preceding it.
For example, halfway through a true crime podcast, a morning commuter jerks the wheel to narrowly escape colliding. When discussing the podcast with a coworker later that day, the driver can readily recall the intricacies of the episode’s second half but only has a vague memory of how it began.
Clarifying the link between trauma and memory can enhance how we evaluate eyewitness testimony, inform PTSD treatments, and assist clinicians in combating memory decline in brain disorders such as Alzheimer’s.
“It’s a clean finding, and it opens up an entirely new dimension for understanding emotion’s impacts on memory,”
said lead author Paul Bogdan, whose Ph.D. research at the University of Illinois Urbana-Champaign formed the basis for this study.
Mental Health and Unpleasant Memories
Bogdan did his research in the Dolcos Lab, which is led by psychology professors Florin Dolcos and Sanda Dolcos. For over 15 years, the Dolcoses have investigated the link between mental health and memory, specifically undesirable memories that intrude into our daily lives, deteriorating mental health and exacerbating anxiety, despair, and PTSD. Their research yielded an emotional security system designed with cognitive therapies to protect emotional security and maintain attention in the face of troubling recollections.
Studying traumatic memories is tricky, the researchers say, because our brains tend to auto-edit negative experiences. Big ideas trump details, peripheral features concede to central ones, and specific moments are cut loose from their context: the where, when, and “what else,” Florin Dolcos said.
Our ability to place a series of memories along a timeline is currently poorly understood in regards to how negative emotion affects it.
“Suppose your partner unexpectedly insults you in the middle of an otherwise neutral discussion. Later, when you are trying to make sense of the encounter …, will you more accurately remember what happened before or after the insult? Existing research does not give us a clear answer,”
Bogdan said.
Pairs of Sequential Images
But Bogdan’s new research might. His team orchestrated two identical experiments: an initial study of 72 participants to pin down their procedures and predictions, and a replication study with 150 participants to confirm the results.
First, participants were shown a series of images that simulated a string of memories. Half of the photos produced negative emotions, while the other half were emotionally neutral. To contextualize the photographs and make them more memory-like, participants were asked to privately envision themselves traveling between the sites depicted and creating a creative story arc to connect them.
This “promoted the feeling that pairs of sequential images are meaningfully related,” the researchers wrote.
An hour later, participants viewed pairs of images from the series. For each pair, they were asked whether the second picture occurred immediately before or immediately after the first. They were also offered a “neither” option and could indicate if they did not remember the order.
Memory Flow
Results were consistent across both studies. The participants’ ability to accurately place the second image improved when the negative memories occurred before the neutral ones on the timeline.
Individuals performed better at recalling neutral images that came after a negative image was shown to them; conversely, if a neutral image was shown to participants first, they were better able to recall the negative images that came before those.
In other words, memory flows from negative to neutral.
“So, our results suggest that if insulted in a conversation, one would better retrieve what was said immediately afterward than what was said immediately beforehand,”
Bogdan said. Researchers argue that this is counterintuitive.
“You might imagine that humans evolved to have a good memory for what led to negative things. If you got bit by a snake, what foolhardy thing were you doing beforehand?”
Bogdan said.
Prelude to Trauma
One explanation is that negative emotional spikes (for example, upon sustaining a snake bite) cause a rush of focus and alertness, telling our brains to take exhaustive notes about what happens next and squirrel them away for future use.
But the prelude to trauma employs a much less diligent notetaker. This casts a dubious eye on scenarios like witness testimonies, where contextual details are paramount.
“Knowing that people are more likely to miss details leading to something negative that happened, we can be more cautious about statements related to events that have led to a crime, compared to memories of what happened after, which we know will be sharper,”
Florin Dolcos said.
Reattaching To Context
These findings shed light on the mechanisms underlying PTSD, wherein an objectively neutral activity can cause an involuntary surge of negative emotions, making them applicable in both clinical and legal contexts.
“For example, a war veteran hearing a loud noise and inferring that their building will soon collapse due to an explosion,” Florin Dolcos said. “This happens because there is a rupture between the memory of the traumatic experience and its original context: the what breaks from the where and the when.”
Taking back control over traumatic memories, then, requires reattaching them to their context — their original place and time. The researchers hope to incorporate this strategy into cognitive therapies for people with PTSD.
Sanda Dolcos says that utilizing positive emotions to reconstruct stronger, more focused memories for individuals who require them could be another therapeutic approach in addition to calming the storm of bad memories.
“As people age, problems with memories become more serious, especially conditions like Alzheimer’s. The memory for context suffers the most. If we know exactly what’s happening, we can build future strategies to better encode information that will help us help others with those conditions,”
she added.
Reference:
- Paul C. Bogdan, Sanda Dolcos, Kara D. Federmeier, Alejandro Lleras, Hillary Schwarb, Florin Dolcos. Emotional dissociations in temporal associations: opposing effects of arousal on memory for details surrounding unpleasant events. Cognition and Emotion, 2023; 1 DOI: 10.1080/02699931.2023.2270196