Aftermath of distressing event more memorable than events that preceded it, study suggests

Halfway through a true crime podcast, an early morning commuter jerks the steering wheel to narrowly avoid a collision. When discussing the podcast with a colleague later that day, the driver can easily remember details of the second half of the episode but only has a hazy memory of how it began.

A new study led by psychologists at the Beckman Institute for Advanced Science and Technology suggests that we remember the moments immediately following a distressing episode more clearly than the moments before it. Clarifying the relationship between trauma and memory can improve how we evaluate eyewitness accounts, inform therapies to treat PTSD, and help clinicians combat memory decline in brain disorders like Alzheimer’s disease.

This study appears in the journal Cognition and emotion.

“This is a clear finding, and it opens up an entirely new dimension for understanding the impacts of emotions on memory,” said lead author Paul Bogdan, a Ph.D. Research conducted at the University of Illinois at Urbana-Champaign formed the basis of this study.

Bogdan’s research was conducted in the Dolcos Lab led by psychology professors Florin Dolcos and Sanda Dolcos. For over 15 years, the Dolcos have studied the relationship between mental health and memory, particularly unwanted memories that intrude into our daily lives, degrading mental health and worsening anxiety, depression and PTSD. The result of their research is an emotional safety system, designed with cognitive therapies that protect emotional safety and preserve concentration in the face of disturbing memories.

According to researchers, studying traumatic memories is tricky because our brains tend to automatically edit negative experiences. Big ideas are more important than details, peripheral features give way to central ideas, and specific moments are cut off from their context: the where, the when and the “what else,” Florin Dolcos said.

So far, there is little evidence to explain the impact of negative emotions on the moment, our ability to place a sequence of memories along a timeline.

“Suppose your partner unexpectedly insults you in the middle of an otherwise neutral discussion. Later, when you try to make sense of the encounter… will you remember more vividly what happened before or after the insult?” » said Bogdan. “Existing research doesn’t give us a clear answer.”

But Bogdan’s new research just might. His team orchestrated two identical experiments: an initial study with 72 participants to identify their procedures and predictions, and a replication study with 150 participants to confirm the results.

First, participants viewed a series of images simulating a series of memories. Half of the images elicited negative emotional reactions and the other half were emotionally neutral. To contextualize the images – and make them closer to memory – participants were asked to privately imagine themselves traveling among the photographed locations and create a creative story arc to connect them together. This “fostered the feeling that sequential image pairs are related in a meaningful way,” the researchers wrote.

An hour later, participants viewed pairs of images from the series. For each pair, they were asked whether the second image occurred immediately before or immediately after the first. (They were also given the option “none” and could indicate if they did not remember the command.)

The results were consistent in both studies. Participants’ ability to accurately place the second image improved when negative memories occurred before neutral memories on the timeline. If participants saw a negative image first, they were better at remembering the neutral images that followed it; Conversely, if participants were shown a neutral image first, they could more consistently place the negative images that preceded them.

In other words, the memory shifts from negative to neutral.

“Our results therefore suggest that if one is insulted during a conversation, it is better to retrieve what was said immediately afterwards rather than what was said immediately before,” Bogdan said.

It’s not intuitive, the researchers say.

“You might imagine that humans evolved to have a good memory of what led to negative things,” Bogdan said. “If you were bitten by a snake, what rash thing would you do before?”

One explanation is that negative emotional spikes (for example, following a snake bite) cause a surge in focus and alertness, signaling our brains to take exhaustive notes about what happens next and save them for use. future.

But Prelude to Trauma employs a much less diligent note-taker. This casts a questionable light on scenarios like testimonials, where contextual details are paramount.

“Knowing that people are more likely to miss details leading up to something negative that happened, we can be more cautious about statements related to events that led to a crime, compared to memories of what happened afterward, which we know will be more accurate.” » said Florin Dolcos.

As relevant in a clinic as in a courtroom, these findings help clarify the mechanisms underlying PTSD, where an objectively neutral activity can trigger an involuntary surge of negative emotions.

“For example, a veteran hearing a loud noise and inferring that his building will soon collapse due to an explosion,” Florin Dolcos said. “This happens because there is a disconnect between the memory of the traumatic experience and its original context; the what becomes detached from the where and when.”

Regaining control of traumatic memories therefore requires relating them to their context, place and time of origin. Researchers hope to integrate this strategy into cognitive therapies for people with PTSD.

In addition to alleviating the whirlwind of negative memories, another therapeutic avenue could be to use positive emotions to reconstruct stronger and more precise memories for those who need them, according to Sanda Dolcos.

“As people age, memory problems become more serious, especially in diseases like Alzheimer’s,” she said. “It’s memory for context that suffers the most. If we know exactly what’s happening, we can develop future strategies to better encode information that will help us help others in these conditions.”