A team of psychology researchers used fMRI scans to learn why certain moments carry such lasting power.
Many days blur together in our memories, but emotionally charged moments tend to leave a much sharper image.
These experiences tend to stay with us for a long time, often becoming the milestones of our lives—while highly negative memories can also become intrusive, coming to mind vividly and unexpectedly.
A new psychology study in Nature Human Behavior adds to our understanding of why emotional memories are so powerful.
The team, led by University of Chicago PhD student Jadyn Park, found that emotional arousal enhances memory encoding by strengthening cohesion across brain networks. Using fMRI scans during more natural, narrative settings, the researchers were able to track how emotional moments triggered a state when different networks that usually play separate roles start working together.
Their findings illuminate an aspect of memory that has long puzzled researchers.
“Think of the brain as an orchestra made up of many different sections. Sometimes they play separately, and other times they come together in harmony—what we call an ‘integrated state,'” explained psychology Assistant Professor Yuan Chang (YC) Leong, the study’s senior author.
“Emotional arousal helps conduct this orchestra, bringing the sections together, and when that happens, our memories become more lasting.”
Most prior research on emotional memory has used relatively simple stimuli, exploring reactions to single words or static pictures. But in everyday life, Leong notes, our memories come from complex, unfolding experiences—similar to a movie or a story.
The team wanted to understand how emotional arousal shapes memory in more natural settings. They also wanted to look beyond individual brain regions, as prior studies focused heavily on areas like the amygdala and hippocampus.
Their study combined existing fMRI datasets across institutions and sites to create a large sample. This brain imaging method allows researchers to measure the whole brain at once, giving them a more comprehensive picture of the areas and connections stimulated as study participants watched movie clips and listened to stories.
The researchers used three different methods to determine how emotionally salient various naturalistic stimuli were. They asked people to subjectively rate how emotionally arousing a particular scene was, they used a large language model to gauge how arousing scenes were, and they measured people’s pupil dilation as a physiological measure of arousal.
The researchers used the mathematical framework of graph theory to show that emotion strengthens memory by changing how the whole brain works together, versus just individual parts The team found that when participants were watching highly arousing scenes, the brain shifted into a more integrated state. In turn, this increased integration predicted how well people then remembered the scene.
The findings could lead to medical interventions that could make memories more or less sticky. By stimulating or suppressing the parts of the brain network that function as the “bridges,” there’s an opportunity to increase or decrease the level of integration in the brain that strengthens memory.
“We found that when participants are experiencing these highly emotional events, diverse brain regions tend to be more coordinated with one another, or are more integrated,” Park says.
“If we can deliberately disrupt or enhance that integration, it may open the door to interventions that help weaken traumatic memories.”
More immediately, the study offers a new set of tools to probe memories in different ways. It marks a major step in allowing researchers to better measure what makes emotional memories stick.
Source: University of Chicago
