ST. LOUIS — Most of our experiences in life are fabricated from earlier memories, a new study finds, but researchers say how we perceive and respond to each experience depends on how well we can recall even the most trivial aspects of those memories.
The study, conducted by researchers from Washington University, found that “change detection” plays a large role in how we construct reality. While we may not be able to change events in our past, we remember them well or not so well, and that memory greatly affects how our brains frame the events happening in the present — and even models what will occur in the future.
“Memory isn’t for trying to remember,” explains co-author Jeff Zacks, professor of psychology and brain sciences at the university, in a release. “It’s for doing better the next time.”
Zacks and his team created the “Event Memory Retrieval and Comparison Theory,” or EMRC, which builds on previous research by the group. The EMRC suggests that the brain is continually comparing sensory input from present experiences with working models of similar past events it constructs from related memories.
When “real life” doesn’t match the brain’s “event model,” prediction errors surge and change detection sets off a chain reaction of cognitive processing that rewires the brain, strengthening memories for the older model events and the new experience.
For the study, groups of healthy older and younger adults viewed video clips of a woman acting out a series of small, everyday activities, such as cleaning dishes or preparing to exercise. A week later, the groups were shown similar videos in which some small event details had been changed.
“When viewers tracked the changes in these variation-on-a-theme videos, they had excellent memory for what happened on each day, but when they failed to notice a change, memory was horrible,” says Zacks. “These effects may account for some of the problems older adults experience with memory — in these experiments, older adults were less able to track the changes, and this accounted for some of their lower memory performance.”
In other words, remembering or forgetting even the smallest details of an event can greatly impact how we perceive a new experience, even if it’s similar to the old one.
“Our study lends support to the theory that predictions based on old events help us identify changes and encode the new event,” says Zacks. “Memories of recent experiences are valuable because they can be used to predict what will happen next in similar situations and help us do better in dealing with what’s happening now.”
The study was published in the Journal of Experimental Psychology: General.