Forgetfulness as we get older may be due to the changing way we perceive events as we age, according to a new study.
The study, conducted at Washington University in St. Louis, found that perception is influenced by a part of the brain called the medial temporal lobe (MTL), which declines in functioning in old age.
“When you think back on what you did yesterday, you don’t just press ‘play’ and watch a continuous stream of 24 hours,” said psychological scientist Heather Bailey, Ph.D., of Washington University in St. Louis, who led the study. “Your brain naturally chunks the events in your day into discrete parts.”
Bailey and her colleagues hypothesized that older adults may have difficulty with memory for everyday events because they don’t segment them in the same way as they’re happening.
In the study, older adults, including some who had Alzheimer’s type dementia, watched short movies of people doing everyday tasks, such as a woman making breakfast or a man building a Lego ship. They were asked to separate the movie into chunks by pressing a button whenever they thought one part of the activity was ending and a new part beginning.
Afterward, the researchers asked the participants to recall what happened in the movie. They also measured the size of the older adults’ MTL using structural magnetic resonance imaging (MRI).
“The older adults who showed atrophy in the MTL weren’t as good at remembering the everyday activities, and they weren’t as good at segmenting and chunking the events as they were happening,” said Bailey.
“MTL size accounted for a huge portion of the relationship that we saw between participants’ ability to segment and their memory for the events.”
According to the researchers, this means that what people are doing while they are going through their daily lives — how well they’re segmenting their experiences into separate memories — has an influence on how well they will remember those experiences in the future. And how well they are able to segment and remember is partly due to how well their MTL is functioning, she adds.
Focusing on how to better form new memories may be one way to improve older adults’ memory for everyday events, even for those adults who have clinical diagnoses like Alzheimer’s, she noted.
“Alzheimer’s disease attacks the MTL in the early stages of the disease,” she said. “But even with MTL atrophy you may be able to train people to chunk better, which might help them to remember their everyday activities better, too.”
Bailey and colleagues hope to further investigate the link between event perception and memory to see if they can combat memory impairment in older adults.
“We want to see if we can intervene at an early point in perception, if it will affect memory,” she said.
The study was published in Psychological Science.