Older adults actually have too much information in their brains, creating ‘cluttered memories’

TORONTO, Ontario — It’s quite common, perhaps even expected, for memory to decline as people age. However, new research indicates older individuals simply have too much information bouncing around in their heads, resulting in “cluttered memories.” It turns out wisdom really does come with age! Researchers from the Baycrest Centre for Geriatric Care in Toronto say the trick is figuring out how to reliably recall that wisdom.

The study characterizes a “cluttered memory” as one that struggles to recall specific or detailed information and events in comparison to younger people.

“These results may explain why wisdom and knowledge continue to grow as we age, even as memory declines,” says senior study author Dr. Lynn Hasher, senior scientist at Baycrest’s Rotman Research Institute (RRI), in a media release.

On a day-to-day basis, and at any age, the human mind constantly blocks out unnecessary information. For example, focusing on the road above all else while driving. As we grow older, however, the mind’s inhibition skills deteriorate, making it harder to focus on specific information. According to study authors, this results in a “flood” of information and memory impairment among older adults.

“When older adults try to remember one particular detail, they experience more difficulty because that one detail has become connected to all sorts of other details in their mind, and they need to filter through them all. For example, imagine you know five people named John, and you’re trying to remember one specific John’s last name. You will find this more difficult than if you only know one person named John. That is similar to what happens when older adults try to recall specific details,” Dr. Hasher explains.

Older adults ‘store’ more information than younger people

This was no short-term study. The team analyzed over 20 years’ worth of research from Dr. Hasher’s lab to produce this latest report. They also included additional behavioral and neuro-imaging studies analyzing memory function in old age.

During a few of those behavioral studies, both young and old adults viewed a series of pictures with words attached at the top of the image. The words served as distractions. The participants had to focus solely on the images first and then determine if the next picture they saw was the same as the previous image. Next, researchers subtly asked each person about the words attached to the images they tried to ignore. For instance, if the word “hydrogen” appeared on an earlier image, study authors asked, “What is the most abundant element in the sun?”

Older participants performed much better than younger subjects during that second task, indicating that while young adults ignored the words during the first task (as instructed), the older participants still “stored” the words in their memories. Numerous additional studies have produced similar results.

Is all that clutter a good thing?

Neuro-imaging studies came to similar conclusions. During one such research project, both young and older adults looked at pictures pertaining to two totally different categories (faces and landscapes, for example). Then, with the images out of sight, the team asked participants to recall just one of the categories. As participants recalled the images and categories, scientists measured brain activity to assess which image categories were being “held” in their minds.

Brain activity revealed that, unlike younger adults, older adults remembered both relevant and irrelevant image categories,” reports lead author Dr. Tarek Amer, a postdoctoral fellow at Columbia and Harvard University, and former graduate student in Dr. Hasher’s lab. “This suggests that the older adults were remembering these images when they were supposed to be ignoring them, supporting the idea that older adults process and store too much information.”

Surprisingly, the study notes that there are actually some benefits that come from having a cluttered memory. To start, this study strongly suggests a cluttered memory is a sign of wisdom and lots of knowledge. The report also speculates older individuals may “better utilize their prior knowledge and distractions in their environment for decision-making purposes and in creative tasks.”

“In research labs, we tend to focus on precision of memory, but in real life, precision hardly matters. As researchers, we may be overestimating the disadvantage that older adults have with their memory and underestimating the advantages,” Dr. Hasher concludes.

The study is published in the journal Trends in Cognitive Sciences.