Many older adults are asking the same question. “What have we done differently as we got older that would make our brains change?” Neuroscientists and psychologists puzzle over the question all the time, “Why does age change memory function.”

A new study published in Psychological Science by researchers at the University of Toronto’s Rotman Research Institute, took a look at one puzzle piece: how older and younger adults encode and recall distracting, or irrelevant information. They hope their research can help scientists better understand aging and memory. 

Prior to their study most psychological scientists had focused on the how we intend to learn. They did not take into consideration that background noise can influence our memory and behaviors, and that it can change with age. “Our world contains so much information; we don’t always know which is relevant and which is irrelevant,” said Nigel Gopie, who co-wrote the study with Fergus I.M. Craik and Lynn Hasher.

They divided 125 subjects ects between the ages of 19-59 into two groups. Two types of memory were tested: “implicit” memory, which influences behavior even if the person is not aware (example: product placement in a grocery store for the items with the highest profit margin at eye level); and “explicit” memory, such as trying to remember the grocery list you left at home.

After testing, the subjects were asked to press a button in response to colors of words and random letter strings on a computer screen. The words themselves were not relevant; it was the color of the words. They then completed word fragments. In one test of implicit memory, the prior testing was not mentioned. In the other test, words from the color task were used to complete the fragments (explicit memory).

Older subjects did better on implicit memory testing, while the younger participants did just the opposite – better on the explicit memory testing.

“We believe younger people remember in deep, elaborative ways: conceptually —spontaneously creating semantic or imaginary associations among words and ideas,” said Gopie. To find the study’s words, “they had to search.” They used explicit memory.

“Older people encode things ‘perceptually,’ in a more sensory way,” he continued. “They also don’t filter out irrelevant stimuli. All of the information ends up ‘all over the place,’ and is more accessible in the implicit mode.” When trying to remember explicitly, like a person’s name – elders are often stumped.

The scientists believed the decline in mental “resources” as we age accounted for the shallower processing of the older adults. To test their theory, “they made the younger people more like the older people” by taking away some of their resources. “While performing the color task, participants had to listen to numbers and say the second of any two consecutive odd numbers aloud. While their attention was divided, the younger people performed as their elders did: better on implicit than explicit memory,” said Craik.

“We’re learning all the time, whether we know it or not,” says Gopie. The problem is that we only have so much brainpower to access all this information. When we get distracted it doesn’t make any difference what age we are, we behave the same.



About the author:

Ron White is a two-time U.S.A. Memory Champion and memory training expert. As a memory keynote speaker he travels the world to speak before large groups or small company seminars, demonstrating his memory skills and teaching others how to improve their memory, and how important a good memory is in all phases of your life. 



Association for Psychological Science – Making the ‘Irrelevant’ Relevant to Understand Memory and Aging :