Why older people remember details less well
What: Getty Images/Carol Yepes
Where was my key again, what was the name of the new neighbor again? With age, the ability to remember names or places diminishes. Now there is a logical explanation for this: the drawer principle.
Man knows this from the wardrobe or from that one kitchen drawer that you have been wanting to clear out for months: the storage compartments are stuffed to the brim. As soon as you rummage around in it, all sorts of things fall into your hands – but rarely what you are looking for.
One can probably imagine the processes that take place in the brains of older people when retrieving memories in a very similar way. This is the conclusion of the cognitive scientist Lynn Hasher from the Canadian Baycrest’s Rotman Research Institute in an article that has now appeared in the journal “Trends in Cognitive Sciences”.
The fact that seniors have problems remembering certain details is not because they remember too little information – but too much.
For their meta-analysis, Hasher and her team summarized the findings from more than 20 years of research; both from our own laboratory studies and from the work of other scientists. They found that healthy 60- to 85-year-olds had a much harder time suppressing irrelevant information than younger adults. This constant sifting out of unimportant impressions is indispensable in everyday life; For example, it allows you to drive with concentration even though the radio is on.
According to Hasher, however, this filtering function decreases with age. The brain is “flooded” with information – which is at the expense of memory: This makes it difficult for seniors to track down a specific detail among all the others in their memory. “For example, imagine you know five people named John and you’re trying to remember the last name of a particular John,” Hasher explains. “You’ll find that harder than if you only know one person named John.”
But what exactly is the reason for this? Hasher’s team has identified three disruptive factors that get in the way of seniors’ memories. First, there is recently used information that is no longer relevant but is nevertheless edging back to the fore; second, the large pool of prior and general knowledge that is unintentionally tapped into when remembering; and third, the unimportant impressions from the current environment – a constant background noise that awakens all sorts of mental associations.
Younger people can easily ignore these disruptive factors. In older people, the researchers conclude, however, cognitive control declines with age. Your brain works more inefficiently, the unimportant is no longer separated so cleanly from the important. This has been proven in numerous experiments, both in behavioral studies and in imaging processes.
In behavioral tests, subjects were shown pictures with random words above them. The latter served as a diversionary maneuver. All participants were asked to memorize the motif and ignore the word. In a later test, the words were queried. While the seniors recalled the corresponding terms, the younger ones couldn’t remember them at all – as if the distractions had never existed.
The same effect was seen in studies in which subjects were asked to remember only one of two image categories shown previously. As the measurements of brain activity revealed, the older participants’ memories also processed the irrelevant images – although they were supposed to ignore them.
But there’s also good news: Retrieving seemingly unimportant details can have surprising benefits. Thanks to them, seniors are more creative and can make better decisions, Hasher explains. “This could explain why wisdom and knowledge continue to grow with age, even as memory declines.”