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It seems to be a fact of life that memory performance decreases as we age, but new research helps to understand what precisely is decreasing, why and points towards strategies that might help. A study published in the journal Memory suggests that older adults perform less well on working memory tasks as they do not forget information that is no longer relevant . This might sound like a good thing, but it leads to overload of memory processes, damaging memory performance.
The media has widely reported recent research which shows that memory processes start to decline at 45 years of age . With increasing attention paid to the impact of dementia on individuals, families, society and healthcare services, memory research is very much in the spotlight. Although it’s important to understand when memory starts to get worse, it’s also vital to come to grips with what happens to memory processes. This might give us clues to how to improve memory.
Memory is a complex set of processes, which may decrease at different rates or in different ways. Thus, Italian researchers at the University of Padua decided to focus on “working memory” — the part of memory that holds information at the ready so it can be processed (to go into “long-term memory”) or used to complete tasks. A now historical example would be looking up a number in a phone book before dialling it out — the numbers are held in working memory, like planes in a holding pattern, before coming in to land as we dialed the number. In real life, information often changes or gets supplemented. This means we have to update our working memory. This updating needs to remove no longer needed information and to retrieve the still needed information. The process then is rather complex and understanding how it works in people of different ages might provide clues as to what is happening as memory declines.
In the study, scientists aimed to examine any differences between younger and older participants in updating working memory. Data were collected from 26 “younger” adults (average age of 27.81 years) and 26 “older” adults (average age of 68.77 years). Because memory processes can work differently with different types of information, this experiment used verbal and visual tasks. In the verbal task, participants were asked to recall the last 4 letters in a string of letters read out to them. This sounds simple enough, so how does this test out the “updating” process? Participants did not know how long the string of letters would be, so every time another letter was given, they had to update their memory of the last 4 letters. The longer the list, the more updating required. Correct responses and incorrect recall of letters no-longer in the last 4 letters of the string were recorded. For the visual task, participants saw squares on a 5 by 5 table light up and had to recall the position of the last 4 lights in the sequence.
When only 4 items were given (so that no updating was required), older adults performed poorly on both the verbal and the visual task compared to younger adults. Older adults performed even worse on longer lists of items, where more updating was required. Older participants incorrectly updated their memory by stating that letters or light positions given earlier in the sequence were in the last 4 presented. Thus, it appears that older adults hold on to information that isn’t needed anymore.
This subtle finding is potentially very important — older participants aren’t forgetting things, rather they seem to be remembering too many things and therefore overloading the memory system. Additionally, it appears that in some cases, errors in memory did not reflect a failure of updating but sometimes simply that people waited until the end of the task before trying to recall. Older adults seemed to rely more often on the fact that recently provided information is held in the working memory quite well with the absence of great effort.
This research helps us to lift the lid on memory decline and to try to understand what is happening in more detail. Working memory performance is worse in older adults compared to younger adults. This itself is helpful, however the study also suggests that this is because memories are not being updated as efficiently and because older adults used less effort to keep items in the working memory.
Now, at this point, it’s always good to ask “so what?”. Well, first come the limitations of the study. From a single study we can’t infer too much. The study is an experiment and uses abstract tasks, which might not reflect real-life activities and therefore real-life cognitive processes. The researchers have inferred from the errors made to attempt to understand the processes, but that is the challenge of this type of research into processes that can’t be seen and people are not necessarily aware of these processes. Now, the so-what that is potentially very useful — a more in depth understanding of what is happening with older adults memory, we might be able to create training activities to enhance working memory based on updating and effort.
We accept that decline in body and mind is part of normal aging. However, there may be things we can do to slow or lessen these declines. Physical activity, healthy diets and staying active all seem to lessen the impact of aging. For psychological processes, research is required to understand how processes are declining. Although scientists are still exploring interventions to treat memory loss, the study reviewed here helps to understand what processes are active. Using working memory and engaging in updating of information and doing tasks that require effort to remember may be beneficial. So keep your working memory active and be wise by using effort to remember rather than tricks.
Fiore et al. Age differences in verbal and visuo-spatial working memory updating: Evidence from analysis of serial position curves. Memory. 2012 Jan;20(1):14-27. Epub 2011 Dec 2.
Singh-Manoux et al. Timing of onset of cognitive decline: results from Whitehall II prospective cohort study. BMJ. 2011 Jan 5;344:d7622.