By guest blogger David Robson

Aristotle once compared the human mind to a wax tablet. When we are young, the wax is warm and soft; it is easy to make an impression and record our thoughts and feelings. With age, the wax hardens – the older impressions fade, and it is harder to carve out new images in their place.

This view of memory, at least among the general public, has changed little in the 2300 years since. Many of us still believe that the brain’s “plasticity” – its ability to adapt, change, and pick up new skills – decreases as we get older, much like Aristotle’s stiffening wax. Combined with a general cognitive decline, this is the reason why it’s assumed “you can’t teach an old dog new tricks”.

Yet modern science tells a more positive story: memory is more pliable than we imagine, even in old age. In fact, according to work by Dayna Touron at the University of Carolina, a large problem may simply be confidence – older adults don’t trust their memories, and so don’t realise their full capacity. She uses the example of learning a new route with GPS. Long after they have committed the route to memory, older adults are more reluctant than younger people to give up SatNav Sally. Indeed, over the last few years, Touron has amassed some compelling evidence for the importance of older people’s lack of confidence, which she presents in a recent review for Current Directions in Psychological Science.

For instance, Touron once asked participants to perform a tedious verbal task: they were given a table of random word pairs (e.g. dog-potato) and they then had to judge whether another list of word pairings contained any of the same word pairs that had appeared in the original table. Importantly, all the participants were told they could refer back to the original table if they wanted to, but they didn’t have to if they could remember the pairings. The older participants (aged between 60 and 75 years) were more reluctant to rely on their memories, and so continued looking up each entry – despite the fact that further tests revealed they had memorised just as many of the original word pairs as the younger participants.

In other experiments, volunteers were given a series of algebraic equations to solve. They could solve them initially using mental arithmetic, but each equation appeared multiple times, allowing the participants to learn the answers off by heart. Even so, the older volunteers reported going through the same calculations again and again, rather than relying on their memories of the solutions. Crucially, Touron found that they were perfectly capable of retrieving those memories if they were encouraged by the offer a small cash prize in return for a quick answer. Nor is their reluctance a form of “behavioural inertia” – the habit of sticking to the first strategy you use, however inefficient in the long run. In fact, the older participants are happy to change tack in other kinds of tasks, as long as they don’t involve actively recalling newly learnt information.

In other words, avoiding their memory seems to be a choice – a decision that may come from a poor understanding of the way their minds are working. Touron has found that her older participants underestimate the time and effort required to take the long route around the problems, rather than using their memories as a short cut; they also believe their memories are less accurate than they actually are. Indeed, as you might expect, the less confident they are in their own learning abilities, the less likely they are to make use of their memories during these trials.

Asking volunteers to complete diaries about their everyday activities, Touron has found that older people are just as reluctant to take advantage of their memories in their private lives as in the psych lab – whether they are cooking, driving or learning to use a computer. And that has big implications, she thinks. For one thing, it could be a case of use it or lose it – contributing to a more general mental decline as people age. A fear of misremembering could also lead to reduced self-esteem, perhaps making older folk less adventurous: they might avoid parties if they are scared of forgetting people’s names, for instance, contributing to further isolation and loneliness. For these reasons, Touron is now looking for measures that could encourage older people to have a more youthful confidence in their abilities.

The science makes intuitive sense. If the brain really were a wax tablet, as Aristotle imagined, the answer wouldn’t be to set our tools aside to gather dust and cobwebs; it would be to continue to work the wax with even greater fervour, melting it and moulding it until it was pliable once more.

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Touron, D. (2015). Memory Avoidance by Older Adults: When “Old Dogs” Won’t Perform Their “New Tricks” Current Directions in Psychological Science, 24 (3), 170-176 DOI: 10.1177/0963721414563730

—further reading—

Exploring people’s beliefs about their memory problems

Different mental abilities peak at different times of life, from 18 to 70+

Introducing the SuperAgers – the elderly people whose brains have stayed young

Very old and very cool – recognising a distinct mental strength of the elderly

Companies are more successful when their employees feel young for their age

Post written by David Robson (@d_a_robson) for the BPS Research Digest. David is BBC Future’s feature writer.



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