Factors that enhance memory across age groups

Aims of the study

It is well documented that cognitive abilities change over age. This is clearly evident from the changes seem from infancy to adolescence with increased cognitive ability. Although it is commonly thought that cognitive ability starts to naturally decline in later life, there is no clear picture of on why ‘healthy’ cognitive ageing occurs and how it specifically affects memory.

In this collaboration study between the University of Kent and the University of the Third Age the main aims were to examine memory ability and learning over age. Specifically we were interested in whether certain factors such as meaningful thinking, motivation and reward, which are known to affect memory in younger adults, have a similar effect on older people.

Our theoretical factors were chosen because they have a wide literature that supports their effect on learning and memory.

• Meaningful thinking or processing, such as judging a word’s pleasantness, have been seen to lead to more distinct and stronger memories than un-meaningful judgments/processing.
• Rewards and motivation to gain rewards are seen to increase effort and attention, again improving later memory ability.

Our main research questions were:

• Does the way certain factors affect learning and remembering differ over age?
• Which factors are most useful to different age groups?
• Is there a difference in how these factors influence intentional and incidental learning over age?

When we talk about the difference between intentional and unintentional learning we are talking about the difference between learning after trying to remember compared to spontaneously learning information.

Method

We measured intentional learning by asking participants to memorise lists of words and testing them on them later. Within this test old words that they had studied and new words were presented one at a time and participants had to say if they had seen the word before in the study phase or if it was new.

Later we tested unintentional learning by giving participants a surprise recognition test that followed the same format but only included words that had been presented in the first recognition tests as new (non-studied) words.

We took this design and added in our factors. Therefore we had a study condition where participants did a meaningful judgement (whether the words were pleasant or not) and a non-meaningful judgement. This examined the meaningful thinking factor. They then had two more study conditions where they were either told they would gain rewards for later recognising these words or would not win anything. This examined the reward motivation factor. We then looked at the difference in recognition scores within both the meaningful thinking and the reward factor. This was examined on both the first recognition stage (intentional learning) and the surprise stage (unintentional learning).

Results

Interestingly, when we looked at the results for intentional learning we saw that in both the older and younger groups the recognition memory scores were significantly higher for meaningful compared to non-meaningful thinking. The scores for the meaningful judgements were on average around 40% higher after doing a meaningful judgement during the study phase. This is consistent with our expectations, as when you are judging something in a meaningful way the words you judge have more meaning attached to them than the non-meaningfully judged words.

There was a similar pattern for unintentional learning. For both age groups recognition memory scores were significantly higher after the test for the meaningful judgements. This was consistent with our expectations as when participants were deciding whether they had seen the word during the meaningful task they may have been thinking about whether they had judged the word as pleasant or unpleasant. This in itself is a very meaningful judgement and leads to enhanced unintentional learning.

When we looked at our second factor of reward, the recognition accuracy scores for the rewarded and non-rewarded tasks seem to affect the younger group as they learnt less well than the older group without the reward but were not enhanced by reward. The older adults remained at a high level of accuracy across both these tasks and were not affected by external reward. When we examined the effect of reward on unintentional learning we saw no effect across both groups, suggesting that any effect within the younger group on their first recognition task did not affect how they judged the words on the task and they did not see any effect on the unintentional learning due to this.

Looking at the written and verbal feedback from participants within the sessions, lots of older adults commented on how they were not motivated by the reward but by their internal drive to test their own memory ability. This may explain some of the differences between the groups on how reward affects intentional learning.

In summary

• Both groups had overall the same level of performance despite a 50-55 year age difference.
• Both meaningful processing and motivation to learn are very important and can benefit different age groups in a similar way.
• Meaningful decisions led to an increase in both intentional and unintentional learning compared to non-meaningful judgements. This suggests that if you think about something you want to remember in a meaningful way you will later remember it much better.
• We also saw the importance of motivation on memory, both internally driven and externally driven. When you are interested or motivated to learn you will later remember more.

The results of this project were presented at a University of Kent showcase day and at the U3A South East Regional Research Conference and were published in the journal Memory (see below).

This collaboration was a hugely successful and productive venture and we would like to thank to all the participants for volunteering and the U3A research team for dedicating their time and commitment to making this project a success.

Further information

More about Dr Louisa Salhi and Dr Zara Bergström