Developing memory skills: Activities to improve memory and reasoning skills

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Glynis Laws

Abstract - One problem in the development of children with Down syndrome that most concerns us is the limited short term memory found in nearly all the children we see. Since short term memory is important to most other mental functions including speech and language, we think it is essential to find out more about this aspect of development. This article aims to explain what we mean by short term memory, the ways in which recent research evidence suggests it is important to other language functions, and describes the research undertaken by Trust researchers to date and our current work.

Keywords - Down Syndrome, Memory Skills, Memory Training
Training children with Down syndrome to improve short term memory

One problem in the development of children with Down syndrome that most concerns us is the limited short term memory found in nearly all the children we see. Since short term memory is important to most other mental functions including speech and language, we think it is essential to find out more about this aspect of development. Over the last five years The Down Syndrome Educational Trust has made a considerable investment in memory research with the hope of providing an effective intervention strategy to improve short term memory. This article aims to explain what we mean by short term memory, the ways in which recent research evidence suggests it is important to other language functions, and describes the research undertaken by Trust researchers to date and our current work.
What do we mean by short term memory?

Over the years psychologists have come up with many different theories of how the human memory system might work. One thing that most of these theories have had in common is the idea of at least two types of memory - a long term memory system and a short term memory system. Long term memory is used for memories which have been stored: for example, autobiographical memories for life-events, or all the knowledge of the world that we have. These stored memories are retrieved when we need them. Most parents of children with Down syndrome report that their children have good memories of this type.

Short term memory is, as it sounds, a less permanent affair. This system acts as a store for information that is being currently processed. It is limited in capacity and is extremely fragile. It is the kind of memory we need for reading, speech understanding or mental arithmetic. The most useful conceptualisation of short-term memory has been developed over the last 20 years by Alan Baddeley and Graham Hitch (1,2) and is known as the working memory model. Their theory was developed by studying evidence from numerous experiments and from observing the effects of neurological damage on memory. Their work shows that we probably have one system for dealing with visual or spatial information and another system for dealing with verbal information, both under some kind of central control.

Most research on working memory has investigated the way in which the system dealing with verbal material works. This system is known as the phonological loop. It can hold spoken information for about two seconds. The information in the loop will gradually fade but it can be refreshed if it is rehearsed. Rehearsal is the process at work when we try to remember a telephone number between looking it up in the book and dialling. You might rehearse the number out loud, or equally successfully rehearse the numbers to yourself using a kind of "inner speech". A similar process allows us to "translate" picture material to verbal material. If I show you a sequence of pictures to remember you will probably try to do this by naming the pictures and remembering the names.
Why is short term memory or working memory so important?

The function of this memory system goes well beyond allowing us to remember telephone numbers and shopping lists, useful though these abilities may be. Susan Gathercole and Alan Baddeley (3) have drawn together research describing the development of working memory and its relationship to vocabulary acquisition, speech production, reading and comprehension. I will say a little about the possible role of working memory in each of these language areas.
Learning new words

What happens when a child learns a new word? They learn the meaning of the word of course, so the word becomes linked with a representation of its meaning in the long term memory system. They also need to learn the sound structure of the word and a program for reproducing the articulatory movements necessary to speak the word themselves. In order to successfully transfer the pattern of the word’s sound structure, it is important to have an adequate temporary memory trace in the phonological loop. The more durable the memory trace in the loop, then the more successful transfer of the new word to long term memory will be. Research has shown there is a significant relationship between memory capacity and the ability to learn new words. So children with better working memories learn more new words.
Speech production

Although there is not a lot of research evidence so far, it seems very likely to psychologists that the loop will prove to be an important element in planning and controlling speech output.
Reading

Sue’s article in the last newsletter drew attention to the way in which teaching reading may develop memory skills. However, the relationships between language, memory and reading are complex and likely to be reciprocal. Although research with normally developing children shows a correlation between memory capacity and reading skill, it is difficult to be sure about the direction of causation, and quite plausible that the relationship could work in both ways. Reading activity may promote the use of strategies which increase memory capacity. At the same time, having a better memory can improve reading skills particularly in terms of comprehension. For example, the ability to hold words in short term store must be important for gluing a sentence together long enough to extract the meaning.

These examples highlight the function of memory in language development but all forms of mental functioning are likely to require memory skills. For example, mental arithmetic or any sort of problem solving needs some kind of mental work space, and it is just this that working memory may provide.
Why is short term memory poor in people with Down syndrome?

The cause of poor short term memory development in people with Down syndrome is not, as yet, completely understood. However, there is evidence suggesting that people with learning disabilities fail to develop the kinds of strategies that normally develop throughout childhood and which increase memory capacity. As children develop they come to realise that rehearsing information to be remembered, either aloud or by repeating it to themselves, is important to help them remember it. Organising information to make use of associations between items in a list is another way we can enhance our memory; we can remember a longer list of items from the same category, such as animals, than we can remember when the items are unrelated. Grouping items together also aids recall. For example, we remember a telephone number better when we group the numbers into threes, say, with a pause between each group, rather than try to remember the whole string of numbers.
What can be done to improve memory skills?

Although people with Down syndrome tend not to adopt these strategies spontaneously, they can be taught to use them successfully. Since the early 1970’s a number of researchers have demonstrated impressive improvements in the memory spans of people with moderate learning difficulties who have been trained to rehearse. Charles Hulme and Susie Mackenzie extended this approach to those with severe learning disabilities (4). They taught a cumulative rehearsal technique to a group with Down syndrome and a group with other severe learning disabilities producing significant improvements in memory span.
Memory research at the Sarah Duffen Centre

Irene Broadley was funded by The Down Syndrome Educational Trust over three years to develop a memory training programme to teach rehearsal to children with Down syndrome using similar techniques. The programme also included the teaching of organisation and clustering of items as a recall strategy. The results of Irene’s study have been published in Down syndrome: Research and Practice (5,6,7). 25 children took part in the programme in which rehearsal and organisation were taught in two consecutive blocks lasting six weeks each. The performance of these trained children was compared with that of a control group, matched on age and ability, who received no training.

Both types of training were effective. The children could remember longer sequences of digits, and longer lists of words, both typical measures of memory capacity. There were improvements in memory span when the children were asked to recall lists of spoken words and when the children were shown a sequence of pictures and asked to recall them verbally. However, the most marked results were found under the latter condition where the rehearsal training programme produced an average increase in word span of about 3 extra words, compared with an average increase of about 1 when no pictures were shown.
Maintaining memory skills

To find out whether these levels of skill would be maintained once the training finished the children were re-assessed two months, and then six months, after the initial post-training assessments. Their performance remained at a higher level than the untrained children although the difference between the groups was reduced by the fact that the control children also made some improvement over the same period. The trained children also did better than the control group on a series of tests designed to assess whether they could generalise the use of the trained skills to other tasks such as remembering a complicated instruction.
Longer term follow up

In the summer term this year, we visited 14 children who had taken part in Irene’s study to assess their current language and memory function. These are the children which Sue mentioned in the last newsletter who also provided us with such interesting information on the effects of reading. Their current word spans are now much below the levels achieved immediately after training, although they are not quite so low as their pre-training scores. This small difference between pre-training spans and current spans is probably accounted for by developmental increase. In fact, when we compared the scores for these children with the scores achieved by children who were the same age at the beginning of the study as they are now, we found no difference between them. In other words, their memory capacity is now what would be expected for untrained children of their age. These results will be described and discussed more fully in an article to appear in the journal in the near future.

You may wonder why we are still interested in teaching memory skills if the effects diminish over time. We were not surprised to find the effect of the training had disappeared after nearly three years. The children we saw have not continued with memory training. What the children had been taught was a skill which, like most skills, needs to be practised to be maintained. If we had taught the children reading skills for a short period and then stopped, we would be not be surprised some years later to discover they were no longer reading.

Despite the loss of the memory skills over time, this research has given us some important information. We know now that it is possible to extend the memory capacity of children with Down syndrome. The fact that they achieved longer memory spans, if only for a short time, shows that the limited spans we normally find are due more to a lack of strategy or understanding on the part of the person with Down syndrome about how to remember, rather than being limited by their biology.
Current research

This academic year we have started a new project which aims to train as many children as possible with Down syndrome in Surrey. We want to make sure the effects of the training found in Irene’s study can be reliably reproduced, to look at possible differences in the effects for children of different ages, and hope to find out more about the memory process generally. In addition, we are hoping that after the initial intensive memory training course, the schools taking part will feel able to continue using the training materials on an occasional basis sufficient to maintain the skills. Our hope is that, if working memory capacity can be sufficiently improved, and the improvement can be sustained over time, then we may see it having some effect on the aspects of language development described earlier. In other words, that the children will find learning new vocabulary easier and that their reading comprehension will be better.

An important aim of this memory research has been to devise a programme and materials suitable to offer parents and schools for training the children. We have now produced a special "memory trainer". This is available for sale, together with a set of about 60 pictures and full instructions for training the rehearsal strategy. The pictures have been commissioned from a professional artist by The Down Syndrome Educational Trust and are very attractive. If you are interested in buying the training package, see the advertisement in the next Newsletter.
Who should train memory skills?

Irene trained some of the children herself and others were trained by "keyworkers" who were either parents, teachers or teaching assistants. The training was successful, and the children enjoyed learning, whoever worked with them. What we think may be more important is that the children continue to practise the skills in the longer term. If the initial training takes place at school, then when the child moves up to a new class, the new teacher needs to be told about the rehearsal training. If the training takes place at home, parents need to ensure that the skill is maintained beyond the initial sessions.

We do know that training memory skills can lift the memory performance of children with Down syndrome. We do not know yet whether maintaining this improved performance will have an effect on the children’s language development. But we do think it is worth trying to find out.
References

1. Baddeley, A.D. & Hitch, G.J. (1974) Working memory in G. Bower (Ed.), The Psychology of Learning and Motivation, (Vol.8). New York: Academic Press
2. Baddeley, A.D. (1986) Working Memory. Oxford: Oxford University Press
3. Gathercole, S.E. & Baddeley, A.D. (1993) Working Memory and Language. Hove: Lawrence Erlbaum Associates
4. Hulme, C. & Mackenzie, S. (1992) Working Memory and Severe Learning Difficulties. Hove: Lawrence Erlbaum Associates.
5. Broadley, I. & MacDonald, J. (1993) Teaching short-term memory skills to children with Down syndrome. Down syndrome: Research and Practice, 1, 56-62. Available Online: http://www.down-syndrome.net/library/periodicals/dsrp/01/2/056/
6. Broadley, I., MacDonald, J., & Buckley, S. (1994) Are children with Down syndrome able to maintain skills learned from a short-term memory training programme? Down syndrome: Research and Practice, 2, 116-122.