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4. Working memory

Working memory can be thought of as a mental notepad that is used for storing information in mind for a short period of time whilst thinking about another task. For example, maintaining in mind a long list of instructions while implementing each step.

There is a limit to the amount of information that can be held in working memory. Working memory capacity gradually increases during childhood, reaching adult levels at around 14-15 years of age.

Working memory is important for learning and engaging with activities at school. It is important for remembering and following a list of instructions. Working memory is particularly involved in maths, for example to solve a mental arithmetic problem where interim solutions must be held in mind.

Watch this example of a typical task that researchers use to assess working memory capacity in children

Narrator: Similar tasks can be used to assess both short-term memory and working memory. Short term memory is the capacity for holding information in mind ready for use. One way to assess a child’s short term memory capacity is to use a digit span task, like this one:

Researcher: I am going to read out some numbers. I want you to repeat the numbers that I’ve read out in exactly the same order. So if I say “2, 7”, you say “2, 7”, ok? So let’s try one: 9, 5.

Child: 9, 5.

Researcher: Good job! Ok let’s try another one. This list will have three numbers in it. Are you ready? 7, 3, 4.

Child: 7, 3, 4.

Researcher: Good job!

Narrator: If the child responds accurately, the length of the list can be gradually increased until the child starts to have consistent difficulties. The length of the list that the child can consistently repeat back in the correct order can be considered their short term memory span.

Working memory differs from short term memory. Working memory involves processing and manipulating information held in mind, and remembering the outcome. A slightly similar task, called a backwards digit span task, can be used to assess a child’s working memory capacity, where the child is required to process the digits and repeat them back in the reverse order.

Researcher: This time I am going to read out some numbers and I want you to repeat the numbers in the reverse order. So if I say “3, 6”, you say “6, 3”, ok? So let’s try one: 1, 8.

Child: 8, 1.

Researcher: Good job! Ok, let’s try another one. This list will have three numbers in it. Are you ready? 5, 4, 9.

Child: 9, 4, 5.

Researcher: Well done!

Narrator: An average adult can process approximately five unrelated words or numbers in their working memory. However, the average five-year-old can only remember 2 unrelated words or numbers.