The ability to store more items in short-term memory indicates a higher IQ, psychological research reveals.
While there may be no limit to long-term memory, short-term memory is much smaller.
The average number of things people can store in short-term memory — whether words, numbers or whatever — is four.
Short-term memory only lasts around 15 to 30 seconds.
Being able to store more than this, suggests an above-average IQ.
However, being able to store these items clearly is NOT linked to IQ.
Dr Keisuke Fukuda, the study’s first author, said:
“Clarity, relates to how well a person can detect small changes.”
In other words, high IQ is linked to the quantity of items a person can store in short-term memory, not the quality.
For the study, 79 people had their fluid intelligence tested.
Fluid intelligence refers to the speed at which the brain works.
It is like the raw power of an engine or the speed at which a computer can process information.
They were then shown between four and eight items on a screen at the same time.
After a second they were shown another object and asked whether it had appeared in a particular location.
People with higher fluid intelligence were better at remembering if they had seen the item before.
However, people with higher fluid intelligence were no better at remembering where the item had been.
Professor Edward Awh, study’s co-author, said:
“The number of things people can remember is robustly correlated with fluid intelligence — the larger number remembered, the higher the IQ.
Resolution in memory is not predictive of IQ at all.”
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The study was published in the journal Psychonomic Bulletin & Review (Fukada et al., 2011).