— Cognitive concept
Working Memory
The cognitive system that temporarily holds and manipulates information during reasoning.
Working memory is the cognitive system that holds information in mind while you actively manipulate it. It's the difference between remembering a 7-digit phone number long enough to dial it (short-term storage) and rearranging those digits in reverse order before dialling (working memory).
Why it matters for IQ
Working memory is one of the strongest individual correlates of fluid intelligence. People with higher working memory capacity can hold more variables in mind during reasoning tasks, which directly enables more complex problem-solving. The Working Memory Index (WMI) is one of the four major indices on the modern WAIS-IV.
How it's measured
The classic test is digit span backward — repeat a sequence of digits in reverse order. People with average working memory can handle 5-7 items; people in the gifted range often handle 8-10. The N-back task is another well-studied measure.
Can working memory be trained?
This was a hot research topic in the 2010s, driven by companies selling brain-training games. The honest answer: working memory training improves performance on the trained task but transfers poorly to other cognitive tasks and barely at all to general intelligence. Adequate sleep is the single biggest lever for actual working memory performance.
Related concepts
- Fluid Intelligence
- Crystallised Intelligence
- The g-factor (general intelligence)
- The Flynn Effect
- Verbal IQ