Working Memory

Short-term memory refers to the passive temporary retention of a small amount of information over seconds. Working memory is a broader construct that includes not only temporary storage but also active manipulation and use of that information. Baddeley's multicomponent model replaced the unitary short-term memory concept to capture how we hold information in mind while simultaneously working with it — for example, understanding a sentence while reading, or tracking an argument while listening.

George Miller's influential 1956 paper suggested 7 ± 2 items (the "magical number seven"). Nelson Cowan's 2001 analysis revised this downward to approximately 4 chunks of information when rehearsal is prevented, suggesting that Miller's higher estimate reflected the use of rehearsal strategies. Capacity can be extended through chunking — organising individual items into meaningful units, as when remembering a phone number as groups rather than individual digits.

Individual differences in working memory capacity are among the strongest predictors of general fluid intelligence, reading comprehension, and mathematical ability. Working memory appears to support learning by allowing students to hold new information in mind while integrating it with prior knowledge and following multi-step instructions. Children with learning difficulties — including dyslexia and dyscalculia — consistently show reduced working memory capacity compared to age-matched peers.

Research findings are mixed. Some training programmes have shown short-term gains on working memory tasks (near transfer). However, reliable transfer to broader cognitive abilities — fluid intelligence, academic attainment — has been difficult to demonstrate, and effects often fade over time. A 2019 meta-analysis by Sala and Gobet concluded that working memory training programmes produce limited and short-lived benefits beyond the trained tasks themselves.