In 1956, Miller first reported on a capacity limitation in the amount of information the human brain can process, which was thought to be seven plus or minus two items. The system of memory used to process information for immediate use was coined “working memory” by Miller, Galanter, and Pribram in 1960. In 1968, Atkinson and Shiffrin proposed their multistore model of memory, which theorized that the memory system was separated into short-term memory, long-term memory, and the sensory register, the latter of which temporarily holds and forwards information from sensory inputs to short term-memory for processing. Baddeley and Hitch built upon the concept of multiple stores, leading to the development of the multicomponent model of working memory in 1974, which described two stores devoted to the processing of visuospatial and auditory information, both coordinated by a central executive system. Later, Cowan’s theorizing focused on attentional factors in the effortful and effortless activation and maintenance of information in working memory. In 1988, Cowan published his model—the scope and control of attention model. In contrast, since the early 2000s Engle has investigated working memory capacity through the lens of his individual differences model, which does not seek to quantify capacity in the same way as Miller or Cowan. Instead, this model describes working memory capacity as the interplay between primary memory (working memory), the control of attention, and secondary memory (long-term memory). This affords the opportunity to focus on individual differences in working memory capacity and extend theorizing beyond storage to the manipulation of complex information. These models and advancements have made significant contributions to understandings of learning and cognition, informing educational research and practice in particular. Emerging areas of inquiry include investigating use of gestures to support working memory processing, leveraging working memory measures as a means to target instructional strategies for individual learners, and working memory training. Given that working memory is still debated, and not yet fully understood, researchers continue to investigate its nature, its role in learning and development, and its implications for educational curricula, pedagogy, and practice.
