Working Memory Characteristics and Functions

Working memory is the cognitive structure in which conscious processing occurs. 

We are only conscious of the information currently being processed in working memory and are more or less oblivious to the far larger amount of information stored in long-term memory. 

Working memory has two well-known characteristics: When processing novel information, it is very limited in duration and in capacity. 

We have known at least since Peterson and Peterson (1959) that almost all information stored in working memory and not rehearsed is lost within 30 sec and have known at least since Miller (1956) that the capacity of working memory is limited to only a very small number of elements. 

That number is about seven according to Miller, but may be as low as four, plus or minus one (see, e.g., Cowan, 2001). 

Furthermore, when processing rather than merely storing information, it may be reasonable to conjecture that the number of items that can be processed may only be two or three, depending on the nature of the processing required. 

The interactions between working memory and long-term memory may be even more important than the processing limitations (Sweller, 2003, 2004). 

The limitations of working memory only apply to new, yet to be learned information that has not been stored in long-term memory. 

New information such as new combinations of numbers or letters can only be stored for brief periods with severe limitations on the amount of such information that can be dealt with. 

In contrast, when dealing with previously learned information stored in long-term memory, these limitations disappear. 

In the sense that information can be brought back from long-term memory to working memory over indefinite periods of time, the temporal limits of working memory become irrelevant. 

Similarly, there are no known limits to the amount of such information that can be brought into working memory from long-term memory. 

Indeed, the altered characteristics of working memory when processing familiar as opposed to unfamiliar material induced Ericsson and Kintsch (1995) to propose a separate structure, long-term working memory, to deal with well-learned and automated information. 

Any instructional theory that ignores the limits of working memory when dealing with novel information or ignores the disappearance of those limits when dealing with familiar information is unlikely to be effective. 

Recommendations advocating minimal guidance during instruction proceed as though working memory does not exist or, if it does exist, that it has no relevant limitations when dealing with novel information, the very information of interest to constructivist teaching procedures. 

We know that problem solving, which is central to one instructional procedure advocating minimal guidance, called inquiry-based instruction, places a huge burden on working memory (Sweller, 1988). 

The onus should surely be on those who support inquiry-based instruction to explain how such a procedure circumvents the well-known limits of working memory when dealing with novel information.

Source : https://www.tandfonline.com/doi/pdf/10.1207/s15326985ep4102_1?needAccess=true