ABSTRACT
It is tempting to view human memory as an archive that the individual draws upon to perform a range of activities many of which are concerned with procedures relating to work. Indeed some researchers have acknowledged that our long-term memory specifically stores such procedural memory and this type of memory tends to remain intact even when brain damage leads to profound amnesia (Lishman, 1987). However, material withdrawn from long-term memory, and fresh input from external sources, is represented in working memory, i.e. real-time memory, and the contents of this real-time memory change second by second unless we retain material by some type of rehearsal. Because our working memory has a very limited capacity (within a given time period) and it is subject to a perpetual influx of new material while we are conscious its usefulness is limited by the rate at which we can update its contents (Morris, 1991). Memory updating involves the extraction of useful input and its synthesis with other material held in consciousness in real-time. For example, if one is reading a book then sentences are parsed and ones
understanding of the text is updated but the verbatim text is not held. One extracts meaning, in real-time, and what is extracted is largely dictated by ones current understanding of the story at the time of reading. Someone who can do this more rapidly than another individual while attaining the same level of comprehension could be said to be a more efficient real-time processor. However such real-time data capture and synthesis need not be limited to the process of reading; the role of memory updating has been stressed in air traffic control (Yntema, 1963) and within command and control scenarios (Morris and Jones, 1988; Morris, Milne, Jones and Quayle, 1991). This literature is reviewed, from an ergonomic standpoint, by Morris (1991) and in theoretical terms by Morris and Jones (1990). Indeed it could be argued that memory updating may be a limiting factor in the comprehension of what is happening in the workplace (or elsewhere) at any given moment. Our own simulations of complex tasks, described in the above papers, suggest that information overload occurs largely because human real-time processing rate lags behind the rate of input into working memory.
