ABSTRACT
The mental workload associated with performing a cognitive task is a limiting factor in the efficiency of performance. Such tasks can be seen as loading up working memory. There is a tendency to consider working memory capacity as being limited by the number of ‘chunks’ of information held in short-term memory (Miller, 1956) or in terms of the time taken to rehearse items by repetition (the word length effectBaddeley et al. 1975). However we argue that there is indeed a capacity limitation in terms of the amount of information that can be retained by rehearsal but this is less important than the through put per unit of time. This has been dealt with in a more elaborate form elsewhere (Morris, 1991).
