Interaction of concurrent generative and expressive activity in production of typewritten lists

Ten touch-typists type lists of abbreviated month names under four directional instructions (Forward, Backward, Centre-out and End-in). The lists were typed on a teletype unit linked to a laboratory computer, and the duration of Start, Inter-word, Inter-letter, carriage Return, and Quit response times (RTs) were recorded throughout production of each list. The major effects of direction of listing were on the Inter-word RTs. However, there were also consistent effects on Inter-letter RT (an index of keyboard skill) and Return RT (an index of list formatting operations). These results are discussed in relation to the notion of a ‘working memory’ of limited capacity.