Theoretical and practical considerations in the design of special-purpose keyboards and operator training procedures
This thesis deals with theoretical and practical issues of special-purpose keyboard design and operator training precedures. It is in two parts.The research discussed in Part A was carried out in support of two contracts from the Post Office and had two main objectives: first, to provide information needed for the selection of a new keyboard design for use on foreign destination coding desks and second, to evaluate one component of a computerbased training system for operators of the new keyboard.In relation to the first objective, four keyboard designs were evaluated, namely the 2x6,4x4,10-key chord and 10-key sequential. On the basis of the results of three experiments, the 10-key chord keyboard was chosen and recommended to the Post Office as the most efficient of the four layouts.The computer-based training system for operators of foreign destination letter coding desks consists of three stages. In this thesis only the first such stage is discusssed, namely the Keyboard Familiarization, which involves developing the skill of keying chord patterns. Four different computer-based training methods are presented, discussed and evaluated in an experiment specifically designed for this purpose.The main issue of Part B is speed-accuracy tradeoff relationships in a keyboard task. Following a discussion of the limitations of typical Choice Reaction Time models and the benefits of studying speed-accuracy tradeoff relationships, another analysis of the data of Experiment 4 is presented. In this analysis, the speed and accuracy of any given response are examined in terms of those of the preceding response.These findings are discussed in the light of established theories and it is concluded that no known theory can fully account for the obtained results. A new theoretical model is presented to explain them. Finally, this new model is assessed and its implications for keyboard operation and operator training are considered.