Automating Blood Pressure Measurements: The Division of Labour and the Transformation of Method

To what extent can computers undertake ‘human’ tasks, and what role do people play when computers begin to do ‘their’ jobs? This chapter offers an empirical analysis of the scope of medical computers in everyday applications, using, as a vehicle for investigation, a machine that is designed to detect and measure human blood pressure (BP). The paper describes experiments using ‘novice’ volunteers who, following written instructions, attempted to measure BP with a traditional sphygmomanometer. Producing reasonable results proved extremely difficult: the procedure is inherently complicated. It is clear that more experienced staff also deviate from the ideal instruction-based model: variations in techniques and results are widespread. But fieldwork shows that the machine, introduced to standardize the process, is successful: it produces acceptable readings that are comparable over time. The paper investigates how the machine is able to do this. I argue that the division of tasks between human and sphygmomanometer, and between human and computer, has changed. The computer now performs what was previously a human task — but only a slice of the overall task. Furthermore, the computer uses a technique that is different from that traditionally used by people. The task is transformed during its automation. I suggest why some other tasks may be suitable for computerization, and why some that are not should remain essentially human, social activities.