> By taking away the easy parts of his task, automation can make the difficult parts of the human operator's task more difficult. Several writers (Wiener and Curry, 1980; Rouse, 1981) point out that the 'Fitts list' approach to automation, assigning to man and machine the tasks they are best at, is no longer sufficient. It does not consider the integration of man and computer, nor how to maintain the effectiveness of the human operator by supporting his skills and motivation.