12-7] IMPORTANT CHARACTERISTICS OF THE HUMAN OPERATOR 647 



10 20 30 40 



TIME IN DARK (minutes) 



Fig. 12-29 Effect of Low Oxygen Tension on Sensitivity of the Visual System. 



With the advent of high-speed systems, the importance of time of 

 response or recognition becomes a critical factor in the design of the system. 

 When the human operator is part of the system, his response characteristics 

 can influence design. Fig. 12-30 shows the result of an experiment in which 



□ 0.1 Effective Foot Candles 



0.5ft Diameter 



8.0ft Viewing Distance 

 o 2.0 Effective Foot Candles 



3.0ft Diameter 



12.0ft Viewing Distance 



3 4 5 6 7 

 NUMBER OF CIRCLES 



Fig. 12-30 Reaction Time as a Function of Display Variables. 



