BIOLOGY IN HUMAN AFFAIRS 



ahead of him beside the tracks. He must not be easily 

 susceptible to distraction or to panic. There are certain 

 skills and correct job habits which need to be thoroughly 

 automatized. In many respects the requirements are similar 

 to those of the crane operator, the aviator, the locomotive 

 engineer, the chauffeur, or any one who has to control a 

 moving machine, manipulating handles by means of move- 

 ments which are relatively simple but which must be 

 made at the right time, quickly and correctly, in the midst 

 of a changing situation. 



We fitted up a modest psychological laboratory near the 

 offices of the medical examiner and the supervisor of 

 employment and training. When men came to take a 

 physical examination, some psychological tests were also 

 given, designed to measure speed and accuracy of response, 

 consistency of serial action, flexibility, oscillation, per- 

 severation, resistance to distraction, range of peripheral 

 vision, and similar attributes. Some of the tasks consisted 

 of pressing the right buttons as various electric lights 

 flashed momentarily. Other tests made use of the familiar 

 street-car controls — the electric power handle, air-brake 

 lever, gong, etc. — all connected with suitable recording 

 apparatus. 



These psychological tests were used for research and as 

 clinical aids to supplement, in certain instances, the analy- 

 sis of a man's difficulties made by studying the detailed 

 descriptions of his accidents, interviewing him, and observ- 

 ing him at work. A number of supervisors were specially 

 trained to ride with the motormen and note the points 

 on which they individually needed further training or 

 supervision. A man's accident record was first examined to 

 see whether there was a particular type of accident to 

 which he was prone. One man had had five collisions in as 

 many months. The supervisor who observed him in action 

 reported that he was competent, skillful, and careful. 



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