PSYCHOLOGICAL PROGRAM AND TECHNIQUE. 



185 



The subject very easily understood his task. He had to be especially 

 warned, however, to hold his head still by keeping it pressed firmly 

 against the rest and biting on the soft wooden peg with his teeth. He 

 was repeatedly told that he must make his eye do all the moving and 

 that he should see one mark clearly before looking for the other. The 

 subject was instructed also to refrain from winking at the time of moving 



Fig. 50. — Ground plan of the apparatus and arrangement for photographing eye movements. 



S, black screen surrounding the subject's field of view; R and L, right and left fixation marks sepa- 

 rated by 40°; H, hood of camera; Z, lens in front of subject's eye, E; M^ and M^, mirrors for 

 reflecting beam of light indicated by arrows; 2, frame carrying shield, ^, drops down and 

 exposes eye to light as signal for movements to begin; C, cords for operating eye-reaction, 

 stimulus device. The camera, located at the other end of the hood H, is not indicated in 

 the diagram. 



the eye.^ The black screen which enclosed the subject's field of view 

 (5, figure 50; B, figure 35) was of particular service in eliminating all 

 distracting objects, so that it was unnecessary to warn the subject to 

 refrain from looking at other objects than the correct fixation-points. 

 Two series of movements were recorded on each photographic plate. 

 The camera was moved slightly to one side at the beginning of the sec- 



'Miles, Carnegie Inst. Wash. Pub. No. 266, 1918, p. 81. 



