EFFECTS OF ALCOHOL ON HAND AND EYE 

 COORDINATION 



KNIGHT DUNLAP 



The Johns Hopkins University 



In work at various times during the last five years, I have 

 noticed certain effects of alcohol on hand^nd eye coordination, 

 which resemble the effects of oxygen insufficiency. In some 

 cases where the alcoholized reactor shows little mental effects, 

 and little effect on most motor coordinations, there is neverthe- 

 less a noticeable deterioration in voluntary movements of the 

 hand and fingers where both speed and accuracy are required, 

 as in marking charts, drawing simple figures, or in writing. 

 Great individual differences are also found in this respect. In 

 order to make further tests on this point, and to obtain methods 

 which might possibly be applied to the study of causes of ineffici- 

 ency other than alcoholic, the test sheet reproduced in figure 1 

 was made up. 



In this sheet, nine pathways are provided across the page, 

 each pathway having 20 turns at right angles. The pathways 

 are approximately J inch wide, and the distance straight across 

 from the beginning of each to the end is a trifle over 5 inches. 

 Certain confusion lines are added to demand strict visual atten- 

 tion. The beginning of each pathway is marked by an "x." 



In the test, the reactor is required to trace each pathway with 

 a pencil, starting from the cross at one end, and not touching 

 any line of the sheet. To provide uniformity, a metronome is 

 used, and the reactor required to trace each straight portion of 

 the pathway with one beat of the metronome. Tracing a single 

 pathway, from left to right requires therefore twenty-one beats 

 of the metronome. By adjusting the rate of the metronome, 

 the proper degree of difficulty can be secured. Each stroke of 

 the pencil is approximately f inch long, and the strokes required 



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