PSYCHOLOGICAL MEASUREMENTS. 



617 



Table 179. — Range of eye-movement speeds 

 shown by a group of 6S normal men, 

 series of 1917. 



[Records taken from the right eye and with 

 the left eye covered.] 



series of 63 left movement averages is 13.9 a, showing a coefficient of 

 variability within the group of 13 per cent. The movements to the 

 right fall within a narrower range than those for the left. The average 

 fastest speed is 75, and the slowest 128. The distribution between 

 these extremes is sensibly normal, the mode occurring at 91 to 100. 

 The average for the whole series of 63 individual averages is 97.8 cr. 

 The standard deviation is 11.7 (t and the coefficient of variability for 

 movements right therefore equals 12 per cent. 



The measurements taken on the normal subjects during normal 

 experiments by Dodge and Benedict in connection with their alcohol 

 investigation gave the following results as averages of the first normal 

 series for 7 subjects: Speed for movements to the left, 101 a] for move- 

 ments to the right 99 <t. There is 

 fair agreement between these to- 

 tally different groups of individ- 

 uals. 



With the subjects used by Dodge 

 and Benedict, the eye movements 

 were taken in the afternoon and 

 evening. In the case of the nor- 

 mal series of 1917 the time of day 

 was always between 7 and 10 p.m. 

 and following a hearty supper. 

 The measurements with the sub- 

 jects on reduced diet were inva- 

 riably taken in the morning and 

 following the light breakfast at 

 the Laboratory. The eye reac- 

 tions and eye movements were 

 successive measurements. 



The average results for Squads A and B are given in tables 180 and 

 181. We have no normal records for Squad A. The first three dates, 

 that is, November 4, 18, and December 16, for Squad B are normal in 

 the sense that the diet had not then been reduced. November 4 (see 

 table 181) shows an average for movements to the left of 95.1 (r, and 

 for movements to the right of 88.9 <j. The time required for move- 

 ments of 40° to the left, registration being from the right eye and with 

 the left eye covered, is noted to be longer than similar movements to 

 the right. As this is seen to be characteristic of the records for the 

 low-diet research, it is prominent also in the averages of the normal 

 series of 1917, and moreover in the normal records taken by Dodge 

 and Benedict. The reason for this discrepancy between the time 

 requirement for right and left movement can not be definitely assigned 

 at this time. We have considerable data on the problem and it is 

 under investigation at the Nutrition Laboratory. The averages for 



