INDIVIDUAL CASES
100 mm. hand with compound motions.
A glance at the charts shows for individual records a few examples of inhibition of voluntary control for both constant and mean errors, it being much more marked in the case of mean errors.
These lapses of control appear for constant errors for A. with l.h.e.c. at 160 and 180 beats, for mean errors for G. with l.h.e.c. at 200 and with r.h.e.c. at 180 beats; for Le. with l.h.e.c. at 50 and with r.h.e.c. at 160 beats; for A. with l.h.e.c. at 200 beats; thus giving evidence that the visual element has a steadying effect, and that the left hand is less reliable save for Le.
There seems reason for contending that the compound motion can be carried out, as arranged, without loss of accuracy or regularity on the part of the ruling hand, and further that the subjects are pretty generally apt to react to a given stimulus within certain rather narrow limits of accuracy.
The evidence is here pretty conclusive that the right-handed subjects, as a whole, show greater accuracy by about 25% for the more dexterous hand; but it will be wise to consider the individual cases on this point.
Greater regularity and accuracy for the right hand is attained by all right-handed subjects, while the preference of Le. for the left hand is clear but much less definite.
For individual cases:
The evidence again is fairly well marked that the more practised hand will give a better account of itself even when visual control is not called on.
The results for compound movements of the hand for 1 and 10 cm. lines are summarized as follows: