xlviii Journal of Comparative Neurology. 



vision, to less extent, among the mountaineer Indians. It is a matter 

 of common observation that young children often exhibit a tendency 

 to look at pictures reversed. The explanation offered by Dr. Cook 

 that the image is more easily interpreted by reason of the reversion of 

 the image upon the retina is obviously untenable, for the same thing 

 would then apply to natural objects. A tentative explanation may 

 be offered as follows : In the child the position of the image upon the 

 retina is an absolutely indifferent matter, and is interpreted by experi- 

 ence as a result of association. To the child, as to the savage, the 

 picture is, in a manner, an unoriented image, and sustains no neces- 

 sary relation to his own person (the only absolute standard). When 

 then orientation is attempted it is natural that objects which stand 

 highest in the field of view and thus nearest the head should be placed 

 in such a position as to be actually nearest the observer. This pro- 

 duces a reversed position which is only corrected when the person 

 comes to make a direct comparison of the pictured with the real 

 image. 



The Origin of Right-handedness. 1 



Professor Baldwin has carried out some very interesting experi- 

 ments respecting the causes which lead to the development of one 

 side in advance of the other. 



It was found in the case of the child experimented upon that dur- 

 ing the fifth to ninth months of her life there was no appreciable pre- 

 ference for the right hand when an object is placed within easy reach 

 and equally accessible to both hands. When, however, the object was 

 placed so far away as to be out of easy reach the right hand was al- 

 most uniformly employed; thus, when the object was twelve inches 

 away the right hand was used twenty-nine times and the left only five 

 times while severer distance tests called out the right hand uniformly. 



Again if the object were exhibited at one side of the median line 

 the result was the same except that the right hand was called more 

 strongly into action. The use of colored objects proven to be espe- 

 cially attractive to the child had the same effect. It should be noticed 

 that the tendency to use both hands in grasping at near objects is 

 twice as great as that to use either separately and where one hand is 

 preferred the other tends to symmetrically accompany it. A survey of 

 correlated facts leads to the view that there is a fundamental connec- 

 tion between the rise of speech and the rise of right-handedness. 



Baldwin, J. M. Pop. Science Monthly, XLIV, 5. 



