260 BIOLOGICAL ASPECTS^OF HUMAN PROBLEMS 



Another faculty, closely connected with the 

 quality of beauty, is the almost instinctive analysis 

 of objects with respect to symmetry. In nature the 

 property of bilateral symmetry, especially vertical 

 symmetry, is extremely widespread. We see it in 

 animals, in man, in trees, fruits, leaves, and flowers, 

 and in many inanimate objects. So accustomed are 

 we to such symmetry that we lose sight of its impor- 

 tance as an element of beauty. A few simple experi- 

 ments will convince any one that even the most 

 irregular scrawl attains a certain quality of interest 

 or even of beauty when so duplicated as to form an 

 outline having vertical symmetry. The explanation 

 of this aesthetic quality is to be found in the peculiar 

 arrangement of visual perception in the cerebral 

 cortex, through which each half of a vertically 

 symmetrical object is twice represented in the same 

 perceptual centers. 



Visual impressions may be devoid of aesthetic 

 quality, or they may be distasteful, or they may be 

 distinctly agreeable and make the appeal which we 

 designate the beautiful. Few impressions are quite 

 indifferent in respect to aesthetic quality, there being 

 nearly always something in form, color, or compo- 

 sition capable of exciting pleasure in sensitive and 

 trained nervous mechanisms. On the other hand, 

 however low may be the aesthetic quality of a visual 

 impression, it is almost certain to yield to the intellect 

 some information having some grade of value in 

 self-preservation. From this standpoint nothing is 



