380 THE POPULAR SCIENCE MONTHLY. 



ON ACQUIRED FACIAL EXPRESSION. 



BY LOUIS EOBINSON. 



A LTHOUGH from infancy upward we are all, whether we 

 -*- know it or not, close students of physiognomy, and although 

 a number of books, the result of much careful research, have 

 been published upon the scientific aspect of the subject, there are 

 certain facts connected with facial expression which, though often 

 remarked upon, have never received explanation. With two of 

 these both of which bear upon the causes of acquired expression 

 of a more or less permanent character I propose briefly to deal 

 in this article. I refer to the similarity of visage displayed by 

 nearly all members of certain trades and professions ; and to the 

 likeness which often becomes apparent on the faces of people 

 (generally married couples) who live together. 



In addition to the bony framework, there are three chief 

 anatomical factors which go to make up the expression of the 

 face. These are the skin, the subcutaneous cushion of fat which 

 contains the numerous blood-vessels, and, lastly, the facial mus- 

 cles. The nerve supply is abundant and peculiar. The integu- 

 ment receives sensory branches from the fifth cranial nerve, the 

 blood-vessels are under the control of the sympathetic system, 

 and the muscles which have to do with expression receive motor 

 impulses from the brain via the seventh cranial or facial nerve, 

 first accurately described by Sir Charles Bell. It is to these 

 numerous slips of muscular tissue, with their controlling tele- 

 graphic nerve fibers, that I wish especially to direct attention. 



It is, of course, obvious to all who have an elementary knowl- 

 edge of physiology that any movement of any part of the face is 

 owing to the contraction of certain muscles, and that every such 

 contraction must take place at the command of an impulse con- 

 veyed to the muscles by means of the motor nerves. 



Into the historical evolutionary explanation of these move- 

 ments it is not my intention here to enter. Let it suffice to say 

 that there can be little doubt that they one and all represent some 

 adaptation of the bodily structures to certain physical needs (pos- 

 sibly long obsolete) which accompanied the emotions of which 

 the movements are now an index ; just as the wagging of a dog's 

 tail, which is now regarded as a mere sign of pleasurable excite- 

 ment, was in the first place of vital importance as a signal to his 

 comrades that game was afoot. 



The connection between the muscles of expression and the 

 emotional centers in the brain is of a most intimate character, and 

 is largely independent of the will, although by strong volition 

 any consequent movement of the features may generally be pre- 



