22 Thaddeus L. Bolton and Eleonora T. Miller 



feeling of effort is the psychological correlate of a bodily atti- 

 tude. To make an effort is to place the body in the position in 

 which all the muscles whose contractions can assist at all in the 

 task are made to contract simultaneously and successively in 

 the direction that will accomplish the work best. Efforts and 

 feelings of effort are accompaniments of more or less widespread 

 bodily activities. In this respect they relate themselves to the 

 emotions with this distinction — that in effort it is the voluntary 

 muscles that take the leading parts. The emphasis is laid upon 

 them. When any effort is to be made, there is a tendency to 

 revert to former types, to primitive modes of acting, such as are 

 found in instinctive performances, where all the bodily move- 

 ments are directed toward a single point, as upon an enemy in 

 combat. All the muscles are innervated even when the contrac- 

 tion of one is desired, and too when the contraction of that one 

 will better suffice alone. How, then, do the accessory movements 

 that thus arise fall out and disappear, leaving only the desired 

 muscular contraction? The method is that of trial and error 

 which is the principle that seems to underlie all learning. An 

 effort is made and a large group of muscles contract, the essential 

 and the inessential. In the following effort there appears a ten- 

 dency for the muscles in the group to vary in relation to one 

 another with respect to the parts they take in the movement. 

 Let us say that some inessential muscles do not join in the proc- 

 ess. The contraction is successful. The absence of these is 

 noted and in the next effort care is taken to see that they remain 

 uncontracted. Their association with the essential muscles is 

 thus broken up and their contractions become less likely to arise 

 during succeeding efforts. In this way one after the other of the 

 accessory contractions is eliminated until the movement is re- 

 duced to its lowest terms. But let us suppose that in the ten- 

 dency of the group to vary some essential muscle fails to con- 

 tract, in which case the contraction is not a success. This is 

 noted by the reagent and it is seen to that the former group is 

 contracted together. Thus the tendencies to vary are checked 

 when essential elements are dropped and augmented when ines- 

 sential elements fail to appear. If this tendency to vary is 



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