Some Aspects of Attention 319 



tion is improved. Further, attention involves varying de- 

 grees of effort, and these are marked by varying intensity of 

 certain bodily processes. Attention under difficulties is 

 accompanied by a rigid position of the body, by holding the 

 breath, and by various muscular effects, aside from the pro- 

 cesses which, like frowning, are concerned with the adapta- 

 tion of the sense organ to receive an impression. These 

 general bodily effects of attention are all such as to suggest 

 that the body is to be kept as quiet as possible during the 

 attentive state. In other words, no reaction is to be made 

 to the object attended to except such as may be necessary 

 to allow its being carefully discriminated from other 

 objects. Attention, in its intenser degrees, at least, seems to 

 involve a state of suspended reaction. 



Not every case, then, of response adapted to the vital im- 

 portance of a stimulus is a case that suggests as its psychic 

 aspect attention to the accompanying sensation. When, for 

 example, a reaction of especial speed is made to contact with 

 a moving stimulus, the speed of the reaction would itself 

 indicate that the sensations produced are not attended to. 

 The proper situation for attention would be the situation in 

 which the reaction needs to be suspended until the stimu- 

 lus is fully discriminated. Now such careful discrimination 

 does not appear to be characteristic of reactions that are 

 largely based on inherited nervous structures. Many facts 

 concerning the instincts of animals, that is, their inherited 

 reactions, indicate that these are extremely rough adjust- 

 ments of behavior to environment until refined by individual 

 experience. Hudson observed, for example, that newly 

 born lambs on the South American plains had a tendency to 

 run away from any object that approached them, and to 

 follow any object that receded from them. They would 

 follow his horse for miles as he rode along, and would run 



