VOLUNTARY ACTIVITIES 



219 



snidi brain 



' level 



mvcscle 



spinocl 

 cTora 



evidently not fixed and invariable but are flexible and modifiable 

 and may become changed or conditioned by factors in the environ- 

 ment. The organism begins to 

 relate factors in the environment 

 to his activity. This results in 

 the changing of the original re- 

 flex. Certain acts may be con- 

 sciously inhibited, that is, di- 

 verted or blocked. For example, 

 a child instinctivelv makes known 

 his wants by crying. He has 

 learned that when he cries, he has T6<i^toj- o^'ral' ' effector 



always been picked up. One day, in response of the second level, centers 

 ■I n 1 .1 j_ • 1 ii^ the spinal cord and mid-brain exercise 



ne fands that crymg does not control, a number of activities wui re- 

 bring the desired attention. He ^""' 



stops after a while, and, in time, learns to express his wants in 

 another way. The changing is due to consciousness. It probably 

 explains the beginning of the learning process or conscious acts. 



Voluntary activities. Any act involving will or thought is a 

 voluntary act. The name '' voluntary " refers to the wdll. All 

 activities, excepting the so-called inherited reactions, performed 

 for the first time are voluntarv acts of the will. When the 

 activity requires attention, memory, judgment, or association, a 

 great many associative neurons are used. For example, the hand 

 is put in water and is held there while a decision is made as to 

 whether the water is of the desired warmth. Then the hand is 

 withdrawn. The sensation is received by the skin as the receptor. 

 The impulse travels along an afferent axon to the spinal cord, up to 

 the brain. A number of neurons located in the brain are stim- 

 ulated, bringing about a condition of consciousness, and resulting 

 in attention. Meaning becomes attached to the sensation that has 

 been received and a mental decision is possible. A comparison may 

 be made with previous water used in washing ; the thought may 



