381 THE MAINTENANCE OF THE INDIVIDUAL 



such activities are closely tied up with hormone activity. Definite 

 changes in the body are recognized as associated with certain emotions. 

 Sudden fright causes the heart to beat faster, the hair "stands on end," 

 the face blanches, and the digestive glands cease their accustomed 

 activity. The biologist sees in these physical accompaniments of 

 the "feelings," changes that hark back to native behaviors, actions 

 that make for self-preservation. Under the stress of unpleasant 

 emotions the glandular activities of the digestive tract are reduced, 

 so that more blood flows to the muscles, thus allowing greater muscular 

 activity. The automatic sympathetic nervous system invokes secre- 

 tion from the adrenal glands which in turn tune up the sense organs 

 to greater sensitivity and the circulatory and respiratory systems to 

 greater activity, with a resulting increase in oxygen and in food to the 

 muscles. Emotions are evidently self-preserving activities, but they 

 also add and subtract much from the lives of men. The highly 

 emotionalized person who has his "ups and downs" may get more out 

 of life than his lethargic neighbor, but he also suffers more deeply and 

 may make more mistakes in judgment when under emotional stress. 



What Is Intelligence? 



The term intelligence has been much misused, for we are apt to read 

 our own point of view into the actions of lower animals. Psychologists 

 say that an animal is intelligent when behavior is flexible enough 

 to make it profit by experience. Stereotyped functions having a 

 pattern handed down by heredity have been shown to be native 

 behaviors. Patterns of conduct not inherited, but acquired by 

 many repetitions, are habits. The intelligent act shows choice. It 

 involves analysis of a situation and the comparison of past experi- 

 ences in relation to the present, that is, there must be memory or a 

 record of past events. In addition, the intelligent act also involves a 

 synthesis with past experiences built up with the aid of memory and 

 imagination. Intelligent animals show a certain amount of insight. 

 Intelligence involves the solving of problems, in other words, the 

 directional mind set toward a goal. 



Intelligence in animals appears to be correlated with a definite 

 development of the cortical layer of the cerebrum. Although the size 

 and weight of the brain have little to do with intelligent action, the 

 size of the cerebrum in relation to the rest of the brain is definitely 

 correlated with intelligence. More than this, the number of convo- 

 lutions in the surface of the cerebrum, with a consequent increase 



