=Psychological Warfare as a Branch of Psychology.= Good propaganda can be conducted by persons with no knowledge of formal psychology. The human touch, the inventive mind, the forceful appeal--things such as these appear in the writings of gifted persons. Thomas Paine never read a word of Freud or Pavlov, yet Paine's arguments during the Revolutionary War played subtly on every appeal which a modern psychologist could catalogue. But war cannot, in modern times, assume a statistical expectation of talent. Psychology makes it possible for the able but ordinary statesman or officer to calculate his persuasion systematically and to obtain by planning those results which greater men might hit upon by genius. What can psychology do for warfare? In the first place, the psychologist can bring to the attention of the soldier those elements of the human mind which are usually kept out of sight. He can show how to convert lust into resentment, individual resourcefulness into mass cowardice, friction into distrust, prejudice into fury. He does so by going down to the _unconscious_ mind for his source materials. (During world War II, the fact that Chinese babies remain unimpeded while they commit a nuisance, while Japanese babies are either intercepted or punished if they make a mess in the wrong place, was found to be of significant importance in planning psychological warfare. See below, page 154.) In the second place the psychologist can set up techniques for finding out how the enemy really does feel. Some of the worst blunders of history have arisen from miscalculation of the enemy state of mind. By using the familiar statistical and questionnaire procedures, the psychologist can quiz a small cross section of enemy prisoners and from the results estimate the mentality of an entire enemy theater of war at a given period. If he does not have the prisoners handy, he can accomplish much the same end by an analysis of the news and propaganda which the enemy authorities transmit to their own troops and people. By establishing enemy opinion and morale factors he can hazard a reasoned forecast as to how the enemy troops will behave under specific conditions.