CAREFUL READING
Read the following passages carefully. Decide on the best answer and blacken the corresponding letter on the ANSWER SHEET. 

     A major aspect of psychology called behaviorism developed from research on learning. It was introduced in 1913 by the American psychologist John B. Watson, who felt psychologists should study observable behavior rather than states of consciousness or thought processes. He believed changes in behavior result from conditioning, a learning process in which a new response becomes associated with a certain stimulus.
     Watson's approach to behaviorism was strongly influenced by the research of the Russian physiologist Ivan P. Pavlov during the early 1900s. Pavlov's experiments with animals proved that certain reflex actions can become conditioned responses to entirely new stimuli. For example, a dog's mouth begins to water as a reflex when the animal smells meat. Pavlov rang a bell each time he was about to give meat to a dog. Eventually, the dog's mouth began to water when Pavlov merely rang the bell. The flow of saliva had become a conditioned response to the ringing of the bell.
     Watson demonstrated that responses of human beings could be conditioned in a similar manner. In an experiment, he struck a metal bar loudly each time an infant touched a furry animal. The sound scared the child, who in time became frightened by the mere sight of the animal. Watson felt he could produce almost any response in a child if he were able to control the child's environment.
     During the mid-1900s, the American behavioral psychologist B. F. Skinner became known for his studies of how rewards and punishments can influence behavior. He believed that rewards, or positive reinforcements, cause behavior to be repeated. Positive reinforcements might include praise, food, or simply a person's satisfaction with his or her own skill. Punishments discourage certain behavior and warn people to avoid situations in which they might be punished. Skinner conclude that positive reinforcement is more effective in teaching new and better behaviors. His work led to the development of teaching machines, which are based on positive reinforcement.