ABSTRACT
Since the individual deals with the environment, it is important for him to know the environment and to master it sufficiently for his needs and purposes. He gets to know it by using his senses, and he acts on it and masters it to some extent by using his muscles. So much was said in the chapter on Interaction with the Environment, and something more was added in the chapter on Development. But we have left to this latter third of the book any full consideration of the question, how he knows and masters the environment. It is a difficult question but one on which psychologists have done a large amount of investigation. It branches out into many special questions on the senses, learning, memory, and thinking.
