How do management theories describe work and employee behavior?

"Scientific management: A system of management developed by Frederick W. Taylor and based on four principles: developing a scientific approach for each element of a job, scientifically selecting and training workers, encouraging cooperation between workers and managers, and dividing work and responsibility between management and workers according to who can better perform a particular task. Theory X: A management style, formulated by Douglas McGregor, that is based on a pessimistic view of human nature and assumes that the average person dislikes work, will avoid it if possible, prefers to be directed, avoids responsibility, and wants security above all. Theory Y: A management style, formulated by Douglas McGregor, that is based on a relatively optimistic view of human nature; assumes that the average person wants to work, accepts responsibility, is willing to help solve problems, and can be self-directed and self-controlled. Theory Z: A theory developed by William Ouchi that combines U.S. and Japanese business practices by emphasizing long-term employment, slow career development, moderate specialization, group decision-making, individual responsibility, relatively informal control over the employee, and concern for workers."