Further education, including a master's and doctoral degree, is required and can be earned sequentially, or degrees can be broken up with periods of practical work and research. As the title suggests, this type of psychology has a deeply rooted focus on research and experimentation. Experimental psychology uses the scientific method to create and empirically test hypotheses to answer questions, including those related to behavior and the mind. With enough research, experimental psychologists can even develop theories that allow them to describe, explain, and predict human behaviors. Humans are not the only subjects studied by experimental psychologists; animals are studied and included in experiments and, of course, treated humanely