A basic tenet of this paper is that, from the time of the ancient Greeks, Western thought has distinguished between rational processes unique to humans and the processes governing animal behavior. A model of motivation, emotion, and the cognitive/physiological interaction that can be applied to both animals and humans is presented. The special implications of language are discussed, and emotion is defined. An argument is posited that language makes humans different in fundamental ways from animals, because it allows behavior to come under the control of principles of logic and reasoning that are mediated by language and that are functionally independent of biology. In addition, the materials suggest that with language comes social motivation, involving conformity and obedience to culturally patterned social rules. (JAC)