This paper gives an overview of research in human and animal imitation mechanisms. The different types of imitative behavior are described as well as the evolutionary reasons for imitation abilities in humans and animals. Known and hypothesized mechanisms behind imitation are also covered. The concepts Goal emulation, Response facilitation and Stimulus enhancement are often confused with pure imitation. The differences are described and discussed followed by an overview of Priming and how it relates to these three concepts. The involved mechanisms are finally described using a modified model for cognitive control, inspired by Miller and Cohen (1994). The model combines concepts from imitation and priming. A similar model for behavior recognition, which is an important part of imitation, is also suggested. It integrates perceptual attention, priming, and cognitive control and addresses the ambiguity problem inherent in demonstrated behaviors. Both models are suggested for implementation and evaluation in a physical robot.