Excerpt: "A cognitive process in which individuals change response patterns through imagining themselves engaging in the desired responses rather than by observing another person model the responses. Since these new responses are weak, even at the imaginal level, it is essential that they be reinforced in order to strengthen and maintain them. This reinforcement normally is self-administered. Covert modeling thus involves a combination of modeling and self-control procedures, all conducted internally in the form of thought and fantasy."
Bufford, Rodger K., "Covert Modeling" (1999). Faculty Publications - Grad School of Clinical Psychology. 300.