Tacts
Chapter Five of Verbal Behavior discusses the tact in depth. A tact is said to "make contact with" the world, and refers to behavior that is under the control of generalized reinforcement. The controlling stimulus is nonverbal, "the whole of the physical environment". It can undergo many extensions: generic, metaphoric, metonymical, solecistic, nomination, and "guessing". It can also be involved in abstraction. Lowe, Horne, Harris & Randle (2002) would be one example of recent work in tacts.
Read more about this topic: Verbal Behavior