22.2. The Extended Tact
In Verbal Behavior, Skinner opens the discussion of the “extended tact” with the quote shown below. Skinner limits his analysis to “tact extension,” but the principles underlying that type of extension also seem to be at work in all the other types of elementary verbal relationships discussed earlier, including the audience relationship. This section of the tutorial introduces you to the basic concepts involved in the extension of verbal behavior, and also introduces basic categories of extension. Finally, it deals with some special concepts related to the problem of extending verbal behavior to the control of private stimuli.
But a verbal repertoire is not like a passenger list on a ship or plane, in which one name corresponds to one person with no one omitted or named twice. Stimulus control is by no means so precise. If a response is reinforced upon a given occasion or class of occasions, any feature of that occasion or common to that class appears to gain some measure of control. A novel stimulus possessing one such feature may evoke a response. There are several ways in which a novel stimulus may resemble a stimulus previously present when a response was reinforced, and hence there are several types of what we may call ‘extended tacts.’
~ B.F. Skinner, Verbal Behavior, p. 91