CLASSICAL (RESPONDENT) CONDITIONING
When a biological reflex (such as salivation to food) becomes associated with a previously neutral stimulus (such as a tone), that stimulus comes to elicit a similar reflexive response. Pavlov’s classic (1927) experiments demonstrated that dogs could learn to associate a tone (conditioned stimulus) with food (unconditioned stimulus), and salivate to the tone alone (unconditioned response to food, but conditioned response to tone). A more mnemonic term for this kind of learning is respondent conditioning (after Skinner, 1938), because it emphasizes that behavior occurs in response or reaction to an eliciting stimulus in an involuntary manner (as contrasted with operant conditioning as discussed below).
Pavlov’s contemporary, J. B. Watson (1913; 1919) also studied the condition ability of reflexes and aimed to catalogue which habits or reflexes could be considered “natural” and which “learned.” As part of that research program, he provided the classic demonstration of conditioned fear in Little Albert by introducing a previously neutral white rat into a room and following that with a loud noise, inevitably leading to the presence of the rat alone being sufficient to elicit fear.
Despite the apparent ease with which respondent conditioning can occur, there are significant limits. Generalization to other stimuli goes only so far. Fear of a white rat generalized to other furry objects, but not to a wooden duck (Bregman, 1934). Animals made nauseous by a blue liquid will avoid other liquids with the same taste or odor, but they will not associate the nausea with blueness (Garcia & Ervin, 1968). The ostensible principle here is that we are biologically prepared to associate tastes or odors to food and fears to sounds or appearances (see also Seligman’s 1971, p. 312, description of phobias). Still, conditioned emotions are one important level of learning, which interacts with behavioral and cognitive acts (as discussed more fully below).