Modulation of unconditioned defense reflexes by a putative emotive Pavlovian conditioned stimulus

Four experiments showed differential modulation of defensive unconditioned responses (URs) in rabbits by contextual stimuli that Brandon and Wagner (1991) have shown similarly to modulate conditioned eyeblink responses. Two 30-s auditory cues, A and B, were differentially paired with shock. Tests were presentations of a response-eliciting probe stimulus within A, B, or a comparable blank interval, Experiments 1 and 2 demonstrated that A and B differentially facilitated eyeblink URs, and Experiments 3 and 4 showed that A and B similarly differentially facilitated startle responses elicited by airpuffs to the ear. These data are consistent with a characterization of Pavlovian conditioning that distinguishes between emotive and sensory conditioning and assumes that conditioned emotional responses similarly modulate specific conditioned and unconditioned defensive reflexes (Konorski, 1967; Wagner & Brandon, 1989).