Effects of threat intensity on sensory preconditioning.

Although emotional intensity is known to shape fear generalization in direct conditioning, its impact on higher-order associative learning processes is unknown. Sensory preconditioning, a form of higher-order learning, allows us to infer potential threats in the absence of direct experience by linking neutral stimuli through prior associations. Here, we examined whether threat intensity during first-order conditioning amplifies sensory preconditioning. Participants first learned associations between neutral pairs of category images (preconditioning). In a subsequent Pavlovian conditioning phase, one category was paired with either a high- or low-intensity aversive unconditioned stimulus (US), between-groups. Finally, participants were re-exposed to categories from preconditioning without the US in a transfer test of conditioned learning, both immediately and the next day. While both groups showed equivalent transfer of shock expectancy, only high-intensity conditioning showed transfer of skin conductance responses (SCR) on Day 1 and generalization of SCR to safety stimuli on Day 2. High versus low intensity conditioning also produced non-specific increases in episodic memory for stimuli encoded during the transfer test, whereas low-intensity conditioning selectively and retroactively enhanced memory for stimuli pre-associated with the conditioned stimulus. Altogether, results indicate that high-intensity emotional experiences may cast too wide a net, inflating the sense of what is important and relevant while diminishing the specificity needed for adaptive emotional responding.