Relational memory structure among prior neutral episodes guides Pavlovian threat responses.

Learning about danger through exposure to harmful events relies on Pavlovian conditioning, which enables individuals to prepare for potential threats when encountering warning signals in the future. Sensory preconditioning further shows that defensive significance can extend to neutral cues associated with a subsequently conditioned stimulus, even when those cues have never themselves been paired with an aversive outcome. Here, we asked whether this principle extends to a relational memory structure assembled across separate neutral experiences, and whether cues closer to the conditioned threat cue within this structure evoke stronger defensive responses. Participants first learned overlapping pairs of neutral images that together formed an abstract linear graph. The following day, the two images at opposite ends of the graph were differentially paired with mild electric shocks, establishing them as threat and safety signals. When later exposed to the remaining images under risk of shock, participants exhibited graded defensive responses across self-report and physiological measures that varied systematically with relational distance from the conditioned cues. These findings extend the principle of sensory preconditioning from elementary arrangements to a multistep relational memory structure, showing that the organization of prior neutral memories can shape the graded expression of defensive responses.