Self-punitive behavior: Differential effects of stimulus change on fear of preshock area cues

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Two experiments investigated the effects of stimulus change on fear conditioned to apparatus cues in the self-punitive paradigm. In the first experiment, segment cues were changed in a preshock segment (the lower startbox or first runway segment) for half of the subjects (rats) prior to the start of 15 punished-extinction (PE) trials. Hurdle-jump learning following PE trials indexed the amount of fear elicited by cues in each segment. Of subjects tested in the startbox, subjects exposed to changed stimuli showed less fear than subjects exposed to unchanged stimuli. Subjects tested in the first runway segment did not differ as a function of stimulus change. In the second experiment, three groups were tested: The stimuli.were changed in the lower startbox, in the first runway segment, or were unchanged prior to the start of 15 PE trials. Half of the subjects in each condition with changed stimuli were tested in the preshock segment with changed cues, and half were tested in the preshock segment with unchanged cues. When subjects were exposed to changed cues in the startbox, fear of the changed startbox cues was significantly lower than fear of the unchanged first-segment cues. When subjects were exposed to changed cues in the first segment or to unchanged cues, the levels of fear conditioned to the various preshock cues did not differ. The results support the theory that the level of fear conditioned to apparatus cues during PE trials depends on the spatial/temporal relationship of the cues to shock onset (Dean & Pittman, 1991).