Multiple fear-related stimuli enhance physiological arousal during extinction and reduce physiological arousal to novel stimuli and the threat conditioned stimulus

- Involved Pavlovian conditioning, extinction, extinction generalization test, and extinction retest.
- Compared extinction with CS+ and CS− and generalization stimuli and 'extinction-as-usual'.
- Multiple stimuli increased physiological arousal to both CSs during, and negative CS evaluations, after extinction.
- Multiple stimuli reduced physiological arousal to novel stimuli and CS+ after extinction but did not alter negative CS evaluations.
- No group differences were observed in subjective anxiety ratings.