title: One-trial overshadowing: Evidence for fast specific fear learning in humans.
abstract: Adaptive defensive actions necessitate a fear learning system that is both fast and specific. Fast learning serves to minimize the number of threat confrontations, while specific learning ensures that the acquired fears are tied to threat-relevant cues only. In Pavlovian fear conditioning, fear acquisition is typically studied via repetitive pairings of a single cue with an aversive experience, which is not optimal for the examination of fast specific fear learning. In this study, we adopted the one-trial overshadowing procedure from basic learning research, in which a combination of two visual cues is presented once and paired with an aversive electrical stimulation. Using on-line shock expectancy ratings, skin conductance reactivity and startle reflex modulation as indices of fear learning, we found evidence of strong fear after a single conditioning trial (fast learning) as well as attenuated fear responding when only half of the trained stimulus combination was presented (specific learning). Moreover, specificity of fear responding tended to correlate with levels of state and trait anxiety. These results suggest that one-trial overshadowing can be used as a model to study fast specific fear learning in humans and individual differences therein.
authors.affiliation: Center for Learning Psychology and Experimental Psychopathology, KU Leuven, Leuven, Belgium; Center for Excellence on Generalization in Health and Psychopathology, KU Leuven, Leuven, Belgium. Electronic address: kim.haesen@kuleuven.be.
authors.forename: Kim
authors.initials: K
authors.lastname: Haesen
authors.affiliation: Center for Learning Psychology and Experimental Psychopathology, KU Leuven, Leuven, Belgium; Center for Excellence on Generalization in Health and Psychopathology, KU Leuven, Leuven, Belgium. Electronic address: tom.beckers@kuleuven.be.
authors.forename: Tom
authors.initials: T
authors.lastname: Beckers
authors.affiliation: Center for Learning Psychology and Experimental Psychopathology, KU Leuven, Leuven, Belgium; Center for Excellence on Generalization in Health and Psychopathology, KU Leuven, Leuven, Belgium. Electronic address: frank.baeyens@kuleuven.be.
authors.forename: Frank
authors.initials: F
authors.lastname: Baeyens
authors.affiliation: Center for Learning Psychology and Experimental Psychopathology, KU Leuven, Leuven, Belgium; Center for Excellence on Generalization in Health and Psychopathology, KU Leuven, Leuven, Belgium; Department of Psychiatry, Harvard Medical School, Boston, USA; Department of Psychiatry, Massachusetts General Hospital, Boston, USA. Electronic address: bram.vervliet@kuleuven.be.
authors.forename: Bram
authors.initials: B
authors.lastname: Vervliet
mesh_terms: D001007:Anxiety / Q000523:psychology; D003214:Conditioning, Classical / Q000502:physiology*; D004558:Electric Stimulation; D005239:Fear / Q000502:physiology*; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D013216:Reflex, Startle / Q000502:physiology; D013997:Time Factors; D055815:Young Adult
keywords: Anxiety disorders; Fear conditioning; Generalization; Overshadowing; State anxiety; Trait anxiety