Generalization of conditioned fear along a dimension of increasing fear intensity.

Journal Article (Journal Article)

The present study investigated the extent to which fear generalization in humans is determined by the amount of fear intensity in nonconditioned stimuli relative to a perceptually similar conditioned stimulus. Stimuli consisted of graded emotionally expressive faces of the same identity morphed between neutral and fearful endpoints. Two experimental groups underwent discriminative fear conditioning between a face stimulus of 55% fear intensity (conditioned stimulus, CS+), reinforced with an electric shock, and a second stimulus that was unreinforced (CS-). In Experiment 1 the CS- was a relatively neutral face stimulus, while in Experiment 2 the CS- was the most fear-intense stimulus. Before and following fear conditioning, skin conductance responses (SCR) were recorded to different morph values along the neutral-to-fear dimension. Both experimental groups showed gradients of generalization following fear conditioning that increased with the fear intensity of the stimulus. In Experiment 1 a peak shift in SCRs extended to the most fear-intense stimulus. In contrast, generalization to the most fear-intense stimulus was reduced in Experiment 2, suggesting that discriminative fear learning procedures can attenuate fear generalization. Together, the findings indicate that fear generalization is broadly tuned and sensitive to the amount of fear intensity in nonconditioned stimuli, but that fear generalization can come under stimulus control. These results reveal a novel form of fear generalization in humans that is not merely based on physical similarity to a conditioned exemplar, and may have implications for understanding generalization processes in anxiety disorders characterized by heightened sensitivity to nonthreatening stimuli.

Full Text

Duke Authors

Cited Authors

  • Dunsmoor, JE; Mitroff, SR; LaBar, KS

Published Date

  • July 2009

Published In

Volume / Issue

  • 16 / 7

Start / End Page

  • 460 - 469

PubMed ID

  • 19553384

Pubmed Central ID

  • PMC2704105

Electronic International Standard Serial Number (EISSN)

  • 1549-5485

International Standard Serial Number (ISSN)

  • 1072-0502

Digital Object Identifier (DOI)

  • 10.1101/lm.1431609


  • eng