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Published October 2015 | Supplemental Material + Accepted Version
Journal Article Open

An Enhanced Default Approach Bias Following Amygdala Lesions in Humans


Approach and avoidance constitute a basic dimension of all animal behavior. Although a large number of studies have investigated approach and avoidance elicited by specific sensory stimuli, comparatively little is known about default approach biases when stimulus information is absent or reduced. The amygdala is well known to contribute to approach and avoidance behaviors in response to specific sensory stimuli; we tested whether the amygdala's role might extend to situations in which stimulus information is reduced. In a novel task, 3 patients with rare bilateral amygdala lesions (and control subjects) made approach-related judgments about photos of intact faces and of the same faces with all internal facial features occluded. Direct comparisons of the judgments of these stimuli isolated a default bias. The patients showed a greater tendency than the control subjects to rate occluded faces as more approachable than whole faces. These findings suggest that the amygdala's role in approach behavior extends beyond responses to specific stimuli.

Additional Information

© 2015 The Author(s). Received 10/6/14; Revision accepted 4/1/15. Published online before print September 3, 2015. Author Contributions: L. A. Harrison and R. Adolphs developed the study concept and design. Testing and data collection were performed by L. A. Harrison and R. Hurlemann. L. A. Harrison performed the data analysis and interpretation under the supervision of R. Adolphs. L. A. Harrison drafted the manuscript, and R. Adolphs provided critical revisions. All authors approved the final version of the manuscript for submission. We thank Dirk Scheele, Yoan Mihov, Ronnie Bryan, Mike Tyszka, Julien Dubois, and especially the patients for their assistance. The authors declared that they had no conflicts of interest with respect to their authorship or the publication of this article. This research was funded by grants from the National Institute of Mental Health (Grant P50MH094258), the Gordon and Betty Moore Foundation, and the German Research Foundation (DFG). Supplemental Material: Additional supporting information can be found at http://pss.sagepub.com/content/by/supplemental-data Open Practices: All data have been made publicly available via Open Science Framework and can be accessed at https://osf.io/8cktf/. Task instructions can also be accessed at https://osf.io/8cktf/. Because of confidentiality concerns, the photographs used as stimuli are not available at Open Science Framework, but they can be obtained for research use by contacting Laura A. Harrison, lauraharrison@caltech.edu. The complete Open Practices Disclosure for this article can be found at http://pss.sagepub.com/content/by/supplemental-data. This article has received the badge for Open Data. More information about the Open Practices badges can be found at https://osf.io/tvyxz/wiki/1.%20View%20the%20Badges/ and http://pss.sagepub.com/content/25/1/3.full.

Attached Files

Accepted Version - nihms677957.pdf

Supplemental Material - DS_10.11770956797615583804_AdditionalResults.pdf

Supplemental Material - DS_10.11770956797615583804_OpenPracticesDisclosure.pdf


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