Abstract
When people are being evaluated, their whole body responds. Verbal feedback causes robust activation in the hypothalamic-pituitary-adrenal (HPA) axis. What about nonverbal evaluative feedback? Recent discoveries about the social functions of facial expression have documented three morphologically distinct smiles, which serve the functions of reinforcement, social smoothing, and social challenge. In the present study, participants saw instances of one of three smile types from an evaluator during a modified social stress test. We find evidence in support of the claim that functionally different smiles are sufficient to augment or dampen HPA axis activity. We also find that responses to the meanings of smiles as evaluative feedback are more differentiated in individuals with higher baseline high-frequency heart rate variability (HF-HRV), which is associated with facial expression recognition accuracy. The differentiation is especially evident in response to smiles that are more ambiguous in context. Findings suggest that facial expressions have deep physiological implications and that smiles regulate the social world in a highly nuanced fashion.
| Original language | English |
|---|---|
| Article number | 3558 |
| Journal | Scientific Reports |
| Volume | 8 |
| Issue number | 1 |
| DOIs | |
| State | Published - 1 Mar 2018 |
Bibliographical note
Publisher Copyright:© The Author(s)2018.
Funding
The authors would like to thank Craig Berridge, Allison Blumenfeld, Stephanie Carpenter, Crystal Hanson, Judy Harackiewicz, Roxanne Hoks, Cathy Marler, and Wendy Berry Mendes for their assistance and helpful comments. Magdalena Rychlowska and Adrienne Wood provided critical feedback during the revision process. Stella Mayerhoff, Josh Lucas, Sarah Hervdejs, and Mathias Hibbard were instrumental in collecting data. We also acknowledge the tireless contribution of our two confederates A.J. Laird and Zeus Markos. This work was supported by the National Institutes of Mental Health [grant number T32MH018931-26 to J.D.M]; the U.S. – Israeli Binational Science Foundation [grant number 2013205 to P.M.N. and E.G.S.]; and the National Science Foundation [grant number 1355397 to P.M.N.]. Further support for this research was provided by the Graduate School and the Office of the Vice Chancellor for Research and Graduate Education at the University of Wisconsin-Madison with funding from the Wisconsin Alumni Research Foundation. Sources of financial support had no influence over the design, analysis, interpretation, or choice of submission outlet for this research. Data are available by contacting the corresponding author.
| Funders | Funder number |
|---|---|
| National Institutes of Mental Health | T32MH018931-26 |
| U.S. – Israeli Binational Science Foundation | 2013205 |
| National Science Foundation | 1355397 |
| National Institute of Mental Health | T32MH018931 |
| Wisconsin Alumni Research Foundation | |
| Office of the Vice Chancellor for Research and Graduate Education, University of Wisconsin-Madison | |
| Graduate School, University of Oregon |