Short alleles, bigger smiles? The effect of 5-HTTLPR on positive emotional expressions.

• DOI: 10.1037/emo0000074
• Publication Date: 2015-06-02T12:34:01Z
• Authors: Claudia M. Haase; Ursula Beermann; Laura R. Saslow; Michelle N. Shiota; Sarina R. Saturn; Sandy J. Lwi; James J. Casey; Nguyen K. Nguyen; Patrick K. Whalen; Dacher Keltner; Robert W. Levenson
• Keywords: 5-HTTLPR

The present research examined the effect of 5-HTTLPR polymorphism in serotonin transporter gene on objectively coded positive emotional expressions (i.e., laughing and smiling behavior using Facial Action Coding System). Three studies with independent samples participants were conducted. Study 1 young adults watching still cartoons. 2 young, middle-aged, older a thematically ambiguous yet subtly amusing film clip. 3 middle-aged spouses discussing an area marital conflict (that typically produces both negative emotion). Aggregating data across studies, results showed that short allele predicted heightened expressions. Results remained stable when controlling for age, gender, ethnicity, depressive symptoms. These findings are consistent notion functions as emotion amplifier, which may confer susceptibility to environmental conditions.