“Using a sample of 440 scientists from a social networking site for researchers, multiple raters coded smile intensity (full smile, partial smile, or no smile) in publicly available photographs. We found that scientists who presented a full smile had the same quantity of publications yet of higher quality”
See: Lukasz D. Kaczmarek, Maciej Behnke, Todd B. Kashdan, Aleksandra Kusiak, Katarzyna Marzec, Martyna Mistrzak & Magdalena Włodarczyk (2017): Smile intensity in social networking profile photographs is related to greater scientific achievements, The Journal of Positive Psychology.
A full copy of which may be found here.
Note: The image is from lead author Dr Kaczmarek’s website