That 'you look tired' sleepy-face is real

... genetic and some of this is prejudice," said Dr. Jeffrey Salomon, an assistant clinical professor of plastic surgery at Yale University School of Medicine. Lack of sleep is easily recognizable because everyone has experienced it, he explained. ...

http://www.philly.com/philly/health/HealthDay679924_20130906_Looking_Sleepy_Speaks_Volumes__Study_Says.html