Such expressions may be etched in your genes, a new study shows.
The study, published in Proceedings of the National Academy of Sciences, comes from experts at University of Haifa in Israel.
They included graduate student Gili Peleg and Eviatar Nevo, PhD, professor of evolutionary biology and director of the university's Institute of Evolution.
Peleg, Nevo, and colleagues studied 21 people, each from a different family, who had been born blind.
The researchers interviewed participants and 30 of their relatives to provoke facial expressions of sadness, anger, and joy.
An analysis of videotaped interviews showed similar facial expressions among the blind participants and their sighted relatives.
Since the blind people couldn't have learned those expressions by watching their relatives' faces, genetics might explain the family facial patterns, the researchers note.
For instance, one of the blind men in the study had been abandoned by his mother two days after birth, according to the researchers.
The man and his birth mother met again when the man was 18 years old and on rare occasions afterwards.
"Nevertheless, they demonstrated a unique family facial expression signature," the researchers write.
But the study doesn't link any particular genes to facial expressions.
"Although we are still far from discovering the genes that influence facial expression, our study is an essential stage in the process of unraveling the genetic basis of facial expressions," the researchers write.
SOURCES: Peleg, G. Proceedings of the National Academy of Sciences of the United States of America, Oct. 24, 2006; vol 103: pp 15921-15926. News release, Proceedings of the National Academy of Sciences of the United States of America.
By Miranda Hitti
Reviewed by Louise Chang