How Many Muscles Does It Take to Smile?

You've likely been told (or read in a forwarded e-mail) that it takes fewer muscles to smile than it does to frown, and that, in light of this fact, you should smile more often. There are quite a few numbers that get tossed around when this line is used. Some claim it takes 43 muscles to frown and 17 to smile, but open Aunt Milda's chain letter and you might be surprised to learn it takes 26 to smile and 62 to frown. And some naysayers claim it's quite the opposite, that in fact it takes more muscles to smile than to frown.

When we make facial expressions, we're essentially transmitting a packet of information that can be received, read and interpreted by others. By contracting or expanding our facial muscles in different degrees and combinations, we can produce thousands of different messages that provide cues to our overall emotional state, our short-term feelings about our immediate environment, our mental well-being, our personality and mood, our physical health, our creditability and whether or not we view others as being creditable.

The smile -- transmitted either consciously or subconsciously -- is viewed across cultures as a sign of friendliness, especially when greeting someone. Frowns, too, are generally recognized as indicating sadness or disapproval.

There are 43 muscles in the face, most of which are controlled by the seventh cranial nerve (also known as the facial nerve). This nerve exits the cerebral cortex and emerges from your skull just in front of your ears. It then splits into five primary branches: temporal, zygomatic, buccal, mandibular and cervical. These branches reach different areas of the face and enervate muscles that allow the face to twist and contort into a variety of expressions.

However, nobody has really come up with a definitive number for how many muscles it takes to smile or frown -- one person's smile is another person's smirk. Also, not everyone has the same number of facial muscles; some have more, enabling a wider range of expression, while some people actually have 40 percent fewer [source: Devlin].

The truth is that people smile -- and frown -- differently, even when presented with similar stimuli. There is an even wider range of variety when one begins using different expressive muscles for the eyes, mouth, nose and forehead.

So will this divisive matter ever be resolved?

Smile vs. Frown

While nobody could possibly tell you with accuracy exactly how many muscles you use when you smile (43? 17? 26?), it's possible to tell you the minimum number of muscles that are used in the most insincere, subtle, restrained, mouth-only smile or frown.

If we analyze a smile that only raises the corners of the lips and the upper lip (the smile you give when you bump into your former boss in the grocery store, perhaps), then there are five muscle pairs (or 10 total muscles) that accomplish this. Two muscle pairs primarily raise the upper lip, while three other muscle pairs are tasked mainly with raising the corners of the mouth.

If we reduce a frown only to the lowering of the corners of the mouth along with a slight downward pouting of the lower lip, we're dealing with only three muscle pairs (one pair to drop the lower lip, and two pairs to lower the corners).

Counted individually (as you might count your biceps to be two different muscles, instead of one muscle pair), we reach a tally that very well may turn our understanding of the universe completely on end: 10 muscles to smile, and six muscles to frown.

But before you abandon your smile for a look of mild disappointment in order to conserve energy, consider that we can reduce both a smile and a frown even further, so that each is produced merely by raising or lowering the corners of the mouth into a robotic expression. In this case, we have a tie: two muscle pairs (for a total of four) to "smile," and the same number to "frown."

While such expressions would hardly be recognized as a proper smile or frown, the fact that the same amount of effort is used to produce one or the other means that the scientific minds of this generation and the next will have to continue searching for a good reason for humans to put a smile on their faces -- and not a frown of equal but opposing effort.

Want to know whether laughter's the best medicine and how smiling can change your mood? Try the links to the HowStuffWorks articles that follow.

Muscle Smile FAQ

How many muscles does it take to frown?

Varying numbers get tossed around when it comes to claiming the number of muscles it takes to frown. A frown that merely lowers the corners of the mouth with a slight downward pouting of the lower lip uses only three muscle pairs, which means six muscles to frown. And if that frown is further reduced to a robotic expression, it uses only two muscle pairs, or four muscles.

Does it really take more muscles to frown?

It depends on the frown, or the smile. If you think of a frown as just lowering the corners of the mouth, then it takes an equal number of muscles (four) to frown and to smile.

How many muscles are in a smile?

If we look at a smile that only raises the corners of the lips and the upper lip, it takes only five muscle pairs, or 10 total muscles, to do so. However, if the smile is further reduced to a robotic expression of just raising the corners of the mouth, then it takes only two muscle pairs (four muscles) to smile.

What is the smiling muscle?

The zygomaticus major is the muscle that we think of as the smiling muscle.

Lots More Information

Sources

Ackerman, Kenneth J, Ph.D. "The Universal People." (May 13, 2009) http://www.udel.edu/anthro/ackerman/universal_people.pdf
DataFace. "Facial Expression: A Primary Communication System." (May 14, 2009)http://www.face-and-emotion.com/dataface/expression/expression.jsp
Devlin, Kate. "Missing facial muscles make some look glum." The Daily Telegraph. June 17, 2008. http://www.telegraph.co.uk/scienceandtechnology/science/sciencenews/3344681/Missing-facial-muscles-make-some-look-glum.html
Ekman, Paul; et al. "Final Report To NSF of the Planning Workshop on Facial Expression Understanding." Aug. 1, 1992.http://www.face-and-emotion.com/dataface/nsfrept/nsf_contents.html
Foreman, Judy. "A Conversation with: Paul Ekman; The 43 Facial Muscles That Reveal Even the Most Fleeting Emotions." The New York Times. Aug. 5, 2003. http://www.nytimes.com/2003/08/05/health/conversation-with-paul-ekman-43-facial-muscles-that-reveal-even-most-fleeting.html
Lewis, Michael. Handbook of emotions (second edition). Guilford Press, 2004. ISBN 1593850298, 9781593850296.http://books.google.com/books?id=SQ8F7zdhORwC&printsec=frontcover#PPA236,M1
Nicolay, Christopher W., Ph.D. Associate Professor, UNCA Department of Biology. E-mail correspondence. May 14, 2009.
Patel, Alpen A., MD. "Facial Nerve Anatomy." Mar. 18, 2009. http://emedicine.medscape.com/article/835286-overview