Smiling fighters are more likely to lose

The day before mixed martial artists compete in the Ultimate Fighting Championships (UFC), they pose with each other in a staged face-off. A new study has analysed photographs taken at dozens of these pre-fight encounters and found that competitors who smile are more likely to lose the match the next day (pdf via author website).

Michael Kraus and Teh-Way David Chen recruited four coders (blind to the aims of the study) to assess the presence of smiles, and smile intensity, in photographs taken of 152 fighters in 76 face-offs. Fighter smiles were mostly “non-Duchenne”, with little or no crinkling around the eyes. Data on the fights was then obtained from official UFC statistics. The researchers wanted to test the idea that in this context, smiles are an involuntary signal of submission and lack of aggression, just as teeth baring is in the animal kingdom.

Consistent with the researchers’ predictions, fighters who smiled more intensely prior to a fight were more likely to lose, to be knocked down in the clash, to be hit more times, and to be wrestled to the ground by their opponent (statistically speaking, the effect sizes here were small to medium). On the other hand, fighters with neutral facial expressions pre-match were more likely to excel and dominate in the fight the next day, including being more likely to win by knock-out or submission.

These associations between facial expression and fighting performance held even after controlling for betting behaviour by fans, which suggests a fighter’s smile reveals information about their lack of aggression beyond what is known by experts. Moreover, the psychological meaning of a pre-match smile appeared to be specific to that fight – no associations were found between pre-match smiles and performance in later, unrelated fights. Incidentally, smaller fighters smiled more often, consistent with the study’s main thesis, but smiling was still linked with poorer fight performance after factoring out the role of size (in other words, smiling was more than just an indicator of physical inferiority).

If fighters’ smiles are a sign of weakness, there’s a chance opponents may pick up on this cue, which could boost their own performance, possibly through increased confidence or aggression. To test the plausibility that smiles are read this way, Kraus and Chen asked 178 online, non-expert participants to rate head-shots of the same fighter either smiling or pulling a neutral expression in a pre-match face-off. As expected, smiling fighters were rated by the non-expert participants as less physically dominant, and this was explained by smiling fighters being perceived as less aggressive and hostile.

Of course, the researchers are only speculating about what’s going on inside the minds of the fighters pre-match. It’s even possible that some of them smile in an attempt to convey insouciance. If so, Kraus and Chen said “it is clear that this nonverbal behaviour had the opposite of the desired effect – fighters were more hostile and aggressive during the match toward their more intensely smiling opponents.”


Kraus, M., and Chen, T. (2013). A Winning Smile? Smile Intensity, Physical Dominance, and Fighter Performance. Emotion DOI: 10.1037/a0030745

Image reproduced with permission from the first author.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

32 thoughts on “Smiling fighters are more likely to lose”

  1. When I was a teenager I trained in karate. I remember my instructors telling us solemnly never to smile while sparring. One even went so far as to warn that anyone who did would lose teeth! Makes more sense now after reading this.

  2. I always laugh and smile during fights because i love it so much but i never smile at the weigh ins or before. I will have to take this up with my Sports Psychologist Rebecca Symes,. i hope she lets me smile still hahah

    Nick Chapman AKA The Headhunter MMA Fighter

  3. Confident fighters are relaxed. Nervous or scared fighters smile because they're trying to LOOK relaxed.

  4. This isn't surprising, a smile during a fight/dispute shows fear/uncomfortableness/nervousness/submission. It's similar to a nervous laugh.

  5. it seems like the champs like GSP, Silva, Jones, JDS, Couture, had a lot of confident smiles at the face off.

    Isn't a smile a sign of confidence also.

    Did anyone pay for this study? let me guess us Taxpayers probably.

  6. I'm skeptical. Most fighters are nervous before fights, I doubt one particular physical instantiation means much in relation to the nervousness instantiated by the “neutral” stare. 76 staredowns is a drastically insufficient sample size.

  7. This is really interesting. I want to read more about this study and see the statistics. A smile can mean a lot of things, confidence, fear or nervousness.

  8. Many fighters such as Fedor or Gomi rarely looked into the eyes of their oponents and they still won…. Isnt that a form of weakness??

  9. LOL you can mean mug all you want and you can still lose fights… Look at diego sanchez

  10. Interesting….I am going to file this away in the interesting category. Now i have to take this up with my, Interesting Category guy,
    Wiley E Coyote. I hope he lets me fill another chapter of fun so I can create a new category for stuff

    Wiley E. Coyote AKA the Road Runner and also a champion in the making. MMA Fighter and somewhat of an all around lady killer…Peace!

  11. your a nobody bud. internet, watch and play to much ufc on a video game type of guy… HENSE your 'anonymous' input! internet dreamer/tough guy

  12. you exhibit A had LOTS of trouble with condit. All he had was wrestling.. Lied about hurting his hand cause his knock out wasnt working for him the few times that he actually connected good… Johnny is one dimentional. He had trouble with koscheck, 2 more rounds and condit would have knocked him out.. GSP still years ahead of this chump.. Why you riding his dick?
    He beat a bunch of people who have been in the sport forever and are on the verge of backing down there careers for trainer positions in gyms. They all got beat by GSP already and never fought the same. fitch doesnt care much bout being a champ, so theres an advantage already that hendrix had (hunger) lets not forget hendrix lost to a MUCH smaller welterweight in Rick Story. Oh, koscheck gave him LOTS of problems. Thats right mike pearce another wrestler he had trouble with.. So whats he think he's gonna just walk in and take out George just cause he's thrown a few lefts that have knocked guys out? hahaha fan base who dont acknoledge the actual talents and movements of a man rather then go by a highlight reel of a bunch of washed up fighters or guys who were never anything and started fighting one day.. Atleast johnny has had 1 advantage over most. YEARS of COLLEGIATE wrestling. So he wont be able to take george down, and come 3 round 4th and 5th, johnny just gonna be a pilon for george. Then it will become wrestling practice. Maybe the better wrestler with in the later rounds!

  13. its a different smile when one man has no emotion and the other has a big smile… Thats the fear. He is intimidated by the non emotions so smiles. Also that smile is to give the eyes an extra couple seconds of focus on your opponents eyes without truly having to look away yet.. GIving your apponent the idea that you're not scared, but secretly in there heads they couldnt wait for that smile and stare down to end cause they were shitting themselves inside.

  14. thats cause your getting caught all the time in the fight and dont want your fans or the people you carelessly brag about yourself to, to see weakness inside you. Even though your most likely getting lit up! Stop getting tagged in your apparent (fights)

  15. but diego didn't have those submissiveness, fear, or lack a of aggression in his fights. You should read the article again

  16. You could smile to hide your true intention, to be looked like a weak person which may make the other opponent lower his guard. But then again, I would think smiling in front of your opponent make you seem cocky and make opponent really want to mess you up.

  17. They tell you not to smile in Martial Arts because it's disrespectful to your opponent. Not because it makes you look weak.

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