Have you ever caught your significant other smiling to themselves (or at their phone) and wondered what could possibly be making them so happy if it’s not you? Recently, on TikTok, people have posted videos of their boyfriend or partner smiling and laughing unconsciously while asleep and wondering just why he looks so happy.
If you’ve caught your boyfriend or significant other smiling or laughing in their sleep or are curious about what could cause this, there’s some fascinating science behind it.
Why Do People Smile or Laugh During Sleep?
“A lot of what happens while we sleep is our brain randomly firing and bringing up or creating thoughts and memories, so it’s no surprise that we laugh or smile in our sleep. Our brain may be scanning through something delightful or amusing, and our facial muscles are responding as they would if we were awake,” says Dr. Michelle Drapkin, Owner and Director of the Cognitive Behavior Therapy (CBT) Center.
Interestingly, human fetuses and newborns start smiling during sleep long before they do so while awake and interacting with their caregivers. How often this sleepy-time smiling continues into adulthood, and whether it’s a true reflection of genuine emotion, isn’t clear, but scientists have actually studied this phenomenon.
What Research Says About Smiling During Sleep
In a study published in the Journal of Sleep Research, 100 control participants, 22 sleepwalkers, and 52 individuals with REM sleep behavior disorder had their facial muscles associated with smiling and laughing closely monitored while these people slept. (1) Results showed that 8 percent of people in the control group smiled during sleep, primarily during REM sleep (7 percent) and a bit during non-REM sleep (1 percent). Some sleepwalkers also smiled or laughed during certain stages of sleep, like N2 and N3. The REM sleep disorder group had the highest numbers, with half smiling and a third laughing during REM sleep.
The expressions ranged from mild smiles to open-mouth grins and full-on laughs. Over half of these were Duchenne smiles, the genuine kind involving both the mouth and eyes. Around half of these happy expressions were linked to rapid eye movements, suggesting a connection to vivid dreaming. Interestingly, these smiles and laughs didn’t come with a significant increase in heart rate, pointing to a state of calm happiness rather than excitement.
Why Your Boyfriend Might Be Smiling While He’s Asleep
“We might be remembering something from earlier that day, that year, or something completely nonsensical,” says Dr. Drapkin. After all, the firing that happens isn’t perfect; it can also be a hodgepodge of random stuff. “And, a smile could not really be a smile but just your lips flinching like when babies have gas and aren’t really smiling even if we wish they were,” adds Dr. Drapkin.
According to Niloufar Esmaeilpour, MSc, RCC, SEP from Lotus Therapy & Counselling Centre, neurologically, even when a person is asleep, their brain is awake and processing daily experiences and feelings. Dreams may also evoke different emotions, the positive ones being happiness, humor, and joy, each resulting in physical expressions such as smiling or laughing. “This might be a reaction to the content of such a dream that appears funny or pleasurable to the sleeping individual, even if they don’t remember it when they wake up,” she says.
“Smiling or laughing during one’s sleep, on some level, relates to the subconscious mind attending to unresolved issues or unwinding from pent-up feelings and thoughts,” says Esmaeilpour. It creates a coping mechanism in which the mind can turn anxiety or stress into more controllable forms of their opposites, such as humor, she adds.
What Do We Think?
So, to answer the question posed by TikToker Tana Marie in her video showing her sleepy boyfriend laughing and smiling while sleeping, he might be having some pretty great dreams. (2) On the other hand, he could just have gas.
On a more serious note, very frequent or intense episodes may need further investigation since it is related to sleep disorders or neurological conditions that require professional attention, according to Esmaeilpour.
Sources
1. Clé M, Maranci J-B, Weyn Banningh S, Lanfranchi J, Vidailhet M, Arnulf I. Smiling asleep: A study of happy emotional expressions during adult sleep. J Sleep Res. 2019; 28:e12814. https://doi.org/10.1111/jsr.12814
2. @tanapitlifewysock, “the things that go through a women’s mind…” TikTok; https://www.tiktok.com/@tanapitlifewysocki/video/7309020384324586798?_r=1&_t=8nr6CMWTH2J; December 5, 2023.
Drapkin, Michelle. Author interview. July 2024.
Esmaeilpour, Niloufar. Author interview. July 2024.
