Why Do Babies Smile in Their Sleep? Are They Dreaming?

Although early parenthood can be exhausting, it’s difficult not to pause and admire your precious bundle as they sleep.

Perhaps you were putting your little one to bed and noticed them suddenly smiling in their sleep.

First thought: This is too adorable! Second thought: What does this mean — could they be dreaming?

Why do babies smile in their sleep? Newborn and young babies tend to smile due to an involuntary reflex during REM (rapid eye movement) sleep as new information is being processed in the brain. As babies grow, greater interaction with their environment can trigger a more recognizable social smile during sleep.

Not only is their first sleeping smile a cute milestone, but it also indicates an amazing new developmental step in their cognition and communication skills.

Keep reading to find out why your baby smiles in their sleep, what age can expect to see the first smile in your newborn, tips on making your baby smile, and when they start to dream.

Baby Smiling in Sleep – What To Know

Babies smile in their sleep for many reasons — some out of reflex, others in response to a memory — but either way, it’s an adorable sight!

Let’s learn a little more about the different types of baby smiles plus normal movements during sleep and more.

Why Babies Smile in Their Sleep

It’s believed that your baby’s developing brain plays a large part in smiles during sleep as they are processing new information and experiences during their day, resulting in an emotional response to memories of sights or sounds.

Their REM (rapid eye movement) sleep phase is thought to trigger a smiling reflex due to vivid dreams, according to pediatrician Dr. Arti Sharma.

Another reason for a smiley baby during sleep could be the comfort and relief brought on by passing gas, which can be more likely in babies suffering from colic.

Reflex Smile vs. Social Smile

Reflexive smiles tend to occur in very young babies before their first true social smile and are usually very brief and occur without any real reason or visual stimuli, much like the involuntary reflex of a kick in the womb.

This type of smile can happen so early in fact that 4-D ultrasound scans have been able to record the reflexive smiles of fetuses at around 33 weeks!

Social smiles, meanwhile, tend to happen at around 3-4 months old once your baby has had time to take in their new environment and pick up on social cues.

This is considered a true voluntary smile in reaction to other people and shows their communication skills are developing well.

If they are beginning to smile during social interactions during the day, the memory of this experience will be processed as a social smile while they slumber too.

Newborn Baby Smiling in Sleep

Newborns can begin smiling in their sleep as early as 2-3 weeks old as their brains begin responding to and producing stimuli.

Some experts believe that a newborn’s smile may be a physical response to a pleasant experience either happening in the present (the happy hormones released while being cradled) or in a dream about the comfort felt in the womb or during breastfeeding earlier that day.

A baby’s facial muscles are activated when they dream, which can cause their mouths to open, resulting in an expression resembling a smile. These “smiles” may also be accompanied by cooing sounds.

A newborn baby sleeping under a white blanket with a smile on his face.

Older Baby Smiling in Sleep

As your baby grows, their interactions with people and the world around them will become more frequent, leading to more and more information being processed during sleep.

Making sense of all the new information, sounds, sights, and people in their lives may make them more active in their sleep, leading to wide social smiles and sometimes even cute fits of laughter, which researchers believe is your baby’s way of practicing their newfound emotions.

Do Newborn Babies Dream?

Newborns may not experience true dreaming in the way we understand due to their brain’s immaturity and limited experiences.

While REM sleep often contributes to vivid dreams in older children and adults, neuroscientists believe that this serves a different purpose for newborns and infants, allowing their brains to build pathways and develop language instead.

What Age Do Babies Dream?

It’s believed that babies do not begin truly dreaming until around 2 years of age, but their dreams at this stage are far from complex.

Fascinatingly, psychologist and pioneer of sleep research Dr. David Foulkes has found that even children aged 4 and 5 have dreams resembling static slide shows with no memories and few emotions, while true vivid dreams of structured narratives only kick in at around age 7 or 8 when children develop self-awareness.

Baby Movements While Sleeping

Alongside smiles, it’s common for your baby to suck their thumb, throw their arms up, and display bodily twitches and kicks while they pass through REM and non-REM sleep cycles, which make the muscles relax and stiffen periodically throughout the night.

These twitches are normal and are known as myoclonic twitches caused by sudden muscle contractions or muscle relaxation.

You know that startling jerky feeling like you’re falling in your sleep? That’s a form of myoclonic twitching.

If your baby experiences a regular bout of these twitches while they are awake, e.g., a series of jerky movements followed by stiffening, it’s wise to speak to your doctor.

In some cases, this can be a case of benign neonatal convulsions, but in other cases, it may indicate seizures.

When Do Babies First Smile?

A baby’s first real smile can appear near the end of their second month, but it could be later.

At this point, they are sleeping less than in their newborn stage and have more time to communicate and interact with you.

In fact, “Are they smiling yet?” is one of the main questions a pediatrician will ask at your little one’s 2-month checkup.

Newborns Smiling at 1 Week

You’ll spot these early newborn “reflex” smiles that happen involuntarily and have done so since they were in the womb!

This is usually in response to some internal stimuli such as going to the bathroom, passing gas, or hunger.

External stimuli may also cause an involuntary “smile” in your newborn such as someone touching their face, which may cause them to raise their cheek muscles in reflex, according to the Sleep Foundation.

Newborn Smile After Feeding

Newborns may smile involuntarily after feeds due to the contended, sleepy feeling it brings or the closeness with mom.

However, research has found that newborns could smile in response to sweet smells and tastes, so it could all be down to that yummy breast milk!

Baby Smiling at 3 Weeks

In their first 6 weeks of life, babies will still be smiling reflexively, so your 3-week-old could be grimacing for a few seconds rather than smiling due to gas.

They could also be trying to mimic your facial expressions by experimenting with their own facial muscles.

A cute baby smiling while wrapped in a pink blanket.

How To Make Your Baby Smile

Social or involuntary, every smile on your baby’s face is a thing of joy and worth encouraging at every opportunity you get.

Here are some surefire ways to make your little one smile!

  • Engage with them during feeds, dressing, bathing, diaper changing. etc. Talk to them, sing a song, and pull silly faces.
  • Read to them.
  • Play peekaboo!
  • Sing a nursery rhyme (or any age-appropriate song!).
  • Match their reaction. If they smile or laugh, do the same back with enthusiasm.
  • Gently touch or blow on their skin.
  • Make funny noises. Raspberries, popping sounds, and squeaky voices are all good
  • Get a pet to help you out. Play with your dog or cat in front of them. Use your cheesiest doggy voice for extra success!
  • Put on a puppet show.

Related Questions:

When Babies Smile in Their Sleep, Do They See Angels?

It’s said that if your baby smiles in their sleep it’s because an angel is smiling back at them.

Another belief in spiritual circles is that angels can tickle a baby, causing them to smile and laugh, and your little one’s smile is said to indicate good luck and a good mental balance.

Why Do Babies Twitch in Their Sleep?

According to researchers at the University of Iowa, an infant’s body will twitch during REM (rapid eye movement sleep) due to sensorimotor development.

During this process, circuits are being activated throughout an infant’s developing brain and body, informing your baby about their limbs’ capabilities.

Closing Thoughts

To summarize, babies will smile in their sleep for many reasons:

  • A reflex as their brain makes sense of all the new sights, sounds, and experiences of the day.
  • A social smile as they remember a funny interaction.
  • Baby’s relief from passing gas!

It’s also normal for your little one to display twitchy movements in their eyes and limbs during their active REM sleep cycles.

Just be sure to speak with your doctor if these twitches continue while they are awake as this may warrant medical attention.