Why are pacifiers soothing?

It’s almost magical – pop that little pacifier in a fussy baby’s mouth and their cries melt away as they drift off to sleep. There’s no denying this staple infant gadget has strong soothing powers. But what exactly gives the pacifier its calming juju? Why does this simple device act like a hypnotizing sleep charm for restless babies?

As it turns out, there are fascinating scientific reasons behind a pacifier’s ability to lull cranky infants into dreamland. The satisfying of instinctual sucking needs, rhythmic motions, pain relief and other factors all work together to induce a zen-like state.

Parents and caregivers have utilized pacifiers’ soothing effects for ages, but understanding the science behind it sheds new light. From tapping into primal reflexes to triggering key networks in the brain, pacifiers are cleverly designed to leverage an infant’s needs.

Read on to learn the facts on why various mechanisms make pacifiers such adept soothers and sleep promoters for fussy newborns. Understanding the method to pacifiers’ magic will help you wield their soothing powers judiciously and get baby drifting off on cloud nine.

Why are pacifiers soothing

How babies respond to pacifiers

Whether or not a pacifier works to soothe a child can vary based on several factors. Some babies may be unresponsive to pacifiers, while others eagerly accept them for comfort. There are a few key reasons why a child may or may not take to pacifiers:

Age and development play a big role

Newborns in the first 6 weeks of life have an extremely strong sucking reflex and are more likely to readily accept pacifiers. However, they start losing interest around 3-4 months as sucking needs decrease. By 6 months, many babies become resistant as needs change and exploring objects orally becomes more enticing. Pacifier acceptance windows tend to close after the first year.

A child’s baseline temperament can impact pacifier affinity

Some babies are more easily overwhelmed and have a high need to suck for self-soothing. Fussier babies tend to love pacifiers more. Meanwhile, mellow babies sometimes take or leave them.

Physical factors

Factors like hunger, teething, reflux, and oral anatomy also determine pacifier effectiveness for calming. Babies with colic or gastric distress may reject pacifiers more. Teething babies often increase sucking for pain relief. Proper nipple size and shape must conform to the mouth.

Lastly, early exposure matters

Introducing pacifiers in the first few weeks when sucking needs peak makes acceptance more likely. Delaying introduction after 3-4 months can result in outright rejection. Babies accustomed to thumbs/fingers may also refuse pacifiers.

With so many variables at play, it’s not surprising some babies bliss out with pacifiers, while others could take them or leave them, or reject them entirely. Watching your child’s cues, keeping age appropriateness in mind, and maintaining flexibility are keys to pacifier success.

Reasons why pacifiers are soothing

Natural Sucking Instinct

Sucking is one of a baby’s core instinctual reflexes, together with grasping, rooting, and moro reflexes. The sucking need emerges while still in the womb as the fetus sucks their thumb or fingers for comfort and stimulation. This reflex continues powerfully after birth. A pacifier taps right into this primal urge to suck and receives immediate acceptance.

Non-Nutritive Sucking

Babies have two types of sucking needs – nutritive sucking to feed and non-nutritive sucking for pleasure and self-soothing. Pacifiers satisfy non-nutritive desires between feedings, essentially tricking babies into thinking they are feeding. This releases natural calming and pain-relieving endorphins in the brain.

Oral Stimulation

The nipple provides oral stimulation by activating nerve endings in the mouth. This sensation alone can be pleasurable and distracting for infants. It explains why babies start rooting and searching for a pacifier as a source of comfort.

Rhythm and Motion

The repetitive, cyclic motion of sucking is both organizing and soothing for babies. The predictable rhythm lulls them into a peaceful, relaxed state. The pacifier nipple also moves with the motion of the jaw, reinforcing this calming pattern.

Promotes Sleep

The combination of oral stimulation and rhythmic sucking motions triggers important neural connections that induce sleep. It causes drowsiness by lowering heart rate, breathing rate, and stress hormones. This parasympathetic nervous system activation primes babies for deeper sleep.


Pacifiers allow babies to independently self-soothe without parental involvement. The ability to control this coping mechanism themselves is inherently calming. Sucking also masks discomforts like hunger that could prevent sleep.

Familiarity and Security

The pacifier itself becomes a familiar object associated with soothing and comfort. Babies recognize their “passy” and are conditioned to relax when it’s offered, similar to how infants associate parents with safety.

Pain Relief

In addition to releasing calming opioids, pacifier sucking is thought to activate higher brain centers that close neural “gates” to pain perception. This offers safe, temporary pain relief as the brain focuses on pleasurable sucking sensations.

Final Thoughts

Parents and caregivers have long appreciated the sleep-inducing and soothing effects of pacifiers. Now the science is unpacked showing how non-nutritive sucking, oral stimulation, rhythmic motions, and conditioning all interact to calm and relax fussy babies.

Pacifiers leverage basic infant reflexes and needs to quickly provide comfort and relief. When used judiciously, they remain a safe and effective tool in a parent’s toolbox to quiet a restless baby.

Just be sure to follow size and safety guidelines, and consider weaning pacifier use after the first year. With the right precautions, pacifiers’ magical soothing powers can give both baby and parents a bit more peace.


  • Editorial team

    A team comprising oral health care professionals, researchers, and professional Writers, striving to impart you with the knowledge to improve your oral health, and that of your loved ones. 

  • Lilly

    Lilly, aka, Liza Lee, is a passionate community oral health officer and our lead writer. She's not only well-versed in performing a multitude of dental procedures, including preventive, restorative, and cosmetic, but also an avid writer. Driven by the significant oral health burden all around her, Lilly strives to build capacity and promote oral health. She envisions making a lasting impact by advancing research, prevention, and promotion efforts to alleviate oral health disparities. Please share your views and opinions on my posts.

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