Published on Jan. 29, 2018
When you have a newborn, they don’t do much other than sleeping, feeding and pooping. As babies grow older and become more aware of their surroundings, they begin offering some of the most rewarding moments for parents—smiles and laughter.
Few things compare to hearing your baby giggle, which naturally makes parents want to see that reaction again and again, even if it involves a tickle here or there. You may know why you tickle your baby, but what’s actually happening in your baby’s brain during tickling?
What Science Says About Tickling and Babies
According to Eric Morley, M.D., a pediatrician at MemorialCare Medical Group - Long Beach (Los Altos), when it comes to understanding what kind of brain activity tickling triggers in babies, the short answer is that no one knows for sure.
He explains that scientists and philosophers have been wondering about tickling for nearly 2,000 years, asking questions like:
- What is actually happening in your body when you are tickled?
- Why can’t we tickle ourselves?
Why Tickling Often Leads to Laughter
"We often laugh when tickled,” says Morley, “and it is not exactly clear whether this is a result of the sensation of being tickled or a conditioned response evolving from repeated playful behavior associated with tickling and laughter of the tickler.”
This suggests that laughter may not always be a direct response to the sensation itself, but rather something babies learn through repeated social interaction.
When Babies Start Responding to Tickling
Morley explains that babies generally do not begin laughing until around four months of age, and laughter specifically in response to tickling may not appear until closer to six months.
New research suggests that before six months, babies may not yet connect the tickling sensation with the person delivering it.
“Rather, they just feel the 'tickle' sensation,” adds Morley, “but don’t really understand its origin.”
Morley notes that more research is needed to fully understand how complex the tickling response really is in babies.
Why Tickling a Baby Is So Hard to Study
The Challenge of Interpreting Infant Responses
Why is tickling in a baby so difficult to understand? Trung Tristan Truong, M.D., a pediatrician at Saddleback Medical Center in Laguna Hills, California, explains that evaluating a baby’s response to touch or tactile sensory input can be extremely challenging.
Truong believes a baby’s reaction to tickling depends largely on:
- The context in which it occurs
- The baby’s developmental stage
How Development Affects a Baby’s Reaction
“A younger infant may not necessarily enjoy or dislike being tickled,” explains Truong, “due to perhaps relative lack of other sensory awareness, as well as an immature social connection.”
He says tickling may simply trigger:
- A motor (movement) response
- A general arousal response
As babies grow and mature, Truong explains their responses should change as their senses—particularly visual and auditory—become more developed.
Mood, Environment and Emotional Cues Matter
As infants develop, they may begin to like or dislike tickling depending on the situation and their emotional state.
Truong notes this can be influenced by whether a baby is:
- Happy
- Hungry
- Tired
“A baby who is content and playful and is being tickled by a parent who is expressing affection and making cute sounds will more likely enjoy the experience and result in laughter as the baby perceives love and caring from the parent.”
How Parents Can Tell if Tickling Is Welcome
While there may never be a definitive answer about exactly what happens in a baby’s brain during tickling, parents can look to their baby’s reaction for guidance.
Most parents are able to gauge their baby’s comfort level. If tickling seems to make your baby uncomfortable or scared, it’s best to stop.
As babies get older, they may begin to understand the concept and motivation behind tickling, allowing them to laugh, giggle, or even clearly tell you when they’ve had enough.