Our fast-paced and large world can sometimes make it hard to concentrate. When this happens, we may find ourselves sticking our tongues out as we get in the zone and focus.

Children stick out their tongues when they’re thinking deeply, like when they’re writing or riding a bike. As adults, we also use our tongues as a tool, pressing them to the roof of our mouths or teeth when trying to boost our focus levels.

When difficult tasks arise, what makes us tense this muscle and pull a funny face?

The hands are to blame

Gillian Forrester from the University of London recently delved into this intriguing question. She explained her conclusion to LiveScience: “What we’ve found is what people mean is they [stick out their tongue] when they are doing something delicate that requires fine motor activation of their hands.”

Overlapping language and motor regions

One theory explaining the phenomenon is called motor overflow, where crossover in brain activity causes this unusual behavior. Neuroimaging tells us that the regions of the brain involved in dexterity and language overlap, possibly explaining the fine motor task that is tongue movement “spilling over” when trying to concentrate on language.

Mimicking the hands

There is also an evolutionary component to the story. Another study explains that our mouths shadow our hands because these were first involved in language. Looking at our closest living relatives, apes, they primarily use their hands as tools to communicate, therefore it is likely early homo sapiens did also.

It is theorized that as humans evolved, we came to use our mouths and tongues to get a message across. However, this millions-year-old behavior is still hardwired in us. “That’s likely why you see so much gesturing going on when we speak and why vision is our primary sensory tool,” Forrester stated.

Multiple other studies have come to the same hand mimicking conclusion. One even found a relationship between the size of objects our hands picked up with the amount children’s mouths opened.

Why do children stick their tongues out more?

It is most likely that children engage in this activity more because they haven’t been able to suppress it yet. Our world teaches us this behavior is not professional or normal, so we are likely to train ourselves to stop through social conditioning.

The difficulty of learning new tasks is also at play here. Tying our shoelaces as an adult is a pretty mundane task, though as a child there is a lot to remember here. As we memorize these precise, articulate movements, our adult brains don’t have to engage as much, therefore, there’s not as much spillover from our tongues.

Realizing how our brains develop and the funny quirks of human behavior could lead to a deeper understanding of speech disorders, including stuttering, speech sound disorders, and childhood apraxia of speech. Speech disorders are currently not that well understood and therapies are still at a basic stage. Hopefully, research such as this can lead to more effective ways to treat these conditions.