Has your baby left you at wits’ end, what with the shoes, toys and sweaters—and everything in between—making their way into her mouth? Rest assured that every baby does this, and it’s totally normal. In fact, it’s a prerequisite to being a healthy infant.
“The brain is a novelty-seeking organ,” explains Jill Stamm, Ph.D., co-founder of the New Directions Institute for Infant Brain Development and an associate clinical professor of psychology in education at Arizona State University in Tempe. “Everything is new to babies. They need to know: Can I eat it, or can it eat me? Can I use this thing, or is it potentially harmful? They have to gather information about everything; it’s what their brains require.”
But why does everything end up in the mouth? It all has to do with those little sensory- seeking things called neurons. “The mouth and hands have the most neural real estate in the entire body,” says Stamm, who is the author of Bright from the Start: The Simple, Science-backed Way to Nurture Your Child’s Developing Mind from Birth to Age 3 (Penguin Press). In other words, babies get the most sensory input from those areas. That’s also why so many suck their thumbs, even in utero—they’re engaging both neuron-rich areas at once.
While there can be great variability in when babies meet their milestones, most should begin mouthing objects by about the age of 3 months, when they’ve mastered hand-to-mouth control. This (admittedly long) phase will last several months, until the brain moves on to other challenges. “When a child is starting to articulate with words, she often stops putting everything into the mouth because it is busy doing other things,” Stamm says. If your baby isn’t grasping and mouthing objects by 6 months, bring it to your pediatrician’s attention.