Q: Why is my child so interested in touching and mouthing toys?  I thought that by now, she’d be doing more playing.

A: For your baby, that’s just about the most fun she can have!  By 9 months, babies really enjoy and are getting quite good at exploring objects with their eyes, hands, and mouths. These explorations are guided by their curiosity about: What is this? What does it feel like in my hands and in my mouth? What does something that looks like this feel like?” 

Take the example of a baby picking up and mouthing a block. As an adult we know (or can imagine) exactly what the various characteristics of a block are. There is a smooth surface, it is shaped like a cube, it is the size of a small box, it has edges that feel different than the flat sides, etc. While for adults this knowledge is almost automatic, babies are delighted by the discovery of the physical features of objects. They are equally interested in the connection between sights and sensations—that a side that looks smooth also feels smooth in the mouth and hands. When holding and putting the cube in her mouth the baby learns about features such as smoothness, coolness, side, edge, and corner. 

If you watch your baby closely enough, you can see these discoveries happen as she moves the cube around in her hands, puts it in her mouth, takes it out and looks at, puts it back in, and so forth. Watching for this, and gently supporting and guiding your baby, can also be delightful for you. It’s exciting to “get” what your baby is up to while she is playing: Oh, it looks like you found the edge. 

This process is essential for later learning. Imagine if, as a preschooler, your child had to suck every wooden block she was stacking in order to figure out which was the edge and which was the side.  Instead, after having explored blocks over and over again, your child comes to expect that each block will have the same basic characteristics. By mouthing and handling objects as a baby—safely, of course—she becomes “fluent” in ideas like side, edge, and corner.  She doesn’t have to “re-discover” blocks each time she plays. This enables your child to automatically apply this knowledge to solve more and more complex problems, like how to build a block tower. 
 
This response was developed in partnership with Robert Weigand, Director, Child Development Laboratory Arizona State University.