Ask a Scientist: How Do Toddlers Learn About Invisible Things? (Part One)
We know a lot about when children learn about things like colors and amounts, but when and how do children begin to understand things they can't see? Rebecca Williamson is an associate professor at Georgia State University studying toddlers' grasp of ideas they can't observe just by looking.
"A lot of our scientific thinking is based on unobservable theories and abstract concepts and properties that we can't see, like weight," Williamson said. "So it's a really important idea for us to understand as we get into more abstract thinking."
Williamson has explored when children begin to grasp concepts like weight and sound. She has also looked at how children learn these concepts with the idea that such knowledge could be useful to parents and teachers. The experiments she ran are so interesting that I'm going to split them into two separate blog posts. Today: Weight. Next week: Sound.
Williamson did her post-doctoral work at the University of Washington's Institute for Learning and Brain Science and holds a Ph.D. in developmental psychology from Stanford University. She is now an assistant professor at Georgia State University in Atlanta, where the weight experiment discussed below was conducted.
This conversation with Williamson has been edited for length and clarity.
Your research is mostly on how young children learn about things they can't see. Is that an accurate way to describe it?
Yeah, it's a great way to describe it. Our past literature looks a lot at visual properties. But the work that we're talking about today has to do with properties that aren't visual.
Is your research trying to determine at what point in their development kids can learn about things like weight? Or is it trying to figure out how you can teach them those things earlier?
My research looks at how kids learn from other people. These are just two of the things that we've looked at to try and understand children's learning better. Most of my research is looking at establishing when it is that children have understandings of these different concepts and are starting to use them. I hope that if we can make sense of how kids learn, we might develop better teaching practices, especially for really young kids.
So, at what age do kids start to get the concept that some things are heavier than others?
Weight is something that kids tend to struggle with. Our research looked at a particular weight task: When [can kids] learn to sort objects by weight? We showed them four objects that were the same, but two of them were heavy and two were light. We were interested in really how we could help them figure out to sort [the objects] by weight.
If you just give kids the objects and don't tell them what to do with them, they don't sort them by weight very often at all. But if you show them sorting by weight, even if you don't tell them anything, kids at 4 years old were picking up on that. At 3 years old, they weren't learning how to sort by weight.
We do have other research in the past that shows that if you show sorting by something like color, kids can pick that up at age 3. Even the sounds that objects make, kids will sort those at age 3 after seeing somebody sort by them. But for weight, it wasn't until age 4 that they were able to do it.
It looks like you used toy rubber duckies, and they were the same exact size and color. By looking, nobody could've sorted them. You had to pick them up.
Yeah, that's the idea. We wanted this to be this internal property. So you're not using visual cues; you're using what you feel when you handle them. When you see the adult sort them [in the video], it looks like [the adult is] just placing two and two together. You can't tell that they are different weights. What we think is going on, and we're not positive, is that kids are watching the adult's behavior, they're seeing them sort that way, and they're thinking, "Huh, what's she doing? Why's she doing that?" And that's cueing them that weight might be an important thing.
Can kids at 3 hold something heavier and something lighter and say, "This one's heavier?"
At age 3, a lot of kids do know the words "heavy" and "light." Even infants show some recognition of different weights. So if you give them heavy things to manipulate versus things that are light to manipulate, young kids behave differently with them. But actually figuring out to sort them and group them by this property was something that 3-year-olds weren't [able to do].
Do you have any suggestions for ways parents or preschool teachers might apply the findings from your research?
What's really encouraging to me is the idea that your examples are a great way for children to learn. So just watching what you do, kids are great at that. They can pick up all kinds of information. Even things like [sorting by] weight, which isn't obvious from what you're doing, [are things] they can start to learn about. So show kids what to do when you're trying to teach them. It's a really great way for them to learn.
Photo: Rebecca Williamson, courtesy Georgia State University