Ask a Scientist: How Do Toddlers Learn About Invisible Things? (Part Two)
We're back. This is the second conversation in a two-part post on how children learn about invisible things. Read the first one here.
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 went ahead and split them into two separate blog posts. Last week: Weight. This 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 sound experiment discussed below was conducted.
This conversation with Williamson has been edited for length and clarity.
Before we get to your research about sound, there a previous study where an adult would press a buzzer and the other adult would act angry, and the toddler would avoid pressing the buzzer while the angry adult was watching but as soon as the angry adult turned around the child felt he could press the buzzer without repercussions. Did that study lead you to the research you did?
That research is work by Betty Repocholi and colleagues at the University of Washington. I was a post-doc there and she was across the hall from me. The task she did involved many different objects where somebody would do something and another person would get annoyed at it. Then you look at whether the child would reproduce the action or not.
So she was right across the hall from me and we got to talking one day and I thought it was really interesting that one of these objects made this really loud noise and this person sitting right there just has their back turned or even just was reading something.
That person is obviously going to hear the buzzer, right?
Yes. But the kids were 18 months, and that didn't seem to influence them. This is kind of a tough thing to test in the lab, the understanding of sound. And people are always finding that it seems like maybe kids aren't not ARE NOT?--MB understanding this quite as early as it seems like they could or should. So with our research we just wanted to dive in and see when they do.
Can you briefly explain the experiment?
We tested two groups. One was 24 months and the other was 36 months; so 2- and 3-year-olds. We were interested in looking at whether they understood the effects of sounds on other people.
We gave them toys, some of which made noise and others that didn't. For example, one tube was filled with bells versus another one that was filled with feathers. We gave kids a chance to play with those, to experience those.
Then we introduced something new to the situation. We brought in a little baby doll, and for half the kids we told them, "Oh, the baby's asleep. Don't wake up the baby."
The other half were told, "The baby's asleep, but nap time's over. Time to wake up the baby."
What we found was the kids who were told it was time to wake up the baby were more likely to shake the louder toy and make more noise with it than they were before the baby was there.
On the other hand, when the baby was [supposed to stay] asleep, we found the kids were more likely to be quieter than they were before the baby was introduced.
So that was as early as 24 months that kids began to understand that noises affect other people?
That's right. Something we found interesting about the effect was that is was seen more strongly in children with siblings. We looked at whether it was an older sibling or a younger sibling and that didn't really make a difference. It was really just if you had a sibling.
What we think might be going on is that if you have siblings, you get a lot more experience with sounds and the effects of sounds than you do without them. It's not even just waking up, but being in a house where people are talking and you get to see your voice or your actions changing people's behaviors.
OK, but in that earlier study, the 18-month-old kids did not seem aware that sounds could affect other people. So somewhere between 18 and 24 months this becomes a thing?
The problem is that the study with 18-month-olds wasn't really designed to test this, so we're not positive. We'd really like to push it down for ages and see [how younger toddlers] do on something that's designed to test this understanding of how sound affects others.
It's not just knowing [that noise affects people]; it's also being able to [act on that knowledge]. I think that's something that toddlers still struggle with. Our data suggests they know what to do. They have an idea of how their sound influences others. But it doesn't mean they can always pull it off.
Do you have any suggestions for ways parents or preschool teachers might apply the findings from your research?
It gives anybody trying to teach a child how to behave an idea that at 2-years-old they probably can make sense of this idea that their behaviors are influencing other people. It's not something that's out of their grasp. Whether they're able to [act on that knowledge] is something different. But it is [a concept] you can introduce to your child. It's something they should be able to make use of.