Back in 2005 my daughter Charlotte, then a four-year-old, took part in a study to see how kids stack up mentally against chimpanzees. I wrote about the ambivalent experience of watching her as both a father and a curious science writer in the New York Times. The emerging lesson of the study, led by Yale grad student Derek Lyons, was that children overimitate even though they should know better. Lyons showed the children how to get a toy out of a container, adding in lots of unnecessary tapping of walls and sliding of rods and such. Other scientists had tested chimpanzees on similar contraptions and found that they pay more attention to the basic mechanics of the task at hand. As a result, the chimps generally leave kids in the dust (Charlotte included).
Two years later, Charlotte is far too sophisticated for such child's play. And Lyons is finally publishing the results of his study (with co-authors Andrew Young and Frank Keil) in the Proceedings of the National Academy of Sciences. The paper--along with short videos of some of the kids in action (not including Charlotte)--are all available for free through the joy of open access.
One reason that the project took so long was that Lyons has spent a long time making sure the patterns hold up. He observed about 100 kids, and put them through a wide range of tests. He also addressed a lot of alternative explanations for his results--many of which were raised by astute readers of this blog. For example, he found that the evidence did not support the idea that the kids overimitated simply to please him and his colleagues. He also let some of the kids figure out on their own how to get the toy out without showing them any extra useless steps, and they could quickly solve the problem. (Charlotte created a particularly dramatic data point by ripping the wall off of one of Lyons's boxes.) Skeptics can judge for themselves from the paper if Lyons has successfully made his case.
It's funny that this paper comes out the same week as Japanese researchers report that young chimpanzees do an awesome job of memorizing numbers--far better than humans, in fact. In both cases, it's shocking to think that any other species could do better on the sorts of tasks that seem to tap into what makes us uniquely human, such as math or solving puzzles. But there's no reason to think of ourselves as simply the top of some great chain of being, superior in all ways to the rest of life. We have evolved to adapt to a particular niche, and the strategies we've evolved to solve problems in that niche are not perfect. Closely imitating others is a wise thing to do in a social species like our own, but it's not hard to get kids to overimitate as a result.
Incidentally, if you want to find out more about this experiment, be sure to check out Lyons's impressive new web site, Hello Felix.
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Sure children may over-imitate, but how can we be sure that chimps simply couldn't catch the complex series of steps and instead focused on the final movement (i.e. open the drawer, grab the candy)? I guess Lyons checked for this by setting up some tests where a long sequence of steps was actually needed to get to the food? I don't know, something like walk at the end of the room, open a drawer, grab the orange key, walk back, use the key to open the container, grab the candy. How long is the chain of events that children and/or chimps can remember? Does the situation change with age, as it does for drawing?
Also,I wonder how much influence this tendence to over-imitate may have had in establishing certain ritual practices. Such as, a neolithic hunter remembered that the past time he caught a prey, he happened to cross a river. from then on he will wash himself of whatever sin he has before starting to hunt... silly? mah... I don't know...
Hi Luca,
This is such a good question I couldn't resist chiming in. It's true that memory issues could potentially explain the fact that the chimps didn't overimitate. Fortunately, the two psychologists who did that chimp study added a very clever experiment to control for that possibility. Namely, they showed a different group of chimps an adult going through the same sequence of steps to get food out of an *opaque* puzzle box (the first one was transparent). When the box was opaque, such that one couldn't tell which actions were necessary and which weren't, the chimps copied everything the adult did. Thus, it really seems that chimps ignore the adult's unnecessary actions in the *clear* box condition simply because they can tell that those actions aren't important, not because they don't remember.
For kids, on the other hand, the Puzzle Box seems to be "cognitively opaque" even when it's physically transparent. They always copy everything that the adult did, even when lots of countervailing pressure is brought to bear as we did in the PNAS studies.
The ritual question is also really intriguing. I do wonder sometimes how kids' overimitative tendency might connect to adult superstitious behavior.
Thanks Derek.
It's clear now. Did they by any chance try to make the final step (e.g. open the drawer) as not-last in the sequence?
to reuse the same example:
1)open a drawer, grab the orange key, flip it into the air, walk back, use the key to open the container, grab the candy
versus
2)open a drawer, grab the orange key, walk back, use the key to open the container, flip it into the air(=perform an unnecessary ritual), grab the candy
I am curious to see if chimps skipping the unnecessary step and the children doing it could be connected with our 'rituality'. Then am sure the professionals in the filed could set it up much better than this.
I think what we're seeing is that humans are smart (intelligent?) enough to know that we don't know. It's the same phenomenon as hearing a 20 something lab assistant say "Everything happens for a reason". Even as adults we're programmed to wait for the adult (God?) to explain things. Possibly a semantic problem or functional problem? The word WHY. Because we look for and frequently find an explanation for "things", we assume there's an explanation for us existing.