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Photo of Sally Boysen Sally Boysen as seen on
Animal Einsteins: Thinking About Thinking

Click on Sally's photo to read a brief bio.

q I have seen many counting studies in chimps (and other animals), but all of them seem to involve addition. Has there ever been a well documented/significant study involving subtraction? I know that the concept of negative operations takes quite a while to develop in children, is it the same for chimps, or is it beyond their cognitive ability? Joseph

A We did some work on subtraction some years ago with one chimpanzee, but did not develop it as a full experiment at the time. We plan to conduct just such a study in the coming months, as we now have 5 adult chimpanzees with counting skills. I just tried a few trials (literally) on Friday (2/12) with Sheba, age 17, and Darrell, age 19, and both "got the idea" about subtraction right away. I simply showed them, for instance, 4 candies, put a piece of cardboard in front of the candy, gave the chimp 1 candy, and then turned on their computer keyboard with a variety of numbers displayed. Each chimp, when tested this way, got the right answers to approx. 6 subtraction problems each, right off the bat! It was VERY exciting!

So, it looks like chimpanzees do, in fact, have the necessary cognitive abilities to grasp the concept of subtraction.

q Could the chimp find the soda can in the model room if it was shown where it was in the large room? Elizabeth H., biology student at St. Bernard's Central Catholic High School, Fitchburg, MA

A What a good idea! Both ways of looking at children's understanding of scale models was done by Dr. Judy DeLoache, Univ. of Illinois, Dept. of Psychology, whose work we modeled with the chimps. She had half of the children she tested find the item in the real room, after seeing it hidden in the model; the other half of the kids saw it hidden in the real room first, then had to locate the miniature version in the model. So far, we have only had the chimps watch as something is hidden in the model first. We plan to do just that study, however, this spring, when the weather gets warmer here in Ohio. Because the model we are now using is one of the chimps' outdoor play area, we need to wait for the snow and ice to disappear before the chimps will be willing partners again!

q In your experiment of hide and go seek, is it possible that the chimp is using his sense of smell to find the object in the room? That's a well developed sense that a child does not possess, so wouldn't that affect the experiment a little? Monica

A A: Chimpanzees' sense of smell is pretty comparable to ours, so odor cues would not help them find a hidden item in the room. The part of the brain that controls smell, the olfactory bulb, is about the same size as ours, and thus does not support the kind of use of odor for finding food, etc., as it does in other animals, such as rats or pigs, both of whom have extremely developed and superior olfactory capacities.

q My students were extremely interested in the scale-room experiments and kept commenting on the number of times you checked and double-checked with the animals to judge their understanding of where the items were being hidden in the model before they searched the real room. When the students compared how the conversation was handled with the humans, they said that the little children weren't questioned as many times as the animals were before being led to the real room. Did the part we see just not contain a good representative of the conversations between the adults and the children? Thanks for your time!! :-) Jackie Robertson

A You were right! We did spend more time making sure the chimps paid attention to where we hid the item, etc., than Dr. DeLoache (who studies children's understanding of scale models) needed to. The chimps' attention span is much, much shorter than even the most hyperactive child, and so it requires that we work very hard to try and make sure they pay attention so that we will have as good a chance as possible for finding out if they have the cognitive ability to do something (like the scale model task).

Since we already know that their attention span is so short, we try to make sure that isn't the reason that they can't perform some skill or do well on something we are testing them on. So, WE pay more attention, in a sense, for them, so all they have to do is try to show us how well they can think about some new concept. There is no question that we are "supporting" their limited attention spans in this way -- but we think that is just part of the teaching process when working with this highly intelligent, nonverbal, WONDERFUL species.

Indeed, they are not the SAME as humans, are they? Their limited attention span is one significant way in which they differ, although there has been virtually no experimental studies of it so far. As you might expect, we plan some in the near future, and in fact, we believe that it is attention differences between male and female chimps that accounts for their differing abilities with the scale model task such that males cannot really perform well, and female chimps are excellent at showing their understanding of the relationship between a scale model and the real space it represents. Imagine that?! Something that females (chimps!) are better at than males (chimps). What is the forest coming to?

q I am interested in pursuing a career in researching and/or working with animals like the work you do with chimpanzees. I was wondering if you could send me more information about your work and some advice on how to get started on a career like this. Beth

A How can you prepare for a career in primate cognition research? Get as strong a science and math background as you can, at every level of education, including high school and then college. In terms of college courses, I was on a pre-med/pre-vet path initially, and so I took lots of courses in zoology, including physiology, embryology, mammology, ethology (animal behavior), behavior genetics, biology, chemistry, statistics, experimental psychology, physical anthropology, etc. I also took specialty courses where I could find them, such as primate behavior in the anthropology dept., comparative psychology, in the psych. dept., and advanced courses in animal behavior in the zoology dept. I ended up with a triple major in undergraduate school including psychology, zoology and anthropology.

It took me some time to get to my current position, although I was involved in full-time research part of the time between when I graduated with my Master's degree. I did about 5 years of undergraduate work, two years for a Master's degree in Psych., then approx. 4 years for a Ph.D., with 3 years of full-time research with an ape language project between when I finished my Master's and my Ph.D. It has been 25 years since I graduated from undergrad school, but then again, this project did not exist until I started it.

(Webmaster's note: For more information about careers, check out Cool Careers in Science, featuring advice from scientists who have appeared on Frontiers.)

q Sally, Great show. My kids (ages 3 to 9) and I all enjoyed the show and your and your work with chimps. My 9 year old looks at science in a new way -- as interesting. Thanks! Rich

A Rich, thanks for your message. It was great to hear that your 9-year-old has some new ideas about science. We need ALL the good brains we can train, to help solve the difficult problems that our world faces; that means boys and girls, women and men, from places on the planet. Science isn't all about test tubes, and white lab coats, and geeky people -- it's about adventure, excitement, mystery, detective work, and, if you are lucky or well prepared to recognize something of potential importance in your results, exploring the world through science is AWESOME! Imagine knowing something that maybe no one else knows, and then getting to share that with the world? Too cool.

q How did you like working with chimps? Are they usually cooperative with the experiments, as we see on the show, or are they sometimes bored or noncooperative? Maggie and many other viewers

A Can't you tell that I LOVE working with chimps? I HAVE to be around them; it is a bit of a disease, I am afraid. The chimps have the full range of behaviors just as you see in your children or perhaps yourself! Some days they are absolutely wonderful, cooperative and so much fun; others days, they are spoiled brats (some of them, like Digger, who is an adolescent male about 9-1/2 years old, who loves to spit at the female chimps through the cage bars, and really make them mad! They scream and scream when he does this, and the more they scream, the worse he acts! Who does that sound like, eh? Any of you have any little sisters or little brothers who do those kinds of things?? No? Gee, I guess I was wrong; I thought that you would all really understand what kind of teasing and "sibling rivalry" I was talking about...

The chimps often try to test the limits of our patience, for sure. But, everyone, chimps and humans alike, forgive chimps and their teachers. All in all, it is a wonderful, wonderful experience to share their lives, and none of us would give it up for anything!

q I have a daughter who is 23 months old. She is extremely verbal, so I have a little more insight into the workings of her mind than the average mom of a toddler. I did a home version (using a doll house) of the identical-room-hide- and-seek just to see what would happen. For the first trial, I hid the doll house baby in the bathtub and her favorite dolly in our tub. I shut the door to her room to hide the dolly. She found it immediately. Same thing with the second trial and our living room sofa. Then, she only looked for the dolly on the sofa (no matter where the doll house dolly was hidden.) I thought that was weird until she told me this, "Baby (her big dolly) wants to hide under the blanket." It didn't matter what I wanted to do, Baby had a mind of her own and wanted only to hide under the blanket on the sofa. Which leads me to my question about testing the minds of toddlers. Could toddlers fail to perform in the hide-and-seek tests for other reasons than an inability to do abstract thinking? Wendy Lym

A Wow! What a great developmental psychologist you are! I loved hearing about the mini-study you did with your daughter. It certainly is a possibility that the younger children who failed the scale model task has other ideas about what "the game was all about," like your daughter, who made up her own creative rules. However, one of the great things about approaching a complex question like this through an experiment is that it gives us more ideas about how to better address the questions, because from the results, we ask MORE questions and come up with other experimental questions (also called hypotheses) to ask, just as YOU did.

See? I told you that you were a good psychologist -- the trick is to come up with another method or task that might better ask the question about how young children's minds operate, and in laboratories all over the US and the world, these kinds of studies are being done. As I think I mentioned on the show, we are probably more limited by our own limited abilities to "think about thinking" and devise innovative ways to explore such complicated things like "minds" that it will keep the lots of human minds busy for many generations to come, in order to understand just exactly WHY your toddler came up with her own innovative twist on the scale model task! Asking those questions, and searching for the answers, not matter how difficult they appear, is certainly one way that humans do, in fact, differ from other species. What we do with the answers, however, affects all creatures on the planet, and thus we carry a responsibility which we must take very, very seriously.

q Do the chimps appear to demonstrate the intuitive awareness, empathy, and inter-animal communication in any other situations? Do they do it when something good is going to happen, like being fed or played with? Anna Marie

A Yes, the chimps do appear to have awareness, empathy, and certainly lots of inter-animal communication, all the time, in situations which are "good" (when treats are being distributed or we are playing a game of chase back and forth in front of their outdoor play enclosure), or "bad" (temper tantrums, minor fights, etc.). They have a very, very rich emotional and communicative life, and it is very easy for us to also empathize (!) with the reactions to all kinds of situations that are similar to our own experiences.

q Your work with chimps and pigs is amazing. Do you work with dogs at all? I have two cocker spaniels, 3 and 4 years. They are the love of my life. I truly believe they are far more intelligent than we give them credit for. My 4 year old appears to think abstractly and figures things out on her own. She appears to think about everything she does before she does it. Please respond. Thank you. Jana

A I have worked with a border collie for the past few years, although he is, like the pigs, "retired" to my house in the country. We worked with him on gestural/verbal communication also, and he was able to get to a point in his training that we could construct a string of gestures or verbal commands such as, "Sit by the big white dumbbell," or "Fetch the small black ball." He was extremely distractible, however, much more so than the pigs, who ALWAYS had their eye on that piece of apple or raisin you were going to reward them with, when the test trial was over! Smithers, the border collie, is a great, loyal dog, despite his "attention-deficit disorder!"

I, like you, am also a "dog person," and have had as many as 5 at a time. I currently have a Bassett that grew up with Sheba (the chimp); Skylar, the dog, was Sheba's birthday present when she was 6 years old. That means Skylar is now 11, which is hard to believe; she is bit arthritic and crotchety in her old age, but Sheba still enjoys seeing her a couple times a year. There hasn't been very much experimental work done with dogs, but I agree with you; many are extremely intelligent, and make great subjects for cognitive studies. In our case, we decided we needed to focus more on the chimps, who were growing up very fast and really need more attention from us. As it turned out, both students who were working with the dog and pigs respectively, graduated and moved on to other phases of their lives, so it was a good time for the animals to move to the country!

We have also done another study to look at something called object permanence. That is the idea that when a child (or animal!) watches as, say a toy, is hidden, they then search for it in the last place they saw it. Object permanence emerges in human infants around 12 mos.; before that, you can show them a cute toy, then hide it under a blanket, for example, and they just seem to forget it exists! The old "out of sight, out of mind" trick. But, once a baby (or dog, or chimp, or maybe even a pig?) has object permanence, they understand that just because something isn't in view doesn't mean it no longer exists -- and they look for it!

We tested 55 pet dogs of all breeds on an object permanence task by having them eat dog chow from a dish that was on the back of a radio-controlled car. After they ate briefly, the car began moving and moved inside a wooden A-frame apparatus, and essentially "disappeared." We were interested in whether or not the dogs would understand that they could go to the other end of the A- frame, to the second door, and wait for the car to emerge out the other side. About 50% of the dogs did this, and it was amazing to watch. Dogs who failed to solve the task were those who were uncomfortable in the novel test setting (we tested them in a large dock area of the chimp center). In other words, those dogs whose temperament was such that they stayed close to their owners, did little exploration in the new space, and didn't really eat (too stressed?), and thus were not comfortable, did not show object permanence. It was a very fun study, and earned the high school student who used it as her science fair project a blue ribbon!


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