Where's Mom? In experiments with chicks imprinted on toy objects, hatchlings showed rudimentary number skills when searching behind screens for their parents.
Image: Courtesy of Rosa Rugani
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Scientists have been skeptical of claims of mathematical abilities in animals ever since the case of Clever Hans about 100 years ago. The horse, which performed arithmetic and other intellectual tasks to delighted European audiences, was in reality simply taking subconscious cues from his trainer. Modern examples, such as Alex the African grey parrot, which could count up to six and knew sums and differences, are seen by some as special cases or the product of conditioning.
Recent studies, however, have uncovered new instances of a counting skill in different species, suggesting that mathematical abilities could be more fundamental in biology than previously thought. Under certain conditions, monkeys could sometimes outperform college students.
In a study published last summer in the Proceedings of the Royal Society B, Kevin C. Burns of Victoria University of Wellington in New Zealand and his colleagues burrowed holes in fallen logs and stored varying numbers of mealworms (beetle larvae) in these holes in full view of wild New Zealand robins at the Karori Wildlife Sanctuary. Not only did the robins flock first to the holes with the most mealworms, but if Burns tricked them, removing some of the insects when they weren’t looking, the robins spent twice as long scouring the hole for the missing mealworms. “They probably have some innate ability to discern between small numbers” as three and four, Burns thinks, but they also “use their number sense on a daily basis, and so through trial and error, they can train themselves to identify numbers up to 12.”
More recently, in the April issue of the same Royal Society journal, Rosa Rugani of the University of Trento in Italy and her team demonstrated arithmetic in newly hatched chickens. The scientists reared the chicks with five identical objects, and the newborns imprinted on these objects, considering them their parents. But when the scientists subtracted two or three of the original objects and left the remainders behind screens, the chicks went looking for the larger number of objects, sensing that Mom was more like a three and not a two. Rugani also varied the size of the objects to rule out the possibility the chicks were identifying groups based simply on the fact that larger numbers of items take up more space than smaller numbers.
For the past five years Jessica Cantlon of the University of Rochester has been conducting a series of experiments with rhesus monkeys that shows how their numerical skills can rival those of humans. The monkeys, she found, could choose the lesser of two sets of objects when they were the same in size, shape and color. And when size, shape and color were varied, the monkeys showed no change in accuracy or reaction time. One animal, rewarded with Kool-Aid, was 10 to 20 percent less accurate than college students but beat them in reaction time. “The monkey didn’t mind missing every once in a while,” Cantlon recounts. “It wants to get past the mistake and on to the next problem where it can get more Kool-Aid, whereas college students can’t shake their worry over guessing wrong.”
Elizabeth Brannon of Duke University has conducted similar experiments with rhesus monkeys, getting them to match the number of sounds they hear to the number of shapes they see, proving they can do math across different senses. She also tested the monkeys’ ability to do subtraction by covering a number of objects and then removing some of them. In all cases, the monkeys picked the correct remainder at a rate greater than chance. And although they might not grasp the deeper concept of zero as a number, the monkeys knew it was less than two or one, conclude Brannon and her colleagues in the May Journal of Experimental Psychology: General.
Although Brannon feels that animals do not have a linguistic sense of numbers—they aren’t counting “one, two, three” in their heads—they can do a rough sort of math by summing sets of objects without actually using numbers, and she believes that ability is innate. Brannon thinks that it might have evolved from the need for territorial animals “to access the different sizes of competing groups and for foraging animals to determine whether it is good to stay in one area given the amount of food retrieved versus the amount of time invested.”
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20 Comments
Add Commentthis is really interesting...we often tend to anthropomorphise animal behavior,maybe because we have in the back of our mind always the magic of evolution (we consider them as inferior to us)..the reality is different : most animals probably have little time to count,being concerned with more basic things like dayly survival: am sure if they had all the necessary time they would learn even quite quickly (even trigonometrics !),like the horse of the article...
Reply | Report Abuse | Link to thisThis article was interesting because it re-built my reality about animals.
Reply | Report Abuse | Link to thisNow, I'm curious about up to how many each species can count. :)
This article was interesting because it re-built my reality about animals.
Reply | Report Abuse | Link to thisNow, I'm curious about up to how many each species can count. :)
This article was interesting because it re-built my reality about animals.
Reply | Report Abuse | Link to thisNow, I'm curious about up to how many each species can count. :)
Well, we know that Hiromi can count to three... ;-)
Reply | Report Abuse | Link to thisHow can I get paid to waste time and money determining if animals can count. I'm sorry but to what end, will they build us a rocket or solve a problem? no.
Reply | Report Abuse | Link to thisthis is a surprise.. for years .. I've used a technique long known to photographers.. go into a blind with someone else.. the other person leaves..
Reply | Report Abuse | Link to thisOnce the 2nd person leaves, the birds flock back as if no one was in the blind.
If I entered the blind alone.. the birds never came back.
I was told this was because birds can NOT count.. and this trick even works if the other 'person' is a dog!
The time and moneys are spent in order to help combat the point of view you gave.
Reply | Report Abuse | Link to thisWhat use is building a rocket to discover what's beyond our planet when we can't be bothered to understand or appreciate what is around us now? If we disregard the thoughts and understanding of the creatures around us, what are we to do with any we find elsewhere?
Intelligence; consciousness is already quite varied given our limited knowledge on the subject. Go talk to someone who isn't neuro-typical about how they think.
You've illustrated the problem this kind of research ultimately aims to solve.
can these monkeys do my statistics homework?
Reply | Report Abuse | Link to thisI'm wondering if the monkeys can do my statistics homework.
Reply | Report Abuse | Link to thisIt is quite often that scientific research is done for the sake of knowledge itself and the fruits of this knowledge are sown later. A recent nobel prize winner won his prize on the research of why certain jellyfish glow. Besides making things glow how on earth could this help anyone? The truth is that he discovered a class of proteins that glow in ultraviolet light. We have been able to genetically modify animals so that they express this protein in certain ways. Beyond the cute glow in the dark mice we have been able to see finer details in brain structures by modifying certain types of cells to glow different colors. This has been immeasurably helpful in the study of the brain. This is only a small part of the benefits of this research but it illustrates the point.
Reply | Report Abuse | Link to thisyou know what "Ungolythe" your correct and I appreciate a non-snide response, sometimes I forget my manners.
Reply | Report Abuse | Link to thisAnimals that can count look cute to me.
Reply | Report Abuse | Link to thisThere is a subtle difference between counting and recognizing a quantity of objects. Try pouring 5 pills out of a medicine bottle into the palm of your hand. You can recognize the 5 objects almost instantly without actually counting them. That is because there is a separate part of your brain that is gnetically wired to recognize quantities of objects up to 10 or so (guess why 10). This ability may be what is being demonstrated in test animals. The process of counting is fundamentally different. We do not recognize a quantity of objects. Rather we do a one-to-one comparison between the objects and a number sequence that we have learned. I have never heard of any animal doing that, but I would not be surprised if higher primates could be taught to count.
Reply | Report Abuse | Link to thisi'm wondering if animals have other abilities believed to only belong to humans
Reply | Report Abuse | Link to thisi want to know if animals have other abilities believed to only belong to humans
Reply | Report Abuse | Link to thiswhat animals do the best in mathematic?
Cats seem unable to count. A female with newly born blind babies having to transfer them and her place, will make a final journey to collect the uncounted and non-existant "last" kitten after all the actual ones have already been moved.
Reply | Report Abuse | Link to this"Cats seem unable to count" That may be different (too many variables to judge just that) . . it could be that they are fine with "spot" judging numbers of objects in a single view (ie this is more then that and that) but 2 different views at different times are not linked. Or they can't "count" to zero. infact zero is surprisingly hard consept as it can and often is considered "nothing" or non and thus has no relation to counting something since it does not exist. Or it could be that they can't remember a count well. again this is not surprising since internal verbalization helps us remember . . try to count to 10-20 by just saying "one".
Reply | Report Abuse | Link to thisManaging the variables is the hardest element here and just about anything can be going on.
The idea of a view not a count giving a stimulus for an animal's subsequent activity is valid. But obviously the view is different after the cat's kittens have been transferred to the new place. So when the mother cat views them she cannot be certain that they are all present compared to when her family was at its previous location. If she could count then she would have no need to make a final return journed to see if there are any remaining kittens that need to be transferred.
Reply | Report Abuse | Link to thisConsequently it is logical to conclude that cats cannot count (or at least a mother cat who has recently given birth).
I think you are missing the point. "counting" not only going 1 2 3 4 I have 4 as we do . . it is understanding when you have more or less and other even more subtle things. Knowing you have say 4-6 kittens (witch is a big number for most animals) and remembering it long term may really not be useful for the cat since there is the ease (physically and mentally) to do a final check and to be entirely sure all are moved and safe. safer to check then rely on counting. (only another possability)
Reply | Report Abuse | Link to thisAlso just because of these and other possibilities it is VERY hard to study any animal behavior. Concluding anything decisive by only a casual observation is a sure way to come to a bad conclusion. (so it is NOT logical at all since there is way too much assumption of modivation not controled for)
Even monitor lizards have been capable to understand numbers of objects up to 6 . . so this is not even just a mammal and bird thing.