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The Average Bear Is Smarter Than You Thought


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Yogi Bear always claimed that he was smarter than the average bear, but the average bear appears to be smarter than once thought. Psychologists Jennifer Vonk of Oakland University and Michael J. Beran of Georgia State University have taken a testing methodology commonly used for primates and shown not only that the methodology can be more widely used, but also that bears can distinguish among differing numerosities.

Numerical cognition is perhaps the best understood of the core building blocks of the mind. Decades of research have provided evidence for the numerical abilities of gorillas, chimpanzees, rhesus, capuchin, and squirrel monkeys, lemurs, dolphins, elephants, birds, and fish. Pre-linguistic human infants share the same mental modules for representing and understanding numbers as those non-human animal species. Each of these species is able to precisely count sets of objects up to three, but after that, they can only approximate the number of items in a set. Even human adults living in cultures whose languages have not developed an explicit count list must rely on approximation rather than precision for quantities larger than three. For this reason, it is easier for infants and animals to distinguish thirty from sixty than it is to distinguish thirty from forty, since the 1:2 ratio (30:60) is smaller than the 3:4 ratio (30:40). As the ratios increase, the difference between the two sets becomes smaller, making it more difficult to discriminate between them without explicit counting.

Given that species as divergent as humans and mosquitofish represent number in the same ways, subject to the same (quantity-based and ratio-based) limits and constraints, it stands to reason that the ability to distinguish among two quantities is evolutionarily-ancient. That is, it is more likely that the ability emerged early in evolution than for the multiple cognitive systems to have developed identical limits and constraints multiple times over evolution.

Vonk and Beran argue, however, that there’s one problem with that argument. Most of the species that have been studied with respect to numerical cognition have been social: primates, cetaceans, and birds such as corvids and parrots. Given this, they reason, it is possible that the ability to estimate the number of items in a set may be related to the necessity for tracking members of the social group. A non-social animal – even a large-brained one such as the black bear – may therefore not possess this ability.

Alternatively, if numerical cognition is not related to sociality, then black bears should indeed be able to discriminate sets on the basis of numerosity. Further, their performance should decline as the ratio increases, just as for human infants, human adults from cultures without count lists, non-human primates, cetaceans, and birds.

One of the things that Venk and Beran were interested in was whether bears can discriminate sets of dots solely on the basis of their numerosity, rather than some correlated variable, such as surface area. Therefore, they created two different types of test trials. In congruent trials, the number of dots in each set was correlated with their surface area. In incongruent trials, the number of dots in each set was not correlated with their surface area.

Imagine that Yogi Bear spies two picnic blankets. On one blanket, there are three giant picnic baskets, and on the second there are two average-sized ones. If Yogi chooses the three giant baskets, it would be unclear whether he was choosing on the basis of number or volume, since they’re correlated. However, if he chooses three smaller baskets instead of two giant ones, then it is more reasonable to assume that the choice was based on number. Similarly, in this experiment, if the bears were only successful on congruent trials, then no conclusions could be drawn about their numerical abilities, per se.

An example of an incongruent trial, since the set with more dots also has smaller surface area.

But Vonk and Beran weren’t just interested in determining the numerical abilities of non-social carnivores. Because different methods are often used to assess the mental capabilities of different species, it is sometimes difficult to directly compare the results from different experiments. When it comes to working with primates and birds, researchers often use computerized stimuli displayed on touch screens. To signal a choice such as “this set has more objects,” the monkey or ape presses on the screen with a finger. Birds usually peck at it with their beaks. Vonk and Beran wanted to know if they could get bears to tap a screen with their noses. By making the experimental methodology as similar as possible across species, it becomes more reasonable to directly compare performance across species.

Three captive American black bear siblings (Ursus americanus) from the Mobile Zoo in Wilmer, Alabama, participated in the experiment. Researchers trained the bears to respond to a touch screen by pressing their noses against it. During training, Brutus was rewarded with a melody and with honey roasted peanuts, banana pellets, dried banana chips, yogurt-covered raisins, or wafer cookies after choosing the larger of the two sets, each of which contained between 1 and 10 dots of varying sizes. Dusty and Bella were rewarded for choosing the smaller of the two sets. When they chose the wrong option, the computer responded with a loud buzz.

One of the bears eyes the touch screen.

The bears were most successful when the correct answer could be selected on the basis of both number and surface area, while they were significantly less successful when number was incongruent with surface area. This was particularly true for Bella and Dusty, who were rewarded for choosing the sets with fewer dots. It was apparently hard for them to overcome their desire to choose the set with the larger surface area.

However, even for incongruent trials, all three bears performed better than would have been predicted by random chance. The researchers reasoned that while surface area was perhaps more salient, the three bears were also able to represent numerical quantities. Surface area alone couldn’t have been responsible for their decisions. Number itself must have played at least some role in their performance.

Like all other species that have ever been tested, the bears’ performance was better when the ratio was small (and therefore, the numerical distance between the two sets was large) than when the ratio was large. They were better able to distinguish 2 from 10 (1:5 ratio) or 2 from 8 (1:4 ratio), for example, than 4 from 5 or 8 from 10 (both 4:5 ratio). The graph at right shows Brutus’s performance for the one of the conditions. As the ratio increases, his performance decreases towards random chance.

Together, these findings indicate that it may be easier for bears to choose larger amounts over smaller amounts. When considering picnic baskets, this strategy makes sense, but it isn’t clear why this preference would persist for abstract, two-dimensional dots on a computer screen, or when choosing the smaller amount is rewarded during training. Vonk and Beran say that choosing the greater amount or greater number of items may simply be more intuitive than choosing the smaller amount or number. This would be consistent with evidence that human children have an initial preference for “more.”

Several questions remain. What role might sociality have in shaping numerical cognition? How might the different needs of predator species compared with prey species impact the way that number is represented? One puzzling finding was that bears were less successful at identifying the set with more dots (for Brutus) or less dots (for Bella and Dusty) when the dots were moving instead of stationary. Why might this be?

Numerical cognition is a favorite topic among comparative psychologists, so these questions will no doubt be addressed in the coming years.

The main contribution of this research, however, is broader than the nuances of dot-counting. Often, researchers focus on species most closely related to humans (e.g. primates and domesticates such as dogs), or those easiest to test and house in a laboratory (such as fish and birds). By demonstrating that the minds of large carnivores such as bears can be probed using touch screens, other researchers may be encouraged to expand their research programs to include bears and other under-studied species.

“It is exciting,” Vonk and Beran write, “to consider that such divergent species can be tested in the same way to promote a fuller picture of comparative cognition and the diverse forces giving rise to both similar and distinct traits.” In that sense, their paper is a comparative call-to-arms. In order to more completely understand the way that minds are made, a broader approach must be considered, which begins by studying species that occupy social and physical ecological niches that are different from those that are most familiar.

ResearchBlogging.orgVonk, J., & Beran, M. J. (2012). Bears ‘count’ too: quantity estimation and comparison in black bears, Ursus americanus. Animal Behaviour DOI: 10.1016/j.anbehav.2012.05.001

Header image via Wikimedia Commons/Ken Thomas. Bear with touch screen via Dr. Jennifer Vonk, used with permission.

Jason G. Goldman About the Author: Dr. Jason G. Goldman received his Ph.D. in Developmental Psychology at the University of Southern California, where he studied the evolutionary and developmental origins of the mind in humans and non-human animals. Jason is also an editor at ScienceSeeker and Editor of Open Lab 2010. He lives in Los Angeles, CA. Follow on . Follow on Twitter @jgold85.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. RCWhitmyer 12:23 pm 06/20/2012

    One picnic basket, two picnic baskets, three picnic baskets….

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  2. 2. JamesDavis 12:38 pm 06/20/2012

    That experiment is all fine and dandy, and the bears probably thought those colored dots were berries, so they probably chose the screen that had the most berries. What I want to know about bears is, can they understand you when you talk to them and respond to commands like a dog does? We have a very young black bear in this town and every time the door at the supermarket stays open longer than usual, the little bear runs like crazy out of the woods and goes in and gets upon the produce counter and eats all the lettuce and apples that he can before the cop arrives. They always have to call the same state policeman to come and get the little fellow because he will not let anyone else touch him. The cop scoops him up in his arms and carries him outside as he is talking to him and the bear grunts like he is talking back to the cop and explaining why he was up there eating all the apples. The cop calls him his little shoplifter as he sets him down and tells him to go back to the woods and the little fellow trots back into the woods. Is that bear understanding what the cop is saying to him? It sure doesn’t seem like the bear is going back to the woods out of fear.

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  3. 3. quizzical 1:39 pm 06/20/2012

    James, That is an interesting story. If it is not made up, (just a possibility) it demonstrates a lot more about bears and communication than concocting some artificial situation that must be taught to the bear in the first place. Researchers must be very careful in designing an experiment that includes too much of imagining the outcome and its reasons.

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  4. 4. Jason G. Goldman in reply to Jason G. Goldman 2:31 pm 06/20/2012

    @JamesDavis: I’m not sure there’s any reason to suspect that the bears thought that the dots were berries. There’s more to berries than color… as far as your anecdote, I’m afraid I can’t provide much insight, though I can say this: dogs spent tens of thousands of years undergoing domestication, making them highly sensitive to human social cues. And then, dogs still need months of training to understand verbal commands (and, even then, there’s the Clever Hans issue: are they always responding to the auditory stimulus itself, or some correlated body posture, or tone of voice, or something?). Without knowing more about your particular bear, I can’t say, but I doubt it’s had any training. Certainly, its not been domesticated.

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  5. 5. Gatnos 5:51 pm 06/20/2012

    Imagine that! A real scientific article without any blatant liberal political message. What is this magazine coming to?

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  6. 6. Ravanar 5:54 pm 06/20/2012

    It seems to me that all creatures that care for their young would have to have a rudimentary ability to count up to the average number of babies for their species in order to keep track of their brood.

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  7. 7. Jason G. Goldman in reply to Jason G. Goldman 6:08 pm 06/20/2012

    @Ravanar: if the average number of cubs that bears have is less than three (litters are usually 1-3 cubs), then they’re just fine, since they can represent precise quantities up to three. but given that the constraints are identical even for mosquitofish, for example, who don’t care for their young, it doesn’t seem likely that numerical abilities are related to child-rearing… probably just a coincidence.

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  8. 8. Mythusmage 10:43 pm 06/20/2012

    #2

    More a case of familiarity I’d say. The cub knows the cop and knows the cop isn’t going to hurt him. Seems to me that people need to start closing doors, or the store owner needs to get a self-closing door.

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  9. 9. parobinson 7:25 am 06/21/2012

    On the subject of psychology, I would be interested to know if anyone out there is doing research into 1) why some people see “liberal media bias” everywhere they look, 2) why they persist in reading/viewing those media, and 3) why they feel they have to comment on it all the time.

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  10. 10. parobinson 7:54 am 06/21/2012

    For a brief moment I was puzzled by the bottle of Windex next to the bear’s cage, then I realized it was to clean the snot off the touch screen. (If I were media-paranoid, I might have thought it was a deliberate product placement.)

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  11. 11. jack.123 7:41 pm 06/21/2012

    Horses would be a good subject to study.They are smarter than dogs,and have a sence of humor.Any horse no matter how well trained will branch a rider if given the chance,and then turn around and snicker at having got away with it.And then play the one step away game with you.I can’t think of any animal that can count that is more playfull.Anyone who didn’t grow up with a horse has missed one of life’s greatest pleasure.

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