Giraffes' statistical skills make researchers question big brain theory

Would giraffes pick an event with 99% chances of success, or 1% of failure?
Amal Jos Chacko
A giraffe at the zoo.jpg
A giraffe at the zoo.


The ‘Big Brain’ meme going viral in 2016 and appearing in our social media feeds ever since has reinforced the notion that a bigger brain implies a more intelligent creature while taking a sarcastic tone at times.

Research agreed so far; with the ability to make statistical inferences observed in animals with large brains relative to their body size, such as the parrot.

Even though humans consider ourselves the cleverest of the lot, we struggle to put on our statistician hats while making everyday, regular decisions.

Numerous self-help books prodding us to think and act logically tell us that when asked to pick between two events, one of which has a success rate of 99% and the other a failure rate of 1%, human beings tend to choose the former, even though both these events represent the same odds.

Scientists have now found an anomaly to this “big brain” notion of ours.

Research published in Nature, one of the world’s most influential and peer-reviewed scientific journals, points to the lanky lowly giraffe being capable of judging probabilities. What the chances, eh!

An experiment involving carrots and zucchini (no, not for you) was carried out where researchers would first show their subjects see-through boxes containing both these vegetables and then pick one from each tub without letting the subject see.

Even though this experiment was carried out in different proportions of the vegetables, giraffes were observed to choose the hand more likely to contain a carrot.

What does this mean? Do giraffes love carrots just like rabbits? Um, probably not.

In later experiments, researchers divided the tubs in half and restricted themselves to picking vegetables in the top half. The ratio of carrots to zucchini differed in the top half compared to the entire tub and would require a combination of spatial reasoning and probabilistic evaluations.

Although three of the giraffe subjects were baffled at this prospect, the fourth subject figured the test out after just one round and kept picking carrots since then.

These experiments were conducted after taking measures to ensure that the giraffes would not make their choice based on the smell of the vegetables.

So what does this mean? Do giraffes love carrots just like rabbits? Um, maybe? That’s not the point here.

Giraffes, despite having small heads and a smaller brain within, performed just as well as chimpanzees in these tests.

The researchers involved offer two explanations, reports ArsTechnica. Perhaps the giraffe lives a life involving complex herd dynamics and an assortment of food that inculcates this reasoning, even with little mental capacity to spare. Or perhaps probabilistic reasoning isn’t as rare as we think among animals.

Even though they can process probabilities and chances, it isn’t always on show when presented with a task that requires a combination of abilities.

Does that not make them more human?

Study Abstract

The ability to make inferences based on statistical information has so far been tested only in animals having large brains in relation to their body size, like primates and parrots. Here we tested if giraffes (Giraffa camelopardalis), despite having a smaller relative brain size, can rely on relative frequencies to predict sampling outcomes. We presented them with two transparent containers filled with different quantities of highly-liked food and less-preferred food. The experimenter covertly drew one piece of food from each container, and let the giraffe choose between the two options. In the first task, we varied the quantity and relative frequency of highly-liked and less-preferred food pieces. In the second task, we inserted a physical barrier in both containers, so giraffes only had to take into account the upper part of the container when predicting the outcome. In both tasks giraffes successfully selected the container more likely to provide the highly-liked food, integrating physical information to correctly predict sampling information. By ruling out alternative explanations based on simpler quantity heuristics and learning processes, we showed that giraffes can make decisions based on statistical inferences.

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