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Can Bees Understand the Concept of “Zero”?

Michael Egnor


A new paper in Science claims that honeybees can understand the abstract concept of “zero.” From EurekAlert!:

Scientists have discovered honeybees can understand the concept of zero, putting them in an elite club of clever animals that can grasp the abstract mathematical notion of nothing.

By demonstrating that even tiny brains can comprehend complex, abstract concepts, the surprise finding opens possibilities for new, simpler approaches to developing Artificial Intelligence.

In research published in the journal Science, Australian and French researchers tested whether honeybees can rank numerical quantities and understand that zero belongs at the lower end of a sequence of numbers.

An insect’s abstract comprehension of zero is a big deal, according to Associate Professor Adrian Dyer from RMIT University in Melbourne, Australia:

“Zero is a difficult concept to understand and a mathematical skill that doesn’t come easily — it takes children a few years to learn,” Dyer said.

“We’ve long believed only humans had the intelligence to get the concept, but recent research has shown monkeys and birds have the brains for it as well.

“What we haven’t known — until now — is whether insects can also understand zero.”

As well as being a critical pollinator, the honeybee is an exceptional model species for investigating insect cognition, with previous research showing they can learn intricate skills from other bees and even understand abstract concepts like sameness and difference.

But bee brains have fewer than 1 million neurons — compared with the 86,000 million neurons of a human brain — and little was known about how insect brains would cope with being tested on such an important numeric skill…

The bees were trained to choose an image with the lowest number of elements in order to receive a reward of sugar solution.

For example, the bees learned to choose three elements when presented with three vs. four; or two elements when presented with two vs. three.

When Howard periodically tested the bees with an image that contained no elements versus an image that had one or more, the bees understood that the set of zero was the lower number — despite never having been exposed to an “empty set”.

The scientists credited the bees with more intelligence than some humans:

“If bees can learn such a seemingly advanced maths skill that we don’t even find in some ancient human cultures, perhaps this opens the door to considering the mechanism that allows animals and ourselves to understand the concept of nothing.”

Can bees really comprehend “zero”? Can they really comprehend abstract concepts? Not likely. No subhuman animal has ever been shown to be capable of abstract thought. It’s important to understand what is meant by “abstract.” Abstract thought is thought about concepts removed entirely from particulars. Abstract thought is thought about universals. For example, contemplation of mercy or justice or nutrition or logic or imaginary numbers is abstract thought. 

Non-abstract thought is perception, which is common to animals (and to man) and entails thought about particular things — specific people or an apple or a figure on a piece of paper. Animals (and man) are capable of comparing perceptions — comparing a large object and a small object, or a bright object and a dark object. Such comparisons of perceptions of particulars has been called (by Aristotle) sensus communis. Sensus communis is what animals do when they evaluate and compare particular objects. Abstract thought, which is a power only of man, is the ability to think without particulars at all. It is an immaterial power of the intellect.

An example of sensus communis is when my dog complains that his food dish in empty. His whining does not mean that he comprehends “zero” food or that he contemplates the nutritional consequences of missing dinner. He just notes that his food dish doesn’t have anything in it, although it usually does, and he wants something in it. He’s using his sensus communis to distinguish a full from an empty dish. It’s not abstract thought about his dog food. It’s particular perception that he has no food, and wants some. That’s how dogs think. 

In the bee experiment, the researchers trained the bees to seek out white cards with fewer rather than more black circles (by rewarding them) and ultimately the bees sought out cards with no black circles. This doesn’t mean the bees understood the concept of zero, or that the bees understood any mathematics at all. 

All animal vision (including human vision) depends on edge detection: neurons in the visual cortex respond actively to transitions of contrast in the visual field caused by edges. Cards with more black circles have more (and more complex) edges, and the bees were trained to associate less edges with food. No edges at all (zero) is less edges than some edges, so the bees select the “zero” card because they associate it with food. This is all sensus communis — the comparison of patterns with more or less edges and the association with food. There is no abstract thought here — no “concept of zero.” 

Notably, the autofocus on a camera works the same way. Autofocus focuses well on scenes with edges, and often hunts and won’t focus on scenes with few edges (like a blank white wall — “zero” for the honey bees). This doesn’t mean that my camera “comprehends” zero and refuses to focus on it. It is merely a manifestation of a system that works by edge detection, which is common to cameras and to animal vision. 

There is no reason to infer that bees understand the concept of zero or that they think in abstract concepts at all. In fact, in order to think in abstraction, one must have language, because without particulars, abstract thought must have content that is linguistic. Bees have neither abstract language nor abstract thought. 

Animal research that purports to demonstrate abstract thought invariably stumbles on the same fallacy: the confusion of sensus communis with genuine abstract understanding. Sensus communis evaluates particulars, and abstraction evaluates universals. 

Honeybees don’t understand mathematics. They can compare patterns and be trained to respond differently to different patterns, but that does not mean that they think abstractly. Abstract thought is an immaterial power of the soul, and only human beings have immaterial souls. Only human beings are capable of abstraction. 

Photo: Has this bee demonstrated a capacity for abstract thought? By RMIT University.