The concept of zero may seem easy to you, but many human societies struggled with the idea.
However, some of the world’s smartest animals understand zero, and now that group includes the honey bee.
Scientists trained bees to understand numbers by rewarding them when they landed on a surface containing a lower number of black dots. This experiment showed that these tiny insects understand what zero is.
Zero is a lot more than you might think.
The concept of using a mathematical number to represent “nothing” is a complicated idea that stumped many civilizations for a long time. Ancient Egyptians added a symbol for zero to numerical charts around the 18th century B.C., but the concept befuddled the ancient Greeks, and Roman numerals famously lacked a symbol for zero until much later.
The concept of zero is therefore an interesting test for the intelligence of animals. Dolphins, parrots, and primates, for example, have demonstrated the ability to learn about zero, while most humans can pick up the idea at around age 4. But now, a much more surprising animal has joined the “elite club” of animals with demonstrated knowledge of zero: honey bees.
In a new study published today in the journal Science, a group of researchers led by Scarlett Howard of the Royal Melbourne Institute of Technology outline an experiment to test the bees’ grasp of numbers. The bees were shown white surfaces with differing numbers of black objects (between two and five). The scientists then trained groups of bees to understand the concepts of “greater than” and “less than” by rewarding the insects with a sugar solution when they landed on the surface with either more or fewer objects.
An individually marked honeybee inspects stimuli with either 3 or 4 elements before choosing to land on the correct “lower” number. After learning this type of rule with many combinations, bees understand that an unfamiliar presentation of an empty set is less than any other number of elements presented.
After the bees were trained this way, they were shown objects with one and zero black objects on them. The bugs consistently identified the surface with zero objects as the lower number. What’s more, the bees’ accuracy increased when they were given an the option of higher numbers next to zero, which is a trait also observed in other animals’ learning.
The true grasp of zero demonstrated by the honey bee is limited, but the insects reliably identified “nothing” as a lower amount than various numbers of objects without having been exposed to zero before. It’s a remarkable display of understanding from a creature with fewer than one million neurons in its brain, while humans—including the ancient Greeks—have 86,000 million neurons.