Treating "nothing" as a number is a conceptual leap that took people thousands of years, and children learn it late. Bees were , and then shown a blank surface against a single shape. What did they choose?
The blank. And , the easier the choice became, which is the signature of a continuous representation of quantity, familiar in humans too. That is the strong evidence: it shows the blank sits on the same scale as one and two, rather than in a category of its own. The bees learned no numeral and did no arithmetic.
Zero looks like a concept that needs language and symbols, so a question about a bee sounds odd. What was tested here is more modest and sharper: whether the blank sits on the same scale that one and two sit on.
The bees were trained to fly to the picture with fewer shapes to get sugar water. The rule was learned on ordinary numbers only, and a blank surface never appeared in training.
In the test they were given a new choice: a single shape against a blank surface. They preferred the blank.
The detail that strengthens the conclusion is that the larger the other number, the easier the choice became. That is the signature of a continuous representation of quantity, familiar in humans too, and it shows the blank is placed at the bottom of a scale rather than in a separate category. The bees learned no numeral and did no arithmetic, and what was shown is of inside a choice task.
wat. Bees never trained on zero chose a blank surface when it was set against a single shape, as though the blank sat below one.
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A basic representation of zero needs no language, no written symbols and no large vertebrate brain.
How do we know?
In three experiments bees were trained on comparing quantities, tested against new sets, and finally against an empty set that had never appeared in training.
What is still unknown
The bees did not learn the numeral 0 and did not perform human arithmetic. The result shows a non-symbolic concept of an empty set inside a choice task.
Learn something?
Where to next
Can the first digit of a number give away a fraud?numbers
Is the hexagon really the best way to divide up a surface?bees
What can a bumblebee learn but never invent on its own?bees