字幕表 動画を再生する 英語字幕をプリント Zip, zilch, nil, nada, nothing. We have a lot of words to describe zero. A number without which we wouldn't have the likes of James Bond or the code that makes this video play on YouTube... It's a number that came into existence only 1,500 years ago, a blip in the evolution of humans. Yet, it's considered one of the most important discoveries in our history … But if you ask a kid under the age of 6 ... “Arthur, do you know what zero means?” “Uh…” “A number?” “It's none.” They might be able to tell you that zero is nothing, but they don't understand that it is a quantity like other number, a concept that even a tiny bumblebee can learn. “There's nothing there.” Children understand the natural counting numbers long before they understand the number zero. Mom: "Can you show me how to get to zero if you have one cookie?" “Now how many cookies do you have?” Andreas Nieder believes that humans must comprehend four distinct stages of zero to fully understand the number ... The first stage is simple: the ability to notice a stimulus or the lack of one. When you turn on a light bulb, for example, your eyes recognize the presence of that light and send visual information to the brain. Without light, the neurons don't do anything. So in the second stage, our brain has to learn how to react to nothing. The third stage is tougher: understanding that zero is less than one. And it's this stage that kids struggle with. Because even when a toddler can understand that zero represents something, like the absence of a cookie, they still don't understand that it represents an actual quantity. In an experiment with four year olds ... researchers asked the toddlers to pick cards with the fewest dots, and when they compared a blank card and a card with one dot, less than half of the kids got the answer right. Without understanding this concept, Nieder says humans can't use zero as a number, the fourth and final stage. Mom: If you had one cookie and you took it away how many do you have? Miriam: Two! Mom: Two?! But how the brain gets to that point is still unknown. So while our own brains may still be a mystery, researchers are finding answers in some seriously less complex ones. The brain of a bee has 100,000 times fewer neurons than the brain of a human, yet scientists in Australia were able to teach them that zero is a quantity less than one. Scarlett Howard: “One of the things we wanted to test for was this concept of zero that we see in these seemingly more advanced animals like primates and parrots. And so we did and we got a really interesting answer.” In a study similar to the one done with the young kids, researchers presented bees with cards showing different numbers of dots. And the bees were rewarded with sugar water when they selected the card with the smallest amount. After the bee correctly chose the smaller number 80 percent of the time, the researchers upped the challenge. They added blank cards to the test. Howard: “So the important thing from this first experiment show us that bees that were trained to always choose the lower number in training, regardless of not having seen an empty set before and never having been rewarded for it, chose the empty set.” Bees also showed that they understood zero as a quantity on the number line, because they more accurately chose the empty set when comparing it to a larger number like five or six than when they compared it to just one. Howard: “They're more accurate with numbers that are further apart, which is called “numerical distance effects.” And it's something that's defined as being very important to show that an animal or even a human has an understanding of number quantity. The findings of this study suggest the ability to understand zero may be more widespread in the animal kingdom than previously thought. And, it's possible that in deconstructing how the bees compute numbers, we could make better, more efficient computers one day. Plus, studying the brains of bees and other animals can help scientists better learn how humans understand zero, enough to do our algebra homework — or just look for more cookies. Mom: “What is nothing?” Who knew that nothing could this complicated? Hi, if you want to learn more about how bees are impacting the food that you eat, make sure to check out this video from our sister channel Verge Science. And thanks for watching.