The number 0, or the concept symbolizing “the absence of any value,” is a human invention. This fact makes it even more impressive that animals can understand the number 0.
Through experiments, scientists have found evidence that bees and rhesus macaques understand quantities that can also have a value of zero. According to a new study published by the University of Tübingen, Germany, in the Journal of Neuroscience, crows also possess this remarkable ability.
Crows, bees, and rhesus macaques understand that quantities can also have a value of zero.
This intelligent bird not only understands that zero is a quantity, recognizing that “nothing” is also something, but it can also form the concept of the smallest value within a range of imagined values in its mind.
“These animals do not need the concept of zero in their daily lives,” co-author of the study Andreas Nieder told ILF Science. “But they are smart enough to learn this abstract concept.”
The researchers trained the crows to play a video game, sitting in front of two screens, one displaying four dots and the other showing no dots. While the birds performed the tests, experts monitored their brain activity. Previous experiments had shown that crows contain neurons that are stimulated when they see a specific number of dots on the screen; however, no experiments had demonstrated that neurons also responded similarly when looking at a screen with no dots.
After the experiment, they discovered that the crow’s brain contains specific neurons that activate whenever the bird sees the number zero—but this was not the only discovery. When the crows made mistakes, such as misjudging a screen showing three dots as displaying four dots, the new research team accurately assessed the complex cognitive abilities of the birds.
Crows conducting the experiment.
“Crows confusing a screen with no dots as having one dot occurred more frequently than mistakes between zero dots and two,” Professor Nieder noted. “This is likely to happen when crows can understand that no dots represent the smallest value in a numerical range.”
According to the professor, another noteworthy point is the difference between crow brains and primate brains. The closest common ancestor of the two species existed 320 million years ago, and crows do not possess the neocortex found in the brains of mammals. Yet, evolution has still granted crows the ability to recognize abstract concepts like zero.
By unraveling the puzzle surrounding the concept of zero, science may discover the evolutionary mechanisms that allowed humans to evolve to the point of grasping and utilizing the concept of zero as a tool.
