Sydney, Feb 4 (The Conversation) – The way humans naturally arrange numbers in ascending order from left to right may not be unique to our species. Recent studies reveal that bees, despite their tiny brains, also follow a similar numerical arrangement, providing fresh insights into how the brain processes numerical and spatial information.
The concept, known as the mental number line, describes how numbers are typically organized in the brain, often in a left-to-right sequence. While this preference is widely observed in humans and some other animals, researchers have sought to understand whether it extends to species with vastly different brain structures, such as insects.
Tracing Numerical Order Back in Evolution
To explore this phenomenon, scientists examined honeybees—creatures known for their impressive cognitive abilities, including basic arithmetic, recognizing the concept of zero, and distinguishing between odd and even numbers. Given that humans and insects last shared a common ancestor more than 600 million years ago, studying bees provides valuable evolutionary context for how number ordering might have developed.A European research team found that bees tend to arrange numbers in a left-to-right pattern, akin to many humans. Building on this, a new study led by Jung-Chun (Zaza) Kuo and her supervisory team investigated how numerical and spatial cognition interact in bees.
Testing the Tiny Mathematicians
To examine bees’ numerical orientation, researchers conducted an experiment where free-flying bees were trained to associate a reference number—three circles—with a sugary reward at the center of a large circular screen. Once the bees established this connection, they were presented with images containing different quantities—two circles (a lower number) and four circles (a higher number).Bees had to choose between identical images of the higher or lower numbers placed on the left and right sides of the screen. If they systematically preferred larger numbers on the right, it would indicate a left-to-right numerical arrangement similar to that seen in humans.
Findings: A Rightward Bias in Bees
The results confirmed that bees tend to place larger numbers on the right. However, an interesting variation emerged: while they preferred larger numbers on the right, they did not exhibit a strong preference for smaller numbers on the left. This deviation may be attributed to an overall right-side bias observed in the bees' movements, influencing their numerical orientation.Additionally, when tested for a vertical ordering preference, bees showed no clear inclination to arrange numbers in an upward or downward sequence. However, they did display a preference for numbers positioned toward the bottom of the screen.
What This Means for Brain Function
These findings reinforce that the tendency to organize numbers spatially from left to right is not exclusive to humans. Alongside previous studies in birds and primates, this suggests that evolution may have favored this particular cognitive pattern across diverse species.The study also highlights how brain asymmetries—such as humans’ preference for right-handedness—may play a fundamental role in structuring thought processes. Understanding these shared cognitive traits can provide deeper insights into how information processing evolved in the animal kingdom.
Ultimately, the bees' numerical orientation supports the idea that the way we process numbers may be more deeply rooted in biology than previously thought, extending far beyond the human brain.