It's not just humans who can count: Newly published research suggests chicks seem to have a number sense, too.
Scientists found that chicks seem to count upward, moving from left to right. They put smaller numbers on the left, and larger numbers on the right — the same mental representation of the number line that humans use.
"Our results suggest a rethinking of the relationship between numerical abilities and verbal language, providing further evidence that language and culture are not necessary for the development of a mathematical cognition," said study lead author Rosa Rugani, a psychologist at the University of Padova in Italy. [5 Seriously Mind-Boggling Math Facts]
The left-to-right way of thinking about ascending numbers seems to be embedded in people's mental representations of numbers, but it's not clear exactly why. Is it an artifact of some long-lost accident of history, or is it a fundamental aspect of the way the brain processes numbers?
To help answer those questions, Rugani and her colleagues trained 3-day-old chicks to travel around a screen panel with five dots on it to get to a food treat behind it. This made the five-dot panel an anchor number that the chicks could use for comparison with other numbers.
After the chicks learned that the five-dot panel meant food, the researchers removed that panel and then placed the chicks in front of two panels, one to the left and the other to the right, that each had two dots. The chicks tended to go to the left panel, suggesting that they mentally represent numbers smaller than five as being to the left of five.
When the researchers put the chicks in front of two panels that each had eight dots, the chicks walked to the panel on the right. This suggests the chicks mentally represent numbers larger than five as being to the right of five, the researchers said.
In a second experiment, the researchers repeated the whole process, but started with a panel that had 20 dots instead of five. They then added two other panels that had either eight or 32 dots. Sure enough, the baby chicks tended to go to the left when the screens had just eight dots, and to the right when they had 32 dots, according to the findings published in this week's issue of the journal Science.
"I would not at all be surprised that the number spatial mapping is also found in other animals, and in newborn infants," Rugani said.