Baby chickens have number sense too, and can count like humans on a left to right sequence, a new study found.
Researchers at the University of Padova experimented on 60 newborn chicks by presenting them with different shapes and patterns before choosing a direction. They chose the chicks as subject because they can easily monitor their development immediately after hatching. The team was hoping that by studying the chicks, they will learn more about how humans develop knowledge of spatial locations and numbers.
The researchers taught the chicks as early as three days after hatching to salvage food from behind a sign with different shapes to represent numbers. Then the chicks were shown two photos that represented numbers. They counted the number of times the chicks chose either left or right.
The experiments showed that the chicks chose right about 70 percent of the time when the photo on the right had 8 dots while the left side had 5. But when they placed the photo with 8 dots on the left then 20 on the right, 70 percent of the chicks went to the left. The results remained consistent when they used other shapes and colors to represent numbers.
"They associate small numbers with the left space and larger number with the right space, and this resembles the humans' behavior in responding to numbers," Dr. Rossa Rugani, study leader from the University of Padova, told Live Science.
The researchers admitted that they weren't sure why the chicks were displaying the left-to-right bias similar to humans, but they believe that this can provide insight into the evolutionary origin of the humans' mental number line.
"All we can judge is behavioural responses. Therefore, we don't actually know if it is a real 'number line' but it strongly resembles what is observed in the human number line," Dr. Rugani said to BBC News.
The study is the first to test whether animals have a mental number line or the left-to-right counting bias that humans have.
The study was published in the Jan. 29 issue of Science.
