Baby chicks, like most people, have a mental number line which places lower numbers to the left and higher ones to the right, according to new research.
The basis for the study was that scientists were interested in testing whether the left-to-right number line typical in people is an artifact of human culture or a more innate characteristic. Regardless of cultural background and mathematical training, all humans seem to have an intuitive sense of numerical magnitude (what is called “numerosity”).
In order to examine how animals might correlate numbers of different sizes with physical space, the researchers trained three-day-old chicks to find food behind a panel with five red dots. When the trained chicks were presented with two panels, each with two dots, 71 percent of them approached the leftmost panel first in search of food. However, according to National Geographic’s Not Exactly Rocket Science, when the chicks instead encountered two panels that each had eight dots, the same number of chicks turned right.
In a separate experiment, where eight was a smaller number of dots than the training panel, which had 20, the chicks turned to the left panel of eight dots, suggesting that they processed the numbers relative to one another, rather than by their absolute value.
Discussing the findings with Live Science, lead author Rosa Rugani of the University of Padova, Italy said: “This resembles humans’ behavior in responding to numbers.”
The findings have been published in the journal Science. The research paper is titled “Number-space mapping in the newborn chick resembles humans’ mental number line.”
