Chuck Bednar for redOrbit.com – Your Universe Online
Usually calling somebody a bird-brain is meant as an insult, but it might be time to rethink that as new research reveals baby chicks can not only count, but also have the same basic concept of a left-to-right number line as humans.
In research published Friday in the journal Science, researchers from the University of Padova and the University of Trento in Italy report that experiments involving 60 three-day-old chicks revealed that the creatures can become familiar with the concept of placing smaller values to the left and larger ones to the right on a mental number line.
As part of those experiments, the baby birds were familiarized with a target number (5) and were able to spontaneously associate a smaller number (2) with the left space and a larger one (8) with the right space. Furthermore, the larger number (8) was itself associated with the left space when the chicks were presented with a second, higher target number (20).
While the existence of this mental number line is common in humans, this marks the first time that the left-right association has ever been observed in animals, according to BBC News. Lead investigator Dr. Rossa Rugani told the British news agency that it was unclear what caused the chicks to make the choices that they did, but the results were apparent.
“All we can judge is behavioral 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,” she said.
While humans are capable of making consistent associations between numbers and spatial locations, the researchers note that it is not certain how much of this is learned and how much of it develops automatically. Even in Arabic countries, where adults read from right to left, it is not clear if education produces the relationship, or just fine-tunes it in terms of direction.
Dr. Rugani explained that baby chicks were a good model to test this behavior, since they can be monitored shortly after hatching. She and her colleagues created experiments to determine if they also linked smaller and larger numbers which different spatial locations, training the birds to get food from behind a sign that displayed a number of shapes.
The chicks were then presented with two copies of a different number, and the researchers recorded how often each one selected the left-hand or right-hand one. If the new number was smaller than the training number, the chicks went left about 70 percent of the time, and if it was larger, they went to the right about 70 percent of the time.
Furthermore, the effect was found to be relative. Chicks went to the right if shown 8 when the original number was 5, but to the left if the target number was 20. Additional experiments saw the authors slightly alter the presentation of the numbers, but the results were unchanged, even when the smaller number was presented using different colors or larger shapes.
“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,” Dr Rugani, a psychologist at the University of Padova, told Discovery News.
“A number is not either small or large in an absolute sense, but rather it is smaller or larger with respect to another number,” she added. “[The chicks] associate small numbers with the left space and larger number with the right space, and this resembles the humans’ behavior in responding to numbers… I would not at all be surprised that the number spatial mapping is also found in other animals, and in newborn infants.”