From toddler puzzles to more sophisticated graphs in middle school, people in Western cultures learn to put numbers in order from left to right, much like they learn to read. However, Arabic readers, who read from right to left, organize lower numbers on the right. So, it would seem that associating numbers on a mental number line is learned cultural. Except a new study shows that baby animals, specifically 3-day-old chicks, count or order numbers by putting smaller ones to the left and bigger ones to the right.
Non-verbal baby animals could associate smaller numbers with being on the left and bigger numbers on the right, according to a research study detailed in Science magazine. The research involving the fuzzy chicks was conducted by a team of scientists at the University of Padua in Italy.
The study session started with the team training 64 baby chicks to find their food by going behind a panel that had five dots on it. After the fuzzy birds began to associate the five-dot panel with food, the research team switched out the panel.
They first replaced the panel with two that were side by side and had two dots on each. Seventy percent of the time, the chicks went over to the left panel to look for their food. This was interpreted as meaning the chicks mentally thought of two days as to the left of five.
Next, the panels were replaced with ones that had eight dots each. Now, the chicks looked for the food behind the right panel about 70 percent of the time. This suggested that the birds believed the higher number of dots was to the right of five, and that the chicks order numbers using left-to-right spatial mapping.
The researchers then repeated the process, but this time trained the baby chicks to look for food behind a panel with 20 dots on it instead of five. They then replaced the 20-dot panel with two other panels; the first set had eight dots and the second had 32 dots. Just like in the first round, the baby chicks overwhelmingly proceeded to the left when the screens had just eight dots, versus to the right when they had 32 dots, which replicated the behavior before.
According to the researchers, judging amounts of food or numbers of predators is an important tool for survival. Clearly, monkeys, pigeons, monkeys, even some fish and other nonhuman species have an innate ability to count. However, the ability may just be distinguishing rough magnitudes of numbers versus precise numbers.
Studies involving humans indicate that people automatically create a mental scale when they are presented with a task involving numbers. Asked to do tasks like categorizing them as even or odd will result in people using one number as an anchor and placing smaller ones on the left and larger ones on the right. The findings of the new research suggest that some version of the left-to-right way to order numbers may be used by little chicks, too.
By Dyanne Weiss