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| This is the way I view numbers, along a spatial sequence. (Photo credit: Wikipedia) |
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By ERICA GOODE
Asked to picture the numbers from one to 10, most people will imagine a straight line with one at the left end and 10 at the right.
This “mental number line,” as researchers have termed it, is so pervasive that some scientists have argued that the spatial representation of numbers is hard-wired into the brain, part of a primitive number system that underlies humans’ capacity for higher mathematics.
Now Italian researchers have found that newborn chicks, like humans, appear to map numbers spatially, in the same way.
The chicks, trained to seek out mealworms behind white plastic panels printed with varying numbers of identical red squares, repeatedly demonstrated a preference for the left when the number of squares was small and for the right when the number was larger. The research, led by Rosa Rugani, a psychologist who at the time was at the University of Padova, appeared in the journal Science.
The researchers said the findings supported the idea that the left-right orientation for numbers is innate rather than determined by culture or education – a possibility that was raised by some studies that found that in Arabic-speaking countries where letters and numbers are read right to left, the mental number scale was reversed. But the new research, Dr. Rugani and her colleagues wrote, indicates that orienting numbers in space may represent “a universal cognitive strategy available soon after birth.”
Tyler Marghetis, a doctoral candidate in psychology at the University of California, San Diego, said: “We have brains that evolved for fighting and finding food, not for doing calculus. So one of the hopes of this kind of research is that it will tell us something about the basic building blocks we have access to in building up these more human concepts.”
But Mr. Marghetis said that the studies demonstrated only that the chicks associated rough quantities that were smaller or larger with left or right, not that they represented precise numbers in a mental line. And he cautioned against leaping to the idea that chicks are capable of the same complex abilities as humans.
Judging amounts, either of how much food is available or how many predators are nearby, is an important tool for survival. And many nonhuman species – including chickens, monkeys and even some fish – have some ability to count, though these may be a capacity to distinguish rough numerical magnitude rather than precise numbers.
Human studies indicate that when presented with a task involving numbers people automatically create a mental scale, using one number as an anchor and locating smaller numbers to the left and larger ones to the right. The new research suggests that some version of this may be true for chickens. “We cannot think of any other, and simpler, explanation for the behavior of the chicks than assuming the training number is 1) remembered and 2) compared with the number seen at test,” Dr. Rugani said in an email.
Taken from TODAY Saturday Edition, The New York Times International Weekly, March 14, 2015
