Before toddlers learn to master symbolic counting–where “one” stands for a single object and “two” indicates double that–they pass through a developmental stage of verbal tallying. In this phase, asked how many apples are in a group of three, a young child might say “one, one, one” or “one, two, three” or “apple, apple, apple,” in a form of proto-counting. They understand there are three apples, but they don’t quite yet have the ability to express that number in the abstract form of “three,” alone.
Inspired by this knowledge, Diana Liao, a neurobiologist and post-doctoral researcher at the University of Tubingen in Germany, decided to ask the obvious question: Can crows do it too? Spoiler alert: they can, according to a first-of-its-kind study published May 23 in the journal Science. Carrion crows can control their vocalizations and correspond the number of those calls to a cue, in a form of proto-counting, per the new research.
The study adds to the growing laundry list of cognitive abilities that corvids (the bird family including crows, ravens, magpies, and jays) possess. The new work also aids in the quest to uncover the evolutionary origins of humans’ mathematical ability. By studying other animals’ capacities and limitations, scientists can get a better idea of where and how our own numeracy comes from.
“It’s a really neat study,” Jessica Cantlon, a professor of psychology at Carnegie Mellon University who researches quantitative reasoning and was uninvolved in the crow investigation, tells Popular Science. In humans, the connection between the vocal system and our mathematical brain is a key part of our number sense. “When you start using vocalizations to represent things out in the world it kind of changes the way you think…that [is the way that] counting emerges in humans over development and over evolutionary time,” she explains. “It hasn’t been clear that any other animal could do…
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