Canadian researchers have shown that humans just aren't cut out to discern certain pitches like their feathered friends. Testing completed on humans, rats, and three different species of birds shows that the birds--even ones that have been raised in isolation--are better at identifying, classifying, and memorizing absolute pitches than both humans and rats, with humans performing just slightly better than rats.
"It's amazing how dissimilar the results of this test are when you compare humans and birds," said Dr. Chris Sturdy, a psychology professor at the University of Alberta. "Humans and rats are weak by any standard, and they're just awful when you compare them to the songbirds."
For the study, humans were given monetary rewards when they memorized or recognized the pitches that were played for them, while the birds (zebra finches, white throated sparrows, and budgerigars) and rats were given food rewards.
Sturdy said humans actually perform fairly well in tests of relative pitch, which refers to the relationship between two pitch sounds played one right after the other, allowing the listener to use one pitch as a reference for the other. However, when humans try to comprehend absolute pitch, which refers to pitches played alone without any external standard to contrast them with, their ability is "lackluster at best," he said.
Sturdy believes that it is too early in the ongoing research to speculate extensively about the cause of the striking difference between the absolute pitch processing abilities of birds and mammals. Whatever the cause, Sturdy thinks it cannot be special to humans because other mammals (rats) are no better at judging absolute pitch than humans.
The latest findings from this study, which are published this month in the journal Behavioral Processes, take the researchers to the middle stages of an ongoing project to determine if all birds are better equipped than all mammals to understand absolute pitch. Absolute pitch testing is planned on more mammals and bird species. The goal is to create a map of absolute pitch understanding among as many animals as possible.
"How animals understand absolute pitch may get to the heart of the origins of musical perception," Sturdy added. "Once we can determine the extent of the differences in absolute pitch perception, then we can begin to understand why these differences exist and why our mammalian brains work the way they do."
The study was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC). Sturdy's work is also funded by the Alberta Ingenuity Fund and by the Canada Foundation for Innovation (CFI).