Xiao Liwu made his public debut Thursday at the San Diego Zoo. Fans crowded around the exhibit, their camera lenses extended, hoping to catch a glimpse of the 5-month-old giant panda cub. If they're lucky and actually do see the 16-pound panda (his Chinese name means "Little Gift"), there'll be much oooing and aaahing.
You'd have to be heartless not to agree that pandas, especially the youngest of them, are as cute as all get-out. Right? But why?
The New York Times tried to answer that question back in 1987:
"Ask the people at the zoo, and they say things like 'It's the eyes' and 'It's the black and the white.' Ask a behavioral neuroscientist like Dr. Edgar E. Coons, and he will say that giant pandas are the world's most adored animal for a very simple reason: they set off an almost sublime combination of 'hedonic mechanisms.' 'Cues' to Say 'Ooh' and 'Aah.'
"The big eyes in their black sockets, the round face, the pug nose, the way giant pandas tumble about like toddlers: 'There is considerable evidence that these things are what are known as innate releasers to our parenting instincts,' says Dr. Coons, a New York University psychologist who studies the mechanics of pleasure and pain."
In 2005, The Washington Post asked Stephan Hamann, a psychology professor at Emory University, to explain why humans think certain animals are cute. Hamann conducted studies using functional magnetic resonance imaging (fMRI) to measure tiny changes in brain activity.
His studies "found that 'cute' pictures cause increased activity in the middle area of the orbital frontal cortex, located behind the bridge of the nose, and in the amygdala, the emotion-control center of the brain responsible for fear and arousal," the Post reported.
"According to Hamann, increased activity in the middle orbital cortex is usually associated with pleasure and positive emotion. Some evidence suggests the brain activity there is greater when the stimulus is 'neotenous,' which is to say it has juvenile characteristics a button nose, big eyes, a large wobbly head, chubby extremities or pudgy cheeks."
Many researchers have concluded that "cuteness, or 'baby schema,' is an evolutionary adaptation that triggers nurturing responses from adults allowing survival of the cutest, in Darwinian terms," the Post said.
NPR's Kitty Eisele had been a panda skeptic until she got hooked watching Tai Shan, the National Zoo's panda cub, in 2005:
"OK. I get it now. I understand. I wasn't in the club before, but now I'm up late and I'm not sleeping and I'm watching him do everything for the first time. It's the first time he scratched his nose, the first time he stretched his legs, the first time he rolled over. After so much waiting, he's finally arrived and I can't stop staring. He is a miracle. He's our panda. And like much of my city, I am mesmerized watching him on my computer on panda cam."
In a blog post last year, NPR's Robert Krulwich explored the mystery of the panda, from the panda's perspective:
"Every giant panda, said evolutionary biologist Stephen J. Gould, is a riddle. A contradiction. Each one is, first, a soft, furry ball of adorableness 'with a large, round head and clumsy, cuddly body' that we all want to hug. That panda, said Gould, 'exists in our mind.'
"Then there's the hidden panda, the real one that isn't as we imagine, that lives in the wild and that panda, Gould wrote, 'has remained essentially a mystery.' "
George Schaller, a scientist from the Bronx Zoo, studied pandas in the wild, where he found that they are "rarely romantic, don't cuddle and are certainly not like the pandas of our minds," Krulwich wrote.
"As to what goes on in a real panda's mind, Schaller says he has no idea. After years spent tracking, poop collecting and bamboo measuring, he says pandas remain deeply strange to him. He knows everything they do, but he can't say much about who they are."
(Avie Schneider is NPR.org's business editor.)