Barbie is in trouble. Her merchandise is being outsold by the upstart "Bratz" dolls, which have a much more cartoony look. And if you've got issues with how Barbie's proportions may set unrealistic expectations, the Bratz dolls should send you screaming into the streets. Big heads, short bodies, tiny waists, and giant facial features... a living creature modeled after Bratz would be a walking, talking horror.
But we love 'em. (YOU might not, but "we" the consumer whose dollars, euros, and yen have voices of their own, we are speaking loud and clear.) Why?
More importantly, is there a larger principle at work here? Something that someone like me, who wants to make a living as a cartoonist can capitalize on? Well, I wouldn't be asking the question this way if I didn't think there was.
We like Bratz dolls, cartoon characters, and anime eyes, because they show us how we feel. They are proportioned a lot like our sensory homunculi - the distorted human figure drawn to reflect the relative sensory space our body parts occupy on the cerebral cortex. Here -- read up on it. Wikipedia is a wonderful thing.
NOTE: The Wikipedia article is quick to point out that in the psychological/philosophical disciplines any argument whose conclusion requires the existence of an actual homunculus, or "little man" inside our heads, is fallacious because the "little man" doesn't exist. But now we're mixing our metaphors and overburdening the term -- the "little man" homunculus doesn't exist, no. The mapping of our sensory nerves is a physical thing, however, and CALLING it a homunculus doesn't make it not exist.
So... we like big eyes because we are so dependent upon our own eyes for understanding the world. (Well, that and the dilated pupil effect, but I digress). We like big hands because our OWN hands are the principle tools of our sentience, reversible thumbs and all. We like big lips because anything that we consume must pass between them.
And the flip-side is true -- when you look at a barbie doll, or any of the more proportionally correct figures, the absence of exaggeration leaves us cold. Arm and legs, knees and elbows, bodies and buttocks -- these are not bits with which we experience the world, so when we see them in true proportions, there is no emotional impact.
This also explains why the computer animation in The Incredibles and the puppets in Wallace and Gromit and Corpse Bride resonate with us, while the much more "realistic" animation in Polar Express is just creepy. The Uncanny Valley is less and less a mystery when you consider the sensory homunculous.
So... there's the crackpot theory. It's possible there's actual scholarly research along these lines. If there's not, I'm sure there's a Schlocker out there who could get his or her PhD with a dissertation along these lines (including demonstrating that it's false, thanks to choice bits of evidence I've overlooked or ignored.) For now, though, it's a nice predictor for consumer behavior, and it gives me an excuse to continue being "cartoony" rather than "realistic" in my artwork. Because, you know, I COULD be all realistic and stuff. No, really, I could. Don't give me that look. I'll draw you, I will, and your homonculus has a REALLY big nose.