Facial Expressions, Culture, and Stories

During an event at the Newton Free Library last night, I asked the presenter Gareth Hinds (BEOWULF/Candlewick) a question that's been on my mind when it comes to comics:

Me (paraphrased; I sounded more incoherent): "One thing I don't like in manga is when artists use darker skin for evil characters. And there's a certain genre of movie where fat people always get killed first. Big noses, pudgy bodies, slanty eyes -- how do you avoid using the lazy shortcut of stereotypes in portraying character traits to your readers?"

Gareth Hinds (paraphrased; he sounded more eloquent): "I don't have a hard-and-fast rule, but am very aware of that issue. I pick extras for my graphic novels who can communicate the emotions I need for the story with great facial expressions. So in MERCHANT OF VENICE, for example, I didn't draw Shylock with a big nose -- I looked for a model who could sneer really well."
I liked his answer, but now I have another question. People of different races and ethnicities communicate rage, humor, fear, shame adoration, lust, wonder, malice, and other emotions by using slightly different non-verbals. In South Asian markets, North Americans can get confused when a vendor closes his eyes and tilts his head to one side -- which means "okay," not "time for a nap." And trepidation is signified by raising your eyebrows and holding your tongue between your teeth, not opening your mouth wide.

Science Daily reports on the differences between Japanese culture, where the focus tends to be on the eyes, and North American culture, where we concentrate on the mouth:
These cultural differences are even noticeable in computer emoticons, which are used to convey a writer's emotions over email and text messaging. Consistent with the research findings, the Japanese emoticons for happiness and sadness vary in terms of how the eyes are depicted, while American emoticons vary with the direction of the mouth. In the United States the emoticons : ) and : - ) denote a happy face, whereas the emoticons :( or : - ( denote a sad face. However, Japanese tend to use the symbol (^_^) to indicate a happy face, and (;_;) to indicate a sad face.
In RICKSHAW GIRL, when my character Naima is frustrated with a friend, I wrote that she stuck out her tongue. Illustrator Jamie Hogan created a gorgeous full-page spread depicting that action -- one that readers have told me is their favorite in the book. While reviewing the galley before publication, it struck me that sticking out a tongue in Bengali culture might imply regret, not anger. After much internal debate, I decided to keep my doubts to myself and leave the non-verbal as I wrote it. But to this day when I'm reading aloud to a class and get to that part of the story, my authorial conscience flinches.

Here's my question: should writers depict facial expressions or non-verbals in a way that's easily understood by the culture consuming the story, even if it might not be "authentic?"