I think they happen when a minority of extremes is perceived as the majority.
Let’s take gay guys for example. Most people who are immediately identifiable as gay are so identifiable because they are flamboyantly, outrageously gay. They may be the few willing to step up and say, ‘‘Yeah, I’m gay, what of it?’’ I don’t think it’s unreasonable to acknowledge that there have been core groups of gay men with identifiable superficial characteristics in common. Go to a gay club and you’ll see what I mean. There’s an entire culture there, part of which grew out of the burden placed on so many to stand up for their rights as human beings. As Margaret Cho bluntly put it, ‘‘If I have to fight my entire life for the right to fuck, then dammit, I’m going to kick up my heels and fuck!’’ The lisp is, to some extent, a part of that culture and shared bond of living in a society that is largely hostile to homosexuals. Asking ‘‘why’’ the lisp came to be is kind of a chicken and egg question, but I lean toward it being an environmental social phenomenon. IME the lisp seems to crop up in groups, not individuals who have never been exposed to other gay men.
Now, hidden behind that minority of lisping, prancing extremes is an entire population of gay men who don’t look or act much differently than any other man. There is, if you will, a rainbow of diversity among gay men. There are gay men at the grocery store, at your job, in your family, driving your bus, and you probably don’t even know it because they do not exhibit those stereotypes.
The problem is, people don’t notice or identify the quiet, average gay men as gay. So they form the impression that ‘‘gay men talk with a lisp’’ when in fact it’s only a small minority of them that do.
Obligatory Onion Link
So too with the ‘‘Asians are smart/good at math’’ thing. Where are Asians most noticed by the general population? Why, in colleges and business, of course–exactly where you’d notice something like intelligence. Nobody notices the poor ones toiling away in sweatshops or those average middle-class Asian families because those aren’t cases where you would readily assess intelligence. I woudl also venture that a lot of Asians who gain scholarships and internships and jobs abroad do so because they are remarkably smart, and many of the truly stupid Asians are stuck without opportunity in their homelands. Thus, only the outliers stand out.