As long as there is a link, does it matter if the chicken or egg came first?
I mean, conservatism? Really? What's this gonna do besides cause a shit-storm?
I mean, going by my experience, most of the dumb people in my life tend to be social conservatives. And most of the smart ones are not. Of course, there are exceptions to that. I wouldn't know of the science behind this study, as I am not interested enough to really dig deep to find out. But it does match my experience, and the experience of many others I know.
What has your experience been?
The question is not whether most of the dumb people you know are conservative, but whether most of the conservatives you know are dumb. Even then, that most of the dumb ones are conservative will skew the figure a bit (as will the GOP actively recruiting the dumb and/or bigoted for the past half century, but that is on them.
Basically, there is a big difference between saying, "stupidity usually makes people conservative" and "being conservative usually demonstrates stupidity."
Atheism is a religion like abstinence is a sex position. - Bill Maher