That "science" was done, apparently, by employees/consultants of online dating sites. Not like I'm saying there's any bias there, but it seems like just another tip for finding that significant other: smile, have good teeth and hair, be "sensitive" to feelings, and ... oh yeah ... use good grammar. Also, please purchase our services.

I agree with Robert. It's funny, but I don't think it's real science. Correlation does not imply causation.

It is, nonetheless, a curious correlation.