Sitelink Titles in Google SERPs

I've noticed a recent change in Google in that they are showing far more sitelinks (the links under a listing in Google to different pages of the same domain) for the 1st ranked site than they used to. One page I've seen had 12 sitelinks under it. That's so many that there was only ONE other search result under the first site. Obviously, it makes a lot of sense to try to get more sitelinks under your site. With sitelinks, it's pretty easy to push down your competition so far that users don't even see them.

Knowing how important sitelinks can be to SEO, I am really curious as to HOW Google seems to choose the title of sitelinks. Google seems to choose arbitrarily. From what I can tell, it has little or nothing to do with standard meta tags, the title attribute, the file name (i.e. "index.php" or "links.htm", etc.). However, I noticed for a couple sites using Open Graph meta tags, the meta property "og:title" was almost always the same as the title of the sitelink. Is this a coincidence? Am I grasping at straws? Or could making the "og:title" meta tag of a page help Google identify the title for the sitelink

Note: I did post this question in another thread about a month ago, with no replies, and this question was sort of off topic from the thread anyways, so I figured it'd be fine if I post it in a new thread. Really looking for answers here.