How to control which contacts appear first when composing an e-mail?

After upgrading to iOS 6, something seems to have changed when I compose an e-mail. I think it used to show recently-used contacts first. In anycase, now, when I enter my wife's first name, I don't see her first; I see anyone with that first name (it's a fairly common first name and I have other contacts with that name that I rarely e-mail). Note that I'm using Google Sync (Exchange-based) as as a syncing with my company's Exchange server. Is there any way to change or control which contact appears first when I type a certain first name?