After observing their behavior for over five years, I have really gotten to know the midwesterners as a people.
I've discovered a new favorite tell that 60% of the time, works every time.
When a midwesterner gets on a train or a bus (and I am talking about a corn-fed, directional-college-educated, cell-phone-holder-on-his-belt real Midwesterner, not one of those big-city-livin' Chicago types) - they will sit down and look around, not with the quick glance of "is there a goddamned pigeon on this train," but the slow and easy gaze of someone surveying the surrounding prairie, or soy bean fields or whatever you have out here.
I used to think they were scanning the train for any sort of unsavory characters who might give them a one way ticket to pick-pocket town. But, now I'm realizing that is the East Coast skeptic in me. What these people are eyeing for is some one to chat with.
They want someone to talk about the weather (here versus there), how noisy/bright/crowded/expensive things are, how proud they are of their son/niece/grandbaby for moving out to this big old city and how they just ate Ethiopian food for the first time (imagine that! with your hands and everything!).
Occasionally they'll catch the eye of someone who has a "kind soul" or who forgot their headphones at home and strike up this predictable dialogue other times, they'll just wait patiently with their companion (these folks never travel alone, that'd be asking for trouble) and eventually, if the fish aren't biting, they'll just spend the rest of their ride talking about at what stop they're getting off and how people in Chicago sure do keep to themselves.