It's an interesting question, Michelle. There's not an easy answer. I come from an area with fairly diverse European roots, and being able to associate facial features and body types with ethnic backgrounds is something a lot of us picked up just by growing up around that kind of diversity. I remember frustrating a TA in an anthropology class once by correctly guessing which world regions strangers in photos hailed from — based on their faces and bodies. (He was frustrated because he was trying to make the — inaccurate — point that ethnicity can't possibly be visible in someone's appearance.) I guess it's like being able to detect flavor notes in cooking, or identify musical keys and signatures based on sound — you can ask someone how they do it, but it's hard for them to articulate. It's just wired in. No joke, one woman randomly asked me once if I was of Lithuanian descent — I am — and when I expressed my shock, she explained that the giveaway for her was my eyes. (I'm still amazed.)

Anyway, I've asked people what makes me look Jewish. The only concrete thing I've been told is that my hair texture is a big one (curly to the point of frizzy). So it's still a mystery, I suppose. ;)