I got a fair bit through this a while ago, which gives a go at outlining a particular subset of social psychology identity theory. If I may dare to summarise/paraphrase what I remember…:
Everything that we are, as in all of the identities and components of identity that we carry around with us (such as gender, geographic origin, age, etc…), does not exist internally in any absolute singular sense - it only exists in relation to others. I may be a 34-year old man, but I only have the *identity *of a 34-year old man because there are others around me who have other ages and who are of the opposite gender. My income bracket only has any significance in terms of my identity because there are those who earn less and more than me. What it means to be who I am is determined by what it means to *not *be me (and vice versa, in a messy kind of way…) This might sound like a bland truism, but I think the consequences are actually quite far-reaching. We are literally defined by others, and the way that we compare and contrast to/against them. All identity is at first an external, social phenomenon, which is then internalised by the individual. So there is no ‘inner you’, soul, or person ‘deep down’ that you really are - you are just the ‘role’ that you play in front of others: your *persōna *is you. Like this, we are all playing a character - it is impossible not to. The choice we have is *how *we play it, not *whether *we do.
People can’t choose to have identities, then - they just do. And, if they endeavour to not have any sort of identity, then that itself becomes an aspect of their identity - albeit a humourously hypocritical one (doh!).
All of this said, though, some people tend to ham up one particular aspect of their identity while others downplay it (such as geographic origin, a la the OP). Why do some make a big deal of being from a particular place, or of having a particular sexual alignment, or of having a particular religion? I imagine there are lots of reasons, but I suspect that covering up some sort of insecurity plays a part in it most of the time.
“I don’t east sushi because I’m a Southerner!” could mean…
“I am scared of eating raw fish, but I don’t want to admit it - so this Southern identity thing seems like a reasonable enough un-emasculating excuse”
“I feel that, as a Southerner, my origins are not being recognised in this social situation - so here is a way for me to stand my ground and establish where I am from publicly”
“I have fears (legitimate or otherwise) that if my Southern contemporaries were to learn of my eating sushi that I might be though less of, and so will refrain for fear of damage to my reputation”
“I feel that, by way of refusing this particular line of gastronomy on grounds of geographic and cultural origin, I will appear assertive and masculine”