Perspective and world-building are, in my experience, inextricably intertwined. Understand that when I say world building what I mean is both the macro world the character lives in and the microcosm of the individual experience.
Each author can answer the question of nurture versus nature in her/his own way, but it has to be answered. The biggest creative examples I can think of are movies. A different medium to be sure, but still a very applicable example. I love movies almost as much as I love books, but you can do so much more in books than movies because all the special effects occur inside your own imagination.
Back to my point.
One of my biggest complaints is that the characters in too many Hollywood movies are out of touch with the audience and the roles they are trying to portray. A work-a-day schmuck is not going to have access to unlimited funds, martial arts skills, weapons training, a beautiful suburban ranch, and BMWs falling out of his/her ear, but it seems to be the norm in Hollywood.
Characters will take for granted risk taking, expenditure, and cross-societal and cultural experiences.
You shouldn’t though.
I wouldn’t be who I am without my own peculiar limitations and experiences. I think you learn more from a character who has obvious limitations than from one who has no limits on power, money, influence, access. Your world needs to make an internal sense.
Even if you are basing your story on a very different species in a different time frame and a completely different social structure, things should make some sense. Think back on your own experiences and those of your friends and family and find a fault to expose in your character. It will make them more real and if it is tied into their place in the world, all the better in my humble(ish) opinion.