This isn't a question of a high-level personality trait, but a question about the low-level firmware in our heads. The standard myth that we all grow up with is that everyone is born as a blank slate, and the child's environment shapes the person from scratch. This is only partially true, there's a whole lot about our nature that is simply fixed in stone (ok, neurons really) before we even take our first breath. Two obvious examples are the innate human calls of crying and laughter. The weird thing is that most of the rest of our minds are pre-determined by biological evolution too.
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There's far less variation between people than we normally think; a whole lot of us is dictated by the low-level firmware we're born with. We're just acutely sensitive to the relatively minor differences between us, just like you can tell faces apart even though they're all basically the same.
If you're saying is that the relative weights vary between people, so while one person might be very comforted by touch another wouldn't care for it much, I agree with that. But this is just the small amount of variation between different people, the small amount that isn't fixed and can vary person-to-person. This is just a difference-in-degree, not a difference-in-kind. I doubt you can find someone who reacts to touch by immediately beginning to juggle knives or by sneezing. Now that would provide some evidence for the whole blank-slate hypothesis.
Evolutionary Psychology is fascinating stuff. As I said in another thread: "EvPsych basically makes one important observation and asks the natural question leading from it: Just like our eyes and hands, our minds have also been developed in response to evolutionary pressures. What were these pressures and how do they account for the features we see in ourselves, like language, love, laughter, crying, etc?" A good pop-sci book on the subject is The Moral Animal by Robert Wright: http://www.amazon.com/Moral-Animal-Science-Evolutionary-Psyc...