Several XP discussions bring up the idea of "egoless programming". Weinberg's well-known in those circles.

As far as XP goes, though, there's a whole lot more than just regular peer review. Pair programming is recommended for all code that lives longer than a day. The entire team owns the entire codebase; there are no little fiefdoms. Debugging's less important because the code is frighteningly well-tested. The test blindness is lessened, partly because of pair programming but mostly because of test-first development.

XP's not perfect for everyone in every situation, but it takes into account many of these psychological issues.