From Graham Reinders:

Re: Good fences make good neighbors, scientists find (Sept. 13): This article is not valid and based on non relevant assumptions. Mixed neighbourhood violence is absolutely about human prejudice, human greed and human opportunism. We the Species will do whatever we think we can get away with to gain advantage over another. When dictators hold the big stick nobody dares to cheat. When any one group holds the power no other group cheats them. It is all in the perception of what we think we can get away with.