What about this one?

Once Braumoeller took into account both the number of countries and their political relevance to one another, the results showed essentially no change to the trend of the use of force over the last 200 years. While researchers such as Pinker have suggested that countries are actually less inclined to fight than they once were, Braumoeller said these results suggest a different reason for the recent decline in war. “With countries being smaller, weaker and more distant from each other, they certainly have less ability to fight. But we as humans shouldn't get credit for being more peaceful just because we’re not as able to fight as we once were,” he said. “There is no indication that we actually have less proclivity to wage war.”

Article: http://researchnews.osu.edu/archive/wardecline.htm Paper: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2317269&download=yes