Here’s a compelling article by Daniel Kahneman and Jonathan Renshon.  Kahneman is famous for identifying numerous human heuristics and biases in the lab. He received a Nobel prize in economics based on his decades of inspiring work. Renshon is a Harvard doctoral student.

In this article, the authors note that many built-in human heuristics and biases lead our leaders to choose war over peace. Our leaders are “predisposed to believe their hawkish advisors more than the doves.”

Here’s a sample:

People are prone to exaggerating their strengths: About 80 percent of us believe that our driving skills are better than average. In situations of potential conflict, the same optimistic bias makes politicians and generals receptive to advisors who offer highly favorable estimates of the outcomes of war. Such a predisposition, often shared by leaders on both sides of a conflict, is likely to produce a disaster. And this is not an isolated example.

In fact, when we constructed a list of the biases uncovered in 40 years of psychological research, we were startled by what we found: All the biases in our list favor hawks. These psychological impulses—only a few of which we discuss here—incline national leaders to exaggerate the evil intentions of adversaries, to misjudge how adversaries perceive them, to be overly sanguine when hostilities start, and overly reluctant to make necessary concessions in negotiations. In short, these biases have the effect of making wars more likely to begin and more difficult to end.

The excessive optimism of humans is yet another potential pitfall for leaders:

Psychological research has shown that a large majority of people believe themselves to be smarter, more attractive, and more talented than average, and they commonly overestimate their future success. People are also prone to an “illusion of control”: They consistently exaggerate the amount of control they have over outcomes that are important to them—even when the outcomes are in fact random or determined by other forces. It is not difficult to see that this error may have led American policymakers astray as they laid the groundwork for the ongoing war in Iraq.

Once we’ve begun a losing cause, our biases keep us from evaluating losing situations accurately.  The authors frame this problem as the deep-seated human aversion to cutting losses.  This is akin to the sunk cost phenomenon we’ve previously discussed in the context of Iraq.