On Killing: The Psychological Cost of Learning to Kill in War and Society

by Dave Grossman

The Predisposition of the Killer This area considers such factors as: - Training/conditioning of the soldier (Marshall’s contributions to the U.S. Army’s training program increased the firing rate of the individual infantryman from 15 to 20 percent in World War II to 55 percent in Korea and nearly 90 to 95 percent in Vietnam.) - Recent experiences of the soldier (For example, having a friend or relative killed by the enemy has been strongly linked with killing behavior on the battlefield.) The temperament that predisposes a soldier to killing behavior is one of the most difficult areas to research. However, Swank and Marchand did propose the existence of 2 percent of combat soldiers who are predisposed to be “aggressive psychopaths” and who apparently do not experience the trauma commonly associated with killing behavior. These findings have been tentatively confirmed by other observers and by USAF figures concerning aggressive killing behavior among fighter pilots.[9]