People who choose to serve in the military are different from those who don't. The experience of military service then exaggerates the personality differences in small but significant ways, which remain that way when soldiers return to civilian life. These personality differences may play a role in the veterans' high divorce rate, and their other social and occupational problems.
These are the conclusions of a 6-year study, conducted by Joshua J. Jackson and teams of researchers from Washington University in St. Louis and the University of Tubingen in Germany, published in Psychological Science.
In one of the first empirical, prospective longitudinal studies of personality change in adults, the researchers followed German male high school graduates who chose to fulfill their public service obligations in either civilian or military settings. Those who chose military service were generally less neurotic, less likely to worry, and less interested in seeking novel experiences. It is no surprise that they were also less agreeable, i.e., more aggressive, more interested in competition than cooperation and less concerned about the feelings of others than their civilian counterparts.