What Drives Suicide Bombers? The Kamikaze Syndrome
Scientists have long sought to understand why suicide bombers seem willing to sacrifice their lives so readily. Recent research suggests that shared experiences, especially negative ones, can lead to extreme forms of group identification. In these cases, people feel so closely bonded with their group that they are prepared to die for it. This form of cooperation may have been essential for our ancestors’ survival.
Humans and Extreme Altruism
Humans are a unique phenomenon for evolutionary biologists. No other animal is as willing to help others and, in return, receives as much support as homo sapiens. In exceptional situations, this drive can take on extreme forms. Whether it’s Japanese kamikaze pilots during World War II or modern-day suicide bombers, some people are willing to sacrifice themselves for others.
This behavior has always puzzled researchers. How did a trait that drives people to deadly self-sacrifice persist through evolution? After all, soldiers and terrorists often act for the sake of a group with whom they share no family ties.
Unity with the Social Group
A team of scientists led by Sergey Gavrilets from the University of Utah in Salt Lake City set out to find an explanation. Their research was based on the idea that the willingness to fight and die for others must be motivated by something. They called this motive “identity fusion.” In this state, an individual no longer sees themselves as a separate person, but rather as one with their social group.
What fuels this sense of unity, and what role has “identity fusion” played in human history? To answer this, the researchers used computer modeling. Through various scenarios, they discovered the circumstances under which our ancestors developed tendencies toward self-sacrifice and whether these could become ingrained.
Shared Pain as a Key Factor
The results showed that the willingness to stand up for others and sacrifice oneself was likely a necessary strategy for our ancestors. Only in this way could a population survive most dangers and withstand conflicts with other groups. Shared experiences, especially negative ones, were crucial in fostering this cooperation.
According to simulation data, the likelihood of such social behavior increases significantly when group members have endured common negative experiences and pain. Through cooperation, the chances of survival and a shared evolutionary future were much higher than those based solely on family ties or the inheritance of individual genes.
Closer Than Brothers
Gavrilets and his colleagues note that their computer model reflects the conditions in which our ancestors lived tens of thousands of years ago—a time when survival meant constant conflict. Today, life is much easier for modern humans. Extreme forms of confrontation necessary for group survival now seem outdated. However, in extreme cases, this evolutionary mechanism can still appear in modern groups.
The team tested their conclusions using empirical data from various population studies, including research on Vietnam War veterans, jiu-jitsu fighters, fraternity members undergoing initiation rituals, and pairs of twins.
Essentially, the hypothesis was confirmed: the more painful experiences people share, the more likely they are to stand up for each other—even to the point of self-sacrifice. The sense of kinship that arises can even be stronger than family bonds.
“Research has already identified many pathways for the evolution of cooperation. We have added a new, previously underestimated but very powerful mechanism—extreme forms of cooperation through shared experience,” says Gavrilets. In such cases, people become, so to speak, “brothers in arms.” In English, the term “Band of Brothers” refers to military units used in violent conflicts. “In essence, shared negative experiences can make individuals closer than brothers,” the researcher concludes.