Spiritual convictions and group identities inspire terrorist acts, study finds

Islamic militants and their fiercest opponents fight and die for intensely spiritual reasons, a new report finds.

Islamic State (also known as ISIS) soldiers and Kurds who have fiercely battled them sacrifice themselves for sacred, nonnegotiable values, says a team led by anthropologist Scott Atran of the University of Michigan in Ann Arbor. These soldiers’ will to fight also depends on identifying more closely with groups of like-minded comrades than with biological kin, the team reports September 4 in Nature Human Behavior.

Atran’s findings, described in Science News last year, come from frontline interviews with ISIS fighters and members of groups fighting against them — Kurdistan’s army, Iraqi army Kurds and Arab Sunni militias. Online testing of people in Spain, where several terrorist attacks have recently occurred, found a general unwillingness to fight against ISIS. Spaniards also viewed ISIS as spiritually stronger and more dedicated to collective values than citizens of their own country are.

Those results support Atran’s proposal that the fiercest fighters fuse their identities to groups with a common set of sacred values.