Sir

Analyses reported in your News story “Psychologists warn of more suicide attacks in the wake of London bombs” ( Nature 436, 308–309; 2005) depict suicide terrorism as the result of organized campaigns aimed at achieving clear political goals, such as national liberation.

These analyses come from studies of conflicts in areas such as the West Bank and Chechnya, which, although important, may not be applicable to recent attacks. Our research leads us to believe that small-group dynamics and values can trump rational self-interest to produce horrific behaviour in ordinary people.

Bruce Hoffman, of the RAND Center for Terrorism Risk Management Policy in Washington DC, finds that 81% of suicide attacks since 1968 occurred after the terror attacks of 11 September 2001, with 31 of the 35 groups held responsible being Islamic militants or ‘jihadi’. Independent studies by the Nixon Center think-tank and by former US intelligence officer Marc Sageman (presented to the World Federation of Scientists Permanent Monitoring Panel on Terrorism in Sicily, May 2005) reveal that more than 80% of known jihadis live in diaspora communities, often marginalized from the host society, and in hard-to-penetrate social networks that consist of about 70% friends and 20% family. Seeking a sense of community, these small groups bond as they surf jihadi websites to find direction and purpose. In the past five years alone, jihadi websites have increased in number from fewer than 20 to more than 4,000.

European jihadis act, not to achieve a clearly specified political goal, but to oppose a perceived global evil. Reuven Paz, former research director for Israeli intelligence, reports that even in Iraq, jihadis from 14 other Arab countries say that they have volunteered to fight against ‘international evil’ rather than for Iraq itself (see http://www.e-prism.org).

From interviewing would-be suicide bombers and sponsors from Europe to southeast Asia, we have learned that terrorism thrives in people who feel humiliated, either in their own lives or through identifying with others, as seen, for example, in reports from Abu Ghraib prison. We ask questions such as: “What if your family were to be killed in retaliation for your action?”. Almost all answer that, although they have a duty to their families, their duty to God comes first. “And what if your action resulted in no one's death but your own?” The typical response is “God loves you the same”. Such reasoning is not very sensitive to standard cost–benefit calculations or moral trade-offs.

How do we deal with this decentralized global jihadi community? Insights into home-grown jihadi attacks must come from understanding small-group dynamics and psychological motivations, including those that are religiously inspired.

Given the increasing role played by the Internet, efforts should foster alternative peer groups in cities and cyberspace, showing the same commitment and compassion towards their own members as terror groups seem to offer, but in life-enhancing ways and also towards others.