Along with his research on the Tamil Tigers, Scott Atran found that Palestinian terrorist groups (such as Hamas) provide monthly stipends, lump-sum payments, and massive prestige to the families of suicide terrorists. Citing Atran and other anthropological research showing that 99 percent of Palestinian suicide terrorists are male, that 86 percent are unmarried, and that 81 percent have at least six siblings (larger than the average Palestinian family size), cognitive scientist Steven Pinker argues in The Better Angels of Our Nature (2011) that because the families of men in the West Bank and Gaza often cannot afford bride prices and that many potential brides end up in polygynous marriages, the financial compensation of an act of suicide terrorism can buy enough brides for a man's brothers to have children to make the self-sacrifice pay off in terms of kin selection and biological fitness (with Pinker also citing a famous quotation attributed to evolutionary biologist J. B. S. Haldane when Haldane quipped that he would not sacrifice his life for his brother but would for "two brothers or eight cousins").
