Summary of “The New York Review of Books”

Multiple factors interact in complex ways that cause radicalization to emerge in individual people and groups.
Nascent decentralized groups rely on a reputation for success as the prime attractor for new adherents.
Women didn’t become more vulnerable to radicalization over that period-instead, they were targeted for radicalization.
Preliminary findings on Western ISIS fighters indicate that very few recruits were self-radicalized; for the vast majority, radicalization was facilitated through social interaction.
The picture emerging of the Barcelona attackers is more typical of radicalization in Europe.
A more evidence-based approach would be to try to mitigate group radicalization.
Bombarding radicalization hotspots with counter-radicalization programs-which often involves getting teachers, social workers, or community leaders to report on those they oversee-can make residents of those areas feel suspect, which may do more harm than good.
International conflicts, social networks, community, ideology, and individual vulnerabilities all combine to let radicalization emerge.

The orginal article.