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PhD defence

Online Radicalisation: The Use of the Internet by Islamic State Terrorists in the US (2012-2018)

  • J.J. Whittaker
Wednesday 19 January 2022
Academy Building
Rapenburg 73
2311 GJ Leiden


  • Prof. E. Bakker
  • Prof. S. Macdonald (Swansea University)


Online radicalisation has been highlighted by policymakers, the media, and academics as a top security priority in recent years. This thesis unpacks the concept by empirically analysing 201 Islamic State terrorist actors in the US, discerning their pathways into their eventual activity and assesses the role of the Internet. The findings suggest that that while the Internet is ubiquitous, the online domain does not seem to be replacing face-to-face interactions, nor do terrorists that act online demonstrate substantially different experiences to those that do not. In fact, using the Internet may be a hindrance, rather than a help, to would-be terrorists.
The findings also posit three interrelated radicalisation dynamics: Firstly, the consumption of propaganda is part of an ongoing socialisation process in which individuals take to social media to play out a staged authenticity to their peers. Secondly, an examination of the female terrorists shows that many use the Internet to circumvent gender restrictions and instead carve out a radical identity for themselves. Finally, the Internet can act as a “buyers’ market” of limitless information in which would-be terrorists can fulfil their needs in a space with fewer restrictions or constraints. The thesis concludes by outlining its contributions to the academic literature at the empirical, theoretical, and policy-level.

PhD dissertations

Approximately one week after the defence, PhD dissertations by Leiden PhD students are available digitally through the Leiden Repository, that offers free access to these PhD dissertations. Please note that in some cases a dissertation may be under embargo temporarily and access to its full-text version will only be granted later.

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