A Logic-Based Approach to Understanding Lone-Actor Terrorism.

The need for systematic research into behavioural factors of individual terrorists has been highlighted by much recent work on terrorism. Many existing methods follow a hypothesistesting approach in which statistical modelling and analysis of existing data is conducted to either conrm or refute a hypothesis. However, the initial construction of hypotheses is not trivial, nor is the decision upon which of the variables are to be considered relevant for the testings. It has been argued that the lack of a methodical approach to represent, analyse, interpret and infer from existing data presents a pressing challenge to the progress of lone-actor terrorism research in particular, and the terrorism eld more generally. This paper sets a new agenda for such research. We propose the use of a logic programming approach to address the shortcomings of existing methodologies in the study of lone-actor terrorism. Our method is based on transforming characteristic and behavioural codes into a logic program and applying inductive logic programming to learn hypotheses about potentially relevant factors associated with terrorist behaviour, as well as the inuence of specic factors on such behaviour. This paper is an exploratory study of 111 lone-actor terrorists’ target selections (civilian vs. high-value targets) and the agency of their ideological orientation in determining their target choices.