Vectors of evolutionary change: a transdisciplinary model for analysing evolving terrorist organizations

Terrorism studies provide systematic frameworks for innovation as process but lack event-level criteria for identifying which discrete moments, particularly events beyond organizational control, fundamentally redirect a group's developmental trajectory. This paper addresses that gap by introducing the Vector of Evolutionary Change (VoEC), a transdisciplinary analytical model that identifies events critically redirecting a terrorist organization's ideology, structure, operations, or strategic direction. Grounded in Tinbergen's ethological framework and integrating insights from evolutionary biology, narrative criminology, and Critical Terrorism Studies, VoEC extends critical juncture theory by foregrounding self-sustaining transformations triggered by events often beyond organizational control. The model is demonstrated through analysis of the Italian Red Brigades (BR, 1970–1988), drawing on over 17,500 pages of memoirs, judicial proceedings, and governmental reports. Four distinct VoECs are identified: Feltrinelli's pre-formation ideational influence on Curcio's vanguardist frame; the symbolic terminal rupture of the founding nucleus marked by Mara Cagol's death; the operational plateau in BR kidnapping methodology established at Sossi; and the realized strategic catastrophe of the Aldo Moro affair. Each finding challenges prevailing narratives. The VoEC model offers replicable methodology for comparative analysis across different terrorist organizations, with implications for understanding group adaptation, resilience, and decline.