“…An alignment rule by itself is theoretically sufficient to generate collective motion (Leonard et al, 2012;Vicsek, Czirók, Ben-Jacob, Cohen, & Shochet, 1995), as is the combination of attraction and repulsion (Romanczuk, Couzin, & Schimansky-Geier, 2009). Among pedestrian models (Chraibi, Tordeux, Schadschneider, & Seyfried, 2018), the prominent Social Force model (Chen, Treiber, Kanagaraj, & Li, 2018;Helbing & Molnár, 1995;Hoogendoorn & Bovy, 2003) is predicated on attraction and repulsion forces and has convenient mathematical properties (Köster, Treml, & Gödel, 2013). The model successfully simulates key crowd scenarios (Boltes, Zhang, Tordeux, Schadschneider, & Seyfried, 2018;Chraibi et al, 2018) and can generate collective motion under certain conditions (Helbing, Farkas, & Vicsek, 2000;Helbing, Molnár, Farkas, & Bolay, 2001), but does not produce realistic human trajectories (Pelechano, Allbeck, & Badler, 2007) or generalize to novel situations without re-parameterization (Campanella, Hoogendoorn, & Daamen, 2009;Chen et al, 2018).…”