Toward an Operational Dynamical Model of Lateral Manual Interception Behavior.

We develop a dynamics-based model of discrete movement for lateral manual interception capable of generating movements with realistic kinematics. For the present purposes, we focus on the situation of to-be-intercepted targets moving at constant speed along rectilinear trajectories oriented orthogonally with respect to the interception axis. The proposed phenomenological model is designed to capture the time evolution of empirically observed hand movements along the interception axis under different conditions of target arrival location and target speed-induced time pressure. Pattern formation dynamics combine a Duffing stiffness function, allowing for creating a fixed-point attractor at the perceived location of the target arrival on the interception axis, with a hybrid Rayleigh plus Van der Pol damping function. After parametrizing the model for required movement direction (left/right), amplitude, and duration, it adequately reproduces the (variations in) empirically observed kinematics with a single set of four coefficients for all conditions considered. The model is also demonstrated to inherently incorporate speed-accuracy trade-off characteristics.