Intrinsically motivated collective motion
Significance Our study invokes a low-level principle that we believe might motivate animal behavior in general and collective motion in particular—the principle that an agent seeks to increase the number of states that it is able to encounter in the future. This principle should confer evolutionary fitness for rather general reasons that we discuss. We report how the collective motion that emerges from this principle is similar to that seen in animal systems. In particular, coalignment, cohesion, and collision avoidance all emerge naturally, even though none of these are encoded in the principle itself. In this sense, our work proposes a low-level origin for the emergence of collective motion in animal systems. Collective motion is found in various animal systems, active suspensions, and robotic or virtual agents. This is often understood by using high-level models that directly encode selected empirical features, such as coalignment and cohesion. Can these features be shown to emerge from an underlying, low-level principle? We find that they emerge naturally under future state maximization (FSM). Here, agents perceive a visual representation of the world around them, such as might be recorded on a simple retina, and then move to maximize the number of different visual environments that they expect to be able to access in the future. Such a control principle may confer evolutionary fitness in an uncertain world by enabling agents to deal with a wide variety of future scenarios. The collective dynamics that spontaneously emerge under FSM resemble animal systems in several qualitative aspects, including cohesion, coalignment, and collision suppression, none of which are explicitly encoded in the model. A multilayered neural network trained on simulated trajectories is shown to represent a heuristic mimicking FSM. Similar levels of reasoning would seem to be accessible under animal cognition, demonstrating a possible route to the emergence of collective motion in social animals directly from the control principle underlying FSM. Such models may also be good candidates for encoding into possible future realizations of artificial “intelligent” matter, able to sense light, process information, and move.