Flow through Bottlenecks: Stronger Is Slower.

We present experimental results of the flow of programmable robots through a bottleneck. With these agents, velocity and force can be decoupled-a unique feature allowing us to show that, in the absence of physical contact and pushing from behind, and despite the development of clogs, moving faster always improves the flow of discrete systems through bottlenecks. Conversely, the flow is reduced if the robots are allowed to push. This result indicates that the pressure build-up within the system is a necessary condition to observe the effect previously known as faster-is-slower, a generic phenomenon emerging in a variety of discrete systems flowing through a narrowing which we argue should rather be called stronger-is-slower.