  The "faster-is-slower" (FIS) effect was first predicted by computer
simulations of the egress of pedestrians through a narrow exit [Helbing D,
Farkas I J, Vicsek T, Nature 407:487-490 (2000)]. FIS refers to the finding
that, under certain conditions, an excess of the individuals' vigor in the
attempt to exit causes a decrease in the flow rate. In general, this effect is
identified by the appearance of a minimum when plotting the total evacuation
time of a crowd as a function of the pedestrian desired velocity. Here, we
experimentally show that the FIS effect indeed occurs in three different
systems of discrete particles flowing through a constriction: (a) humans
evacuating a room, (b) a herd of sheep entering a barn and (c) grains flowing
out a 2D hopper over a vibrated incline. This finding suggests that FIS is a
universal phenomenon for active matter passing through a narrowing.
