In biology as in communication systems, cellular behavior emerges from interactions among multiple components, but unlike computers, an element of chance contributes to the operation of each cell and population of cells. The effect of chance on behavior is clearly noticeable in clonal populations of bacteria where genetically identical cells exhibit diverse behaviors. Using digital assays we are investigating how gene expression noise might control a complex biological function at the population level by tuning the distribution of single cell behaviors. As model system we use bacterial chemotaxis, one of the best characterized sensory systems in biology.