A report of a computer simulation of human behavior in Bavelas-type communication network experiments. The simulation successfully imitates behavior in the five-man chain network, and does reasonably well for a six-man Y net, but fails on a more complex six-man net. Main features of the simulation are described. In order to simulate human behavior, a number of non-optimal activities were initially permitted in the simulation and were discarded gradually by probabilistic selection of "desirable" patterns of message sending. Results lead one to question the notion of "optimal performance," even for a simple communication task in a small group.