In studies of virtual teams, it is difficult to determine pure effects of geographic isolation and uneven communication technology. We developed a multi-agent computer model in NetLogo to complement laboratory-based organizational simulations . In the lab, favoritism among collocated team members (collocators) appeared to increase their performance. However, in the computer simulation, when controlled for communication delay, in-group favoritism had a detrimental effect on the performance of collocators. This suggested that the advantage of collocators shown in the lab was due to synchronous communication, not favoritism. The canceling-out effects of in-group bias and communication delay explained why many studies did not see performance difference between collocated and remote team members. The multi-agent modeling in this case proved its value by both clarifying previous laboratory findings and guiding design of future experiments.