Transactive memory systems (TMS) theory has attracted increasing attention in the scholarly fields of cognitive, organizational, and social psychology; communication; information science; and management. TMS theory and research, focusing primarily on internal group activities, have paid scant attention to external group activities. This paper contributes to TMS theory and research by a set of proposals on the influence of internal and external group activities on TMS formation and functioning. More specifically, I propose that external group activities, depending on their intensity, influence TMS formation and functioning in project groups.

A previous version of this paper was presented in the annual Academy of Management conference in the USA.