Cognitive research on human memory has primarily focused on how individuals form and maintain memories across time. However, less is known about how groups of people working together can create and maintain shared memories of the past. Such "collective memories" common to all people have been theorized to play a role in the emergence and persistence of a strong cultural identity within groups. Empirical research has been focused on understanding the processes behind the formation of such collective memories, but virtually none has investigated the structure of collective memory. This dissertation examined the extent to which the strength of individual and shared memory structure relates to the formation of collective memory and its persistence over time. Results indicate that both collective memory formation and its persistence over time are strongly tied to the amount of shared organization that develops among individuals, particularly among those who have collaborated with each other to reconstruct the past.