Philosopher Maurice Halbwachs formulated the theory of collective memory. This theory maintains that group thinking is a phenomenon separate from that of individual memory. Maurice Halbwachs suggests that a collective memory is one that is shared by a group of individuals. This memory is formed by the group, absorbed by them and then transferred to others in the group or across society.
After Maurice Halbwachs' initial proposition a number of other philosophers followed suit. Philosophers such as Jan Assmann applied these views to other arenas. Assmann noted a difference between cultural memory and communicative memory. Cultural memory is used as a place to store past events while communicative memory is used in daily life but exists only in the present.
Other thinkers such as Paul Connerton and Pierre Nora extended these concepts of collective memory even further. Connerton proposed that the human body provides a venue for the retention of collective responses and the circulation of collective memories. While Connerton focused on how our bodies host collective memories, Nora provided insight into how an individual's surroundings contribute to the processes involved in collective memory.
A central focus of collective memory is the memories shared by nations or large groups of people of significant events in the history of the group as a whole. Unfortunately, many of these events, such as wars, terrorist attacks or genocide, have negative connotations. These remembrances provide the foundation for collective memory, because the relevant events had a meaningful impact on a large portion of the overall population. Countries will choose which events or incidents to remember and these are often visualized through the construction of physical memorials.
Philosophers also believed that the group produces forms, images and artifacts as a means of ensuring that a collective memory continues to be remembered. Now, with the ubiquity of computers and television, this visualization has entered a new stage of development. Memories are translated into visuals that are disseminated through a wide range of communication channels.
Over time and as technology has evolved, the various ways of representing and sustaining collective memory have expanded to include digitization. In the past, individuals would develop collective memories that were based on individual memories translated through oral tradition. Nowadays, collective memories are created by the media and can be rapidly communicated and controlled by a variety of parties. Critics suggest that this process of digitization has detracted from the sense of community that people once shared, and that, in fact, the collective memories experienced today are not as genuine as they once were.
New theories followed in the wake of these initial concepts. James E. Young's theory of collective memory claims that memory is naturally fragmented on an individual level. These fragments are then collected by individuals, and memories are gathered based on the similarities between of those perceptions.
Kiyoshi Tanimoto, a survivor of the atomic bomb that destroyed Hiroshima, points to the significance of this particular collective memory. This global event, he states, was ingrained in the minds of people around the world. He believes that this particular collective memory created a negative view of the use of nuclear weapons, and has an enduring effect on the global public.
In modern times, the ideology of collective memory has been reinforced in nonfiction books. James Redfield's best-selling book, The Celestine Prophecy, describes collective memory as a continuing process that eventually transcends this plane of existence. His thesis emphasizes the role of the subconscious mind and ways in which collective memory shape reality. Many of his ideas combine philosophies about the role of the future and the present in the development of a collective unconscious.
Many ideas about collective memory have been integrated into New Age religious and belief systems.