a common shared online collective memory. Collective memory and psychological research Though traditionally a topic studied in the humanities, collective memory has become an area of interest in psychology. Common approaches taken in psychology to study collective memory have included investigating the cognitive mechanisms involved in the formation and transmission of collective memory; and comparing the social representations of history between social groups. Social representations of history Research on collective memory have taken the approach to compare how different social groups form their own representations of history and how such collective memories can impact ideals, values, behaviors and vice versa. Developing social identity and evaluating the past in order to prevent past patterns of conflict and errors are proposed functions of why groups form social representations of history. This research has focused on surveying different groups or comparing differences in recollections of historical events, such as the examples given earlier when comparing history and collective memory. Differences in collective memories between social groups, such as nations or states, have been attributed to collective narcissism and egocentric/ethnocentric bias. In one related study where participants from 35 countries were questioned about their country's contribution to world history and provided a percentage estimation from 0% to 100%, evidence for collective narcissism was found as many countries gave responses exaggerating their country's contribution. In another study where American's from the 50 states were asked similar questions regarding their state's contribution to the history of the United States, patterns of overestimation and collective narcissism were also found. Cognitive mechanisms underlying collaborative recall Certain cognitive mechanisms involved during group recall and the interactions between these mechanisms have been suggested to contribute to the formation of collective memory. Below are some mechanisms involved during when groups of individuals recall collaboratively. Collaborative inhibition and retrieval disruption When groups collaborate to recall information, they experience collaborative inhibition, a decrease in performance compared to the pooled memory recall of an equal number of individuals. Weldon and Bellinger (1997) and Basden, Basden, Bryner, and Thomas (1997) provided evidence that retrieval interference underlies collaborative inhibition, as hearing other members' thoughts and discussion about the topic at hand interferes with one's own organization of thoughts and impairs memory. The main theoretical account for collaborative inhibition is retrieval disruption. During the encoding of information, individuals form their own idiosyncratic organization of the information. This organization is later used when trying to recall the information.