Memory and Forgetting: Analogous Processes on Individual and Collective Levels

Thomas J. Anastasio, Department of Molecular and Integrative Physiology, UIUC

Memory can be roughly divided into short-term and long-term. In humans and many other animals, damage to a brain structure known as the hippocampus not only causes antergrade amnesia, in which new long-term memories cannot be formed, but also causes retrograde amnesia, in which old long-term memories are lost. Retrograde amnesia is graded such that long-term memory loss is greatest for events that occurred immediately prior to, and least for events that occurred many years prior to, the hippocampal damage that produces the amnesia. The graded nature of retrograde amnesia suggests that memory is formed through a gradual process by which short-term memory is transformed into long-term memory. This process is called memory consolidation. In this talk I will briefly review findings on amnesia and consolidation in individual brains, and will try to make the case that analogous processes also occurr on the collective level. The results suggest that memory of a collective is MORE than the sum of the memories of the individuals that compose it, and that collective memory is formed, or can be lost, through processes or pathologies that may involve something like a collective hippocampus.