The origin of the concept of memory consolidation is generally credited to Georg Elias Müller and his student Alfons Pilzecker. Their 300-page monograph, published in 1900, proposed that memory is not formed instantaneously at the time of learning but takes time to be fixed (or consolidated). The studies involved lists of nonsense syllables and focused especially on retroactive inhibition, the finding that when two lists are learned in succession, learning the second list interferes with subsequent recall of the first list. On the basis of this finding, they suggested that the processes needed to form memory continue for a period of time after learning, during which time they are vulnerable to interference. While this origin of the consolidation concept is widely known, it is not generally known that the interval across which the putative consolidation process operated in...