Can a memory still exist and be retrievable even if it's forgotten?

The scientific understanding of memory has changed substantially over the past centuries. It has shifted from the philosophical disputes of Plato and Aristotle to the more biologically evident case of patient H.M. Early experiments on various cases have helped shape the fundamental principles of memory, resulting in multiple definitions and theories. In the early 1800s, many people believed that memory loss came from a sickness, but they eventually recognized it had a partial correlation to the brain. In the 20th century, groundbreaking evidence came with the curious case of H.M. (Henry Molaison), who underwent brain surgery to treat his severe epilepsy. Surgeons removed large portions of his medial temporal lobes, which caused memory impairment. This case eventually led scientists to posit the Standard System Consolidation Theory (SSCT), which proposes that newly encoded memory forms at the hippocampus but gradually becomes stored in neocortical systems. For decades, SSCT became the accepted explanation for memory loss and retrograde amnesia. However, more recent research has questioned this framework. Theories like the Multiple Trace theory (MTT) or Contextual Binding Theory (CB) suggest that the hippocampus is required for long-term memory retrieval.


These theories suggest that there are many broader factors for memory loss, such as context, the time the memory was formed, and the patient’s health. This review traces the historical development of memory theory, evaluates whether contemporary evidence supports a traditional system consolidation theory or a context-based alternative (CB and MTT), and makes an approach to tackling explanations for memory loss.