Amnesia is a common plot device in the movies, but these depictions are often wildly inaccurate. For example, how often have you seen a fictional character lose their memory due to a bump on the head only to have their memories magically restored after suffering a second knock to the skull?
There are two different types of amnesia:
- Anterograde amnesia: Involves the loss of the ability to form new memories.
- Retrograde amnesia: Involves losing the ability to recollect past memories, although the ability to create new memories may remain intact.
While most movie depictions of amnesia involve retrograde amnesia, anterograde amnesia is actually far more common. The most famous case of anterograde amnesia was a patient known in the literature as H.M. In 1953, he had brain surgery to help stop the seizures caused by his severe epilepsy. The surgery involved the removal of both hippocampi, the regions of the brain strongly associated with memory. As a result, H.M. was no longer able to form any new long-term memories.
Popular movies and television programs tend to depict such memory loss as fairly common, but true cases of complete amnesia about one's past and identity are actually quite rare.
Some of the most common causes of amnesia include:
- Trauma: A physical trauma, such as a car accident, can cause the victim to lose specific memories of the event itself. Emotional trauma, such as being a victim of childhood sexual abuse, can cause the individual to lose memories of specific situations.
- Drugs: Certain medications can be used to cause temporary amnesia, particularly during medical procedures. Once the drugs wear off, the individual's memory returns to normal functioning.
Films Containing Depictions of Amnesia
- Robocop (1987)
- Regarding Henry (1991)
- The English Patient (1996)
- Memento (2001)
- The Bourne Identity
- 50 First Dates (2004)
- Finding Nemo (2003)
The science blog Neurophilosophy points out two fairly recent films that contain fairly accurate depictions of amnesia: Memento and Finding Nemo.