Karim showed was that each time a memory is used, it has
to be restored as a new memory in order to be accessible
later. The old memory is either not there or is inaccessible.
In short, your memory about something is only as good as
your last memory about it. This is why people who witness
crimes testify about what they read in the paper rather than
what they witnessed. Research on this topic, called reconsolidation,
has become the basis of a possible treatment for post-traumatic
stress disorder, drug addiction, and any other disorder that
is based on learning.