The  Decay Theory of Forgetting

 One important question concerns forgetting.  
Cognitive psychology has addressed this question.  
One theory of forgetting is decay theory.  Decay
theory suggest that we forget something because the
memory of it fades with time.  This theory would
suggest that if we do not attempt to recall an event,
the greater the time since the event the more likely we
would be to forget the event.  Thus, this theory
suggests that memories are
not permanent.
There are other theories of forgetting.  Memory for an
event may reflect interference. The interference
theory of forgetting suggest that we would forget
something because other information learned is
interfering with our ability to recall it.  
  One problem with the decay theory of forgetting is
that we do not know whether the failure to recall
something reflects that it is no longer in our memory,
or that it reflects retrieval failure.  Perhaps it is still
there but we cannot retrieve the memory for some