Habit learning involves learning association
between stimuli (or context) and responses and can
be defined as a stimulus–response (S–R) association
becoming independent of the goal of the action after
a critical number of repetitions of the different events
in the same environment. While declarative memory
supports the learning of relationships among items and
events and appears especially suitable for rapid, even
one-trial learning, habit memory is typically acquired
gradually over many trials through the establishment of
S–R associations that develop outside awareness and
are rigidly organized, with the result that what is
learned is not readily expressed except when the task