How do we know how a melody sounds when
we are not hearing it? We send information
about the melody from our memory to our
auditory cortex(청각피질).
Then ,we experience a mental sound.
Because "Happy Birthday "is sung only on birthdays,
it is not usually there when we want to listen to it.If our ears do not feed the auditory cortex the information about the song , we must get it from our memory .
The information sent from memory
will allow us to have a fake listen . Through this process , we are able to discover things about the song even when we are not hearing it.

요약문.
When we are not hearing a song with our ears ,
the information about the melody in our memory
is sent to auditory cortex and we listen to mental
sound.