Uses Of Intertextuality
Intertextuality is using or manipulating ideas from other media, to then be used in their own media context. This is usually used to show respect towards the owner or the original 'aritist' etc. and is usually referred to as 'Homage or Hommage'.
Psycho's famous shower scene is the perfect example of intertextuality. It is usually this particular scene, other movies tend to revolve around; examples of this include, What lies Beneath, The Stepfather, Fatal Attraction and the student movie, Succubus.