innate release mechanisms and fixed action patterns

• animals have an innate releasing mechanism which is built in and hard wired physiological process or set structures( eg network of neurons in the brain) that generate aggressive behaviour
• An Environmental stimulus (such as facial expression or specific colour/ shape of rival) triggers the IRM.

  the IRM communicates this with motor circuits to release specific sequence of aggressive behaviour .The sequence is called a fixed action pattern
• • Stereotyped- behaviour always occurs in the same way
  • universal - the same behaviour is shown in all members of the species
  • unaffected by learning - Same for everyone regardless of experience and learning
  • ballistic- Once behaviour is triggered it cannot be changed or stopped
  • single purpose- occurs in a specific situation are not in any other