What is P-300 Test?

When the brain recognises a person or a sound, it generates a particular type of electric wave, which is called a P300.

Sensors are attached to the head of a person undergoing a P300 test and the subject is seated before a computer monitor. He is then shown certain images or made to hear certain sounds. The sensors monitor electrical activity in the brain and register P300 waves, which are generated only if the subject has some connection with the stimulus, in this case pictures or sounds.

The subject is not asked any question.

These test are used by investigators to cross check their findings, determine if a suspect is telling the truth or make him reveal facts pertaining to a case.