Brain Mapping Test or the P300 refers to a test which was developed and patented in 1995 by neurologist Dr. Lawrence A. Farwell, Director and Chief Scientist "Brain Wave Science”, IOWA.
In this method, called the "Brain-wave finger printing”; the accused is first interviewed and interrogated to find out whether he is concealing any information. Then sensors are attached to the subject"s head and the person 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 connection with the stimulus i.e. picture or sound. The subject is not asked any questions. Dr. Farwell has published that a MERMER (Memory and Encoding Related Multifaceted Electro Encephalographic Response) is initiated in the accused when his brain recognizes noteworthy information pertaining to the crime. These stimuli are called the "target stimuli”. In a nutshell, Brain finger printing test matches information stored in the brain with information from the crime scene. Studies have shown that an innocent suspect"s brain would not have stored or recorded certain information, which an actual perpetrator"s brain would have stored. In the United States, the FBI has been making use of "Brain mapping technique” to convict criminals.