Brain fingerprinting is a technique that measures recognition of familiar stimuli by measuring electrical brain wave responses to words, phrases, or pictures that are presented on a computer screen. Brain fingerprinting was invented by Dr. B. S. Farwell. The theory is that the suspect's reaction to the details of an event or activity will reflect if the suspect had prior knowledge of the event or activity. This test uses the Memory and Encoding Related Multifaceted Electroencephalographic Response to detect familiarity reaction. It is hoped it might be more accurate than a polygraph (lie-detector) test, which measures physiological signals such as heart rate, sweating, and blood pressure.The person to be tested wears a special headband with electronic sensors that measure the EEG from several locations on the scalp. In order to calibrate the brain fingerprinting system, the testee is first presented with a series of irrelevant stimuli, words, and pictures, and then a series of relevant stimuli, words, and pictures. The testee's brain response to these two different types of stimuli allow the testor to determine if the measured brain responses to test stimuli, called probes, are more similar to the relevant or irrelevant responses.