Brain fingerprinting is a controversial, unproven and questionable technique invented by Lawrence Farwell which he says uses electroencephalography (EEG) to determine whether specific information is stored in a subject's brain. The technique consists of the measuring and recording a person's electrical brainwaves and their brain response.
Comparison of brain fingerprinting with polygraphy showed mixed results consistent with "a mix of proven techniques and dangerously exaggerated benefits".
In 2001, brain fingerprinting was ruled as admissible for court use in Iowa by the decision in Harrington vs. State of Iowa. It was also used in India, until a 2010 Indian Supreme Court ruling. A. R. Lakshmanan, judge and past Chairman of the Law Commission of India, welcomed this ruling, describing brain fingerprinting as "so science-fictional that there were no takers anywhere else in the world".