How Brain Fingerprinting Is Intended to Work

According to its developer, Brain Fingerprinting is designed to determine whether an individual recognizes specific information related to an event or activity by measuring electrical brain wave responses to words, phrases, or pictures presented on a computer screen. Its developer has indicated that Brain Fingerprinting, therefore, is not designed for screening functions, which involves questioning individuals about events unknown to the investigator. Rather, the developer has indicated that an investigator would be able to use this information as evidence for or against a suspect. For example, he has indicated that the technique could be used to determine whether a suspect has knowledge of details connecting him or her to a crime. Probes are unique details of the event or activity that are supposed to be known only to the examiner or investigator and the subject. DOD officials indicated that most DOD criminal investigations do not lend themselves to a Guilty Knowledge Test-based technique, such as Brain Fingerprinting, because these kinds of investigations typically lack the specific information that is needed for administering such a test and because knowledge of the discrete elements of an event or activity may not be limited to only the investigator and the perpetrator. The research expenses, equipment, and training costs exceeded any perceived benefit. Appendix II: Comments From the U.S. Secret Service

Appendix III: Comments From the Federal Bureau of Investigation
What GAO Found

Federal law enforcement and intelligence agencies are seeking to add new techniques to their arsenal of investigative tools. "Brain fingerprinting" measures brain wave responses to determine whether an individual recognizes certain details of an event or activity. Because the technique requires specific information about the event that would be known only to the perpetrator and the investigator, Brain Fingerprinting is not designed as a screening tool--a function that involves questioning a subject about events unknown to the investigator. Instead, an investigator would be able to use certain information as evidence for or against a subject. For example, the technique could be used to determine whether a subject has knowledge of details about a crime. Officials representing the Central Intelligence Agency, the Department of Defense, the Secret Service, and the Federal Bureau of Investigation do not forsee using the brain fingerprinting technique because of its limited use. Furthermore, given the technique's limitations, the research expenses, equipment, and training costs are perceived to exceed benefits.