Overview
Brain Fingerprinting is a proposed investigative technique developed by Dr. Lawrence A. Farwell that measures electrical brain wave responses to determine whether an individual recognizes specific details of an event or activity. The technique uses electroencephalograph (EEG) recordings to detect P300 and MERMER components in response to stimuli presented on a computer screen.
How It Works
The Brain Fingerprinting test presents three types of stimuli:
- Targets: Information made relevant to the subject before testing, expected to elicit P300 responses
- Irrelevants: Plausible substitutes for actual event details that should not elicit P300 responses
- Probes: Unique details known only to the investigator and perpetrator, which should elicit P300 in guilty subjects but remain indistinguishable from irrelevants in innocent subjects
The technique employs bootstrapping statistical analysis to compare responses and yield results with claimed confidence levels exceeding 95% (or 99% using MERMER). The developer has indicated a 100% accuracy rate in research trials.
Federal Agency Evaluations
Multiple federal agencies have evaluated Brain Fingerprinting:
CIA: Funded approximately $1 million in research between 1991-1993 but concluded the technique had limited applicability to counterintelligence operations because it lacks screening capability and requires specific event details unavailable in many investigations. An independent panel in 1993 could not assess validity due to the developer's refusal to share algorithmic information.
DOD: The Polygraph Institute evaluated the technique but concluded research expenses, equipment costs, and training requirements exceeded benefits. DOD officials noted most criminal investigations lack the specific information needed for Guilty Knowledge Test-based techniques.
FBI Laboratory Division: Evaluated Brain Fingerprinting in 1993 and 1999, concluding it had limited applicability to FBI investigative functions. The division identified concerns about:
- Subjective probe selection requiring advanced academic training
- Lack of research on external variables (drugs, alcohol) affecting brain activity
- Research expenses exceeding perceived benefits
Two FBI agents who collaborated with the developer believe Brain Fingerprinting has potential but noted it would require a policy shift in investigative and training methods.
Secret Service: Reviewed information provided by the developer in 1998 and consulted with CIA officials. Concluded limited applicability given the agency's high success rate with polygraph as an interrogative and screening tool.
Legal History
In April 2000, Dr. Farwell administered Brain Fingerprinting to a murder convict in Iowa who petitioned for postconviction relief based on test results demonstrating innocence. The Iowa district court dismissed the application in March 2001, ruling that Brain Fingerprinting evidence was unlikely to change trial outcomes because:
- Neither MERMER nor the developer's mathematical model had undergone independent peer review
- Probe stimulus selection was subjective and did not meet the developer's own criteria
- The P300 effect, while well-established, lacked validation for this specific application
Current Status
As of 2001, only one court case (Harrington v. Iowa) had addressed Brain Fingerprinting evidence. Three scientists interviewed during GAO research expressed the need for more field testing and independent peer review before forensic application.