Rosenfeld is a leading scholar in the study of P300 testing to reveal concealed information. Basically, electrodes are attached to the scalp to record P300 brain activity -- or brief electrical patterns in the cortex -- that occur, according to the research, when meaningful information is presented to a person with "guilty knowledge."
Research on the P300 testing emerged in the 1980s as a handful of scientists looked for an alternative to polygraph tests for lie detection. Since it was invented in the 1920s, polygraphy has been under fire, especially by academics, with critics insisting that such testing measures emotion rather than knowledge.
Rosenfeld and Northwestern graduate student John B. Meixner are co-investigators of the study, outlined in a paper titled "A Mock Terrorism Application of the P300-based Concealed Information Test," published recently in the journal Psychophysiology.
Study participants (29 Northwestern students) planned a mock attack based on information they were given about bombs and other deadly weapons. They then had to write a letter detailing the rationale of their plan to encode the information in memory.
Then, with electrodes attached to their scalps, they looked at a computer display monitor that presented names of stimuli. The names of Boston, Houston, New York, Chicago and Phoenix, for example, were shuffled and presented at random. The city that study participants chose for the major terrorist attack evoked the largest P300 brainwave responses.
The test includes four classes of stimuli known as targets, non-targets, probes and irrelevants. Targets are sights, sou
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