Brainwave Lie Detector: Brainwaves can Spot Criminals

GoodpalStarred Page By Goodpal, 14th Jul 2011 | Follow this author | RSS Feed
Posted in Wikinut>News>Crime

The most detailed knowledge of any crime is always locked away in the brain of the person who committed it. And of course, he will never admit that he committed the crime. What if you don’t have to interrogate or torture him to find out the truth; and how about having a brain reader that can read details hidden in his brain. Sounds too unrealistic? No more. Find out how?

Brain Signals

There are over a billion neurons in the brain that communicate with each other using electrochemical signal. The ongoing changes in these signals, which are measured using scalp electrodes, are recorded as continuous changes in voltage over time, called the electroencephalogram (EEG). The machine is basically a neural amplifier. The recorded signal has the form of cyclic waveforms and is called brainwave pattern.

The EEG records minute, fluctuating potential differences between electrodes placed on the skull. This measure of frequency is relatively crude, but allows us a window into the excitability of the brain. Electrodes are placed on the scalp in an ordered array. Signals from the brain are amplified allowing the microvolt-level potential differences to be detected. The resolution of EEG is quite low, since the brain is about 1 cm from the surface of the scalp. The major distinctions of EEG include alpha, beta, theta, and delta activity – differing in the frequency range.

Four Types of Brainwave Frequencies

Frequency is the rate at which electrical charges move through brain cells. The four basic frequency ranges discriminate levels of arousal or excitability within the brain. In the delta range, waves move very slowly. It is the sleep state where the signal is moving through clusters of neurons very slowly, below four cycles per second, or hertz (Hz). Just above that is theta brainwave range, around 4 to 8 Hz, observed in a deeply relaxed state. Next higher frequency range (8 to 13 Hz) is alpha, a slightly less relaxed state.

The most rapid brain waves are beta, and they reflect activities of a normal waking brain. Beta waves can be further classed as low beta, a relaxed but alert state of 12 to 15 Hz and can go up 35 Hz in states of heightened alertness or restlessness.

For a more detailed description of these brainwaves, you may like to read Brainwave Patterns: Vocabulary of the Brain.

Event related potential (ERP)

Buried in the EEG are signals that reveal information about brain processes. These signals are detected by timing changes in the EEG after events such as listening to a sound or viewing a picture. The resulting activity is called an event related potential (ERP), which clearly stands above the background brain activity. The ERP can be broken down into several basic components represented as positive or negative fluctuations in the ERP waveform at different delays after the stimulating event. These ERP components include signals labeled P1, P2, N1, N2, N400 and P300. Generally, the signals occurring after 250 milliseconds are thought to reflect higher level cognitive processes such as memory or language.

P300 Brain Wave Testing

Research on the P300 testing emerged in the 1980s when researchers looked for an alternative to polygraph tests for lie detection. The polygraphy has been under fire, since its invention in the 1920s, with critics insisting that such testing measures emotion rather than knowledge.

The P300 is a specific electrical brain wave that is triggered whenever a person sees a familiar object. The P300 waves have been understood in electrophysiology to mean that the subject is able to consciously identify and categorize a stimulus. For instance, if a subject has been listening to trombone noises and a flute tone is played, a P300 wave will appear 300 ms later on the EEG machine.

The P300 event-related potential can be used to determine concealed knowledge that only a criminal would know. By placing details of the crime randomly among a list of non-relevant items, one can distinguish criminal from citizen. If an individual recognizes a detail of the crime, it produce a P300 EPR and is likely guilty of, or at least familiar with, the crime.

Due to the specificity of brainwave response, the technique has been labeled brain fingerprinting drawing analogy from identification through fingerprints.

How the P300 Wave Response is Used in Finding the Guilty

This technique provides a potential window into someone's past visual experience because the most detailed knowledge of any crime is always locked away in the brain of the person who committed it. If a person looks at random pictures of weapons, without activating a P300 wave, these objects are presumably unknown to him. But if the murder weapon is shown, and a P300 wave activates, then the person clearly has some experience with that weapon. The suspect’s ERP responses give clues with scientific certainty, whether the story he is telling matches what is stored in his brain. Similarly, if a CIA agent has become a Russian spy his brain will elicit P300 response if objects connected with his spying activities are presented before his eyes.

This technique is highly objective and is used to see if some specific information is stored in the brain or not. Along with other information and evidences from the crime scene the ERP responses can greatly help pointing to the most probable suspects and minimize harassment of innocents.

Advantage Over the Usual Lie Detector Test

This is not an interrogative technique; hence, does not require answering questions. The subject merely wears a headband of electrodes and faces a computer screen, which flashes photographs. The P300 brain activity occurs when meaningful information is presented to a person with “knowledge of guilt.” It reveals objectively whether information is present in the brain, regardless of what the suspect says. Here his brain does the talking which automatically responds through changes in brainwave activity and tells if information on specific details of a crime is “present” or “absent” in the brain’s memory. Since the response is automatic there is no way of suppressing or fooling the system. The technique has been successfully lab-tested on FBI agents and US navy doctors with remarkable accuracy as well as in some real life cases.

On the other hand, lie detection is traditionally done by measuring heart rate, skin conductance, and rate of breathing, etc. These measures are sensitive to individual health issues and critics say they indicate emotions, not knowledge.


If investigating agencies adopt this brainwave fingerprinting technique in their routine investigation, they will be able to narrow down on the most likely suspects in much shorter time. It will also prevent sentencing of innocent people. Being more advanced that the earlier lie detectors, it has an enormous potential in criminal investigation.

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Brain Fingerprinting, Brainwave, Brainwave Lie Detector, Brainwave Technology, Brainwaves, Crime Detection, Criminal Investigation, Electroencephalogram, Event Related Potential, Memory Brainwaves, P300 Brain Wave, P300 Brain Wave Testing

Meet the author

author avatar Goodpal
I am a keen practitioner of mindfulness meditation for past several years. I firmly believe in "goodness" of people, society and world. I regularly write on personal growth and social topics.

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author avatar James R. Coffey
15th Jul 2011 (#)

Hummm . . . seems like just another opportunity to profile and falsely accuse.

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author avatar Steve Kinsman
15th Jul 2011 (#)

Put this machine in the hands of governments and law enforcement and they will abuse it.

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author avatar Goodpal
16th Jul 2011 (#)

Thanks, James and Steve for raising the issue.

Science and scientists did their job; now it for the society, people and politician to decide if and how to use the knowledge for better results. I am a firm believer that ultimately good intentions prevail despite the presence of some bad guys everywhere.

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author avatar Denise O
19th Jul 2011 (#)

It just amazes me what folks can come up with. I am with you, I do seem to fell good does triumph over bad. Only time will tell. Thank you for sharing.:)

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author avatar Gideon Seal
25th Jul 2011 (#)

This machine is my only hope, if only it can become part of the law in RSA.

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author avatar Zenina
25th Feb 2017 (#)

What are your sources?

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