A brainwave for catching a criminal?
2010-09-25 0:00

By Mo Costandi | Guardian.co.uk

A new study suggests criminals can be detected by measuring a brainwave known as P300. In tests it worked remarkably well, but can we really trust it?


John Larson inventor of the polygraph demonstrates his machine at Northwestern University. Photograph: Pictorial Parade/Getty Images


Terrorists could be identified by a brainwave test that detects concealed information about an imminent attack, according to a study by psychologists from Northwestern University in Chicago.

The test, a sophisticated version of the now-discredited polygraph (or lie-detector) test, is based on the so-called guilty knowledge test developed in the 1950s. Whereas the traditional lie detector test involves asking the suspect whether or not they committed the crime in question, the guilty knowledge test focuses on specific details that would only be known to the perpetrator.

In the 1980s, Peter Rosenfeld combined the guilty knowledge test with recordings of the brain’s electrical activity. He exploited a brain wave pattern called the P300, which occurs in response to visual stimuli after a delay of 300 milliseconds, and can be detected with electrodes attached to the scalp.

It is well known that task-related stimuli, or stimuli that are meaningful in some other way, produce a larger P300 response than others. For the guilty knowledge test, this increased response can be a neurological signature of the unconscious recognition of a familiar object, event, or piece of information.

Rosenfeld’s group has already applied the test in a mock crime scenario, using it to identify participants who had knowledge of a stolen object. In the new study, they applied the test to a mock terrorist situation, recruiting 29 university students and dividing them into "guilty" and "innocent" groups.

The "guilty" group was given a document explaining that they would play the role of a terrorist planning an attack, and containing four different options each for how the attack could be carried out, the types of bombs that could be used, locations in Houston, Texas, that could be targeted, and dates in July on which the attack could be carried out.

Having planned the mock attack, they wrote a letter to an imaginary superior, containing the choices they had made, to aid memorisation of the plan details. The participants in the "innocent" group planned a mock holiday instead.

Both groups were then shown a long series of words on a computer screen, while the researchers recorded their P300 responses. Most of the words were irrelevant to the mock attack, but a few were "probes", relating to the specific details in the plans, and were included to evoke a stronger P300 in those participants with concealed knowledge of the details.

The researchers identified all of the "guilty" participants, without incorrectly identifying any of the "innocent" ones. They were also able to identify most of the attack-related details, enabling them to establish where and when each of the mock attacks would take place.

But the real world is infinitely more complex than the carefully controlled laboratory conditions under which the study was carried out. Here, the researchers detected concealed knowledge of a very limited set of details that were already known to them. In reality, an investigator would have little or no information of a planned attack.

Another limitation of the test is that the "probes" could have some meaning to a suspect in some other way. Three of the participants had to be excluded from the study because one of the probes had personal relevance to them, so produced false positive results. Guilty knowledge acquired incidentally could also produce a false positive. Furthermore, there are various countermeasures that can be used to confound the results.

Could these tests be used to establish a suspect’s guilty knowledge after a crime has been committed? This, too, is problematic, because it is based on the assumption that memory is infallible. We have known, however, since the work carried out by Sir Frederic Bartlett in the 1920s that memory is reconstructive, and not reproductive, in nature.

That is, we do not recollect events as they actually happened, but according to our own biases and experiences. Remembering involves stitching together fragments of memories, and errors inevitably creep in. Normally, the memory is accurate enough to be reliable, but occasionally it is not. It may even become increasingly inaccurate with each successive recollection. We can confabulate spontaneously, and false memories can be implanted with relative ease, as Elizabeth Loftus has shown.

Despite lacking validity outside the lab setting, the P300 test and similar techniques, such as "brain fingerprinting", are admissible in some courts of law in the United States and in 2008, India became the first country to use the guilty knowledge test to convict someone of a crime.

It would therefore be wise to properly evaluate how effective these tests are before they are used routinely in the courtroom. And, if that were to happen routinely, to regulate their use by companies who offer them as a service to the legal profession.

Mo Costandi writes the Neurophilosophy blog


Article from: guardian.co.uk




Brain-Computer Interface

Video from: YouTube.com



P300 Brain-Computer Interface

Video from: YouTube.com



Steve Gets a Brain Scan (HD) | A film by the Wellcome Trust

Video from: YouTube.com





Also tune into:

Peter Russell - Awareness, Presence & The Global Brain

Kevin Warwick - "I, Cyborg": Implants, RFID, Microchips & Cybernetics

Kevin Warwick - Artificial Intelligence & The Rise of the Machines in 2020

Lynne McTaggart - The Intention Experiment



Related Articles
Brain Science: Does Being Left-Handed Make You Angry?
“We Want Google To Be The Third Half Of Your Brain.” (Video)
How the Brain Stops Time
Brain’s Wiring: More Like the Internet Than a Pyramid?
Study: Autism can be diagnosed with brain scan
Cooling the Brain for its Own Good
Brain scans being misused as lie detectors, experts say
The Mind Machine Project
How the Unconscious Mind Can Act Out Our Prejudices
"me.exe": Mind Hacking, the Next Tech Frontier
Neuroimaging Of Brain Shows Who Spoke To A Person And What Was Said
’Mind-reading machine’ can convert thoughts into speech
Intel wants a chip implant in your brain
The Mind Has No Firewall
Scientists may soon be able to erase fear and trauma from your mind


Latest News from our Front Page

Anglo-Saxon Sword and Helmet from Staffordshire Hoard Reconstructed
2015-05-29 0:49
Thousands of metal fragments from the Staffordshire Hoard have been reconstructed into two "significant" new 7th Century objects. Researchers have pieced together parts of a silver helmet and a previously unseen form of sword pommel. The hoard, which is valued at £3.2m, was found in a field near Burntwood, Staffordshire in July 2009. Both items have been put on display at Birmingham's Museum ...
ALEC corruption: Legislators and corporate lobbyists meet in secret at Savannah resort
2015-05-28 23:59
The Georgia Legislature has a message for voters: don't ask us about our meetings with corporate lobbyists behind closed doors. The 11Alive Investigators tracked lawmakers to a resort hotel in Savannah last week, where we observed state legislators and lobbyists mingling in the hotel bar the night before they gathered in private rooms to decide what new laws would best serve ...
Swedish politician: US is the true cause of the masses of refugees from the Middle East
2015-05-28 20:13
Editors Note: And who controls US foreign policy? Listen to Jeff Gates. The present Swedish debate about war refugees from the Middle East is an example of peer restricted expression. In the name of political correctness or perceived decency, any questioning of maximum generosity in opening Swedish borders for the refugees is indignantly rejected by the official mainstream. We have a ...
Even if Patriot Act Expires, Government Will Keep Spying on All Americans
2015-05-28 19:52
Government Will Use "Secret Interpretations" to Get Around Legal Prohibitions Mass surveillance under the Patriot Act is so awful that even its author says that the NSA has gone far beyond what the Act intended (and that the intelligence chiefs who said Americans aren't being spied on should be prosecuted for perjury). Specifically, the government is using a "secret interpretation" of the ...
The TPP, Monsanto, Rockefeller, Trilateral Commission, Brzezinski
2015-05-28 19:18
All hands on deck for global, economic, corporate dictatorship There are dots to connect here. They're real, and they're spectacular. Let me begin with a brief exchange from a 1978 interview, conducted by reporter Jeremiah Novak. He was speaking with two American members of the Trilateral Commission (TC), a group founded in 1973 by David Rockefeller and his intellectual flunkey, Zbigniew Brzezinski. NOVAK: ...
More News »