[FOUNTAIN]Liar, liar, brain’s on fire!Criminal investigation is a war against lies. The interrogator presses hard to reveal a criminal act, and the suspect tries to conceal his crime. When there is no physical evidence, interrogators must rely people’s word. Even if someone breaks, investigators cannot be sure how much of a confession is true. The polygraph test, which has been used since the 1920s, detects lies by sensing physiological changes in the heart rate and perspiration of a suspect. However, the lie detector is useless in front of a skilled liar. And those who are timid and fainthearted might fail the test and be wrongfully accused.
That is why criminal psychologists have their shifted focus to the brain. Scholars thought they could assess the credibility of a confession by examining a suspect’s brainwaves when they prompted memories related to criminal actions. A brain sends out different brainwaves depending on what a person is doing, whether concentrating, resting or sleeping.
Lawrence Farwell of the United States disclosed a method to analyze brainwaves called “brain fingerprinting” in 1991. A headband studded with 10 electrodes is put on the head of a suspect, and the device measures the brain’s response when a person is shown images of the crime scene. When a brain perceives a familiar image or a sentence, 0.3 seconds later it emits an electrical signal known as P300. For example, the brain of a criminal will not respond to a picture of a knife in general, but when confronted with a murder weapon, the brainwaves will suddenly surge.
Brain fingerprinting attracted international attention in 2001. Dr. Farwell claimed that a black young man serving a life sentence for murder was not guilty, providing brainwaves as evidence. While his brain did not respond to images of the crime scene, it emitted the P300 signal when he was shown a sentence related to a concert, which the suspect had used as an alibi. Brainwave analysis is over 90 percent accurate. Today, brain fingerprinting is widely used in the United States by the Federal Bureau of Investigation and the Central Intelligence Agency.
Recently, Korean prosecutors and police used a brain fingerprinting technique for the first time on an unsolved murder case. A mother who had murdered her daughter with poison for insurance money was arrested based on a brain fingerprinting test. Criminals can no longer evade justice with the right to remain silent. No matter how hard they try to erase the remains of their crimes, their brains will reveal the truth. I hope that the conventional practice of obtaining false confessions through intimidation will disappear soon.
by Ko Dae-hoon
The writer is a deputy city news editor for the JoongAng Ilbo.