24-12-2009, 01:17 PM
Brain Fingerprinting was invented by Lawrence Farwell. It is a forensic science technique that determines whether specific information is stored in a person's brain by measuring electrical brainwave responses to words, pictures or phrases, which are presented on a computer screen. The theory is that the brain processes known, relevant information differently from the way it processes unknown or irrelevant information . The brainâ„¢s processing of known information, for example, the details of a crime stored in the brain, is revealed by a specific pattern in the EEG(electroencephalogram). Farwell discovered the MERMER ("Memory and Encoding Related Multifaceted Electroencephalographic Response"), which includes the P300 along with some additional features and provides a higher level of accuracy.
The Methdology
The technique uses the fact that an electrical signal known as P300 is emitted from an individual's brain beginning approximately 300 milliseconds after the brain is confronted with a stimulus of special significance, e.g. a rare vs. a common stimulus or a stimulus the subject is asked to count. The application of this in brain fingerprinting is to detect the P300 as a response to stimuli related to the crime or other investigated situation,like,victim's face, a murder weapon, or knowledge of the internal workings of a terrorist cell. the system does not require the subject to issue verbal responses to questions or stimuli, because it is based on EEG signals.
procedure used:
1)The person to be tested wears a special headband with electronic sensors that measure the EEG from several locations on the skull.
2)The person is shown stimuli consisting of words, phrases, or pictures presented on a computer screen which are of three types:
a)irrelevant stimuli that are irrelevant to the investigated situation and to the test subject
b)target stimuli that are relevant to the investigated situation and are known to the subject.
c)probe stimuli that are relevant to the investigated situation and that the subject denies knowing.
brain fingerprinting does not depend on the emotions of the subject, nor is it affected by emotional responses , since brain fingerprinting uses cognitive brain responses.
Difference from polygraph
polygraph measures emotion-based physiological signals such as heart rate, sweating, and blood pressure but it measures the personâ„¢s brain response to relevant words, phrases, or pictures to detect whether or not the relevant information is stored in the personâ„¢s brain.Brain fingerprinting also does not attempt to determine whether or not the subject is lying or telling the truth.
Limitations
Brain fingerprinting detects information-processing brain responses that reveal what information is stored in the subjectâ„¢s brain. It does not detect how that information got there.If the suspect knows everything that the investigators know about the crime for some original reason, then the test cannot be applied.
Case of an eye witness: the fact that witness knows details about the crime would not be incriminating. There would be no reason to conduct a test, because the resulting response would simply show that the suspect knew the details about the crime knowledge which he already admits to have gained gained at the crime scene.
Another situation where brain fingerprinting is not applicable is one where the authorities have no information about what crime may have taken place. It is also not appplicable in in general pre-employment or employee screening wherein any number of undesirable activities or intentions may be relevant. Brain fingerprinting does not determine whether a suspect is guilty or innocent of a crime.Before a brain fingerprinting test can be conducted, an investigator must discover relevant information about the crime or investigated situation.
More details can be found here:
http://en.wikipediawiki/Brain_fingerprinting#Technique
The Methdology
The technique uses the fact that an electrical signal known as P300 is emitted from an individual's brain beginning approximately 300 milliseconds after the brain is confronted with a stimulus of special significance, e.g. a rare vs. a common stimulus or a stimulus the subject is asked to count. The application of this in brain fingerprinting is to detect the P300 as a response to stimuli related to the crime or other investigated situation,like,victim's face, a murder weapon, or knowledge of the internal workings of a terrorist cell. the system does not require the subject to issue verbal responses to questions or stimuli, because it is based on EEG signals.
procedure used:
1)The person to be tested wears a special headband with electronic sensors that measure the EEG from several locations on the skull.
2)The person is shown stimuli consisting of words, phrases, or pictures presented on a computer screen which are of three types:
a)irrelevant stimuli that are irrelevant to the investigated situation and to the test subject
b)target stimuli that are relevant to the investigated situation and are known to the subject.
c)probe stimuli that are relevant to the investigated situation and that the subject denies knowing.
brain fingerprinting does not depend on the emotions of the subject, nor is it affected by emotional responses , since brain fingerprinting uses cognitive brain responses.
Difference from polygraph
polygraph measures emotion-based physiological signals such as heart rate, sweating, and blood pressure but it measures the personâ„¢s brain response to relevant words, phrases, or pictures to detect whether or not the relevant information is stored in the personâ„¢s brain.Brain fingerprinting also does not attempt to determine whether or not the subject is lying or telling the truth.
Limitations
Brain fingerprinting detects information-processing brain responses that reveal what information is stored in the subjectâ„¢s brain. It does not detect how that information got there.If the suspect knows everything that the investigators know about the crime for some original reason, then the test cannot be applied.
Case of an eye witness: the fact that witness knows details about the crime would not be incriminating. There would be no reason to conduct a test, because the resulting response would simply show that the suspect knew the details about the crime knowledge which he already admits to have gained gained at the crime scene.
Another situation where brain fingerprinting is not applicable is one where the authorities have no information about what crime may have taken place. It is also not appplicable in in general pre-employment or employee screening wherein any number of undesirable activities or intentions may be relevant. Brain fingerprinting does not determine whether a suspect is guilty or innocent of a crime.Before a brain fingerprinting test can be conducted, an investigator must discover relevant information about the crime or investigated situation.
More details can be found here:
http://en.wikipediawiki/Brain_fingerprinting#Technique