Brain Waves is reporting that two companies are now advertising brain-based lie detection services based on fMRI brain-scanning technology.
This technology works differently from traditional polygraph-based techniques which measure arousal in the body and are based on the idea that we become more stressed (and hence, more aroused) when telling lies.
Polygraphs are notoriously unreliable and are known to be easily fooled.
In contrast, newer ‘lie detection’ technology typically uses an approach called the Guilty Knowledge Test (pdf) which relies on recognition.
It is known that there are distinct patterns of brain activation when someone recognises a previously seen piece of information, compared to when they do not.
In the Guilty Knowledge Test, a suspected murderer might be shown items from the crime scene to see whether these particular patterns of activation are found. If a recognition pattern is found, this might suggest that they were present at the scene.
The potential use of this technology has raised some serious ethical concerns, however, (see this pdf on neuroprivacy) as it has been touted for use on people without their consent, such as in cases of terrorism or goverment intelligence gathering, and it is still not known exactly how accurate or how easily fooled such tests are.
UPDATE: I’ve just discovered Brain Ethics also has an engaging post on this topic.