The Truth activates a larger part of the brain than lies.

What caused the radiation around the head of this person 12.000 years ago?

According to research of American psychologist of Daniel Schacter (1998) the truth activates a larger part of the brain than lies. The brain processes a truthful memory different then a deceitful memory.

With a true-full memory the electrical activity of the brain increases whilst the lights of a deceitful brain seem to go out.