In all but pathological liars, lying to invent information or to hide
it takes more brain processing than telling the truth.
The older police interrogation technique is the Reid Technique,
because unsophisticated liars behave differently than unsophisticated
truth-tellers. The newer technique is named PEACE, I believe they
simply let the subject tell his story without interruption and then
call him on his inconsistencies later.
I read a SciFi story once where the questions were predesigned, then
presented in random order by automation so it was much harder to
invent a consistent lie in the moment. This might be the "baseline
test" in the new Blade Runner movie. Who knows what probes they had
installed to monitor brain operation, see where the CPU was being
used, equivalent of functional MRI, etc.
https://en.wikipedia.org/wiki/Reid_technique
"Don't Talk to the Police" by Law Professor James Duane:
https://www.youtube.com/watch?v=d-7o9xYp7eE
Brian