Concerning "guilty looks" (whatever those may be): Do microfacial expressions help us to distinguish between the feelings of guilt of parents being unable to protect their child and parents having killed their child?
First off, it's not "guilty looks". That's a complete distortion of the actual technique. And the interviews were only one piece of the total assessment.
What happens when you are deceitful, depending on the circumstances of the lie, you have very brief involuntary expressions which match your true feeling but don't match the expression one expects given what you are saying. What Frank and Ekland hypothesized then went on to demonstrate is that facial expression of emotion is universal with some cultural modification, but not of the basics. When a primate is happy, he/she/it universally makes the same recognizable facial expression of a smile. While some cultures may discourage or encourage smiling so there are differences overall in the expressions, everyone around the world recognizes a smile. By the same token, that smile is reflexive, not under total conscious voluntary control.
George Bush, for example, was a very bad and frequent liar. That smirk he's known for was common when he was giving answers now shown to be false. Of course when I point this out it annoys many members of this forum who are convinced there is no real science here and all we are seeing is confirmation bias. What could be more suggestive of confirmation bias than Ginger's opinion of Bush's dishonesty?
The assumption all lie detecting is bunk, however, is based on the actual confirmation bias, ironically. Ekland has supported his hypothesis and it has nothing to do with looking guilty, with lie detector tests, with professional skill supposedly leading people to get better at detecting deceit. All of those hypotheses and claims have indeed been debunked, but not Frank and Ekland's work. There is a biological basis underlying the hypothesis and demonstrated validity to the hypothesis.
I learned about this technique years ago. And once you start looking for those micro flashes of emotion, not only can you get better and better at seeing them, you can follow up on your observations and see if they were valid or not.
Getting back to the Ramseys, there is a lot more here than just their bizarre behavior in the interviews. No single piece of evidence closes the case. But the totality of it does. Such evidence is not necessarily what one can use in a court of law which requires a certain standard of beyond reasonable doubt. Compare that standard to the OJ case where he was convicted in civil court even while not being convicted in criminal court. Despite the extraneous circumstances in that case, it illustrated the fact there are different standards for conviction and doubt.
I have my opinion. It doesn't include the opinion there was enough evidence to convict the parents in court. My opinion is apparently too certain for Rolfe's liking. I don't assess the accuracy of my opinions based on how many other people agree.