Ask the person questions you know they will lie about and watch their body language very closely. Compare it with their body language when you know they are telling the truth or relaxed. Then when you see signs of the lying body language in future, probe further and see if you can uncover the lie.

My favourite way of doing this isn't even with deception. I use a bit of PUA-style material as follows:

"Hey, I've known you a while now, I reckon I can guess a few facts about you. Here's what I want you to do. I want you to come up with four facts about yourself, but one of them has to be a LIE. Tell me them in any order and I'll see if I can spot the lie. It will be fun, and you'll learn something about yourself!" etc. etc.

People love this kind of thing (because it's about themselves), and they love thinking that you have special powers or an intimate psychic connection with them. Of course, most people on LW would see it as a challenge to mislead me into choosing the wrong lie, but that's not usually what happens in my experience.

It doesn't matter if you don't spot the lie, because if you're paying attention to their body language throughout the whole conversation, you should pick up plenty of their ticks and be able to associate them with particular emotions. You can invert the idea with anchoring too, if you know what you're doing. If you anchor a particular gesture or touch to when they are open and honest with you then you can use it later when you want them to answer truthfully.

It's never a case of people having a single fixed truth-telling body language and a single fixed lying body language, but that when they're lying they subconsciously change something in how they appear. It's "spot the odd one out" which makes the lie easy to spot.

Then there's stuff like looking into the a top corner when trying to remember something. If you ask someone three difficult memory questions and they look into the top left corner for two of them but then look off to the middle-lower right for the other, you can be pretty confident that the odd one out in this case is because they aren't even bothering to try to remember, but are immediately fabricating their answer.

I'm not sure if that was the kind of response you were after. I'm fairly new to these techniques, but I've already found them remarkably effective for cold reading. It's fun, you feed the person an input (question, statement, whatever), and watch very closely at the body language. Rinse and repeat, getting a better feel for their subconscious responses each time. Then you use these to your/their advantage. Ha!

I model motivations and personality too, but I use the body language tricks to speed it up.

What am I missing about this comment? I think it makes a reasonable point, but it's on -2.

Can someone clarify what the issue is, or whether Mark's trolling and I'm just too stupid to realise?

My post didn't come out quite how I intended. It reads like an angry rhetorical question, when it's supposed to be a sincere request for context. I'm baffled by the depth that people go into probing self-help ideas, talking in abstract vaguenesses of "getting things done" without revealing and explaining the personal goals that the techniques are supposed to help them achieve.

Given your profession and obsessive interest in the field PJ, perhaps you can give some examples of the sorts of objectives people need Akrasia-fighting techniques to accomplish? The examples I gave were humorous and the tone provocative, designed to draw out real goals from real practitioners. It was misjudged and looks like MPF, but that wasn't the intention.

I realise my request for examples of people's goals isn't exactly on-topic, but I find it almost impossible to understand the "tricks" and "secrets" people talk about on this topic when it's so divorced from the context of their specific goals. Let's have some examples to help those like me get what you're talking about. You first.