Alright. Let’s see if I can make this coherent.
To simplify matters, I’m going to break this down into separate parts of the body. Also, no one should take anything I say here as fact, take it as a suggestion and test it yourself.
These windows to our souls aren’t all they’re cracked up to be. Although it is possible to notice things like avoidance behaviour in someone looking away, it is also very easy to fake.
There’s also a well known and sparsely practiced theory on the direction people look to access various parts of their brains, the problem with this is that it’s not consistent from person to person. That added to the fact that tells invariably come down to interpretation and it’s difficult to put to much use.
You will notice however that starring down opponents will force a response. Some will respond with a wise crack, some will avoid eye contact, and rarely someone will just stare you down, essentially what you’re looking for is either a behaviour that is either consistent or not with their character (if they’ve walked over to the table, sat down and played half a hand, you should have a fair estimate of their character without much effort).
Random edit without paying attention to context: Eyes are awesome for getting a read on someone but it's usually more to do with assessing their character and confidence. They can also go a long way in determining if something is honest or not but it usually takes some background information on your opponent for this to work.
Possibly the best indicator of moods. A LOT of normal things go in and out of mouths, air, speech, food, water, fingers, fingernails/pencils/pens, etc. People get careless and express things more willingly and honestly with their mouth than most things.
People putting things into their mouth tends to be a good indicator, you know how when you were a little kid and always chewed on the end of your pen and then stopped abruptly when someone told you that people do use it to reinact being a baby and feeding from their mother? When someone sticks something in their mouth in the same manner, consider it the same as them curling into the fetal position.
Tone of voice tends to be reasonably reliable, just watch out for loud/strong speech which is easy to fake under most circumstances. A nervous and shaky voice on the other hand isn’t something people consciously use very often and as such, can be difficult to fake.
Also note that people salivate when they’re either about to eat. They do the same when they’re expecting to rake in a pot. When someone licks their lips, be prepared to fold.
Of primary interest is swallowing. It’s difficult to swallow naturally when you’re worried about making sudden movements and particularly in high pressure, someone swallowing noticeably can be a big sign of weakness. It is however easy to fake.
Hands lie. Basically everything you do with your hands is conscious. I should know but I’m not sure, I think well rehearsed stuff is technically unconscious, doesn’t matter though because we still have to concentrate so frequently on hand movements. People are aware of their hands.
The tells related to them that I like are when someone covers a vulnerable body part, genitals in particular but not overly useful at the poker table, heart and neck are good too though. Obviously this indicates weakness. People don’t tend to think about what they’re instinctively covering.
Hands doing complex tasks like chip tricks tend to break down in high stress, be aware of when they stop halfway through a trick or just freeze up. High stress doesn’t necessarily mean one thing or the other, but in the moment knowing that your opponent is in high stress can be useful.
Note that there’s some stuff about how far out people place chips when betting. Close means they still think it’s theirs and far out is supposed to be over emphasising their strength. Meh, this is rubbish. A lot of people will be too afraid to extend themselves far even when bluffing
, others will at least sometimes be trying to place chips in the same spot.
Just a quick mention, the frontalis muscle (forehead) contracts in many different circumstances, wrinkled foreheads are great billboards of unintentional misinformation.
Another random edit: Just because it's worth mentioning, when people speak and shake their head "no" at the same time, which happens really often, means what they said was dishonest. It can be faked but it basically never is.
Eh.... 677 words. This isn’t supposed to be a book so I’ll end it here.
Let me know what you do/don’t agree with.