Body Language
Margaret Meade believed body language or “macro body language”, was culturally based. Paul Ekman showed us that facial expression, including micro-expressions, are universal and we, as homo sapiens are hard wired to tell what we are thinking through our faces. Yet some “macro body language” has universal application.
Research in the early 21st century tells us that we will disregard a happy face, when paired with an aggressive stance, or dilute a smile when seen with a pre-attack tell (flaring nostrils to get more oxygen to skeletal system in preparation for a fight, for example). So much of our perception was forged on the anvil of evolution.
Meade was one of the first to study various cultures on the tells and how they carrier themselves and their children. Contemporary research has taken the study farther and experienced body language professionals, such as those in the clandestine services, have come up with the “cluster” Theory. No one body language tell is indicative of mental state. Crossed arms can mean guarded position, or the room is cold. So we look for more data points, or clusters, of tell to peek into the window of the negotiator’s mind.
A very small percentage of people, in the single digits, can read body language and consistently accurately predict deceptions, but observations and very strong indicators, such as prior dealings, can make us highly confident what is likely to be going on. If we see clusters of behavioral patterns it may give us insights how they react in a negotiation prompt, and when added with other indicators, you can predict how far they are willing to go based on prompt, and observation.
To use this knowledge base, look at the prompts and ensure you know the disaggregated tells. Only then can you recognize clusters. Clusters can tell you if consistent issues are happening with the participants and can give you insights into what is possible

Neutral Framing
The body posture here seems neutral but look closely. The hands framing the pelvis area is asserting confidence.

Hiding - Standing
The body is “small” shoulders slumped, hands crossed below the waste. This tells of discomfort and wanting to not be noticed, for whatever reason.

Hiding and Done
The body is “small” shoulders slumped, hands crossed below the waste. This tells of discomfort and wanting to not be noticed, for whatever reason. But this takes it one step further with the feet, toes pointing to the exit.
This person is done, wants to be small and run away. Extreme discomfort.

Repulsion
Any fade away, exaggerated here but it may be very slight. This is the repulsion tell, the person wants to get away from the triggering impulse.

Confidence "Happy Feet"
Arms behind the body tells of confidence and foot upturned is happiness or joy.

Stress and Anxiety
Various forms of self-soothing. Thigh touch, face, hair touching, neck and chest, are all forms of soothing or protective tells. The “covering” hands indicate slightly more stress generally.
More Stress Tells

Dominance
Arms behind the head, taking up “real estate” indicate a powerful relaxed position. Contrast with “Hiding” posture, instead of getting small, the dominant get big.

Dominance and Confidence
Arms behind the body tells of confidence and a certain higher status.

Guarded Right +
Sitting guard must be deconstructed. Generally, any physical blockage, like a crossed leg with the thigh between the person you are sitting near or speaking to (here a person is to the right of the model), is a guarded posture. If forms a block. But an upward pointed knee can indicate high spirits and happiness. The blocking thigh and a level or downward pointed knee is a negative sign generally. To get person to “open up” you want your open thigh to face them.

Repulsion - Sitting
This is a sign of disapproval; the model wants to get as far away from the speaker. She does not like what she is hearing and will be unlikely to agree.

Engagement and Focus
Leaning in show engagement, the folded hands are used sometimes to arrest nervous habits. For example, if you catch yourself giving a nervous tell, fold your hands to arrest the nervous behavior, lean in the speaker to show engagement. This looks like a “job interview” posture.

Hiding - Sitting
Notice the legs close together, hands on the knees, this is a small, not wanting to get noticed, an anxiety tell. Prompted by something that may offend or cause someone to withdraw or not want to get noticed.

Confident - Sitting
This is a confident and relaxed sign. Look for changes, if thigh rubbing starts, this indicates self-soothing behavior and stress. If ankles cross, guard is up.

Guarded, Confident - Standing
This shows a dominant posture (arms behind the back) but crossed ankles which is a guarded pose. This mixed signal may change based on inputs.

Leaving Standing
Body asymmetry can tell you the mental state, and it happens with the legs and feet. Look to the feet, the person may be talking, but the toes are pointing elsewhere. This person has left the conversation.