How we change what others think, feel, believe and do
There are about 640 skeletal movement muscles in the human body, as well as 200 or so other internal muscles for movement within organs. There are around 50 muscles in the face, many of which have a particular role in expressing emotion (for example it takes over 20 muscles just to smile).
The complex job of managing and coordinating all the muscles is done by the unconscious mind, directed either through the intent of the conscious mind (such as for walking or talking) or from other unconscious motivations, such as the expression of emotion or tics.
Importantly, we use muscles to communicate. Animals, who do have language, do this, such as when a dog wags its tail or rolls over to show that it is not a threat. In the 95% common mammal genes, we have inherited this physical form of communication, particularly of emotions.
In common with many animals, we watch others to read their body signals and understand what this tell us of how they are feeling and thinking. Given our animal past, this may be done at a subconscious, non-language level, for example where just looking at a person makes us feel relaxed or fearful without us knowing why.
Charles Darwin noted the importance of muscles in emotion:
When movements, associated through habit with certain states
of the mind, are partially repressed by the will, the strictly involuntary
muscles, as well as those which are least under the separate control of the
will, are liable still to act; and their action is often highly expressive.
In other words, you cannot help but show what you feel through your body shape and movement.
We are sometimes known as the mendacious ape as evolution has taught us that deception can be very useful, at least for short-term gains. We hence seek to use deceptive body language to express emotions that we want others to perceive. We smile to make them think we are friendly. We frown or stare at them to indicate displeasure.
When we speak deceptively, we try hard to show we are not lying, for example by holding our bodies still to suppress the signals of guilt or fear of discovery.
Darwin noted of expressive movements:
They reveal the thoughts and intentions of others more truly than do words, which may be falsified.
A problem with this is that it is difficult to consciously control 650 muscles and so we may 'leak' emotions, such as crossing our legs when we are carefully holding our hands at our sides. Facial muscles are particularly difficult to control and are highly visible. Tension in vocal muscles is also out of conscious control.
Darwin also noted in his Inhibition Hypothesis that if you cannot voluntarily activate a muscle, then you will not be able to voluntarily inhibit its involuntary activation in a spontaneous emotional expression.
Where we do not or cannot pay attention, then our true feelings may be exposed. A common example is the lower body. People trying to control their body language commonly hold their arms and head carefully but often forget what their legs and feet are doing.
When different muscle groups display different emotions, we send mixed messages that lead either to confusion or, more likely, suspicion. When I see you smiling but also fidgeting, I wonder if there is something else on your mind.
The best way to change body language is not to hang onto every muscle, trying to be a puppeteer of your own body. As described above, this is virtually impossible to do and makes you look deceptive.
The best approach is to notice your own body language and change your body by changing what and how you are thinking. If you can really believe what you are saying, then your body will naturally align with your speech. If you like the other person, then your body will automatically assume a friendly stance.
This is easier said than done, and some people are better at it than others. In effect, they hypnotize themselves, changing what they feel at will.
Two professions in particular attract those who have natural ability in this area. Actors are trained to 'get into character', thinking and feeling as the person they are portraying. The consummate actor is a blank canvas onto which requisite personalities may be projected.
The other group which tends to be good at this form of self-hypnosis is sales people, who believe their products are clearly superior and for which they develop a deep passion. When we buy, we often buy the sales person as much as the product, so good sales people really do like other people and comfortably engage in subtly persuasive conversation.
Actors and sales people practice a lot. You can do this too. If you have a presentation to do, then do it physically. Set up a video camera and play it back, watching your body language. Then change how you think and keep repeating until you both sound and look great.
To improve your own ability to express emotions well, attention to Emotional Intelligence can help. This includes being able to read and manage your own emotions. If you can do this well, you can then 'infect' others to change what they feel too.
Extreme emotions are highly visible and send strong signals that you may later regret. At the very least, if you can curb the depth of feeling in strong emotion then you will have a better chance at least of not putting off other people.