This research can be traced back to Charles Darwin's studies of emotion and movement in humans and animals.
[8] In the second method, participants are told to assume a certain body posture and then must complete a survey on their current affective state.
[7] Other methods include using neuroscience techniques, such as fMRI's to determine how posture and emotions expressions can affect brain imaging.
Hands clasped behind the back may also signal closed posture even though the front is exposed because it can give the impression of hiding something or resistance to closer contact.
It was reasoned that slouched posture shuts down people and hampers brain processing not allowing clear thinking.
They concluded that erect posture helps people to perform under varying conditions of stress.
Wilhelm Reich, a student of Freud, first drew attention to the relationship between shallow breathing, blocked traffic, the difficulty in experiencing sexual pleasure, and emotional disorders, especially neuroses.
Certain experiences influence the formation of specific areas of muscle, and thus the body's appearance, structure, and attitude.
[20] Constitutional theories in psychology (e.g., Sheldon, Kretschmer) emphasize the relationship between body structure and temperament.
Scientific research on relationship of body appearance and temperament traits was begun in the early twentieth century by German psychiatrist Ernst Kretschmer.
[21] These researchers distinguished between different constitutional variations or physical nature of one's body, psychotic behavior reactions and temperament.
Moreover, there is data claiming that one maintains their posture worse if they listens to the sentences which describe actions of others.
For example, if your task is to maintain your posture rigorously in a state you do it worse when you listen to sentences like these: "I get up, put on my slippers, go to the bathroom".
[25] Researchers found that relying only on verbal communication to determine the emotions of the client resulted in an accuracy of only 66%.
In similar studies it was noted that the arms and legs were the most important bodily factors in signaling low levels of empathy.