This is an interesting question. I think what you are getting at is what people call body language. It is also sometimes called kinesics. You can examine body language in many different areas of life. You can look for this in your interactions with people and even study this in literature. The study of spaces in literature is an interesting topic.
The basic idea is that communication is both verbal and non-verbal. Moreover, sometimes non-verbal communication is more honest in the sense that it is unconscious.
In connection to emotions, the study of body language states that the way people use their bodies in interacting with others and how others use their bodies with respect to you communicates what people are feeling unconsciously. This information is very important in reading people. A person who is good at reading these signs has a great advantage.