Micro-expressions refer to the way our facial muscles and body movements reflect the thoughts that are going through our brain.
Body language is something that can be manipulated to hide our true emotions and which differs for people of different cultures. Micro expressions on the other hand have been found to be universal. People display the same kinds of expressions, irrespective of their cultural background. These are also almost impossible to manipulate.
It takes a lot of research and work in this area to be able to truly understand what is actually going through a person’s head from his body movements. Some people are able to read micro-expressions instinctively and it is usually attributed to a gut feeling rather than the study of the other person’s facial and body movements.