Scientists previously could identify six basic human emotions but the new research could take the number to 21. The basic emotions include happiness, sadness, anger, fear, surprise and disgust. Fifteen additional 'compound emotions' combining different areas of emotions have been identified, reveals a new research.

Identification of these 15 new emotions could prove extremely helpful for assessing the human brain and social communication. It may also help to come up with better ways to treat people with autism and post-traumatic disorder.

Researchers from OSU's College of Engineering used computers to assess and analyze 21 emotions. In the second step, Aleix Martinez and his students traced facial muscles that are used in these emotions like 'happily disgusted' which describes the way you react to a raunchy joke.

The research is considered to be the first step towards learning the way brain decodes and uses facial expressions. Martinez is hoping their research will make doctors procedure a bit easy and they will be able to help patients with some emotional and mental illnesses in a better way.

Martinez said main questions that need to be answered are 'Why does this happen?' and 'how does this happen?' "That will, down the line, allow us to understand which different processes in the brain change when you develop say, depression, which is an anxiety disorder, versus PTSD", affirmed Martinez.

Researchers are now studying 'emotion categories' to know what facial muscle might make to express complex sentiments. To understand cognitive system, it is important the full rainbow of expressions that brain can produce.

As many as 5,000 photographs of 230 college students were assessed. Participants were asked to make facial expressions on the basis of what they felt on different verbal clues.