It is a rule written by government that robots can kill others to save their kinds. So, a robot should know how to decide who is its enemy and who is its friend. It should feel the emotion of love or hate. We can use search technique to find an answer to this but it will result in nothing and will not give emotions. Another way can be the use of knowledge base which will give us as well as robots a brief knowledge to love or hate someone. We can put some pre memories and store them in the robots. These memories consist of different tasks and whether the task is good one or the bad one. If a human helps them then it is a positive task and if human’s act is bad then it’s a negative task. Words software should also be used to check whether words are positive or negative. There are various techniques for emotion recognition which we will discuss in this paper. General Terms Emotion Recognition Techniques, Artificial Intelligence