This work concerns cognitive agents, i.e. agents with mental states such as belief, goal, intention, internalized norms, etc. These mental states can be about facts of the world (including laws of action), about their own mental states, or about the mental states of other agents. Cognitive agents are able to reason about all their mental states. In what follows, we first give an overview of our contribution (Chapter 2), and then more details on the three most important parts of this contribution (Chapter 3). The first part concerns individual cognitive agents; the second part concerns social concepts (that is to say the groups of agents seen in a global way); and finally, the third part concerns the modeling of emotions. In the next chapter (Chapter 4) we list the publications that are related to each part of the previous chapter.