he phenomenon of presenting different aspects of self-concept based on the social context (people and situations involved) is called

The phenomenon you are referring to is known as "self-concept variation" or more commonly, the "social self." This concept highlights how individuals may present different aspects of their identity based on the social context they are in, such as the people they are with or the situations they find themselves in.

This reflects the idea that our self-concept is not static; rather, it is dynamic and can change with different social interactions. For instance, a person might behave more formally in a job interview compared to how they would interact with close friends. This adaptability showcases the complexity of how we perceive ourselves and how we want others to perceive us, ultimately influencing our behavior and social interactions.

Theoretical frameworks such as George Herbert Mead's theory of the self and Erving Goffman's dramaturgical theory also provide insights into this phenomenon, suggesting that individuals often engage in a kind of social performance, adjusting their behavior according to audience expectations and social norms.