Henri Tajfel is a social psychologist whose work was considered pioneering throughout the 1970s. Amongst his studies centred around prejudice and intergroup relations Tajfel is also credited with developing social identity theory.
Social Identity theory is an incredibly useful theory when looking at interactions on social media and networking sites. Tajfel’s theories have been widely studied and researched and there will be posts to follow from some of the theorists who build upon Tajfel’s original work.
Here is a link to BBC Radio 4’s recent episode of Mind Changers which looks back on Henri Tajfel’s Minimal Groups experiments, and hears from Tajfels former students, including Michael Billig.