The application of social psychology to the study of politics is at the heart of the discipline called political psychology. Political psychology has been defined as the “application of what is known about human psychology to the study of politics” (Sears, Huddy, and Jervis, 2003, p. 3). Social psychology has been a more influential source of inspiration for the study of politics than any other subfield of psychology. Indeed, insights from social psychology have been of paramount importance in the study of both political elites and mass political behaviour. The many topics that have thus been studied include political socialization, public opinion, voting behaviour, collective political action, ideology, prejudice, political campaigns, presidential performance, policy making, conflict resolution, terrorism, and genocide (see Jost and Sidanius, 2004). Several insights about these topics have been used in attempts to change political attitudes and political behaviour that are considered undesirable, such as racial prejudice, low voter turnout, and political violence.
In this chapter we focus on three topics that have been central to political psychology: political leadership; voting behaviour; and ideology. We discuss how different types of psychological studies have contributed to understanding these crucial aspects of politics. The field of political psychology comprises at least four different types of studies.
First, some psychological studies are not directly about politics but contribute significantly to our understanding of political processes. A well-known example is Milgram's (1974) study on obedience. Asking subjects to deliver high-voltage electric shocks to other people in a learning experiment has little to do with politics per se. But the underlying principles that are uncovered – that most people obey when asked by an authority (in this case, the experimenter) – are crucial to understanding political behaviour, such as the loyalty of civil servants to their political leaders. These insights contribute, for example, to understanding how the tragedy of the Holocaust could have occurred.
The second type of research concerns studies by psychologists who select political topics as object of their research. An example that we discuss below is Ajzen and Fishbein's (1980) work on the theory of reasoned action. When applying their theory, one of the topics they focused on was voting behaviour. Ajzen and Fishbein's aim was not to explain political phenomena as such.