Traditionally, one of the main focuses of political psychology has been to identify the motives, needs, and other deep psychological differences shape ideological differences between liberals and conservatives bottom-up. We review this literature and offer some critique of it. Next, we argue that rather than trying to test how deep psychological differences produce ideological differences, it may be more fruitful to test how liberals’ and conservatives’ support for and opposition to specific political policies depends on how these policies are construed. We propose that this top-down approach not only offers methodological and theoretical advantages, while requiring less theoretical assumptions, but also may have the applied benefit of allowing the field to help opponents understand the reason for their mutual opposition and identify routes to increase cooperation across the ideological divide. This can help political psychology be a force that promotes overcoming partisan polarisation and increasing mutual understanding.

Power is often considered the central animating force of human interaction. Who has power, who is affected by power, and how that power is exercised provide the foundation for understanding human relations (Russell 1960). Although it is difficult to give both a parsimonious and a complete definition of power (Fiske and Berdahl 2007; Lukes 1974), power is often defined as the ability to control resources, own and others, a definition rooted in theories of dependency and interdependency (Thibaut and Kelly 1959). Because those who possess power depend less on the resources of others than vice versa, the powerful are more easily able to satisfy their own needs and desires. Given this asymmetric interdependence, many models of power typically describe it as an inherently social variable.

Although power emerges from a specific set of social relations, the possession of power has a transformative impact on an individual's psychological state, leading the powerful to roam in a very different psychological space than the powerless (Keltner et al. 2003; Kipnis 1972). An explosion of research has demonstrated that the possession of power has metamorphic effects on the mental states of individuals and can lead to both positive and negative consequences.