The theme of the 2009 Physics Education Research (PER) Conference was Physics Education Research across Paradigms. PER utilizes diverse traditions and frameworks to study learning: cognitive constructs, social and cultural dynamics and neural processes. As a whole PER has not been exclusive in its commitment to a single paradigm or methodology. Four leading researchers who conduct learning research from different perspectives were invited to present their work and interact with the PER community. This was an opportunity for the PER community to examine and discuss the variety of traditions and frameworks relevant to the study of student learning of physics.