What is bullying? A theoretical redefinition

•Recent empirical data and theory suggest the need for a new bullying definition.•We propose a theoretically-driven definition of bullying based on three elements.•Goal-directedness, power imbalance, and harm are the three key elements.•We discuss empirical and theoretical evidence for each of these elements.•We also discuss implications of and challenges to the new definition.

Bullying is a complex and heterogeneous phenomenon that directly affects hundreds of millions of people each year. The importance of bullying has led to research in the last two decades that has produced hundreds, if not thousands, of papers on the topic. In large part this research was stimulated by a definition provided by Olweus in 1993. That definition has proven to be tremendously useful as a starting point for research, but it was created in the absence of recent empirical and theoretical evidence. We propose an updated definition that is explicitly grounded in a unifying theory that encompasses ecological and evolutionary contexts: “bullying is aggressive goal-directed behavior that harms another individual within the context of a power imbalance”. We follow this definition with an examination of the theoretical and empirical support for each of its three elements (goal-directedness, power imbalance, and harm). We suggest that bullying measures should be based on assessments of these three elements of bullying. Our redefinition also emphasizes the importance of considering and altering the cost–benefit analysis of bullying as a cornerstone for successful interventions. Finally we address several specific potential challenges to the definition.