ABSTRACT
A policy intervention might produce discordant effects on different behaviors, with both positive and negative spillover being triggered. Many theories and theoretical frameworks have been proposed to suggest the existence either of positive or negative spillover effects. Focusing on arguments supporting positive spillover first, the main contributions can be ascribed to the concepts of identity, consistency and awareness. The search for consistency and the natural tendency of an individual to be consistent represents a possible explanation for positive spillover on its own, and different consistency theories have been proposed as sound frameworks to explain the phenomenon. Different theories have been proposed to explain negative spillover. Rebound effects are closely linked to negative spillover, but entail a different perspective of analysis. More sophisticated techniques are hence needed to investigate in detail the spillover phenomenon, so as to grasp the underpinning mechanisms explaining the relationships between behaviors.
