The “Effort Elephant” in the Room: What Is Effort, Anyway?

Despite decades of research in the fields of judgment and decision-making, social psychology, cognitive psychology, human-machine interaction, behavioral economics, and neuroscience, we still do not know what "cognitive effort" is. The definitions in use are often imprecise and sometimes diametrically opposed. Researchers with different assumptions talk past each other, and many aspects of effort conservation remain untested and difficult to measure. In this article, we explain why effort is so difficult to pin down and why it is important that researchers develop consensus on precise definitions. Next, we describe major "hidden" sources of miscommunication: areas in which researchers disagree in their underlying assumptions about the nature of effort without realizing it. We briefly review a number of methods used to both measure and manipulate the effortfulness of thinking and highlight why they often produce contradictory findings. We conclude by reviewing existing perspectives on cognitive effort and integrating them to suggest a common framework for communicating about effort as a limited cognitive resource.