Interest in eudaimonia (e.g., growth, meaning, authenticity, excellence) and its distinction from hedonia (e.g., pleasure, enjoyment, comfort, absence of distress) is growing rapidly, as researchers recognize that both concepts are central to the study of well-being. Yet research on these concepts faces challenges as well: findings based on different operationalizations can be quite discrepant; definitions of eudaimonia and hedonia sometimes fall into different categories of analysis (e.g. when eudaimonia is described as a way of functioning, hedonia as an experience); and the terms eudaimonia and hedonia are sometimes defined vaguely or applied to concepts that may be mere correlates. To aid in addressing these challenges, we propose the following terminology and classification for discussing conceptual and operational definitions: (1) degree of centrality—differentiating concepts that are core (i.e., definitional), close-to-core (i.e., given some attention but not central), and major correlates; (2) category of analysis—identifying which of the following categories a definition represents: (a) orientations (orientations, values, motives, and goals), (b) behaviors (behavioral content, activity characteristics), (c) experiences (subjective experiences, emotions, cognitive appraisals), (d) functioning (indices of positive psychological functioning, mental health, flourishing); and (3) level of measurement—identifying whether a definition is used for trait and/or state comparisons. The work of scholars with a program of research on eudaimonia or the distinction between eudaimonia and hedonia is reviewed and discussed within the framework of the proposed classification; several points of convergence and divergence across definitions are highlighted; and important questions and directions for future research are identified. Copyright Springer Science+Business Media Dordrecht 2014
