Happiness is a mental or emotional state of well-being defined by positive or pleasant emotions ranging from contentment to intense joy. Happy mental states may also reflect judgements by a person about their overall well-being. A variety of biological, psychological, economic, religious and philosophical approaches have striven to define happiness and identify its sources. Various research groups, including positive psychology and happiness economics are employing the scientific method to research questions about what "happiness" is, and how it might be attained.