The term happiness is used in the context of mental or emotional states, including positive or pleasant emotions ranging from contentment to intense joy. It is also used in the context of life satisfaction, subjective well-being, eudaimonia, flourishing and well-being. Since the 1960s, happiness research has been conducted in a wide variety of scientific disciplines, including gerontology, social psychology and positive psychology, clinical and medical research and happiness economics. Definitions 'Happiness' is the subject of debate on usage and meaning, and on possible differences in understanding by culture. The word is mostly used in relation to two factors:the current experience of the feeling of an emotion (affect) such as pleasure or joy, or of a more general sense of 'emotional condition as a whole'. For instance Daniel Kahneman has defined happiness as 'what I experience here and now'. This usage is prevalent in dictionary definitions of happiness. appraisal of life satisfaction, such as of quality of life. For instance Ruut Veenhoven has defined happiness as 'overall appreciation of one's life as-a-whole. ' Kahneman has said that this is more important to people than current experience. Some usages can include both of these factors. Subjective well-being (swb) includes measures of current experience (emotions, moods, and feelings) and of life satisfaction. For instance Sonja Lyubomirsky has described happiness as 'the experience of joy, contentment, or positive well-being, combined with a sense that one's life is good, meaningful, and worthwhile. ' Eudaimonia, is a Greek term variously translated as happiness, welfare, flourishing, and blessedness. Xavier Landes has proposed that happiness include measures of subjective wellbeing, mood and eudaimonia. These differing uses can give different results.