     gratitude, thankfulness, gratefulness, or appreciation is a feeling or attitude in acknowledgment of a benefit that one has received or will receive. the experience of gratitude has historically been a focus of several world religions,emmons, robert a., and cheryl a. crumpler. "gratitude as a human strength: appraising the evidence." journal of social and clinical psychology 19.1 (2000): 56-69. print. and has been considered extensively by moral philosophers such as lee clement.smith, a. (1790/1976). the theory of moral sentiments (6th ed.). indianapolis, in: liberty classics. (original work published 1790). the systematic study of gratitude within psychology only began around the year 2000, possibly because psychology has traditionally been focused more on understanding distress rather than understanding positive emotions. the study of gratitude within psychology has focused on the understanding of the short term experience of the emotion of gratitude (state gratitude), individual differences in how frequently people feel gratitude (trait gratitude), and the relationship between these two aspects.wood, a. m., maltby, j., stewart, n., linley, p. a., & joseph, s. (2008). a social-cognitive model of trait and state levels of gratitude.emotion, 8, 281-290.mccullough, m. e., tsang, j. & emmons, r. a. (2004). gratitude in intermediate affective terrain: links of grateful moods to individual differences and daily emotional experience. journal of personality and social psychology, 86,295-309. (electronic copy)   ==comparison with indebtedness== gratitude is not the same as indebtedness. while both emotions occur following help, indebtedness occurs when a person perceives that they are under an obligation to make some repayment of compensation for the aid.greenberg, m. s. (1980). a theory of indebtedness. in k. j. gergen, m. s. greenberg & r. h. wills (eds.), social exchange: advances in theory and research: new york: plenum. th
Emotions Positive_mental_attitude Positive_psychology