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, and has been considered extensively by moral philosophers such as Lee Clement. 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.
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|Look up gratitude in Wiktionary, the free dictionary.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. The emotions lead to different actions; indebtedness can motivate the recipient of the aid to avoid the person who has helped them, whereas gratitude can motivate the recipient to seek out their benefactor and to improve their relationship with them.
As a motivator of behavior
Gratitude may also serve to reinforce future prosocial behavior in benefactors. For example, one experiment found that customers of a jewelry store who were called and thanked showed a subsequent 70% increase in purchases. In comparison, customers who were called and told about a sale showed only a 30% increase in purchases, and customers who were not called at all did not show an increase. In another study, regular patrons of a restaurant gave bigger tips when servers wrote "Thank you" on their checks.
The link between spirituality and gratitude has recently become a popular subject of study. While these two characteristics are certainly not dependent on each other, studies have found that spirituality is capable of enhancing a person’s ability to be grateful and therefore, those who regularly attend religious services or engage in religious activities are more likely to have a greater sense of gratitude in all areas of life. Gratitude is viewed as a prized human propensity in the Christian, Buddhist, Muslim, Jewish, Baha'i, and Hindu traditions. Worship with gratitude to God is a common theme in such religions and therefore, the concept of gratitude permeates religious texts, teachings, and traditions. For this reason, it is one of the most common emotions that religions aim to provoke and maintain in followers and is regarded as a universal religious sentiment. 
In Judaism, gratitude is an essential part of the act of worship and a part of every aspect of a worshiper’s life. According to the Hebrew worldview, all things come from God and because of this, gratitude is extremely important to the followers of Judaism. The Hebrew Scriptures are filled with the idea of gratitude. Two examples included in the psalms are "O Lord my God, I will give thanks to you forever," and "I will give thanks to the Lord with my whole heart" (Ps. 30:12; Ps. 9:1). The Jewish prayers also often incorporate gratitude beginning with the Shema, where the worshiper states that out of gratitude, "You shall love the Eternal, your God, with all your heart, with all your soul, and with all your might" (Deut. 6:5). One of the crucial blessings in the central thrice-daily prayer, the "Amidah", is called "Modim" - "We give thanks to You"; this is also the only blessing which is recited by the congregation together with the leader during their repetition of the Amidah. The concluding prayer, the Alenu, also speaks of gratitude by thanking God for the particular destiny of the Jewish people. Along with these prayers, faithful worshipers recite more than one hundred blessings called berachot throughout the day. In Judaism there is also a major emphasis on gratitude for acts of human kindness and goodness.
Gratitude has been said to mold and shape the entire Christian life. Martin Luther referred to gratitude as "The basic Christian attitude" and today it is still referred to as "the heart of the gospel." As each Christian believes they were created by a personal God, Christians are strongly encouraged to praise and give gratitude to their creator. In Christian gratitude, God is seen as the selfless giver of all good things and because of this, there is a deep sense of gratefulness which enables Christians to share a common bond, shaping all aspects of a follower’s life. Gratitude in Christianity is an acknowledgment of God’s generosity that inspires Christians to shape their own thoughts and actions around such ideals. Instead of simply a sentimental feeling, Christian gratitude is regarded as a virtue that shapes not only emotions and thoughts but also actions and deeds. Jonathan Edwards writes in his A Treatise Concerning Religious Affections that gratitude and thankfulness toward God are among the signs of true religion. Because of this interpretation, modern measures of religious spirituality include assessments of thankfulness and gratitude towards God. Allport (1950) suggested that mature religious intentions come from feelings of profound gratitude and Edwards (1746/1959) claimed that the "affection" of gratitude is one of the most accurate ways of finding the presence of God in a person’s life. In a study done by Samuels and Lester (1985) it was contended that in a small sample of Catholic nuns and priests, out of 50 emotions, love and gratitude were the most experienced emotion towards God.
In the Orthodox, Catholic and Anglican Churches, the most important rite is called the Eucharist; the name derives from the Greek word eucharistia for thanksgiving.
The Islamic sacred text, The Quran, is filled with the idea of gratitude. Islam encourages its followers to be grateful and express thanks to God in all circumstances. Islamic teaching emphasizes the idea that those who are grateful will be rewarded with more. A traditional Islamic saying states that, "The first who will be summoned to paradise are those who have praised God in every circumstance" In the Quran it is also stated in Sura 14 that those who are grateful will be given more by God. The prophet Muhammad also said, "Gratitude for the abundance you have received is the best insurance that the abundance will continue." Many practices of the Islamic faith also encourage gratitude. The Pillar of Islam calling for daily prayer encourages believers to pray to God five times a day in order to thank him for his goodness. The pillar of fasting during the month of Ramadan is for the purpose of putting the believer in a state of gratitude.
Much of the recent work psychological research into gratitude has focused on the nature of individual difference in gratitude, and the consequences of being a more or less grateful person. Three scales have been developed to measure individual differences in gratitude, each of which assesses somewhat different conceptions. The GQ6measures individual differences in how frequently and intensely people feel gratitude. The Appreciation Scale measures 8 different aspects of gratitude: appreciation of people, possessions, the present moment, rituals, feeling of awe, social comparisons, existential concerns, and behaviour which expresses gratitude. The GRAT assesses gratitude towards other people, gratitude towards the world in general, and a lack of resentment for what you do not have. A recent study showed that each of these scales are actually all measuring the same way of approaching life; this suggests that individual differences in gratitude include all of these components.
Association with well-being
A large body of recent work has suggested that people who are more grateful have higher levels of subjective well-being. Grateful people are happier, less depressed, less stressed, and more satisfied with their lives and social relationships Specifically, in terms of depression, gratitude may serve as a buffer by enhancing the coding and retrievability of positive experiences.  Grateful people also have higher levels of control of their environments, personal growth, purpose in life, and self acceptance. Grateful people have more positive ways of coping with the difficulties they experience in life, being more likely to seek support from other people, reinterpret and grow from the experience, and spend more time planning how to deal with the problem. Grateful people also have less negative coping strategies, being less likely to try to avoid the problem, deny there is a problem, blame themselves, or cope through substance use. Grateful people sleep better, and this seems to be because they think less negative and more positive thoughts just before going to sleep.
Gratitude has been said[by whom?] to have one of the strongest links with mental health of any character trait. Numerous studies suggest that grateful people are more likely to have higher levels of happiness and lower levels of stress and depression.
While many emotions and personality traits are important to well-being, there is evidence that gratitude may be uniquely important. First, a longitudinal study showed that people who were more grateful coped better with a life transition. Specifically, people who were more grateful before the transition were less stressed, less depressed, and more satisfied with their relationships three months later. Second, two recent studies have suggested that gratitude may have a unique relationship with well-being, and can explain aspects of well-being that other personality traits cannot. Both studies showed that gratitude was able to explain more well-being than the Big Five and 30 of the most commonly studied personality traits.
Relationship to altruism
Gratitude has also been shown to improve a person’s altruistic tendencies. One study conducted by David DeSteno and Monica Bartlett (2010) found that gratitude is correlated with economic generosity. In this study, using an economic game, increased gratitude was shown to directly mediate increased monetary giving. From these results, this study shows that grateful people are more likely to sacrifice individual gains for communal profit (DeSteno & Bartlett, 2010). A Study conducted by McCullough, Emmons, & Tsang, (2002) found similar correlations between gratitude and empathy, generosity, and helpfulness.
Given that gratitude appears to be a strong determinant of people's well-being, several psychological interventions have been developed to increase gratitude. For example, Watkins and colleagues had participants test a number of different gratitude exercises, such as thinking about a living person for whom they are grateful, writing about someone for whom they are grateful, and writing a letter to deliver to someone for whom they are grateful. Participants in the control condition were asked to describe their living room. Participants who engaged in a gratitude exercise showed increases in their experiences of positive emotion immediately after the exercise, and this effect was strongest for participants who were asked to think about a person for whom they are grateful. Participants who had grateful personalities to begin with showed the greatest benefit from these gratitude exercises. In another study concerning gratitude, participants were randomly assigned to one of six therapeutic intervention conditions designed to improve the participants' overall quality of life (Seligman et. all., 2005). Out of these conditions, it was found that the biggest short-term effects came from a "gratitude visit" where participants wrote and delivered a letter of gratitude to someone in their life. This condition showed a rise in happiness scores by 10 percent and a significant fall in depression scores, results which lasted up to one month after the visit. Out of the six conditions, the longest lasting effects were associated with the act of writing "gratitude journals" where participants were asked to write down three things they were grateful for every day. These participants’ happiness scores also increased and continued to increase each time they were tested periodically after the experiment. In fact, the greatest benefits were usually found to occur around six months after treatment began. This exercise was so successful that although participants were only asked to continue the journal for a week, many participants continued to keep the journal long after the study was over. Similar results have been found from studies conducted by Emmons and McCullough (2003) and Lyubomirsky et. all. (2005).See also gratitude journal.
Recently (2013), the Greater Good Science Center at the University of California, Berkeley, has been offering awards for dissertation-level research projects with the greatest potential to advance the science and practice of gratitude.
According to Cicero, "Gratitude is not only the greatest of the virtues but the parent of all others." Multiple studies have shown the correlation between gratitude and increased wellbeing not only for the individual but for all people involved. The positive psychology movement has embraced these studies and in an effort to increase overall wellbeing, has begun to make an effort to incorporate exercises to increase gratitude into the movement. Although in the past gratitude has been neglected by psychology, in recent years much progress has been made in studying gratitude and its positive effects.