An Examination of The Science of Gratitude and Its Role in Human Happiness

Happiness is a chief human concern because it provides purpose and meaning to our actions. A chief concern of a sub-discipline within psychology resolves around the conditions and prerequisites for human happiness in general. Similar to the philosopher Aristotle’s notion of virtue as a habit, happiness research attempts to find the strong linkages between personal practices and well-being. A “strong linkage” between a practice and its emotional correlate involves some degree of empirical or statistical connection—not just an armchair theory of happiness. Finding personal practices that promote happiness important to empirical researchers, but it is also to society as a whole. When individual members of a society are happy, the aggregate of happiness will rise. Societal happiness does not rise when a new definition of happiness is derived or a new theory is developed; rather, it rises in response to practices that promote positive affect, some of which exist only at the individual level. The focus of this paper is an individual-level practice aimed at promoting positive emotions based on the concept of gratitude.

The word ‘gratitude’ has its origins in the Latin gratus, meaning “thankful” or “pleasing.” Not surprisingly, the history of the term is connected to spirituality as a form of humility, which is a virtue in monotheistic traditions. To the extent that one is grateful to God, who imparts his divine gifts upon humanity, one is correctly acknowledging the role of God in one’s life. In fact, ancient sources have commented that gratitude is a “parent” virtue (Wood, Joseph, & Linley, 2007). The Scottish moral philosopher Adam Smith likewise considered gratitude in the context of a moral study in his Theory of Moral Sentiments, in which he concludes gratitude is necessary for the proper functioning of society (Smith, 1759). Secular concepts of gratitude extend beyond being grateful to God to being grateful to one’s neighbors, family, and friends. Modern notions of gratitude tend to treat the term more so as an attitude or experience, rather than a trait or virtue as described by moral philosophers. For instance, modern English speakers tend not to describe someone as “a grateful person,” but rather about being grateful as a temporary affective state.

In line with the idea that gratitude is an attitude or cognitive state, happiness research in modern psychology tends to focus on the concept’s relationship to subjective well-being, or happiness. In fact, Wood, Joseph and Linley (2007) claim that gratitude has taken a position of mainstream concern in psychological research concerning the happiness question. Scholars such as University of California, Davis Professor Robert Emmons have studied gratitude’s relationship to happiness. Emmons and McCullough (2003) discovered a robust positive effect of gratitude-outlook on subjective well-being in a controlled experiment, providing strong evidence of a link. In addition, Emmons and Crumpler (2000) conclude that gratitude as a pleasant emotional state fosters more positive moods, and expressions of gratitude help people feel happier than they otherwise would be. Knowing that there is an apparent connection between these two constructs in psychology literature, there is a potential for making the general claim that gratitude is a beneficial personal practice.

However, one might ask how we define gratitude so that scientists can evaluate a possible strong linkage to happiness. Watkins, Woodward, Stone and Kolts (2003) set out to derive a measurable account of gratitude, implying a solid definition of the concept. Once again, the issue of whether gratitude is tied to characteristics of individuals or to individual emotional states is a relevant issue. Watkins et al. (2003) provide definitions for both a feeling (“trait affect” as “a feeling of thankful appreciation for favors received”) and as a characteristic (“trait gratitude” as “the predisposition to experience this state”) (p. 432). Evidently, the definition is parsimonious but also adequately explanatory.

The notion of gratitude as a trait also implies some connection to evolutionary theory, and an explanation of this relationship would paint a more complete picture of gratitude within a population. Nowak and Roch (2007) survey the conceptual difference between gratitude and another concept called “upstream reciprocity,” which is the increased likelihood that a recipient of kindness will help another in turn. Similar to Watkins et al. (2003)’s idea of gratitude as an affective thankful appreciation, Nowak and Roch (2007) place gratitude in the context of the evolution of cooperation and find that positive emotions that enhance helping behavior can actually evolve by natural selection. The predisposition to feel thankful appreciation is more likely to produce happier mood states (Emmons & Crumpler, 2000), thus perhaps improving self-confidence and therefore chances for mating behavior. The framework provided by Watkins et al. (2003) is useful here to the extent that it explains the evolutionary pressures acting upon trait gratitude through its close connection to the trait affect that individuals actually experience after receiving favors from another.

Another advantage of Watkins et al. (2003)’s approach to gratitude is the explicit attempt at a measurable, quantifiable operating definition for the concept. Using their Gratitude, Resentment, and Appreciation Test (GRAT), the authors found a reliable and valid measure of dispositional (or “trait”) gratitude. In addition, the test contains a fair amount of construct validity in its ability to predict grateful feelings at some point in the future. Returning to the notion of “strong linkage” in empirical studies of happiness, it is important to have reliable and valid measures of gratitude in order to determine robust correlative relationships and to demonstrate a working personal practice for enhancing subjective well-being. Built upon a strong scientific foundation, a convincing case in favor of gratitude’s role in well-being can be made on a personal level.

The purpose of this paper is to build that case through a treatment of the science of gratitude as it relates to happiness in positive psychology. Focusing upon the individual and what one person does to enhance his or her subjective well-being as a habit, this paper will involve generalizations to anyone capable of thankful or appreciative affect. With generalizations, it is important to note the connection between successful personal practices and a social level of effect; in other words, gratitude as a personal practice may produce a desirable net effect for groups or populations. In addition to surveying what makes for a successful personal practice for enhancing life-long happiness (in the eudemonistic sense of that word), this review will also incorporate information about what empirically works and what does not. A project of that magnitude will proceed from higher levels of organization (social bonds and friendships) to individual behavior (depression and mental illness) to inside the brain in the neuroscience of gratitude. By addressing subjective well-being at each of these levels in the organizational hierarchy, the personal practice emerges as a common theme. Thus, the challenge is to take that scientific evidence and to translate it into a practical, everyday phenomenon for most people, which is a challenge we take up later in this paper.

Gratitude in Social Relationships

Gratitude, by its very nature, is a social emotion, and much of the previous research into its social effects has focused on the repayment of favors (Algoe, Haidt & Gable, 2008). Recently, however, psychologists have begun to focus their research on the potential effects the feeling of gratitude can have on the formation and maintenance of healthy relationships (relationships in which the members indicate strong positive feelings toward one another). In 2008, Algoe, Haidt, and Gable provided the first empirical evidence linking gratitude as an affective state with the promotion of positive relationships. Critically, their investigation was high in mundane realism – they studied real relationships being formed between new inductees into a number of sororities at University of Virginia and their ‘Big Sisters’ – girls who had already been members of the sorority for one year. This mundane realism is essential if the results of their research are to be applied to personal practices that occur in real life, not in the artificially created laboratory settings typical of gratitude research (Algoe, Haidt & Gable, 2008).

To study the formation of relationships between new and existing sorority members, the researchers took advantage of a previously existing initiative at the University of Virginia known as “Big Sister Week.” During this four-day period, each new inductee (“Little Sister”) is randomly assigned to a Big Sister, whose identity is not revealed until the end of the week. The Big Sisters plan events for their Little Sister throughout the week, as well as buying or making them gifts, in an attempt to make them feel welcome as part of their sorority. Algoe et al. (2008) studied how the gratitude (for the gifts that were given) felt by the Little Sister for their specific Big Sister affected both the Little and Big Sisters’ ratings of their relationship, both immediately following Big Sister Week (when the identity of their Big Sister was revealed to each Little Sister) and one month later.

Over the course of Big Sister Week, each Little Sister was asked to complete a questionnaire each time she received a gift from her Big Sister. The questionnaire was aimed at measuring how much the Little Sister “felt grateful” for the gift, how much she liked the gift, how much she felt the gift had come as a surprise, how thoughtful she thought her Big Sister had been in choosing the specific gift, how much she thought the gift had cost her Big Sister, and how much effort she believed her Big Sister had put into providing her with the gift. These questions were asked in order to determine the potential moderating or mediating effects of other social variables indicated by previous research, such as feelings of indebtedness and the unexpectedness of a reward. This was used to distinguish the feeling of gratitude from potentially confounding social factors.

In addition to the questionnaire about how grateful they were for the gift, each Little Sister was required to answer a second questionnaire following the receipt of each gift. This questionnaire was designed to assess the perceived quality of the relationship each Little Sister felt with her Big Sister, and asked how much she believed her Big Sister “understood” her, as well as how much she liked and felt close to her Big Sister. Relationship quality was measured as the average of the responses to all three questions. The researchers found that feelings of gratitude by the Little Sister were predictive of a positive relationship with her Big Sister (p = 0.000). This first part of the study provides evidence that feeling gratitude can indeed be influential in forming positive new relationships with strangers.

At the end of Big Sister Week, once the identity of their Big Sister had been revealed, Little Sisters were asked to assess their relationship in terms of how pleased and how disappointed they were during their interactions, as well as how connected they felt to her. One month following the end of Big Sister Week, the relationship between each Big and Little Sister pair was again assessed, including questions about whether their Big Sister was one of their close friends, whether they felt supported by their Big Sister, and how much time they had spent in each other’s company during the previous week. Algoe et al. (2008) found that the average gratitude indicated by a Little Sister over the course of Big Sister Week was predictive of the quality of the relationship both at the end of Big Sister Week and one month later, though there was no significant correlation found with how much time had been spent together recently. This provides evidence that gratitude can have longer lasting effects, promoting not only the formation of positive relationships, but also their maintenance.

In addition, Algoe et al. (2008) found that the levels of gratitude expressed by Little Sisters were significantly predictive of the Big Sisters’ rating of the relationship quality. This indicates that it is not only the receipt of gifts for which gratefulness is felt that contributes a strong relationship, but that giving these gifts (engendering a feeling of gratitude in another) also has positive effects. The researchers suggest that gratitude can induce a relationship-building cycle, in which the roles of benefactor and recipient are continually reversed. This suggests that positive relationships can be maintained over time by a creating a cycle in which you provide something which induces gratitude in another person, in return for which they attempt to promote that same feeling in you.

Additional support for the hypothesis that gratitude can promote healthy, positive relationships comes from work by Algoe and Haidt (2009). The authors explained to incoming participants that their study was about the effects of interpersonal communication to avoid demand characteristics. A letter-writing task was used to induce feelings of gratitude in their participants (a control condition was also present, as well as an ‘admiration’ condition, as the researchers consider admiration to be in the same family of emotions as gratitude, and wished to avoid ambiguities or confounding between the two). Participants were asked to write a letter to someone they knew, describing a time when that person had done something for them for which they had felt grateful. A questionnaire was given immediately following the letter-writing task as a manipulation check, making sure that the participants were feeling gratitude towards the person, rather than other similar emotions, such as admiration. Participants were then given “background sheets” describing two people with whom they would have a choice to participate in an Instant Messaging conversation. One person was described as having just transferred to the University and was seeking new social opportunities (this person was labeled the “social person”). The second person was described as someone who performed a lot of community service work in the area (the “prosocial person”). Participants in the task were then asked with which person they would prefer to engage in an online conversation.

The researchers found that participants in the gratitude condition indicated that they wanted to meet others like the person to whom they wrote their letter significantly more than participants in the control condition, as well as a stronger desire to “give back” to others. In keeping with this idea, more participants in the gratitude condition indicated that they would prefer to chat with the prosocial person (rather than the social person) because they viewed them as more similar to the person to whom they had written their letter of gratitude. The researchers posited that while persons feeling gratitude primarily wish to give back to the person toward whom they are feeling grateful for some act/gift, they are also willing to extend the positive, relationship-building feelings towards others who are similar to that person. This indicates that gratitude can be helpful in building positive relationships not only between a benefactor and a recipient, but also between a recipient and others who demonstrate qualities similar to the benefactor – that is, gratitude helps build many positive relationships, even if the gratitude is directed toward only one person. The influence of gratitude on promoting and maintaining positive, healthy relationships is important for long-term happiness, because positive relationships are known to “help us get through difficult times and flourish in good times” (Algoe, Haidt & Gable, 2008 p. 429). Because gratitude helps to start positive relationships, it builds a framework for those positive relationships to help us flourish in the future. Furthermore, because gratitude works to maintain those positive relationships over the long term, it allows for the happiness from them to be long lasting.

Gratitude and Mental Health

Throughout the empirical literature, beneficial effects of gratitude on mental health have been shown at multiple levels. The presence of positive emotions is a widely accepted characteristic of happiness, and gratitude can often be easily as a positive emotion. Furthermore, trait gratitude has been positively correlated with the personality trait resilience – the ability to quickly and effectively recover following adverse experiences (Algoe & Stanton, 2011). Moreover, both trait gratitude and resilience have been shown to be linked to the development of more and better coping mechanisms within individuals, with gratitude perhaps acting as a mediator in this case (Algoe & Stanton, 2011).

Fredrickson, Tugade, Waugh, and Larken (2003) provide a compelling summary of the many and varied beneficial effects of positive emotions, including gratitude. One important benefit of positive emotions is their capacity to reverse the adverse physical effects of negative emotions of the mind and body. The experience of many negative emotions, such as fear, anger and sadness, triggers arousal in the body’s autonomic nervous system that, while helpful in making the body alert, focused, and prepared to deal with danger have undesirable effects such as heightened blood pressure and vasoconstriction. Research has shown that the experience of pleasant emotion is beneficial in returning the body to its baseline more quickly than when neutral or negative emotions are experienced (Fredrickson, Mancuso, Branigan, & Tugade, 2000).

A further notable effect of positive emotions, such as gratitude, stems from their capacity to diminish autonomic nervous system activity. One feature of this activity is that it causes the brain to become more focused on the problem at hand. Because positive emotions reduce this effect, they contribute to a ‘cognitive broadening’ when they are experienced following a negative emotional event. This has been shown to lead to more flexibility, creativity, and efficiency in the brain and many researchers believe that this fosters the development of creative and effective coping mechanisms (Fredrickson et al., 2003). This broadening has also been linked to increased dopamine circulation in the brain, which is known to be associated with positive emotions and rewarding experiences (Immordino-Yang & Sylvan, 2010). Furthermore, it has been posited that the development of better coping mechanisms through the experience of positive emotions helps to develop beneficial, long-lasting personality characteristics, including resilience (Fredrickson et al., 2003). That is to say, the brief experience of positive emotions such as gratitude can contribute to the development of long-lasting traits that contribute to positive emotionality and ability to better handle difficult situations. It follows, therefore, that a personal practice aimed at promoting and cultivating gratitude could have long-lasting effects, even if practice were stopped, because enduring personality characteristics are created or promoted. An interesting further effect of this increased resilience is that resilient persons have been shown to be skilled at fostering positive emotions in people to whom they are close. This, in turn, creates a more positive and supportive social network for the person, which is known to be beneficial in better coping following difficult life experiences (Fredrickson et al., 2003; Kumpfer, 1999). Thus, not only is gratitude help people in choosing to seek out, promote, and maintain positive healthy relationships, as shown by Algoe et al. (2008) and Algoe and Haidt (2009), but it also contributes to increasing positivity in one’s existing social network, rendering it more supportive. Others have also suggested that at an intrinsic level, gratitude provides motivation to show thanks and praise to a benefactor, which is helpful in fostering a positive relationship (Algoe & Haidt, 2009). This suggests that the happiness benefits associated with gratitude will be very long lasting.

In 2011, Algoe and Stanton studied the effects of gratitude in combatting negative affect in a group of women diagnosed with metastatic breast cancer. This form of cancer does not have a high survival rate, and is therefore a prominent and ever-present stressor in the lives of these women. In the first part of the study, the women were asked to write about a time within the last month that someone had done something for them, whether they had had positive or negative feelings about the experience. Afterwards, fourteen emotions were assessed, including gratitude (many emotions were assessed in order to hide the target emotion – gratitude - being studied). Participants also completed a questionnaire assessing their perspective on the event – either closed and avoidant (feeling as though they were unwillingly trapped into a situation in which they would have to return a favor), or open and approaching (willing to accept the kindness from the benefactor). It was found that gratitude was highly negatively correlated with closed, negative perspective (r = -0.73) and highly positively correlated with the open, positive perspective (r = 0.83). While these are correlations, and causality cannot be determined, there is nonetheless an evident connection between the affective state of gratitude and a more positive overall perspective. Adopting an open, approaching perspective is more conducive to happiness than a closed and avoidant personality, especially if this positive perspective is extended to other areas of one’s life, bringing them into a more positive light. Algoe and Stanton (2011) refer to this as the ego-transcendence hypothesis.

In the second part of the study by Algoe and Stanton (2011), the participants were asked think of times in the past month when other people had done things for them. They were then asked to indicate how frequently they experienced the same fourteen emotions in response to the favors. The researchers then used an average of a participant’s responses about feeling thankfulness, gratitude, and appreciation to create their “typical grateful response.” This was used to determine whether a participant typically felt grateful towards persons who had performed favors for them over the last month, or whether they typically showed a different emotional response. The participants’ perceived level of support from their social network was also recorded in response to each favor. In the overall sample, a typically grateful response was not significantly correlated with perceived social support; however, researchers performed additional statistical analyses in order to determine whether the correlation between gratitude and perceived social support could be mediated by any particular personality characteristics. They found that for women who were not ambivalent about expressing their emotions, gratitude was positively correlated with their perceived level of social support. Therefore, for some, though not all, persons, trait gratitude can contribute to feeling as though you have a supportive social network. This is highly beneficial when coping with negative affect, and helps aid and hasten recovery following traumatic events (Kumpfer, 1999). Thus, gratitude is not only beneficial through the many routes by which positive emotions improve happiness and mental health, but is also helpful in the opposite side of the issue – combatting and reducing negative affect. Long-term happiness requires not only a high level of positive affect, but also low levels or infrequent experiencing of negative emotions – gratitude fosters both these effects.

The Neurological Foundations of Gratitude

Gratitude is a complex human emotion that requires many different psychological processes to recognize an event requiring gratitude and in producing the feeling of gratitude. The production of gratitude requires first for one to recognize the receipt of an unwarranted service or gift from another. Following recognition of the gift, benefits of receiving must be weighed against the costs of what the gift entails. Costs possibly associated with these gifts may include the necessity to reciprocate with altruistic actions to individuals whom gifts were received from previously. Anticipation of reciprocity is one of the predicted driving forces of human gratitude, and has been shown to be advantageous in animals such as vampire bats who share blood meals with starving roost-mates even when unrelated (Williams, 1984). Following acceptance of a gift, the recipient must experience positive emotions that convert to a feeling of gratitude. Finally, the recipient must encode memories about the gift, and the gratitude felt towards the giver in order for gratitude to have any lasting effect on human emotion. These processes must stem from distinct brain structures that work in unison to form the abstract social value of gratitude.

Recent research has pointed to the possibility of areas of neocortex regulating and interpreting information from the limbic system in studies of the neuroscience of social constructs and values (Zahn et al., 2009). Studies utilizing functional magnetic resonance imaging have found that when contemplating the relatedness of social concepts, such as honorable and brave, mores activation is shown in the superior anterior temporal lobe of the cortex than when compared to a control using physical functions, such as nutritious and useful (Zahn et al., 2007). The superior anterior temporal lobe must play a role in social interaction by providing abstract knowledge of social behavior. Other areas in this study were found to be activated as well including, the orbitofrontal, medial prefrontal cortex, and temporoparietal junction. It was also discovered that he activation of the superior anterior temporal lobe was independent of the valence of the social construct. It made no difference whether the construct had a negative or positive connotation; the area was activated due to the necessity to process the abstract ideas about social values.

Along with cortical structures, much older limbic structures also play an important role in producing gratitude (Immordino-Yang & Sylvan, 2010). The mesolimbic dopamine system plays an enormous role in producing positive affect and encoding reward values. It is possible that the positive affect cause by receiving a gift could be encoded by dopamine neurons much in the same way as Tobler, Fiorillo, and Schultz reported in 2005. Their study examined adaptive properties in spike frequency and coding of dopamine neurons in response to predicted and unpredicted rewarding stimuli. A situation that creates gratitude could be one where w gift or service is given to the recipient and this information if processed in the same way in the limbic system. Adaptive firing rates of dopamine releasing neurons in rewarding structures of the brain could be what are causing the positive, rewarding, emotions that elicit gratitude.

The memory of an event that caused gratitude needs to be recorded and be available for access if it is to have any lasting effect on an organism. Studies show that contemplation on times of gratitude increase activation in the basal forebrain, a structure critical for memory (Zahn et al., 2009.) The basal forebrain is directly connected to the hippocampus by a tract of chologenergic projections. When gray matter of the basal forebrain was atrophied, cognitive functions, such as recalling memories, were impaired. This displays how memory formation is related to forming feelings of gratitude and implies implications for the storage and retrieval of memories of times when gratitude was expressed.

Many studies on neuronal pathways of gratitude have been performed on patients with brain lesions caused by severe head trauma or neurological disease. While not experimental, and therefore unable to say definitively the cause of any findings, these types of studies can shed light on what structures to look at more closely. Richard Emmons (2007) performed a study on patients with severe prefrontal dysfunction. These patients had Parkinson's Disorder, and when compared to healthy individuals on recalling an event where they felt gratitude, they experienced no improvement in mood. The healthy control group did show a significant increase in affect following gratitude recall. Patients displaying frontotemporal dementia show a distinct lack of prosocial sentiments, such as guild, pity, gratitude. The lack of prosocial sentiments was linked to the frontopolar cortex and the septal area using fMRI while applying a moral sentiment test, indicating damage to either one of these regions may be the cause of the blunted social conscious (Moll et al., 2011). What is most interesting about these findings is that both the cortex and limbic system play a role. The development over evolutionary time of the human cortex is what sets humans apart from other species in both intelligence and many prosocial sentiments. The limbic system evolved much earlier than the cortex but it appears that both must play a role together to mediate the abstract social construct. A plausible explanation may entail the limbic system being the source of raw emotion while the cortical structures mediate and choose the proper response based on external stimuli, including perceived social expectations (Mercadillo, Luis Diaz, and Barrios, 2007).

Toward a Personal Practice

As the evidence demonstrates, there is a clear link between subjective well-being, or happiness, and the construct of gratitude. In terms of support, we have discussed definitions of gratitude, the role of gratitude in the formation of healthy friendships, the role that gratitude can play in combating depression, and finally, the neuroscience of gratitude at the most basic level of cognition. Having surveyed the evidence for the link, there still remains the practical problem of clarifying gratitude’s “staying power” (the capability to increase personal happiness over an extended period). In other words, if gratitude can enhance subjective well-being over time, then it may make for a legitimate personal practice that we can recommend and stand behind as a proven method of making individuals happy. In addition, it is hollow merely saying that gratitude is empirically linked to subjective well-being and that gratitude has staying power. The challenge emerges when one tries to lay out how the virtue of gratitude might work in practice.

Bono, Emmons and McCullough (2004) note intervention strategies to increase gratitude in individual research participants and their awareness of the good elements in their lives as prerequisites for well-being. Citing a study by Emmons and McCullough (2003), which examined the effect of making participants briefly list in writing five things they were grateful for in the previous week for 10 weeks, the researchers discovered that individuals who were grateful (as opposed to those who wrote about annoyances or affective events) felt better about their lives on average. Compared to controls, higher ratings of subjective well-being from the grateful participants were accompanied by fewer health complaints, higher levels of exercise over the study period, and higher levels of optimism.

Thus, we can gain insight even from the research literature on how gratitude as a personal practice ought to be implemented. In this case, “counting one’s blessings” served a significant role in raising subjective well-being, as opposed to other kinds of retrospective reflection. However, Bono, Emmons and McCullough (2004) caution against the desire to devote too many emotional resources and time to expressing gratitude.