Joy: a review of the literature and suggestions for future directions

ABSTRACT Despite the large body of empirical and theoretical work that has emerged from positive psychology in the recent decades, surprisingly little work has been done by this field on joy. As a result, the work that has been done on joy is disjointed, and frequently does not build on the previous literature; indeed, the various definitions of joy that psychologists use often conflict with one another. The present article, therefore, seeks to address this gap in the positive psychology literature and provide suggestions for future directions, by placing the existing psychological work on joy in dialogue with itself and also in dialogue with the work on joy done in other fields, including, theology and religious studies, philosophy, and literature. The first part of this paper provides a systematic review of the existing work on joy and aims to develop an overarching framework that can be used to operationalize and define joy. This paper will then provide some suggestions for future directions for psychological research into joy, and will close by suggesting reasons why joy is an important phenomenon toward which positive psychology should turn its focus.


Introduction
While joy, as a concept, has been treated at length in fields such as literature and theology, comparatively little work in psychology has been devoted to studying it. Consequently, the existing work in psychology on joy is relatively small and often not in dialogue with itself, making it difficult to effectively operationalize it and build on the existing work done on it. Therefore, much of this paper has concerned itself with a review of the literature, which revealed that the existing body of work on 'joy' in psychology may not involve reference to a unitary concept, but instead to related, but distinct concepts. For that reason, it is important to delineate the limits of what 'joy' involves. This paper seeks to survey the existing work, to see where common threads emerge, in order to look at unifying the various empirical work and definitions and to suggest future directions. Once this task has been completed, this paper will conclude by gesturing at 'the power of joy,' and by so doing, outline reasons why joy should be a more foundational part of positive psychology's research agenda.
Part I: what is joy?
The Theology of Joy & the Good Life project's account of joy Recently, an interdisciplinary project at Yale University, the Theology of Joy and the Good Life project (TJ&GLP), brought together psychologists, philosophers, and theologians to work toward unifying the disparate strands of work on joy. In developing their definition of joy, as an emotion, TJ&GLP used philosopher Robert C. Robert's definition of an emotion as an affective concern-based construal (Roberts, 2013). Emotions, therefore, are made up of three components: an affective piece (how it feels), a construal (how an individual perceives a situation), and concern (the individual's evaluation of the situation): 'Joy, as a positive emotion (an affective concern-based construal), is a positive affective response to an objective external good, construed rightly and about which one is rightly concerned' (Theology of Joy & the Good Life Overview, 2018). The affective response can be experienced more or less intensely. Additionally, the situation (i.e. the intentional object/the occasion for joy) is experienced as unowed, or gratuitous (Volf, 2015). Furthermore, it is also possible to experience joy as a 'mixed-emotional state': it is possible to simultaneously experience joy and other emotions (such as sorrow). This last point breaks with the previous consensus in the literature, which was that joy is a state in which one is not experiencing negative emotions at the same time (Fredrickson, 2001). Notably, however, this consensus seems to be shifting, as recent empirical evidence suggests that it is possible to experience joy as a mixed-emotional state (Aragón, 2017).
Elsewhere, TJ&GLP clarifies that joy, as an emotion, has a related dispositional state: there are joyful people, who seem to have a lower threshold for the experience of joy, experience joy in more things, and experience joy more frequently. Conversely, TJ&GLP suggests that there may be moods that inhibit the experience of joy (" Miroslav Volf Delves", 2018). Furthermore, although it is in tension with their aforementioned quote that joy 'is a positive affective response to an objective external good, construed rightly and about which one is rightly concerned,' TJ&GLP has indicated elsewhere that joy ' . . . is tied to how I perceive things rather than to what things are in themselves' (Volf, 2015). This means that joy can be 'pathologically afflicted,' such that we take joy in things that are evil, rejoice inordinately, or experience a kind of joy that is selfabsorbed and indifferent to others.

Other accounts of joy
The Oxford Companion to Emotion and the Affective Sciences defines joy this way: Joy is a pleasant state that shares conceptual space with other positive emotions such as gladness, elation, happiness, and, to a lesser extent, amusement. Feelings of joy arise in circumstances appraised as safe, familiar, and requiring little personal effort. Joy is the pleasant state experienced when people have made progress toward important personal goals, especially when that progress is better than expected (Lazarus, 1991). Phenomenologically, joy feels bright and light. Colors seem more vivid. Physical movements become more fluid. Smiles become difficult to suppress. Joy broadens people's attention and thinking. Such broadened thinking is thought to support the playful 'do anything' action tendency associated with joy. Even though the playfulness inspired by joy is often aimless, it has reliable outcomes. Ethologists have long held that play promotes the acquisition of skills. Physical skills are developed and practiced in rough-and-tumble and chasing play, manipulative-cognitive skills are developed and practiced in object play, and social-affective skills are developed and practiced in social play. In this manner, repeated experiences of joy are thought to build people's resources for survival (Fredrickson, 2009, p. 230). Joy, here, involves a state of positive affect, in which one experiences feelings of freedom, safety, and ease. Joy involves changes in visual perception (colors seem brighter), motor behavior (physical movements feel freer and easier, smiling happens involuntarily), and there are characteristic changes in cognition (thinking and attention are broadened and exercised in creative ways). Importantly, joy is here defined primarily in terms of the 'broaden and build' theory, which suggests that some positive emotions, such as joy, expand one's thoughts and actions to facilitate the learning of novel modes of thought and behavior (Fredrickson & Levenson, 1998). The theory suggests that while certain negative emotions provide benefits to the individual on a temporally proximal timescale (e.g. disgust keeps one away from potentially harmful present stimuli), certain positive emotions provide benefits on a much more distal timescale (Fredrickson, 2004). Joy, particularly through the activities of play that result from feeling joy, provides the individual with the opportunity to learn new cognitive and behavioral skills and forge new social relationships and skills, which enhances resilience to future obstacles or threats.
Theologians have unknowingly picked up on the connection between joy and the 'broaden and build' theory. Jürgen Moltmann's Theology & Joy (Moltmann, 1973) argues for a tight connection between joy and play, and Johannes de Silentio (the pseudonymous author of Søren Kierkegaard's Fear and Trembling) describes how the joyful individual has a kind of 'epistemic flexibility,' whereby she regards suffering and disappointments as ripe with possibility for God's eventual and inevitable grace and redemption of the situation (Hough, 2015). Connecting this insight to Fredrickson's broaden and build model for joy, we might say that joy attunes us to being open to new possibilities for relating to our circumstances and perceiving them in a new light. Indeed, de Silentio is suggesting that joy allows the individual to broaden her cognitive and behavioral schemas, in order to open herself and attune herself to opportunities to witness God's redemption of the situations she finds herself in.
As with TJ&GLP's definition, psychologists frequently relate how, in joy, there is often a sense of 'blessedness' or giftedness in cases in which one experiences progress toward goals going faster than expected (Fredrickson, 2009;Lazarus, 1991). Thus, while pleasure is experienced when an outcome that is expected instantiates itself ('entitlement'), joy is experienced when the outcome is hoped for, but not presumed (Miceli & Castelfranchi, 2010) or when the progress toward the goal is at a rate faster than that which one expects (Carver & Scheier, 1998). Some psychologists suggest that joy's adaptive function is to provide motivation to increase one's effort, in the event that progress toward goals gets more difficult (Kreibig, 2014, p. 137). Consequently, in the psychological literature, this aspect of joy, involving a sense of 'blessedness' or giftedness, has primarily been situated in the context of progress toward goals (Ortony, Clore, & Collins, 1988;Scherer, 2001), while TJ&GLP have taken 'giftedness' or 'blessedness' in a much more expanded sense.
Interestingly, recent work by Watkins, Emmons, Greaves, and Bell (2018) may support the idea that psychology's definition of joy should adopt the more expanded sense. In a series of studies, the authors explored the correlations between state and dispositional gratitude and state and dispositional joy over time. The authors constructed and validated state and trait measures of joy, and found that dispositional gratitude was correlated with increases in state joy, and trait joy was correlated with increases in state gratitude. This suggests that being a more grateful person (dispositionally) may potentiate experiences of joy, and being a more joyful person (dispositionally) may potentiate experiences of gratitude, such that there may be a 'virtuous upward spiral' in which joy and gratitude mutually reinforce each other. Importantly, the type of gratitude that here was connected to joy was not explicitly connected with goal pursuit: consequently, this initial research provides preliminary evidence that perhaps psychologists should consider adopting TJ&GLP's more expansive understanding of the role that a sense of gratitude plays in joy. Additional work has found that joy is ranked lowest out of the emotions on control (it cannot be produced voluntarily) (Izard, 1972). Thus, it may be this uncontrollable and unbidden nature of joy that so closely links it with a sense of 'blessedness,' gratitude, or giftedness.
In what has been the most comprehensive study of the phenomenology of the different forms of joy to date, Chris M. Meadows (2014) conducted a study in the 1970s, in which he sorted through thousands of accounts of joyful experience from 333 university students. Meadows eventually established that there are three dimensions of joyful experience: (1) Excited vs. Serene Joy a. Excited Joy is very intense and involves high energy b. Serene joy is quieter and calmer, giving feelings of harmony and unity The first dimension is compatible with TJ&GLP's specification that the positive valence of joy can range from very intense (e.g. powerful joy) to less intense (e.g. quiet delight). Here, we again find that TJ&GLP's more expansive definition of joy, in allowing for both excited and serene joy, manages to bridge a tension between two other dominant accounts of joy. Indeed, on the one hand, certain neurobiological accounts have further linked joy to drives and goal pursuit (joy has been linked to the dopaminergic system, which underlies our drives and urges): 'Drive is stimulating and activating, accompanied by joy, fun and excitement (high pleasure, high arousal) . . . ' (Richardson, McEwan, Maratos, & Sheffield, 2016). Consequently, the 'drives'-line of thinking suggests that joy is inherently excited joy. On the other hand, this line of thinking is in tension with another dominant account, which suggests that joy is an indication that the body is at equilibrium (Damasio, 2003). This model suggests that the body always aims at equilibrium, and so our bodies constantly aim at a more 'serene joy' type of equilibrium state. Importantly, Frijda (1986) proposes that the action tendency associated with joy involves a state of free activation, in which one will readily engage with any new, stimulating activity that comes along. Serene joy, on the free activation model, is therefore not a withdrawn state, but a state in which one is prepared to engage, should the opportunity arise. By allowing for forms of joy that range in intensity from excited to serene, TJ&GLP is able to bring together these two otherwise disparate accounts of joy. It is thus likely that serene and excited joy serve two different purposes and have two different associated behavioral schemas: serene joy aims at restoring the body to equilibrium, while excited joy aims at goal pursuit. We turn now to the second dimension Meadows identified.
(2) Individuated vs. Affiliative Joy a. Individuated Joy is joy experienced as an individual b. Affiliative Joy is joy that is shared with others.
Of note, Meadows found that 70% of the experiences in the study were affiliative, while only 30% were individuated (Meadows, 2014). Since the majority of instances of joy seem to occur in affiliative/social settings, it is likely that joy is primarily for social bonding. This is also compatible with TJ&GLP's understanding of joy as typically being social, although sometimes occurring in individuated forms (e.g. in the pathologically afflicted joy that is selfconcerned).
(3) Anticipatory vs. Consummatory Joy a. Anticipatory Joy occurs when the fulfillment of some desire appears to be imminent b. Consummatory Joy occurs when the desire has already been fulfilled This account maps neatly onto two types of joy outlined by TJ&GLP: consummatory joy is joy because, it happens because some desire has been fulfilled (either some good event has occurred or some distress has been removed); by contrast, anticipatory joy is joy notwithstanding, it is a joy that anticipates that the desire will be fulfilled imminently (Crisp, 2015, pp. xi-xvi;Thompson, 2015). Meadows (2014) then identifies five phenomenological dimensions of joy: (1) Harmony and Unity a. This dimension involves a sense of internal harmony or integration within oneself, and a sense of harmony with the 'other' (including friends, family, nature, etc.) (2) Vitality a. Excited joy involves an increase in 'vitality,' a sense of energy, potency, and aliveness, which activates appetitive systems to direct organisms to seek pleasure and reward. Even in serene joy, there is still more vitality than in other emotional states, such as sadness.
(3) Transcendence a. 'Transcendence, as used here, is a description of the content of consciousness when one senses or has the feeling that he is moving or has moved, soared, or passed beyond ordinary existence. In the midst of a joy experience one may feel she has transcended bounded space and or time, ordinary self-consciousness, the past, or usual personal ego boundaries' (Meadows, 2014, p. 114) (4) Freedom a. Joy involves the experience of physical freedom (fluid and free motor behaviors), and also freedom of thought.
Theologians and Biblical scholars have drawn a tight connection between joy and the sense of physical freedom as exhibited through motor action. David is described in 2 Samuel 6:12-14 as so overcome by his joy in the Lord that he spontaneously leaps and dances in public, not even caring (nor perhaps noticing) that he has not adequately clothed himself. Similarly, the Greek word for leaping for joy (skirtan) is used in the Gospel of Luke to describe how the fetus of John the Baptist leapt for joy in the womb when he encountered the pregnant Mary (Luke 1:41, 44). Later, it is used in Luke 6:22-23 to describe how, when one suffers persecutions, one should 'leap for joy' on account of their reward in heaven (Morrice, 1984, pp. 66-67). Likewise, as aforementioned, there is also a kind of 'epistemic freedom' in joy, whereby one feels free in their thinking.
Altered perception a. In experiences of joy, sensory perception may be altered such that individuals experience heightened awareness of color, depth, touch, etc. In excited joy, colors and sensations seem brighter, sharper, more vivid, and in serene joy, they are perceived as calmer. The perception of time is also altered: in anticipatory joy, the arrival of the thing longed for is felt as imminent; in intense joy, time will 'fly by'; in serene joy, time will seem to pass slowly. 'Finally, joy occurs almost without exception in the immediacy of the present. Sometimes it appears that one is in a state of timelessness in which the awareness of ordinary time is suspended, one is not aware of time and feels outside of ordinary time' (Meadows, 2014, p. 129).
Joy vs. ecstasy The first 'limit' around joy that needs to be drawn is in demarcating the space between joy and ecstasy. As Meadows' transcendence dimension of joy indicates, very intense joy may involve such a high degree of transcendence of the self, that one loses the cognitive aspect of joy (because one has lost oneself). Philosophers Dreyfus and Kelly (2011) explain it this way: 'While bliss [or ecstasy] wipes you out, joy makes you more intensely you. ' (p. 132) Similarly, literary historian Potkay (2007, pp. 27-28) describes it as the following: Ecstasy may be regarded either as joy at its most selfabsenting pitch, or as something quite different from joy. Joy, at least on this side of ecstasy, is about return and fullness, not about standing elsewhere and hollowing out. In ecstasy, self (in some sense) is cleaved away from body, the senses annihilated; absence becomes fulfilment . . . Ecstasy, then, while it sometimes appears as joy at or beyond its limit, as often appears as that which, as a self-negating and necessarily irrational experience, is opposed to the passion of joy. Ecstasy figures an escape from bodily consciousness or life itself, even though the body remains, a residue.
Here, we find the first limit for joy: joy 'makes you more intensely you,' while ecstasy (or bliss) obliterates the self. Indeed, the ancient Greeks saw the state of ecstasy as 'the state of being outside oneself with joywith enthusiasm as the experience of being possessed by a god' (Van Ness, 1996). In common parlance, 'to bliss out' means to space out and disengage the self from the world (Van Ness, 1996). Meadows sees joy and ecstasy lying along a continuum in which 'Certain joy experiences involve a sense of harmony and unity, whereas ecstasy is frequently accompanied by a strong union or merging with nature, everything that is, the divine, or another person' (Meadows, 2014, p. 215). He describes it elsewhere as 'Ecstasy involves a restricted perceptual focus and an absence of discursive thinking or a constriction of the focus of one's cognitive processes. From my perspective, one of the cardinal characteristics of ecstasy is the individual's movement beyond his immediate perceptual field. People feel that they are in another world' (Meadows, 2014, p. 195). Consequently, another way of putting this is that while joy can expand the self, ecstasy loses the self: the intense forms of joy that involve a loss of the self or of self-consciousness qualify as bliss, or ecstasy, but not as joy. The reflexivity of selfconsciousness is critical for it to be an experience of joy, as TJ&GLP explains, 'Unlike happinesswhere very little self-consciousness can work to undo the statejoy seems more durable to human reflexivityindeed, perhaps partially constituted by it' (Mathewes, 2015, p. 66). Indeed, the state of joy is not the one in which the self is obliterated, but the one in which one enters into ' . . . an otherness in which I am more truly "I."' (Duncan, 2017, p. 76).

Joy vs. elation & gladness
The second demarcation will be between joy, and elation and gladness. Lindsay-Hartz (1981) theorized that elation is the state that results from a wish or a fantasy (which is not expected to be fulfilled) being fulfilled, while gladness results from a hope (which is seen as having a real possibility of being fulfilled) being fulfilled, and joy results from experiencing a particular kind of closeness or connection to another person, object, or presence. Elation is associated with feeling that one is floating and a desire to jump up and down, while in gladness the body becomes relaxed; in joy, the body feels as if it is in greater touch with reality and the sensory capacities become heightened (de Rivera, Possell, Verette, & Weiner, 1989). Previous correlational and experimental work has attempted to distinguish the three (de Rivera et al., 1989), and has provided some limited support for distinguishing elation from gladness. It is difficult to decide what exactly to conclude from the study, as it failed to distinguish joy from elation and gladness. Until further work is done, there is no reason to not see elation and gladness as types of joy. The definition of joy that the authors were working with seems unduly restrictive, particularly in light of the definitions currently used in the literature. Consequently, we might say that elation is the type of joy in which the object that is gained was previously seen as one that could not be reasonably expected, and gladness is the type of joy in which the object that is gained was previously seen as having a real possibility of being fulfilled. Another way of putting this is that elation may be more in the territory of dreams being granted, while gladness is more in the territory of hopes being fulfilled.
Joy as emotion, mood, trait, or fruit?
Much of the work done by the TJ&GLP involved not the emotional state of joy, but the associated disposition (or trait) that potentiates joy. Dispositional joy, particularly in the theological literature, is often explored in connection with the treatment of joy as a 'spiritual fruit' and in discussions of how enduring joy is compatible with occurrent experiences of sorrow or persecution; theologian Thompson (2015) relates how: 'Joy is thus both a response to God's salvation in Christ, and the attitude or disposition in the present time that is based on a confidence in God's goodness and gracious disposition toward humankind. In this sense, then, joy cannot be disturbed by external circumstances.' (p. 37).
Consequently, while emotional joy requires both agential aspects (life being led well) and circumstantial aspects (life going well), dispositional joy does not require external circumstances. The suggestion here seems to be that dispositional joy provides an individual with some kind of deep satisfaction with God's goodness and favor toward mankind, and flows out of a confidence in this goodness and favor, potentiating an individual to the experience of joy (should there be any occasion for rejoicing), even amidst sorrow or persecutions. Similarly, consider Confucius' account of dispositional joy: In contrast, those who embrace the Dao find in it a special reservoir of satisfaction and happiness that sustains them in the worst of times and nourishes, fulfils, and delights them when things go well. [Confucius] describes various stages of understanding the Dao, but his goal always is a type of understanding that finds its joy in following the Way. 'The master said, 'To understand [the Dao] is not as good as to delight in it; to delight in [the Dao] is not as good as to find joy in it' (Ivanhoe, 2013, p. 267).
Here too, we are told that dispositional joy provides a 'satisfaction' (c.f. Thompson's 'confidence') even in the worst of times, that potentiates the individual for the experience of joy, wherever it can be found.
The construct for dispositional joy validated by Watkins et al. (2018) explains dispositional joy this way, 'An affective trait refers to a person's disposition for a particular emotional state. Thus, people high in the trait of joy should have a low threshold for joy; they should experience joy more frequently across a wider variety of circumstances.' Consequently, those particularly high in dispositional joy may be able to experience the emotion of joy (when there is the occasion for it), even amidst such a wide variety of circumstances as those including sorrow and persecution. This definition of dispositional joy, however, does not include the additional component that Thompson and Confucius do, the deep sense of 'satisfaction' or 'confidence.' Perhaps this 'deep satisfaction' is reducible to gratitude, so that whatever this additional component in Thompson and Confucius' accounts of dispositional joy amounts to is simply reducible to gratitude. The tight connection observed between gratitude and joy that the authors of the study found may provide support for this idea. If the additional component in Thompson and Confucius' accounts of dispositional joy is not reducible to dispositional gratitude, however, then we need more clarity on what exactly 'a confidence in God's goodness and gracious disposition toward humankind' or 'a special reservoir of satisfaction and happiness' might amount to in psychological terms, in a way that can be helpful for the psychologists seeking to gain further clarity on the trait of joy. It may be that this additional piece is not reducible to secular terms or to any secular analogue. Additionally, Watkins et al. (2018) found that dispositional joy involved ' . . . consistently feel[ing] a subtle but enduring feeling of joy.' Consequently, there may be a phenomenological piece of this dispositional joy (a constant, subtle state of positively valenced affect) that is involved in dispositional joy.
Furthermore, Thompson's account of dispositional joy may not simply be dispositional joy, but may go beyond this. Another TJ&GLP theologian relates how, ' . . . the "joy" to which the New Testament summons its readers is of a different order to that of regular, even exceptional, human experience' (Wright, 2015, p. 41). Joy, here, is a spiritual fruit, as Dearborn (1995, p. 512) relates, ' . . . [joy is] a fruit of the Spirit . . . [and is different] from its circumstantial and emotional counterpart.' There are, then, three types of things that 'joy' could refer to (1) the emotional state, (2) the disposition or trait, (3) the spiritual fruit. There is also a fourth, as Rosenberg (1998) explains that emotions can be explained at the level of emotional state, mood state, and affective state. Consequently, the final level of analysis is (4) the mood, which is a state that is longer lasting than an emotional state, and potentiates the individual to joyful experience, but which is not as stable or long-lasting as a disposition.
Consequently, we have the following levels of analysis for 'joy': (1) Joy as emotion a. Here, one has a positively valenced affective experience involving a concern-based construal.
(2) Joy as mood a. Here, one is potentiated to experience the emotional state of joy (i.e. they currently have a low threshold to experience it, and they 'experience joy more frequently across a wider variety of circumstances'), but it is not as stable nor as long-lasting as a disposition.
(3) Joy as disposition/trait a. Here, one has a disposition to experience the emotional state of joy (i.e. they have a low threshold to experience it, and they 'experience joy more frequently across a wider variety of circumstances'). They may also experience a subtle and enduring feeling of joy. (4) Joy as spiritual fruit a. As in (3), one has a disposition to experience the emotional state of joy (i.e. they have a low threshold to experience it, and they 'experience joy more frequently across a wider variety of circumstances'). They may also experience a subtle and enduring feeling of joy. b. Additionally, one experiences a deep, spiritual sense of satisfaction, confidence, or gratitude, even in the midst of severe persecution, suffering, or sorrow.
More empirical work is needed in order to clarify what (4) Joy as a spiritual fruit is, and, more specifically, what is involved in (4b). The type of joy that is a fruit of the spirit may be an important area of study, particularly since, as aforementioned, an analogue seems to be present in Confucian thought (and likely in other traditions, as well). Furthermore, this type of joy may provide particularly unique insights into the good life, which may be of benefit to theists and non-theists alike. Indeed, de Silentio laments how he wishes he had the spiritual fruit of joy: 'I can bear to live in my own fashion, I am happy and satisfied, but my joy is not the joy of faith, and by comparison with that, it is unhappy' (Kierkegaard, 1843(Kierkegaard, /1983, and Kierkegaard elsewhere relates the importance of the spiritual fruit of joy: 'Neither is Christian consolation a compensation for the loss of joy, since it is joy. In comparison with Christianity's consolation, all other joy is ultimately only disconsolate' (Kierkegaard, 1847(Kierkegaard, /1995).
Miller (2015) has conducted numerous studies investigating the role that spirituality plays in development and in coping with stressors. Similar work could be done to investigate the role that joy, as a spiritual fruit, plays in development and in coping with stressors. The biggest obstacle to such research, however, may be the one observed by Wright (2015, p. 41) when he relates how, joy as a fruit 'is of a different order to that of regular, even exceptional, human experience.' If the individual possessing the spiritual fruit of joy is relatively rare, this raises some concerns with how joy as a fruit can be studied and operationalized.
A parallel can be drawn here to the situationism literature in social psychology, which was applied toward challenging the moral psychological framework put forward by virtue ethics. The situationist experiments revealed that the presence of certain morally irrelevant features in a situation could drastically influence rates of helping and harming behavior (e.g. the presence of a free dime could drastically increase rates of helping [Isen & Levin, 1972]), and many philosophers argued that this experimental evidence revealed that the kind of stable moral character suggested by virtue ethics does not exist (see, e.g., Doris, 1998). One response was that the experimental evidence from situationism does not undermine virtue ethics, because virtue ethics suggests that the truly virtuous individual is actually very rare (Kamtekar, 2004). If this response is correct, then it suggests that insufficient numbers of truly virtuous individuals were represented in these experiments, and so the experiments were not actually studying the virtues and whether or not the virtues exist, but were actually studying other character traits. Similarly, to bring it back to the topic of this paper, it could be the case that joyous individuals are so rare that there may not be enough to reach the statistical power required to use them in empirical studies. Additionally, there is the challenge of how one might go about identifying them. Nevertheless, the initial study done by Watkins et al. (2018) laid a strong foundation in differentiating state and dispositional joy, and more work in this vein needs to be done to further clarify the concept of joy at the four levels of analysis.

Language and cross-cultural considerations
There are two dominant developmental theories of emotions; firstly, the cultural theory of emotion suggests that you can only feel an emotion after you have first witnessed others experience it (Peterson, 2006). Since one's culture dictates the manner in which emotions are exhibited, culture will, to a large extent, shape how one's own emotional capacities develop, such that different cultures may exhibit and experience emotions very differently. By contrast, the innate view of emotions is that emotions develop so long as other basic needs (nutritive and social) are met, such that emotions are experienced and exhibited universally across cultures. Most basic emotions lie on a spectrum between these two, and philosopher Griffiths (1997) also sees the higher cognitive emotions, which are more influenced by conscious thinking, as lying on a spectrum between these two. In other words, emotions have both innate components, and components that are learned. More developmental and cross-cultural work is needed to understand which aspects of joy are innate and which are learned. Additionally, since the research thus far has focused on Western populations, cross-cultural research may also reveal that joy has different or additional functions (e.g. it might not be so closely tied to 'broaden and build') than those proposed thus far.
Cross-cultural work is particularly important since most of the work on joy done so far has involved Western populations, and so it is very possible that these experiments will only reveal to us how Western populations think about and experience joy. One potential concern is that if psychologists define 'joy' based on these studies, this may have cultural impacts as this information is disseminated, such that the psychologists' definition of joy comes to be disseminated into and accepted in the wider culture. This would lead to a kind of self-fulfilling prophecy as subsequent experiments would reveal that increasingly, participants had already adopted the psychologists' definition of joy. Consequently, thought must also be made to the populations to be sampled. Crucially, since many of the experimental paradigms used to investigate joy operate by asking participants to recall instances of joy in their lives, attention must be paid to how different populations may define joy differently. Further challenges in such cross-cultural work also include cultural differences in how and when participants feel that it is appropriate to exhibit certain emotions. For example, research found that Japanese and American participants display the same rates of emotion in private, but once an observer is introduced, Japanese participants do not display as high of rates of emotion (Ekman, 1972;Friesen, 1972). Interestingly, when the participants were taped and the film was played back in slow motion, it was revealed that the Japanese participants were initially reflexively reacting emotionally in a certain way, but were subsequently inhibiting their initial responses. Consequently, experimenters need to pay close attention to the settings under which various cultures believe it is acceptable to display the emotions in question.
Especially important to investigate will be the difference in joy between collectivist and individualist cultures. Cross-cultural research has found that extraversion is more strongly associated with positive affect in individualist cultures (Lucas, Diener, Grob, Suh, & Shao, 2000). If there may be similar trends for joy, we may discover that although existing work in the West has found that joy is associated with being high in extraversion (Watkins et al., 2018), that this association differs between individualist vs. collectivist cultures.
Additionally, cross-cultural work is important because a good deal of previous work has found that culture is able to mediate both experience and one's interpretation of that experience. For example, a study on bilingual Chinese-Canadians found that their experience of guilt was different depending on whether their experience of guilt was mediated through Chinese or English (Lee, Tang, Wan, Mai, & Liu, 2015). When the experience was mediated through Chinese, participants experience the guilt as embodied in their face (the body part associated with guilt in Chinese culture), whereas participants experienced the guilt as embodied in their hands (the body part that is more associated with guilt in Western culture) when the experience was mediated in English. Consequently, since culture can mediate one's emotional experiences, and also one's later interpretations of those experiences, it is very possible that joy is defined, experienced, and interpreted very differently in different cultural contexts. Additionally, cultural differences may also affect participant responses to the measures: for example, Kahneman and Riis (2005) suggest that French individuals report lower levels of life satisfaction because of cultural values that make them reticent to express life satisfaction to strangers, which the authors provided as an explanation of that country's lower levels of recorded life satisfaction.
While the work cited above shows how culture can shape experience and perception of the experience, the language that we use can also shape the phenomenological content of our experiences. For example, because Russian, unlike English, has words that distinguish lighter blues from darker blues, Russians are able to perceive subtle differences between shades of blue more easily than are English speakers (Winawer et al., 2007). Additionally, the Himba tribe of Namibia does not have color terms that distinguish blue from green, although they do have words that distinguish various shades of green. As a result, Himba speakers have difficulty discriminating between blue and green (which English speakers do not), although they are better at discriminating the various shades of green (which English speakers are worse at) (Roberson, Davidoff, Davies, & Shapiro, 2005). Similarly, since language can shape the phenomenological content of our experience, language may also play a large role in the phenomenology of joy. Perhaps cultures that have more words for the different types of joy, experience a broader range of types of joyful experience.
This point about language is particularly important because so much of the nature of 'joy' in the West is characterized by its ineffability. Poet Wiman (2017, p. xviii), in trying to define joy, relates how, ' . . . joy is quite particular in its resistance to particularity.' Similarly, Potkay (2007, p. 2) explains how, ''Joy' is, moreover, what we often speak of as unspeakable, a word that marks the limit of language as it gestures towards the undifferentiated unity before words were or after they shall cease to function as they familiarly do.' Poet Amichai (2015/ 2017) explains that there is a 'blurriness' to the definition of joy because it is not a state which we encounter frequently. Amichai contrasts this to pain, which we can articulate with precision because we are so used to encountering it. 'The precision of pain and the blurriness of joy. I'm thinking of how precise people are when they describe their pain in a doctor's office. Joy blurs everything. I want to describe, with a sharp pain's precision, happiness and blurry joy. I learned to speak among the pains' (Amichai, 2015(Amichai, /2017. Thompson (2015) relates how the author of 1 Peter issues a command to rejoice with an 'unspeakable' or 'indescribable' joy (agalliasthe charai aneklalētōi kai dedoxasmenē) (p. 30). Morrice (1984, p. 19) explains that with the word used, agallian, ' . . . a new verb has been formed . . . It seems that it was felt necessary to form a new word. None of the phrases used in profane or secular Greek was adequate to express joy in Yahweh, the Hebrew God of salvation. ' Potkay (2007, p. 37) simply describes this verse by observing that 'this joy superlatively bursts the limits of language itself.' Perhaps, if in modern times in the West we were to develop new words to describe our otherwise 'indescribable' joyful experiences, we may find our experience of joy transformed. Perhaps if there exist cultures that already have such a rich vocabulary, theirs already has been. Alternatively, we may find that the ineffability is intrinsic to and inextricable from the nature of the joyful experience.

The developmental account and the case of Alypius
Many cognitive scientists want to classify joy as a basic emotion, suggesting that it is developed sometime between 3 weeks (Izard, 1991, p. 132) and 3 months (Lewis, 2016, pp. 285-286) of age. On TJ&GLP's account, however, such an account of the pre-linguistic development of joy is unlikely, since it requires the cognitive aspect (the concern-based construal), which may require language, or at least more developed cognitive capacities than are available in infancy. Nevertheless, infants may experience the non-cognitive, affective aspect of joy. More developmental work needs to be done here, in order to explore at what stage the cognitive machinery becomes complex enough to make a concern-based construal possible, how one learns to make these construals, and how this all links up with the affective piece. Having the developmental picture in place first will be necessary to gain deeper insight into the types of environments that are conducive to the joy-filled life, and into those which impede it.
Moreover, having this developmental picture is also necessary so that we can come to better understand how the cognitive and non-cognitive pieces dynamically interact. Consider the case of Alypius, as related in Augustine's Confessions: Alypius initially construes the gladiatorial spectacles as bad and experiences an aversive reaction to thinking of them. His friends drag him along to a gladiatorial spectacle, and though he turns away and shuts his eyes, his ears 'force' open his eyes: Without any awareness of what was happening to him, he found delight in the murderous contest and was inebriated by bloodthirsty pleasure. He was not now the person who had come in, but just one of the crowd which he had joined, and a true member of the group which had brought him. What should I add? He looked, he yelled, he was on fire, he took the madness home with him so that it urged him to return not only with those by whom he had originally been drawn there, but even more than them, taking others with him. (Augustine, 2008, p. 101).
Whereas previously, Alypius experienced a negatively valenced affective state to the gladiatorial spectacle, he now experiences a positively valenced affective state. Furthermore, whereas previously he construed the gladiatorial games as bad, he now construes them as good, and evaluatively endorses this judgment. Consequently, Alypius' emotional response to the games has changed from repugnance to joy. How has this come about? It appears that the non-cognitive piece (the affective piece) changed the cognitive piece (the concern-based construal): so that he comes to construe gladiatorial games as good. This account reveals that the noncognitive piece (the affective experience) may play a large role in shaping the cognitive piece (the concernbased construal). By contrast, it may be the case that, were Alypius in a moment of reflection to come to see the error of his ways and no longer desire to take joy in gladiatorial games, he could retrain the non-cognitive piece so that he does not experience positive affect at the prospect of watching the gladiatorial games. Consequently, with a more complete account of the dynamic process by which the non-cognitive piece and the cognitive pieces interact, we could have a more complete account of how joy (and particular joys) develop within an individual, and of the types of interventions that could be developed in order to ensure that they take joy in the right things.

Further methodological considerations
The main approach for studying positive emotions in the social sciences involves having participants recall an experience of that particular emotion that they have had, and then to answer questions about that experience (the background conditions, what the experience felt like, other correlates, etc.) (Bok, 2011, p. 10). Other forms of this paradigm involve investigating what inducing the experience of this particular emotion (often through recall tasks) may have on subsequent behavior and cognition (i.e. 'priming' studies). One drawback of this approach is that memory is highly plastic and prone to error; consequently, the events may not be remembered accurately. Additionally, due to a phenomenon known as 'mood congruent recall,' whereby an individual's current mood often colors how they remember previous events (Russo, Fox, Lynn, & Nguyen-Van-Tam, 2001), participants often do not accurately recall or re-experience the experience of the emotion in question. Furthermore, subsequent judgments about that experience may also affect (or have affected) how it is remembered. Finally, social desirability considerations may also play a role, whereby the participant alters their account of the event in question (e.g. to appear more socially desirable to the experimenter, who they presume will read the document in which they recount their experience of joy).
Another approach for studying positive emotions, which avoids the concerns of memory plasticity, is known as experience sampling, or ecological momentary assessment. In this paradigm, participants are alerted at random intervals throughout their day (usually by an automated beeper) and are asked to immediately answer questions about how they are feeling at that very moment when the beeper goes off. This method is highly intrusive and inconvenient for most individuals, as it requires them to stop their current activity at random (and unexpected) intervals throughout the day and answer questions. There is a concern that this inconvenience may induce negative affect and consequently affect the answers given. An alternative method, which has been proven to be just as effective, is known as the day reconstruction method (Bok, 2011, p. 32), in which individuals have a set time in which they recall and answer questions about salient moments from the day before.
One further method of measuring positive emotion is the observer approach, in which third parties rate the experience of individuals that they are observing. This can either be done through the 'known-informant' approach, in which a family member or friend of an individual reports how they perceive that individual's subjective state to be, or it can be done through the 'expert rater' approach, in which an independent third party is trained to classify individuals that they observe, along different measures (Diener, Oishi, & Lucas, 2009). The idea here is that certain experiences of positive emotion can be further verified through the confirmation of a third-party observer. Indeed, cross-cultural work by Izard (1971) and Ekman (1992) have established that joy is the most easily recognizable of the emotions, regardless of culture. Izard found that, for Asians, Europeans, and North Americans, they were able to accurately identify joy greater than 93% of the time. Some work on behavioral correlates of joy has already been done, suggesting that those in a state of joy exhibit a 'chin up' neck posture (Fredrickson & Levenson, 1998;Gross, Crane, & Fredrickson, 2010). Further experiments on other behavioral correlates of joy could investigate whether joy contributes to higher rates of spontaneous helping and other forms of prosocial action (such as charitable donations).
One problem with this approach, for joy, is that some types of joy (at the emotional, mood, or dispositional levels) may not have a distinctive outward profile. Izard and Ekman's work used fairly clear, paradigmatic cases of joy in which the target individual exhibited a broad smile. Certain types of emotional joy, or mood or dispositional joy, may not be so easy to identify. de Silentio laments how he is unable to tell the difference between the truly joyful individual, and the hedonic tax collector. From the outside, they look the same, claims de Silentio, even though the inward reality is completely different. 'No! I examine his figure from top to toe to see if there may not be a crack through which the infinite would peek. No! He is solid all the way through' (Kierkegaard, 1843(Kierkegaard, /1983. Additionally, there is evidence that some of the characteristic expressions of joy are dimorphous, simultaneous involving both happy and sad (or angry) facial expressions and behaviors (Aragón & Bargh, 2017;Aragón, Clark, Dyer, & Bargh, 2015). Finally, Nietzsche's famous parable (which actually originated with the Baal Shem Tov) about how individuals who are dancing appear insane to those who cannot hear the music, indicates the difficulty with the observer approach: unless we have a robust phenomenology of joy through which we understand their inner experience of joy, understanding the outward behavior may provide little insight for us, into the nature of joy.
Longitudinal work, in particular, will be especially important, in order to further explore the developmental trajectory of joy, and the factors that contribute to its flourishing or impede its development. Longitudinal studies also provide the opportunity to explore life outcome correlations (mortality, life satisfaction, marriage/ employment rates, rates of mental illness, etc.) for those who experience joy frequently. Longitudinal work will also allow us to explore whether there are 'set points' for joy, as evidence has suggested there may be for happiness (Costa, McCrae, & Zonderman, 1987;Diener, Sandvik, Seidlitz, & Diener, 1993;Headey & Wearing, 1989). The set point theory of happiness suggests that hereditary and early development factors combine to give each individual a 'set point' for happiness. While their level of happiness will fluctuate over short periods, when viewed over larger periods of time, their happiness will cluster around some kind of baseline. Similarly, might some individuals have a 'baseline' that means that they experience joy more readily, frequently, or across a wider diversity of situations? What types of factors may contribute to this? Previous work has estimated that 40% of the variation in positive emotionality can be explained by genetic factors (Tellegen et al., 1988), which suggests that joy may have a strong genetic or epigenetic component, and also be subject to such 'baselines' and adaptation principles. To this end, perhaps the most effective way of investigating joy would be to compare monozygotic twins reared apart with those reared together. This would provide the clearest picture into the respective roles that nature and nurture play in joy.
While most of the work on joy has been correlational, a few experimental studies on joy have been conducted. As aforementioned, priming joy through having individuals recall previous instances in which they were joyful has the attendant problems of recall bias. My literature review revealed that while there are some good experimental stimuli to induce related emotions, such as video clips that induce elevation (see, e.g., Aragón, 2017), there are not yet any standard stimuli for inducing joy. Experiments studying joy thus far have typically involved a level of imaginative engagement or perspective taking (see, e.g., Aragón & Bargh, 2017;de Rivera et al., 1989) that seems too far removed from the kind of direct interventions that are needed to be confident in its external validity. Nevertheless, it may be the case that participants can be trained to cultivate states that potentiate joy. Gillham, Reivich, Jaycox, and Seligman (1995) found that children who underwent optimism training were much less depressed than the control group, and this effect was observed to have increased even more, at the study's 2-year follow-up. Similarly, there may be some kind of training that can potentiate joy, increasing the frequency (or types) of joy experienced by the treatment group. This line of enquiry would investigate an important question: to what extent can joy be cultivated? Theologian Karl Barth writes that 'It is certainly required of man that he should continually hold himself in readiness for joy' (Barth, 1961, p. 377). Indeed, while the affective side of joy may be difficult to control, one may still be able to control the cognitive piece. Consequently, perhaps by interventions through which participants learn how to construe situations or objects as good or as gift, the noncognitive piece will fall into line and they will experience joy. This may be the secret to the kind of joy that is a spiritual fruit: perhaps these individuals are better attuned to construing more types of situations as gift and as good and with proper concern, potentiating them to the experience of emotional joy.
Additionally, it may be the case that certain behavioral patterns potentiate joy. This is certainly suggested by the fact that, as TL&GLP observes, joy can apparently be commanded, 'Joy is not simply or only the natural response to events, but can be commanded' (Wright, 2015, p. 36). There were a host of Israelite rituals, the performance of which was intended to induce joy (Anderson, 1991). In a foundational series of studies, Fordyce (1977Fordyce ( , 1983 found that by having participants imitate the characteristics of individuals high in well-being, that the well-being of his participants increased. Does joy work similarly: by imitating the characteristics of joyful individuals, can one become joyful? Perhaps not, as de Silentio relates that he can describe how to behave as the joyful individual does and can imitate him, but that de Silentio is unable to be joyful; he says it is like a man who is suspended from the ceiling in a harness and who imitates the motions of swimming: he is still not really swimming, just as de Silentio is not really experiencing the state of joy (Kierkegaard, 1843(Kierkegaard, /1983. This reveals something important, that while behavioral patterns may potentiate joy, they may not directly cause it. Joy may arrive on its own schedule. An additional and related question is the extent to which one can effortfully sustain the state of joy. One potential additional approach would be to use the methods of Experimental Philosophy, a field that seeks to clarify the lay, or commonsense, definitions and intuitions about various concepts. Experimental philosophers typically pose various vignettes to participants that concern some concept that the philosopher is studying, and ask them about the vignettes, in order to gain a better understanding of how laypeople understand these concepts. For example, Nyholm (2011) and Phillips, Misenheimer, and Knobe (2011) have used vignettes to probe participants' intuitions about the concept of happiness, and have found that participants' intuitions about whether or not an individual is truly happy are not solely driven by an assessment of the individual's affective or psychological states, but can also be affected by the participant's evaluations of whether or not that individual is living a good life. My literature review revealed that no studies have yet been run using such third-personal evaluations of vignettes (i.e. rather than first-person recollections) in order to probe lay intuitions about joy. While such work would be worthwhile, this approach has its own drawbacks, as well. A host of evidence on 'affective forecasting' has established that we are bad at imagining how we would feel in certain imagined situations (Brickman, Coates, & Janoff-Bulman, 1978;Schulz & Decker, 1985;Wilson & Gilbert, 2003). Consequently, this approach may not yield much accurate information where it concerns the phenomenology of joy.
Additionally, further studies using functional imaging technology to explore the neurobiological correlates of joy, studies on participants with brain lesions, studies utilizing transcranial magnetic stimulation (TMS) or transcranial direct-current stimulation (tDCS) to selectively activate or deactivate brain regions, or psychotropic interventions could all be used to get at the neurophysiological processes underlying joy. Other physiological correlates such as galvanic skin response, heart rate, pupil dilation, etc., while experiencing joy could also be explored.
One final point about the exploration of joy regards the hedonic treadmill and adaptation. As aforementioned, although experiences of happiness fluctuate, we generally return to our baseline levels of happiness and life-satisfaction, such that subjective well-being is fairly stable across decades (Costa et al., 1987;Diener et al., 1993). Consequently, happiness is subject to adaptation, whereby when we enjoy increased levels of happiness, we habituate to the new level (Brickman & Campbell, 1971). The upshot of this is that we get stuck on the 'hedonic treadmill' and keep pursuing different goods that will make us happy, so that we can experience increased levels of happiness, to which we inevitably habituate, in turn. Kierkegaard expressed this idea in Either/Or, suggesting that the aesthete runs on the hedonic treadmill by using the 'rotation method,' whereby he rotates his pleasures as a farmer rotates his crops, in order to escape the boredom that comes with the habituation to previous pleasures (Kierkegaard, 1843(Kierkegaard, /1987. By contrast, G. K. Chesterton suggests that joy, unlike pleasure, is able to resist habituation. Chesterton illustrates this with the example of how children (and, he suggests, God) seem to possess the ability to continually delight in seeing the same thing over and over. He reminds us that we must become like little children in order to experience true joy: 'It is possible that God says every morning, "Do it again" to the sun; and every evening, "Do it again" to the moon . . . It may be that He has the eternal appetite of infancy; for we have sinned and grown old, and our Father is younger than we' (Chesterton, 1927, pp. 106-107). Perhaps, if joy, unlike happiness, resists habituation, we may be able to 'become younger,' whereby we develop an attunement to joy that resists our habituating to it.

Conclusion
In the first part of this paper, I have proposed that we ought to clearly delineate the limits around joy, so that we are certain of which concept we are speaking. To that end, I have suggested that joy can be viewed as an emotion, mood, disposition, or spiritual fruit. As an emotion, it is a positive affective state involving a concern-based construal, that takes an intentional object construed as good and experienced as 'gift.' The affective side of joy can be experienced as more or less intense: excited joy engages the dopaminergic system and involves vigorously pursuing a goal, serene joy indicates that the body is at equilibrium. Joy is primarily shared with others, and can happen in response to some desire being fulfilled, or in anticipation of the desire being fulfilled (particularly in cases of suffering). Joy involves physical and cognitive freedom to 'broaden and build,' which involves exploring and creating new motor, behavioral, and cognitive schemas and new social relationships and resources. Broadening and building is closely associated with play. At the upper limit of joy is ecstasy or bliss: once too much selftranscendence has occurred, one loses one's selfconsciousness and enters ecstasy, which is not joy. Joy, if anything, involves a greater sense of self-consciousness, whereby one experiences becoming more truly oneself, not losing the self. Elation and gladness may be types of joy.
As a mood, joy is the state in which one is potentiated to experience joy, but it is not as stable or as long-lasting of a state as a disposition. As a disposition/trait, joy involves having a low threshold for having joyful experiences and experiencing joy more frequently across a wider variety of circumstances. As a spiritual fruit, one both has the disposition of joy, and also has some additional piece which involves some constant and pervasive spiritual sense of satisfaction, confidence, or gratitude.
The case of Alypius reveals that the non-cognitive piece may alter the cognitive piece: here, a positive affective state resulting from enjoying the gladiatorial spectacle changed his concern-based construal so that he came to see the gladiatorial games as good, and they came to bring him joy. It may be the case that we can use our concern-based construals (the cognitive piece) to retrain our affective states, so that we experience positive affect in the proper ways, in response to the proper objects. Perhaps the work of cultivating ourselves for joy involves retraining our cognitive piece so that we construe more situations as gift and as good, and in so doing the noncognitive piece will fall into line, as we are potentiated to joy.
Additionally, language and culture can shape phenomenological content, and so more cross-cultural work is needed to investigate the ways in which language and culture shape the experience of joy (particularly since joy, in the West, is often defined by its ineffability). Some further lines of empirical work were suggested, along with the strengths and weaknesses of each possibility.

Joy and the imagination
The imagination, and our ability to experience joy through the exercise of it, plays a host of important functions. Firstly, it provides an important educational function, as the imagination allows us to train our affections. The philosopher McGinn (1997), argues that while the primary mode of ethical discourse and reflection in analytic moral philosophy involves considering the application and analysis of rules and concepts, that the parable is actually a more natural mode of moral thinking and discourse. It is the parable that should be the primary unit of ethical discourse and reflection, and it is through stories that we train and test our moral affections. Similarly, experiencing joy in the imagination, and training it through various stories, daydreams, etc., may train and potentiate an individual to experience joy in the right way, and in response to the right intentional objects (see also Johnson, 2019).
Secondly, experiencing joy allows us to feel more deeply connected to others (real or imagined). Wiman (2017, p. xxxvi) relates how by reading a passage by Edith Stein, you are able to feel some of her joy, 'Obviously, one is not meant to understand this [passage] in the way one understands a newspaper article or even in the way one understands most poetry. You are meant to get lost in its vertiginous precisions, the weird syncopations of syntax and skin. You are meant to feel something of what Stein felt: joy.' Thirdly, the imagination provides the possibility to unite or re-unite oneself with the longed-for intentional object. For example, this allows one to take joy in the memory of one who is deceased. In this case, the intentional object is made present, in the imagination, thereby uniting the individual with their deceased beloved. Similarly, the imagination can also make present a longed-for, future situation. In this way, the anticipated joy of the better future turns into present joy, as the better future is inaugurated and made present in the imagination. The future joy turning into present joy creates a motivational state in the individual, in which they receive additional motivation to work to bring that future about. TJ&GLP relates how joy can be expressed in the three tenses of past (over the good that we have received), present (over the good that is happening to us now), and future (over the good that will come in the future) (Thompson, 2015). 'Joy is the present tense, with the whole emphasis on the present,' as Kierkegaard (1849Kierkegaard ( /1971 wrote, and it is the imagination that brings future and past joys into the present.

Joy and the life story
Potkay takes some of the intentionality of joy to involve situating the intentional object within a narrative context. In order to understand why the intentional object is good, we have to be able to tell a story that properly situates it and explains our joy. After all, as philosopher Alasdair MacIntyre states, 'man is . . . essentially a story-telling animal' (MacIntyre, 1981, p. 216). This is especially important for understanding how joy can happen despite sorrow and suffering. If the sorrow and suffering can be rightly situated in one's life story, such that it will be or has been redeemed or rewarded, then one is able to rejoice. In this way, the life story can transform negative situations and conditions by construing them in positive ways. For example, when the Apostle Paul writes that we ought to be 'sorrowful, yet always rejoicing' (2 Cor. 6:10 New Revised Standard Version), or that 'I am overjoyed in all our affliction' (2 Cor. 7:4), he is relating how he realizes that he is sharing in the larger narrative of the movement from loss/persecution for the sake of the Kingdom to eventual redemption and exultation (a narrative in which Christ is the forerunner) (Wright, 2015). Paul's joy stems from the cognitive realization that he is sharing in this project: that he is internally and narratively integrated by growing into greater union with God, through following the path Jesus laid out (a path that involves suffering). Kierkegaard expresses it this way, 'How different, on the other hand, if the only joy is to follow Christ. Indeed, there can be no higher joy than this: to be able to become the highest . . . ' (Kierkegaard, 1847(Kierkegaard, /1993. Psychologist McAdams (1994McAdams ( , 2001) relates how wellbeing involves vertical integration of all three levels of an individual's personality: biological, psychological, and narrative. Joy results from the recognition of one's internal integration, whereby one recognizes that one's suffering and sorrow (at the biological and psychological levels, respectively), are consistent with, and vital to, one's life story. Kierkegaard, in his Upbuilding Discourses in Various Spirits, drives this point home with the repeated phrase: 'the joy is that suffering is the road' (Kierkegaard, 1847(Kierkegaard, / 1993. Similarly, the literature on posttraumatic growth (Nolen-Hoeksema & Davis, 2002;Tedeschi, Park, & Calhoun, 1998;Updegraff & Taylor, 2000) has revealed that reconstruing a traumatic experience as a situation that was conducive to one's growth, thereby incorporating it into the life story, contributes to an individual's well-being and a higher level of functionality (at least in some respects) than before. This raises the question as to whether suffering, as it contributes to posttraumatic growth, may be conducive to experiencing joy more fully. Although suffering, in itself, is aversive and undesirable, perhaps certain amounts of it are necessary, in order to bring about the type of growth needed to enter into joy more fully.

Joy contagion and transference
Network analysis has discovered that happiness spreads up to three degrees of separation, and that those who are surrounded by many happy people are more likely to become happy (Fowler & Christakis, 2008). Perhaps it is also the case with joy: perhaps the frequency or intensity of joy can spread up to many degrees of separation, and being surrounded by joyful people potentiates joy. A network analysis conducted for joy would prove helpful, as it would provide empirical evidence for the contagion effects of joy. Additionally, experimental work has revealed that sharing with others about positive experiences that one has had increases one's own positive affect (Lambert et al., 2012). Consequently, this suggests that we experience increased joy (or something like it) from sharing about our own joy or good news with others. As theologian Volf (2015, pp. 132-3) writes, 'Joy is best experienced in community. Joy seeks company ("come and rejoice with me") and the company of those who rejoice feeds the joy of each.' The social aspect of joy raises an important question about the nature of shared joy: is it joy that is simulated or shared? When we experience other emotions on another's behalf, we often experience them by having 'put ourselves into their shoes.' By so doing, we are simulating having their experience, in our mind's eye or bodies. If we see our friend hit their thumb with a hammer, we instinctively draw back our own hand and shudder, because we are sympathetically simulating the experience of hitting our thumb with a hammer. Similarly, if one watches another individual parachute off of a cliff, the first individual may experience fear, due to sympathetically simulating the perspective of the second individual.
By contrast, however, there is good reason to think that joy may not always work like that: joy may simply be shared without being simulated. Consider the Greek word for shared joy, sunchairein: it is used in the Septuagint to describe how Sarah, after years of childlessness and finally pregnant in her old age, exclaims that 'GOD has given me good reason to laugh, and everyone who hears will laugh with me [i.e. they will rejoice with me]' (Morrice, 1984, p. 76). Later, sunchairein is used in Luke 1:58 to describe how the neighbors, friends, and relatives of Elizabeth share in her joy at the birth of John the Baptist,' "They were as delighted as she was" on account of "the great favour the Lord had shown her"' (Morrice, 1984, p. 77). In both Sarah's and Elizabeth's cases, we do not have people simulating their joy (i.e. they are not imagining what it is like to have given birth to a child of a promise in old age), people are simply sharing in the joy. Additionally, it is not merely a simple detached gladness on behalf of another's good fortune; instead, it involves active participation in the celebration of the child, even though the good fortune of the birth does not necessarily directly intersect with how one's own life is going. Furthermore, sunchairein is the same word used in the parable of the lost sheep (Luke 15:6). Upon finding his lost sheep, the shepherd exclaims 'rejoice with me!' Here, the shepherd feels compelled to proclaim and share his good news (perhaps because of the aforementioned insight that sharing joy increases one's joy). The joy that is shared in this way, however, seems to be very different from many of the existing accounts previously mentioned, which focused on joy's connection to life going well and being led well. How, then, can one share another's joy when it involves a good seemingly disconnected from the agential and circumstantial dimensions of one's own life? It must be that joy is a self-expanding emotion, such that one can come to identify the good of the other with one's own good. When it goes well for one's friend, therefore, it goes well with oneself. Indeed, Aristotle wrote that an individual's own flourishing requires the happiness of his family and friends, because he 'stands in the same relation to his friend as to himself (his friend being another self)' (Aristotle, 2014, pp. 167-168). Similarly, 1 Corinthians 12:26 relates how when one member of the church suffers, all of the other members suffer with her, but if one part flourishes, all rejoice with her. Here, the self expands, so that it is able to share its joy: allowing oneself to enter into the joy of others, and allowing others to enter into one's own joy by sharing one's own joy (see, e.g., Philippians 2:17). In the process of sharing, the joy itself may get amplified. By engaging in a process of self-expansion, so that the good of the other is seen as one's own good, one is able to construe the situation in which another has some good thing happen to them as positive and worthy, and one delights in it rather than envying their neighbor. As Kierkegaard explains, 'You shall not covet what is the neighbor's and therefore not the advantage granted to him in this life either. If it is denied to you, then you should still rejoice that it is granted to him' (Kierkegaard, 1847(Kierkegaard, /1995.
Part III: the aversive side of joy

Counterfeit joy and schadenfreude
Because joy is often defined in morally neutral terms, it is incumbent upon at least some theorists to engage in the normative work of delineating the type of joy that is normatively desirable (i.e. rightly ordered joy that takes acceptable intentional objects, and is experienced rightly). Without such a framework in place, we will be unable to distinguish normatively desirable joy from pathologically afflicted joy, or what the theologian Karl Barth terms 'counterfeit joy' (Barth, 1961, p. 69). As mentioned earlier, Nyholm (2011) andPhillips et al. (2011) found that participants' conceptions of happiness had a place for evaluative judgments about whether or not the target individual was living a good life. Similarly, Potkay observes that the ordinary concept of happiness includes an ethical evaluation component, but suggests that joy does not: 'Why, for example, does it make sense to say that Adolf Hitler may have experienced moments of joy (even if "evil joy"), but not to say, "Adolf Hitler had a happy life"?' (Potkay, 2007, p. 20). Demarcating the limits of joy in such a way as to differentiate true joy from pathologically afflicted joy (i.e. 'evil joy') will require further reflection on the nature of counterfeit joys.
The joy that takes another's damage as its intentional object is warned against in multiple places in the Bible. Proverbs 24:17 commands, 'Do not rejoice when your enemies fall, and do not let your heart be glad when they stumble.' Furthermore, 1 Corinthians 13:6 explains how one should not take the wrong intentional object for one's joy ('it does not rejoice in wrongdoing'), but ensure that one takes the correct intentional object ('but rejoices with the truth'). The current consensus from the psychological literature is that schadenfreude is the result of mankind's being wired for competition (Millar, Millar, & Tesser, 1988). Consequently, we rejoice in damage to the other, because their damage elevates our relative social standing. Schadenfreude is also an ingroup binding emotion: experimental work has found that one experiences greater schadenfreude for a rival out-group member, the more one identifies with one's own in-group (Combs, Powell, Schurtz, & Smith, 2009;Hoogland et al., 2015). Additional experimental work has found that participants report experiencing pleasure in response to non-rival out-group members' failures, and watching rival out-group members fail is associated with activation of the ventral striatum (VS), an area of the brain linked to pleasure (Cikara, Bruneau, & Saxe, 2011). In sum, one of the forms of counterfeit joy may be schadenfreude, in which watching others fail is often an occasion for (counterfeit) joy, especially when they are a rival out-group member. Schadenfreude is primarily driven by a desire for one's own social standing to increase, and so one takes joy in the misfortunes of others that lower their relative social standing.
Joy that is too intensetears of joy Averill (1975) suggests that we prefer calm and serene emotions to highly activated ones. Our bodies aim at equilibrium, and joy may be the state that is a response to our bodies being in a comfortable, rightly regulated state of equilibrium. As Damasio (2003, p. 137) explains, 'The [somatic] maps associated with joy signify states of equilibrium for the organism. Those states may be actually happening or as if they were happening. Joyous states signify optimal physiological coordination and smooth running of the operations of life.' If joy is too intense, therefore, it may be experienced as aversive, because the intensity of the experience has taken the body out of equilibrium. Evidence for this suggestion comes from the fact that we sometimes shed tears of joy. Intense joy may be an aversive state to maintain, and the tears of joy may be our body's attempt to restore equilibrium (Aragón, 2017). Frey (1985) proposed that crying facilitates well-being, by enabling stress hormones (e.g. cortisol) to be released from the body through the tears. Vingerhoets and Kirschbaum (1997) found preliminary evidence for this, reporting that cortisol levels decreased more dramatically in women who had cried more while watching an emotional video clip. If this stress hormone reduction model is correct, it suggests that at least some types of crying are aimed at bringing the body back into equilibrium, modulating the intensity of the emotional experience (Gračanin, Bylsma, & Vingerhoets, 2014). Moreover, when participants encounter individuals exhibiting smiles of joy, they engage in capitalization responses (which encourages those individuals to increase their joy), but when they encounter individuals exhibiting tears of joy, they engage in downregulation responses (to decrease the other's emotional response) (Aragón & Clark, 2018). This likely suggests that the participants on some level realized that tears of joy indicate that the emotional state is somehow aversive in its intensity, and so they seek to decrease its intensity. Other research found that increasing feelings of ecstasy through stimulating pleasure centers of the brain can also increase feelings of anxiety (Synofzik, Schlaepfer, & Fins, 2012). All of this points to the idea that joy which is too intense may be aversive. Consequently, the type of joy characteristic of 'the good life' may involve a less intense form of joy (i.e. one in which the body is at equilibrium) or one in which the intense joys do not occur too frequently.
Furthermore, religious mystics sometimes describe falling into a deep depression after intensely joyful religious experiences (see, e.g., Julian of Norwich, 1670/ 2015; St. John of the Cross, 1622/1995). Consequently, it may be the case that joy, particularly in its more intense forms, may often be followed by a period of low or negative affect. If we follow an analogous line of reasoning, Damasio relates that mood-enhancing or mind-altering drugs, ' . . . do induce sorrow and depression on the rebound from the joyous highs they produce at first. For example, it is reported that the drug ecstasy produces highs characterized by a quietly pleasurable state and benign accompanying thoughts. Repeated use of the drug, however, induces more and more severe depressions, which follow highs that become less and less so' (Damasio, 2003, p. 138). Analogously, then, it may be the case that just as the pleasurable highs induced by drugs are followed by an inevitable period of depression, so too might it be the case that certain types of naturally occurring joys also are followed by periods of depression, as the brain and body reset back to equilibrium. Wiman (2017, p. xii) describes how 'this lift into pure bliss might also entail a steep drop of concomitant loss.' Discovering the process by which this happens, uncovering the underlying neurobiology, and understanding how to mitigate the resulting depression merit further work.

Part IV: acedia
In trying to understand what joy is, we have explored its relationship to related concepts, such as hope, gratitude, happiness, elevation, bliss, etc. We have also looked at its relationship to its structural opposite, sorrow (or depression). Potkay (2007, p. 2) suggests that 'Joy may also be defined negatively, by differentiating it from related but distinct concepts' and Aquinas writes that 'One opposite is known through the other, as darkness through light' (Aquinas, 2017, ST I.48.I). Perhaps a similar move can be made here, in which we explore joy through what Aquinas suggests is its opposite, acedia. There is perhaps an analogy here to developments made in the early days of positive psychology, where much progress was made in the exploration of the phenomenon of learned optimism (Seligman, 1991) by building off of the literature about its opposite, learned helplessness (Seligman, 1972). Consequently, we might better understand joy if we explore it alongside its opposite, acedia. Indeed, poet Adam Zagajewski (2002/2017, p. 60) calls joy the 'laughing sister of death.' Through better understanding the death that is acedia, how might we better understand joy?
Acedia involves apathy toward, indifference to, or even sorrow of the good as good. Hence, it fails to construe an intentional object that rightly ought to be the source of joy as being good (Aquinas, 2017, ST II-II. 35.I). The Latin ecclesiastical tradition portrays it ' . . . alternately as joylessness and as laziness, as inclining to chattering and as inclining to muteness, as driving one to seek solitude and as driving one to flee one's cell and seek company' (Thorp, 2005, p. 162). The one suffering from acedia is driven to distraction, because their apathy has led to a crushing boredom, and they seek any recourse that could possibly stimulate and distract them from it. The continual drive to distraction, or divertissement (which Mathewes, 2015, p. 79] translates as 'the channel-surfing of the soul'), makes it impossible to live in the present, which is required for joy. The lack of acknowledgement of any self at all crowds out the self-consciousness required for joy (and which is often heightened in joyful experience). In joy, one becomes more truly oneself; in acedia, the self perishes. Moltmann (2015, p. 14) describes the dangers of acedia as the following: ' . . . when we are wounded and resigned and withdraw love from life, we lose interest in living and become apathetic. Then we no longer feel the disappointments, the injustice, and the pains, but we don't really live anymore either. We are spiritually petrified, and our hearts turn to stone. Nothing touches us either, neither good nor evil, and that is the first step on the road to death. It is the death of the soul, which goes ahead of the death of a person.' Indeed, acedia is the ultimate protection against vulnerability, but that also makes it the ultimate protection against joy. In the most intense form of acedia, one experiences a kind of second-order acedia, in which they cannot even bring themselves to care that they do not care. Moltmann (2015, pp. 11-14) also argues that acedia leads us to a 'fun seeking society' (Spaβgesellschaft), while properly situated joy leads us to stand up to injustice, as a vision of a better world encourages us to work to inaugurate it in the present. Perhaps, then, deep and abiding joy that is properly situated in the good life holds the most potential for addressing the acedia of our age.

Part V: why research joy?
Former President Barack Obama repeatedly trumpeted empathy as 'a quality of character that can change the world' (Mieder, 2009, pp. 300-301), and it was around the time of his presidency that 'empathy' was very much in vogue, and heralded by some as the capacity that had the potential to 'save the world' (reflected by the fact that a host of recent research, conferences, and funding have centered around the topic of empathy). Nevertheless, empathy, or more specifically, affective empathy (the emotional response we have to another's emotional state), has become something of a controversial topic recently, with figures such as Paul Bloom, Jesse Prinz, and Peter Singer spearheading the (somewhat misleadingly titled) 'against empathy' movement. They argue that affective empathy can be biased in a host of ways (e.g. by the identifiable victim effect, by biasing individuals toward their in-group at the expense of the out-group, by compassion fatigue, etc.), and so it should be discouraged and cognitive empathy (a more reflective, calculated, and non-emotional form of empathy) ought to be encouraged instead (Bloom, 2016;Prinz, 2011).
Consequently, joy may be better situated than empathy, as a phenomenon on which to focus research, if a motivation is global impact and the promotion of human flourishing. Affective empathy is subject to compassion fatigue or empathic distress fatigue, whereby the aversive emotions experienced in response to another's suffering can be deeply draining and even demotivate an individual from helping the individual in need (Klimecki & Singer, 2012). By contrast, the existing psychological research discussed in this article has shown that joy potentiates action and is energizing. Joy provides the motivational resources to act, to intervene, to improve. Joy is also often contagious, it involves transference as we share and spread joy. One challenge for joy is that just as affective empathy biases individuals toward the in-group, and increases the likelihood that they will be willing to harm out-group members, certain types of joy (as discussed earlier in the research on schadenfreude) may also have this problem. Indeed, Potkay (2007) notes that the joy of the disciples (as depicted in the Gospel of John) may have been of this type of other-excluding joy, involving hostility to the out-group (i.e. it involved opposition to 'the world' and those who are of it). There may, however, be a form of joy that is not inherently other-excluding but is necessarily other-embracing. What might this look like?
The Talmud's explanation for why the Second Temple was destroyed involves a story in which a man threw a wedding banquet for his son, but accidentally invited his enemy. When his enemy showed up at the banquet, the man commanded him to leave. His enemy pled with him three times, even offering to pay for the entire banquet, but was still thrown out. Because of the humiliation he suffered, and because none of the rabbis present at the banquet intervened to help him out, he went to the Roman authorities and lied, saying that a Jewish rebellion was imminent. The Romans then destroyed the Temple. Rabbi Schlomo offered a commentary on this story, suggesting that the man must not have actually been present at his son's wedding banquet when the events occurred, because if he was, he would have been so full of true joy that he would have been unable to reject his enemy. Rabbi Schlomo maintained that 'There is only one antidote to hatred: joy. If we are dreaming of the whole world being one, it will only happen with joy' (Buxbaum, 2002, p. 107).
This form of joy ('other-embracing joy') is in contrast to the counterfeit joy of schadenfreude that takes the harm of another as its intentional object ('other-excluding joy'). Other-embracing joy takes the goodness of union with the other (through self-expansion) as its intentional object. If this form of joy could be cultivated, of the kind that crowds out hate (even for the out-group), and embraces the other in their alterity and on their own terms, then cultivating this form of joy may hold some of the most potential for promoting human flourishing. Though the acedia of our age may be drowning many, more research into joy may enable us to one day soon find the words of life.

Conclusion
This paper argued that the best way forward for synthesizing the existing psychological work on joy, and for providing recommendations for future work, is to more clearly delineate the limits of 'joy,' as a construct. Consequently, I suggested clearer demarcations that can be drawn around joy and identified different, but related concepts that are often confused with joy. Clearer delineations within the concept of joy itself were also proposed, in order to further distinguish the different types of joy. Secondly, this paper explored 'the limits of joy' in another sense, by arguing that certain forms (and frequencies) of joyful experience may actually be detrimental to the good life. Over the course of developing all of these arguments, I suggested areas in which there may be methodological hurdles to be navigated in studying joy, suggested ways in which these hurdles could potentially be navigated, and suggested the areas that I see as the most urgent to address in the interdisciplinary exploration of joy. At the end of the paper, I argued that while much of the literature (theological and social scientific) thus far has focused on exploring joy's relationship to its structural opposite (depression, or sorrow), that future research would do well to also explore acedia's relationship to joy. Finally, I concluded by summarizing what I see to be the upshot of all of the arguments I have made in the paper: that if those researching joy hit upon how to properly delineate the limits of joy so that one could cultivate the right type of joy in the right ways, that joy may be the psychological phenomenon that has some of the most potential for bringing about a greater degree of human flourishing, and may hold some of the most promise for addressing the challenges of our age.