Understanding massively multiplayer online role-playing game addiction: A hedonic management perspective

Massively multiplayer online role-playing game (MMORPG) addiction presents a serious issue worldwide and has attracted increasing attention from academic and other pub-lic communities. This article addresses this critical issue and fills research gaps by proposing and testing a research model of MMORPG addiction. Building on the conceptual foundation of the hedonic management model of addiction and the technology affordance perspective, we develop a research model explaining how MMORPG affordances (ie, achievement, social and immersion affordances) are associated with the duality of hedonic effects (ie, perceived positive mood enhancement and perceived negative mood reduction) and the extent of MMORPG addiction. Using structural equation modelling, we empirically test our research model with 406 MMORPG players. The results show that both perceived positive mood enhancement and perceived negative mood reduction positively correlate with the extent of MMORPG addiction. Furthermore, achievement and immersion affordances are positively associated with the duality of hedonic effects, whereas social affordance is not. Our study contributes to the growing body of technology addiction literature by revealing the relationships between the two hedonic effects and the extent of MMORPG addiction, and by offering a contextualised explanation of the role of MMORPG affordances in these relationships. We offer an alternative perspective on the far-reaching, unintended relationships between technological affordances and addictive technology use. Our study provides game developers and policymakers with insights into preventing MMORPG addiction to create an entertaining, healthy virtual playground. This study has several important implications for practitioners and policymakers. Our findings show that achievement and immersion affordances are positively correlated with mood-modifying abilities, whereas social affordance does not exhibit any significant effect. These findings offer MMORPG developers insights into designing preventive functionalities within MMORPGs. In relation to achievement affordance, MMORPG developers might, for example, consider introducing a voluntary fatigue system, also known as a reward reducing system, that would gradually reduce gained experiences and skill points for players after a certain time limit or prolonged gaming. When players experience some symptoms of MMORPG addiction, they could voluntarily make use of the fatigue system to manage their MMORPG use. The fatigue system might reduce the players' perceived achievement affordance in the gameplay, potentially dissuading them from engaging in potentially dangerous marathon gaming sessions. In relation to immersion affordance, MMORPG developers might, for example, consider introducing alternative login servers that allow players to voluntarily limit the amount of time spent in each gaming episode. Through this functionality, players can log in through a server that limits each gaming episode to 2 hours per day. Such a preventive functionality might reduce the players' perceived immersion affordance from playing MMORPGs. However, we acknowledge that introducing such preventive functionalities to MMORPGs might reduce the players' satisfaction, which in turn could hurt gaming companies' revenue. Game developers are advised to make such preventive functionalities voluntary for players. Thus, players who perceive themselves as vulnerable to MMORPG addiction can make use of such functionalities. Other players, such as those who can regulate their gameplay and/or experience no negative consequences, can continue their usual gaming patterns and derive maximum joy from playing MMORPGs. Our findings also offer psychiatrists insights into possibilities for developing intervention programmes. As seen in the hedonic management model of addiction, players who regard playing MMORPGs as a desirable, useful activity for obtaining a good hedonic tone might repeatedly play the games. Therefore, the success of intervention programmes hinges on helping players identify alternative hedonic sources and activities that are capable of enhancing their positive mood and/or reducing their negative mood. As MMORPGs are tied

body of technology addiction literature by revealing the relationships between the two hedonic effects and the extent of MMORPG addiction, and by offering a contextualised explanation of the role of MMORPG affordances in these relationships. We offer an alternative perspective on the far-reaching, unintended relationships between technological affordances and addictive technology use. Our study provides game developers and policymakers with insights into preventing MMORPG addiction to create an entertaining, healthy virtual playground.

| INTRODUCTION
In response to the call for information systems (IS) research on the dark side of technology use (Tarafdar, Gupta, & Turel, 2015), research on technology addiction has grown steadily in the IS discipline. Most technology addiction studies have been conducted in the context of hedonic technologies, with social networking sites and online games being the most popular research foci (eg, Gong, Zhang, Cheung, Chen, & Lee, 2019;Hyun et al., 2015;Xu, Turel, & Yuan, 2012;Xue et al., 2018). One possible reason for the increasing scholarly attention to online gaming addiction is that more individuals are spending time on online leisure activities every day. Recent market research demonstrates the prominence of gaming in the online entertainment industry, with 86% of Internet users reporting online gaming in the previous month (GlobalWebIndex, 2018). Furthermore, there is ample evidence of the negative consequences of online gaming addiction, such as reduced decision-making ability, interpersonal problems, mental and physical health problems and even death (Lee, 2013;Thomas, 2014;Ye, 2015). Recognising the severity of the problem of online gaming addiction, the World Health Organization included gaming disorder in the eleventh revision of the International Classification of Diseases (ICD-11), and the American Psychiatric Association included Internet gaming disorder as a "condition requiring further study" in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DMS-5), signalling the potential dangers associated with online gaming.
Massively multiplayer online role-playing games (MMORPGs), which involve players customising their fictional in-game characters, interacting with other game players, and exploring never-ending immersive virtual worlds, are regarded as potentially addictive (Bacchini, De Angelis, & Fanara, 2017;Hsu, Wen, & Wu, 2009;You, Kim, & Lee, 2017). MMORPG addiction is a psychological state of maladaptive dependency on playing MMORPGs, which is "manifested through an obsessive pattern of IT-seeking and IT-use behaviours that take place at the expense of other important activities and infringe normal functioning" (Turel & Serenko, 2012 , p. 514). A multinational study finds that the rate of MMORPG addiction among sampled respondents ranges between 3.6% and 44.5%1 (Hussain et al., 2012). Indeed, the MMORPG population has increased steadily, and the top five MMORPGs in 2020 together account for 14.5 million players (Babalon, 2020). Given the large population of MMORPG players worldwide, even a small MMORPG addiction rate would imply enormous challenges to individuals and society. MMORPG addiction is a serious societal issue (Hsu et al., 2009;Kim, Kim, Shim, Im, & Shon, 2013;You et al., 2017), and it deserves further attention from governments, game developers, and the scientific community.
Understanding MMORPG addiction is important to the scientific community for several reasons. First, like the online gaming addiction literature in general, most MMORPG addiction studies stem from the clinical psychology, medical and psychiatry fields. These studies primarily focus on (a) aetiology (eg, risk factors), (b) pathology (eg, assessments and prevalence) and (c) ramifications (eg, negative consequences and treatments). There is a lack of theoretical explanation for the psychological mechanisms underlying MMORPG addiction. Second, the primary reason people play MMORPGs is for entertainment (Mancini & Sibilla, 2017). Although researchers argue that players engage in online gaming to enhance positive mood and reduce negative mood (Barnett & Coulson, 2010), the two types of hedonic effects have not been systematically investigated in the context of MMORPG addiction. The positive and negative reinforcement mechanisms are relevant and appropriate to the study of MMORPG addiction. For example, MMOPRGs use reward schedules-wherein players are presented with numerous tasks and rewarded upon completion-to encourage prolonged gaming (Snodgrass, Lacy, Dengah, & Fagan, 2011b;Taylor & Taylor, 2009).
Additionally, immersion in the virtual worlds of MMORPGs helps players to cope with their negative mood, which in turn encourages continuous gaming (Blasi et al., 2019). Third, researchers have repeatedly called for the inclusion of technology-or context-specific variables in IS research (Hong, Chan, Thong, Chasalow, & Dhillon, 2014). Although there is growing interest in understanding the role of IT artefacts and designs in technology addiction (eg, Nyamadi & Boateng, 2018;Yang, Liu, & Wei, 2016), the effects of contextual factors on MMORPG addiction continue to be under-investigated. Considering that MMORPG addiction is a serious societal issue and gaps remain in the literature, our primary research objective is to enrich our theoretical understanding of MMORPG addiction by examining the relationships among MMORPG-specific variables, the duality of hedonic effects, and the extent of MMORPG addiction.
To achieve our objective, we draw on the hedonic management model of addiction (Brown, 1997) to construct our model. In particular, we examine how the duality of hedonic effects (ie, perceived positive mood enhancement and perceived negative mood reduction) correlates with the extent of MMORPG addiction. We extend the hedonic management model of addiction by using the technology affordance perspective (Markus & Silver, 2008) to examine how MMORPG affordances are associated with the duality of hedonic effects in gameplay.
The article is organised as follows. In Section 2, we review the extant research on technology addiction, online gaming addiction, and MMORPG addiction. We then introduce the hedonic management model of addiction and the concept of technology affordance, which are the theoretical foundations of our study. In Section 3, we present our research model and hypotheses. We describe our methods and report our results in Sections 4 and 5. In Section 6, we discuss our findings, highlight their implications for both research and practice, and outline potential avenues for future research.

| Technology addiction
We note certain research patterns in the IS literature on the increasingly important topic of technology addiction.
First, studies on technology addiction are conducted in the context of utilitarian, dual-purpose and hedonic technologies with divergent foci. For instance, Turel, Serenko, and Bontis (2011) examine addiction to utilitarian technologies in the context of email, focusing on the resulting negative consequences for family (ie, technology-family conflict and work-family conflict) and work environments (ie, work overload and reduced organisational commitment). Soror, Hammer, Steelman, Davis, and Limayem (2015) investigate addiction to dual-purpose technologies in the context of mobile phones, focusing on both the antecedents and the negative consequences. Furthermore, most studies are conducted in the context of hedonic technologies and focus primarily on social networking sites (eg, James, Lowry, Wallace, & Warkentin, 2017;Turel, 2015;Turel & Serenko, 2012). MMORPGs do not receive commensurate scholarly attention in the IS literature. Second, researchers consistently highlight the role of hedonic effects, such as enjoyment (eg, Turel & Serenko, 2012), playfulness (eg, Jia & Jia, 2008) and flow (eg, Theotokis & Doukidis, 2009) in technology addiction. These studies, however, examine such hedonic effects on the extent of technology addiction primarily from the positive reinforcement perspective. There is a lack of attention to the negative reinforcement perspective (eg, reducing negative mood or feeling states) in explaining technology addiction. The relationships between the duality of hedonic effects and technology addiction warrant further investigation. Third, in contrast to studies on positive technology uses-which are rooted in prominent theoretical frameworks such as the technology acceptance model, the IS success model, and the IS continuance model-studies of technology addiction adopt diverse theoretical frameworks and lenses, such as uses and gratifications theory (eg, Li, Guo, & Bai, 2017), cognitive-affectivebehavioural model (eg, Wang, Lee, & Hua, 2015) and flow theory (eg, Zhang, Chen, Zhao, & Lee, 2014). While such theoretical diversity enhances our understanding of technology addiction from different perspectives, this study contributes to the literature by providing a systematic investigation of the duality of hedonic effects and the extent of technology addiction.

| Online gaming addiction and MMORPG addiction
Online gaming addiction is an emerging topic. Young (2009) emphasises that to understand online gaming addiction, it is crucial to know how such addiction stems from the creation of virtual worlds. Online games are video games that are played on the Internet using a variety of gaming platforms (Rollings & Adams, 2006). Online games vary in genre.
There are, for example, first-person shooter games, real-time strategy games, and massively multiplayer online roleplaying games. Each game genre has unique gameplay interactions (Quandt & Kröger, 2014). For instance, firstperson shooter games centre around weapon-based combat from a first-person perspective, whereas role-playing games emphasise role-playing characters in a fictional virtual world. Although online gaming addiction is the subject of increasing scholarly attention, prior studies primarily focus on generic antecedents, such as personality traits and psychopathological conditions (eg, Hyun et al., 2015;Lee, Ko, & Lee, 2019;Mehroof & Griffiths, 2010), and tend to overlook the effects of game-specific variables.
This study focuses specifically on MMORPG addiction. We conduct a literature review to understand the research state of MMORPG addiction, and review studies that focus on MMORPGs in particular and those that examine online gaming addiction in the context of MMORPGs. Our literature review reveals several research patterns that motivate our investigation (see Appendix A of Data S1 for a summary of the studies). Most extant studies focus on examining antecedents or risk factors correlated with addiction. Personality traits are among the most studied antecedents to online gaming and MMORPG addiction (eg, Charlton & Danforth, 2010;Hu, Zhen, Yu, Zhang, & Zhang, 2017;Mehroof & Griffiths, 2010), followed by psychopathological conditions, such as anxiety, loneliness and depression (eg, Hyun et al., 2015;Lee et al., 2019;Mehroof & Griffiths, 2010), and demographic variables, such as age, gender, gaming time and players' experience (eg, Hussain et al., 2012;Hussain & Griffiths, 2009b;Hyun et al., 2015). As most studies stem from the clinical psychology, medical and psychiatry fields, they tend to focus on diagnostic aspects and investigate the direct relationships between antecedents/risk factors and addiction.
The generic factors that predispose players to addiction-such as personality traits, psychopathological conditions and demographic variables-are extensively researched and can be applied to different online game genres, including MMORPGs. However, the effects of MMORPG-specific variables on addiction do not receive commensurate scholarly attention, rendering it difficult to derive contextualised insights into this phenomenon. Nevertheless, MMORPGs are regarded as potentially addictive because of their interactive and immersive structural characteristics (Bacchini et al., 2017;Hsu et al., 2009;You et al., 2017). MMORPGs afford players the possibility to adopt and customise a character in the virtual world with an evolving storyline over time, to socialise and interact collaboratively and competitively with thousands of other players simultaneously, and to immerse themselves in a fantasy world to escape from everyday life. Indeed, IS research consistently calls for the inclusion of technology-or context-specific variables (Hong et al., 2014) and a better understanding of specific IT artefacts and designs in technology addictions (Turel, Serenko, & Giles, 2011).

| The hedonic management model of addiction
The hedonic management model of addiction suggests that performing certain activities for a good hedonic tone (ie, states of relative pleasure and euphoria) is highly related to various forms of behavioural addiction (Brown, 1997;Hussain et al., 2012). Goodman (1990) contends that addictive behaviour functions not only to induce pleasure but also to alleviate internal discomfort. Specifically, enhancing positive mood or relieving negative mood influences behavioural addictions through positive reinforcement and negative reinforcement mechanisms, respectively. The positive reinforcement perspective posits that individuals might become addicted to a certain behaviour if they enjoy the positive aspects of such behaviour. The negative reinforcement perspective suggests that individuals might become addicted to a certain behaviour if such behaviour helps them to cope with negative mood (Chen et al., 2017;Elhai, Dvorak, Levine, & Hall, 2017;Robinson & Berridge, 2003;Wegmann, Stodt, & Brand, 2015). These pathways are not mutually exclusive, and researchers already incorporate both into their investigations of behavioural addictions. For example, researchers find that gambling addiction is associated with both positive (eg, gambling for excitement) and negative reinforcements (eg, gambling for relief of anxiety) (Robbins & Clark, 2015). Elhai et al. (2017) find that smartphone addiction involves two mechanisms-the craving for positive mood and the desire to alleviate negative mood. The hedonic management model of addiction is used to explain a wide spectrum of behavioural addictions intimately involved with hedonic management, such as gambling addiction (Brown, 1993), crime addiction (Brown, 1997), exercise addiction (Kerr, Lindner, & Blaydon, 2008), computer addiction (Charlton, 2002), Internet addiction (Quinones & Kakabadse, 2015) and online gaming addiction (Clark, 2006;Hussain & Griffiths, 2014).
MMORPG addiction is a type of behavioural addiction. Prior studies suggest that the hedonic management model of addiction is useful for explaining the mechanisms underlying MMORPG addiction, given MMORPGs' hedonically rewarding nature (Charlton & Danforth, 2007;Hussain et al., 2012). Although prior research demonstrates the model's applicability in behavioural addiction research, we further this work through attention to MMORPG-specific variables.

| The technology affordance perspective
The concept of affordance-referring to the uses of an object as perceived by the user-was first introduced to IS research by Norman (1998). It has since gained momentum in the IS literature and is increasingly used to explain different phenomena involving technology use, such as online knowledge sharing (Majchrzak, Faraj, Kane, & Azad, 2013), cyberbullying (Chan, Cheung, & Wong, 2019), IT-related organisational changes (Leonardi, 2013;Volkoff & Strong, 2013), and gamification in the workplace (Suh, Cheung, Ahuja, & Wagner, 2017). Technology affordance refers to "the possibilities for goal-oriented action afforded to specified user groups by technical objects" (Markus & Silver, 2008, p. 622). The technology affordance perspective prompts researchers to consider the mutuality between the action to be taken and the capability of the technology.
Prior studies in the IS literature demonstrate the applicability and merits of integrating the technology affordance perspective into theoretical frameworks, as the integration enables researchers to derive contextualised insights into the phenomena of interests (eg, Chatterjee, Moody, Lowry, Chakraborty, & Hardin, 2015;Leonardi, 2013;Suh et al., 2017). For instance, Chatterjee et al. (2015) integrate the technology affordance perspective with the notion of virtue ethics to explain how organisational technology affordances, such as collaboration, organisational memory, and process management affordances influence organisational virtues. Similarly, Suh et al. (2017) integrate the technology affordance perspective with the theory of aesthetic experience to explain how gamification affordances affect user engagement with IS in the workplace. The results show that the three gamification affordances-status, competition, and self-expressionaffordances-positively correlate with flow experience and aesthetic experience, which in turn influence continuance intention to use IS in the workplace. Accordingly, we expect the technology affordance perspective to offer a useful theoretical lens for us to derive a contextualised understanding of MMORPG addiction.

| RESEARCH MODEL AND HYPOTHESIS DEVELOPMENT
Drawing on the hedonic management model of addiction, we explain how the duality of hedonic effects correlates with the extent of MMORPG addiction. We extend the hedonic management model of addiction by incorporating the technology affordance perspective, and explain the relationships between the three MMORPG-specific affordances and the duality of hedonic effects. Figure 1 depicts our research model.

| MMORPG addiction and hedonic management
Adapting the definition of technology addiction (see Turel & Serenko, 2012;Turel, Serenko, & Giles, 2011), we define MMORPG addiction as a psychological state of maladaptive dependency on playing MMORPGs to such a degree that typical behavioural addiction symptoms arise. In the hedonic management model of addiction, when an individual discovers a reliable, continuous source (eg, playing MMORPGs) through which to obtain a good hedonic tone, the individual is likely to prioritise the activity. In turn, this prioritisation might dominate his or her thinking and behaviour, setting the stage for addiction. In particular, our model identifies two pathways for hedonic management-namely enhancing positive mood and relieving negative mood (Brown, 1993;Charlton & Danforth, 2007). Playing MMORPGs is a reliable activity and hedonic source that enhances players' positive mood F I G U R E 1 Research model. Perceived positive mood enhancement and perceived negative mood reduction refer to a user's perception of the system's ability to change his/her mood, not to whether a person's mood changes and relieve their negative mood (Barnett & Coulson, 2010), which puts players at risk of addiction. Previous studies indicate that players who thrive on or unwind by playing MMORPGs might be engrossed in such gaming and thus continue playing (Barnett & Coulson, 2010). When the use of such technology acts as an important mechanism for modifying one's mood, addiction becomes likely (Caplan, 2010).

| Perceived positive mood enhancement
Perceived positive mood enhancement refers to users' perception that playing MMORPGs can enhance their positive mood. The relationship between perceived positive mood enhancement and the extent of MMORPG addiction might be explained through the positive reinforcement mechanism. Reinforcement refers to the strengthening of one's future behaviour (ie, increasing the frequency and duration of that behaviour) whenever that behaviour is preceded by specific antecedent stimuli (Flora, 2012). A behaviour (eg, playing MMORPGs) is positively reinforced when a desirable event (eg, enhancing one's positive mood) is presented as an outcome of that behaviour (Flora, 2012).
The positive reinforcement perspective is regarded as a crucial mechanism that explains behavioural addictions associated with hedonically rewarding activities (Robinson & Berridge, 2003), such as cybersex addiction (eg, Laier, Pawlikowski, Pekal, Schulte, & Brand, 2013;Young, 2008) and social networking site addiction (eg, Turel & Serenko, 2012). In the context of MMORPGs, players are found to experience an increase in positive mood after playing and thus continue playing (Barnett & Coulson, 2010). The positive mood enhancement through various game experiences, such as reward schedules that reward players when they accomplish in-game tasks (Snodgrass et al., 2011b;Taylor & Taylor, 2009), encourages players to continue playing the games. Following the notion of positive reinforcement, we expect that when players perceive that playing MMORPGs can enhance their positive mood, they are likely to increase the frequency and duration of their gameplay, which might thus displace other daily activities and increase the extent of MMORPG addiction. Therefore, we hypothesise that: H1 The higher the extent of the perceived positive mood enhancement, the higher the extent of MMORPG addiction will be.

| Perceived negative mood reduction
Perceived negative mood reduction refers to users' perception that playing MMORPGs can alleviate their negative mood. The relationship between perceived negative mood reduction and the extent of MMORPG addiction might be explained through the negative reinforcement mechanism. Negative reinforcement occurs when the frequency and duration of a behaviour (eg, playing MMORPGs) increase following the removal of an undesirable event or stimulus (eg, relieving one's pain or negative mood) (Flora, 2012). The negative reinforcement perspective suggests that relieving unpleasant feelings is a negative reinforcer-associated with an increase in the frequency and duration of a particular behaviour, which thus increases the likelihood of addiction (Dong & Potenza, 2014). Perceived negative mood reduction is found to be an important antecedent to behavioural addictions (Berczik et al., 2014). For instance, exercising as a means of relieving negative feelings and escaping from everyday difficulties is associated with exercise addiction (Berczik et al., 2014). Prior studies contend that addictions to hedonic technologies might be explained through negative reinforcement (eg, Muñoz-Rivas, Fernández, & Gámez-Guadix, 2010). In particular, playing online games can help individuals avoid everyday hassles and distress, which thus reinforces gaming behaviour and predisposes players to addiction (Bargeron & Hormes, 2017;Hagström & Kaldo, 2014). In the context of MMORPGs, the games allow players to unwind themselves from negative mood, which makes them continue playing (Barnett & Coulson, 2010). For instance, MMORPG players believe that immersing themselves into the virtual world can help them to cope with their negative mood linked to external stressors, and thus they continue to play (Blasi et al., 2019). Following the notion of negative reinforcement, when players perceive that MMORPGs can reduce their negative mood, they are likely to increase the frequency and duration of their gameplay, which might thus displace other daily activities and increase the extent of MMORPG addiction. Therefore, we hypothesise that: H2 The higher the extent of the perceived negative mood reduction, the higher the extent of MMORPG addiction will be.

| Hedonic management and MMORPG affordances
We extend the hedonic management model of addiction by incorporating the technology affordance perspective.
Affordances are defined as "the possibilities for goal-oriented action afforded to specified user groups by technical objects" (Markus & Silver, 2008, p. 622). The affordance concept was first introduced to IS research by Norman (1998), and it has since gained momentum in the IS literature. Affordances serve as a link that unites users with technical objects (Grgecic, Holten, & Rosenkranz, 2015;Markus & Silver, 2008). Markus and Silver (2008) align technical objects with IT artefacts and their component parts, and define functional affordances as the possibilities for goal-oriented action that technical objects offer specific user groups. In this study, the technical objects are MMORPGs and their associated structural characteristics, and the functional affordances are three MMORPGspecificaffordances-namely achievement affordance, social affordance and immersion affordance. Technical objects indirectly influence behaviours involving technology use through salient beliefs (Al-Natour & Benbasat, 2009). Grgecic et al. (2015) suggest that functional affordances shape users' beliefs about such objects. Specifically, functional affordances, which hinge on the relationship between the technical objects' material properties and the users' abilities to grasp them, can be perceived differently and might influence the beliefs associated with such technical objects (Grgecic et al., 2015;Robey, Anderson, & Raymond, 2013). Thus, although players play MMORPGs primarily for hedonic purposes, MMORPG-specific affordances might correlate with varying beliefs about the MMORPGs' abilities to enhance positive mood or reduce negative mood depending on the players' goals, perceptions, or personal characteristics.

| Achievement affordance
Achievement affordance refers to the extent to which MMORPGs offer players the potential or possibility of attaining achievement through playing the game. MMORPGs enable players to obtain in-game achievements. Players can level up their characters, accumulate resources, analyze and understand the game's mechanics and/or compete with players (Yee, 2006a). For instance, the popular MMORPG World of Warcraft (WoW) has ample structural properties that afford achievement potential. In WoW, the character levelling system affords players the possibility of levelling up their in-game characters; the talent point system affords players the possibility of earning skill points when their characters level up; and the battleground affords players the possibility of completing mission objectives to achieve victory. The effects of in-game achievement can be explained through the game reward systems, which provide players with satisfying gaming experiences and pleasure (Wang & Sun, 2011). Specifically, being successful or accomplishing in-game missions can strengthen a player's self-worth and confirm that he or she is competent enough to complete a mission or to battle opponents, both of which are hedonically rewarding (Rieger, Wulf, Kneer, Frischlich, & Bente, 2014;Trepte & Reinecke, 2011).
Prior studies find that in-game achievement can enhance players' positive mood and reduce their negative mood. For instance, Meghdad (2016) finds that players feel excited and satisfied about levelling up in-game characters. Kirby, Jones, and Copello (2014) suggest that in-game achievements are positively associated with players' mood. Hussain and Griffiths (2009a) find that some players treat in-gameachievements-such as killing monsters to alleviate frustration or stepping out of everyday stress by taking control of their virtual lives-as a form of relief.
From the affordance perspective, although MMORPGs offer players the possibility of attaining different achievements, the perceived mood-modifying ability (eg, enhancing positive mood or relieving negative mood) varies according to the players' goals. Therefore, we propose that achievement affordance is positively related to players' perceptions of positive mood enhancement and negative mood reduction. We hypothesise as follows: H3a The higher the extent of the achievement affordance, the higher the extent of perceived positive mood enhancement will be.

H3b
The higher the extent of the achievement affordance, the higher the extent of perceived negative mood reduction will be.

| Social affordance
Social affordance refers to the extent to which MMORPGs offer players the possibility of socially interacting with others through playing the games. MMORPGs enable players to socially interact with others in various ways, such as casual chatting, building relationships, lending support and collaborating with others (Crenshaw & Nardi, ). For instance, WoW has ample structural properties that afford the possibility of socialising. The chat channel gives players the chance to talk to other players either through text or voice chat; the referral scheme affords players the possibility of bringing their real-life relationships into WoW and receiving exclusive in-game benefits when they play together; and the dungeon affords players the possibility of forming small groups and working as a team.
In a team context, players are allowed to specify their roles as tanks, damage dealers, or healers. Social interaction is one of the most effective mechanisms to regulate mood (Thayer, Newman, & McClain, 1994), and in-game socialisation and interaction are hedonically rewarding to players (Wang & Sun, 2011). Social interaction and support can encourage individuals and improve their self-esteem and well-being (Manne & Zautra, 1989), and can also serve as a buffer that allows individuals to unwind from negative mood caused by potentially noxious events (Cohen & Wills, 1985). In particular, a strong social support system (such as those afforded by MMORPGs) can help individuals to pay more attention to the positive aspects of noxious situations such that they perceive these situations as less threatening.
Socialisation is found to enhance players' positive mood and reduce negative mood. Sanders, Dowland, and Furnell (2011) find that players feel pleasure when they socialise with others in MMORPGs, and 96% of the respondents in their study report that they discuss personal issues with their fellow players during game playing. Cole and Griffiths (2007) contend that social interaction represents an element that is crucial to enjoyable gaming. Some players report that they play MMORPGs to reduce loneliness and negative feelings by interacting with friends or making new friends in the game (Hussain & Griffiths, 2009a). From the affordance perspective, although MMORPGs offer players the possibility of socialising and interacting in-game, the perceived mood-modifying ability (eg, to enhance positive mood or relieve negative mood) varies depending on the players' goals. Therefore, we propose that social affordance is positively related to players' perception that playing MMORPGs enhances positive mood and reduces negative mood. As such, we propose the following hypotheses: H4a The higher the extent of the social affordance, the higher the extent of the perceived positive mood enhancement will be.

H4b
The higher the extent of the social affordance, the higher the extent of the perceived negative mood reduction will be.

| Immersion affordance
Immersion affordance refers to the extent to which MMORPGs offer players the potential or possibility of understanding, exploring and discovering the virtual game world and immersing themselves in it (Meghdad, 2016).
MMORPGs enable players to understand and explore the virtual game world through various means. Players can customise characters, create storylines for characters, and explore and discover hidden things that allow them to more fully immerse themselves in the virtual game world (Crenshaw & Nardi, ). For instance, WoW has ample structural properties that afford the potential of immersing oneself in the virtual world. The map navigation function affords players the possibility of retrieving details about places (such as buildings, cave entrances and shops) and discovering new territories; the role-playing system affords players the possibility of defining the roles of their characters (eg, choosing to become a mage who is a powerful spell caster); and the customisation system affords players the possibility of creating and customising their characters in terms of gender, race, profession and appearance. The immersive characteristics are hedonically rewarding for players because they allow players to more fully identify with the virtual worlds and become so immersed in the richness of the game world that they can "lose themselves" (Snodgrass, Dengah II, Lacy, & Fagan, 2013). These absorptive and dissociative experiences can contribute to pleasure (Snodgrass, Lacy, Dengah, & Fagan, 2011a). However, immersion in a virtual game world blurs the boundaries between actual and virtual worlds and allows players to escape from their real-life problems and negative mood (Billieux et al., 2011).
Immersion in a virtual game world is found to enhance players' positive mood and reduce their negative mood.
For instance, some players find immersing themselves in the virtual game world of MMORPGs to be entertaining and rewarding (Lukavska, 2012). Beyond this, however, players often play MMORPGs as a way of escaping from everyday hassles and distress (Hagström & Kaldo, 2014). From the affordance perspective, although MMORPGs offer players the potential for and possibility of various forms of in-game immersion, the perceived mood-modifying ability of gaming (eg, enhancing positive mood or relieving negative mood) varies depending on the players' goals.
Therefore, we propose that immersion affordance is positively related to players' perception that the MMORPGs can enhance positive mood and reduce negative mood. We hypothesise as follows: H5a The higher the extent of the immersion affordance, the higher the extent of the perceived positive mood enhancement will be.

H5b
The higher the extent of the immersion affordance, the higher the extent of perceived negative mood reduction will be.

| Research design and data collection
To test our research model, we recruited MMORPG players who had played WoW 4 weeks prior to the time of data collection to participate in an online survey. The online survey is the most commonly used data collection method in studies of technology addiction (Byun, Niang, & Lee, 2009). With over 7 million active players, WoW is one of the most popular MMORPGs in the world (Gilbert, 2015). Through a market research firm, we invited members of a nationwide (United States) panel of online game players to participate in the survey. The following two screening questions were asked at the beginning of the survey to identify respondents: (a) "Which online game genre(s) do you usually play?" and (b) "Which MMORPG(s) do you usually play?" Screening Question 1 offered multiple choices of different online game genres, such as action game, adventure game and MMORPG. Screening Question 2 offered multiple choices of different MMORPGs, such as Guild Wars 2, Rift and WoW. The respondents were allowed to choose a maximum of three choices for each screening question. Only those who selected "MMORPG" in Screening Question 1 and "WoW" in Screening Question 2 were allowed to complete the remaining parts of the questionnaire.
The other participants were thanked and dismissed.
To ensure data quality in our study, we followed the guidelines advocated in the methodological literature (Steelman, Hammer, & Limayem, 2014). We included human verification features in Qualtrics to flag responses that could have been completed by bots and duplicated. To track which responses were likely from bots, we enabled in our survey setting the "Bot Detection" feature, which uses invisible reCaptcha technology to flag a response as a bot if the score is below 0.5. To detect duplicates, we enabled the "Prevent Ballot Box Stuffing" feature, which flags a response as a duplicate if respondents attempt to complete the survey under the same cookie. We excluded responses that were completed in less than 5 minutes, and presented five attention check questions randomly throughout the questionnaire to identify any possible careless, random, or haphazard responses. The five attention check questions required respondents to select a particular option for certain questions. The five questions were 'Please select "strongly disagree" for this statement'; 'If adding two to the number three equals five, then only select "somewhat agree" and nothing else'; 'If adding two to the number six equals eight, then only select "neutral" and nothing else'; 'If you have been answering honestly thus far, please only select "agree" and nothing else'; and 'Please select "strongly agree" for this statement.' We collected 466 responses and removed 60 responses that were incomplete, flagged as bots and duplicates, or that failed any attention check question, thus yielding a sample of 406 respondents for our subsequent statistical analyses. Of these respondents, 59.4% were male, 40.6% were female and 60.6% were aged 21 to 30. Regarding MMORPG usage, 69% of the respondents played for 1 hour or more daily, and 54.7% of the respondents played at least 5 days a week. Table 1 summarises the descriptive statistics of the sample.

| Measures
We adopted the measurement items of three scales2 for MMORPG addiction from Turel, Serenko, and Giles (2011) and Serenko and Turel (2015). Given the diversity of measurement scales for technology addiction constructs (Byun et al., 2009), there are three approaches for measuring technology addiction. Following Turel, Serenko, and Giles (2011), we measured the extent of MMORPG addiction with the Compulsive Consumption Scale (CCS), the Behavioural Technology Addiction Scale (BTAS) and the Obsessive-Compulsive Scale (OCS). We adapted the measurement items from Lee, Cheung, and Chan (2015) for perceived positive mood enhancement and perceived negative mood reduction. We modified all of these measurement items to fit the MMORPG research context, and modelled them all as reflective constructs. We developed the measurement items for achievement affordance, social affordance and immersion affordance, and modelled them all as formative constructs. We developed the measurement items for achievement affordance, social affordance, and immersion affordance based on Yee's MMORPG motivations scale. Yee's scale takes into consideration both the theoretical underpinning of different gamer types (which represent a wide spectrum of players' goals in playing online games) and the empirical findings from surveying a large group of MMORPG players. Adapting Yee's scale to develop the affordance items is advantageous because it offers a comprehensive picture of what a MMORPG means to a player and how it affords different action possibilities towards fulfilling their goals. Consistent with Yee's operationalization, we modelled the MMORPG affordances as formative constructs because the affordance construct is a combination of the measurement items. The items represent the cause of the construct and are not interchangeable/replaceable. We present the instrument development of MMORPG affordances in Appendix B of Data S1 and summarise the measurement items in Table 2.
We conducted a face validity check to eliminate any potentially problematic items, such as double-barreled, ambiguous and unfamiliar items, and those with complicated syntax (MacKenzie, Podsakoff, & Podsakoff, 2011). As in Hoehle and Venkatesh (2015), our face validity check focused on the items themselves and did not require the participants to rank and respond to the items. Two IS researchers and three PhD students who were familiar with online game

| Preliminary analyses
We assessed the influence of social desirability bias (SDB) by examining the Spearman correlations between MMORPG addiction constructs and the SDB scale (Turel, Serenko, & Giles, 2011). A negative correlation indicates a threat of SDB, and an absence of correlation suggests that SDB has no effect on the constructs. The Spearman correlations between the SDB scale and the three MMORPG addiction scales were respectively rho ADDCCS-SDB = −0.16, P < .01, rho ADDBTAS-SDB = −0.14, P < .01, and rho ADDOCS-SDB = −0.13, P < .01. These correlations were smaller than the correlations between the SDB scale and the compulsive buying scale as reported by Ridgway, Kukar-Kinney, and Monroe (2008) (rho = −0.21, P < .01), and comparable to those between the SDB scale and the technology addiction scales, as reported by Turel, Serenko, and Giles (2011). Although SDB existed in this study, it was minor and did not constitute an issue.
In addition, we conducted three analyses to assess the potential threat of common method bias. First, we conducted Harman's single-factor test using principal component analysis. The first factor accounted for only 35.02% of the variance. In other words, the items in the dataset loaded significantly onto more than one principal component, indicating no single dominant factor (Harman, 1976). Second, we assessed the correlations between the principal constructs and the marker variable organisational commitment-a theoretically unrelated construct (Lindell & Whitney, 2001).   Common method bias exists when all (or most) constructs are highly correlated, including the marker variable, in the correlation matrix. The correlations of the marker variable were trivial or low, ranging between −0.025 to 0.185, suggesting that common method bias did not likely pose a threat to this study. Third, as suggested by Pavlou, Liang, and Xue (2007), we examined the correlation matrix. Extremely high correlations (eg, r > 0.9) typically indicate the threat of common method bias. However, there were no extremely high correlations in the correlation matrixes (see Table 4), and the presence of low correlations (eg, r = 0.02) indicated that no single-factor influenced all of the constructs.

| Model testing
We validated the measurement and structural models using partial least squares (PLS) analysis, with SmartPLS 3. PLS is a component-based approach used to produce estimates with minimal restrictions on data distribution. According to Hair, Hult, Ringle, and Sarstedt (2017), compared to CB-SEM, PLS-SEM has its own merits and capacity to handle the following data and model characteristics. In terms of the data characteristics, PLS-SEM has no distributional and our research model included formatively measured constructs (ie, achievement affordance, social affordance and immersion affordance). Based on the above methodological guidelines and reasons, we used the PLS-SEM approach to test the research model.
Following the two-step analytical approach, we performed a psychometric assessment of the measurement model, followed by an evaluation of the structural model. This approach ensured that the conclusions of the structural model were drawn from a set of measures with desirable psychometric properties (Hair et al., 2017).

| Measurement model
Testing the measurement model involves estimations of the internal consistency, convergent validity, and discriminant validity of the measurement items. Assessments of the reliability and validity of the formative and reflective items follow different guidelines (Hair et al., 2017). Specifically, assessing the measurement model of reflective constructs includes evaluations of reliability, convergent validity, and discrimination validity, whereas assessing the measurement model of the formative constructs includes evaluations of convergent validity, the multicollinearity among indicators, and the significance and relevance of outer weights (Hair et al., 2017). The measurement model results are summarised below. Overall, the formative and reflective measures were all reliable and valid.

Assessment of reflective constructs
Reliability refers to the internal consistency of the measurement items, and it is assessed using (a) Cronbach's alpha and (b) composite reliability (CR). As shown in Table 3, the Cronbach's alpha and CR for all of the reflective constructs were above 0.7, meeting the recommended threshold (Hair et al., 2017). Convergent validity is the extent to which the items on a scale are theoretically related (Fornell & Larcker, 1981). Convergent validity is assessed using two criteria: (a) the average variance extracted (AVE) should be at least 0.5, and (b) all of the item loadings should exceed 0.7 (Hair et al., 2017). As illustrated in Table 3, all of the latent constructs exceeded the recommended thresholds. The AVE values ranged between 0.531 and 0.739, and all of the item loadings exceeded 0.7, indicating adequate convergent validity.
Discriminant validity is the degree to which a scale measures the variable it intends to measure. It is indicated by small correlations among the measures of interest and the measures of the other constructs (Fornell & Larcker, 1981). Discriminant validity is assessed using two criteria: (a) the heterotrait-monotrait ratio of correlations (HTMT), and (b) the square root of the AVE for each construct (Hair et al., 2017). The HTMT values for the reflective constructs ranged between 0.537 and 0.831, that is, below the conservative threshold value of 0.85. The square roots of each of the AVEs were larger than the correlations between the AVE and all of the other constructs (see Table 4), indicating adequate discriminant validity.

Assessment of formative constructs
Formative items are those that cause variance in the formative constructs under scrutiny (Bollen, 1984). Formative items neither correlate with one another nor exhibit internal consistency (Chin, 1998). Therefore, assessing the convergent validity and discriminant validity of formative constructs using the criteria for reflective constructs is not meaningful (Hair et al., 2017).
The assessment of convergent validity involves redundancy analysis to determine whether the formative construct is highly correlated with its reflective global measure (Hair et al., 2017). The results of the analysis showed that the path coefficient for each affordance (ie, achievement, social and immersion affordances) was higher than 0.7, contributing sufficiently to the intended affordance and indicating adequate convergent validity.
We then assessed multicollinearity for the formative items. As formative constructs are predicted jointly by multiple indicators in an analogous fashion, multicollinearity is a major concern. However, multicollinearity was not an issue in our study because (a) none of the bivariate correlations exceeded 0.9 (Tabachnick & Fidell, 2001); (b) the tolerance values averaged more than 0.3; and (c) the maximum variance inflation factor (VIF) was 2.281, below the prescriptive diagnostic of 3.3 (Hair et al., 2017).
Finally, we examined the item weights, loadings and significances of the formative items (Hair et al., 2017). As illustrated in Table 5, the weights and loadings for all of the items were statistically significant (except the weight of SOC1, which was marginally significant), indicating that all of the measurement items made relative and absolute contributions to the formative constructs of MMORPG affordances. These results suggested that all of the formative items should be retained for the subsequent model analyses (Hair et al., 2017). Table 6 summarises the results of the structural model testing with the three MMORPG addiction scales. We performed bootstrapping with 5000 subsamples to test the significance levels of the path coefficients in the research model (Hair et al., 2017). The research model explained a substantial amount of the variance in the dependent variables. In particular, the model explained 44.3% of the variance of perceived positive mood enhancement, 30.3% of the variance of perceived negative mood reduction, and between 16.6% and 29.7% of the variance of MMORPG addiction depending on the adopted measurement scales. Figure 2 summarises the results.

| Structural model
The obtained path coefficients and levels of significance indicated that the majority of the hypotheses were

| DISCUSSION AND IMPLICATIONS
MMORPG addiction is a serious issue worldwide and attracting an increasing amount of attention from the public, governments and the academic community. To address this critical issue and the research gaps, we integrate the hedonic management model of addiction (Brown, 1997) and the technology affordance perspective (Markus & Silver, 2008) to develop a research model that explains the psychological mechanisms underlying MMORPG addiction. In particular, we examine the relationships between MMORPG-specific affordances (ie, achievement affordance, social affordance and immersion affordance) and the duality of hedonic effects (ie, perceived positive mood enhancement and perceived negative mood reduction), and how they correlate with the extent of MMORPG addiction. In the following subsections, we discuss our findings and highlight the implications for research and practice. We conclude the article by addressing limitations and suggesting future research directions.

| Discussions of results
We empirically test the research model with 406 responses from MMORPG players. Our empirical findings provide strong support for most of our hypotheses. We find that both perceived positive mood enhancement and perceived negative mood reduction positively correlate with the extent of MMORPG addiction, confirming the salient role of the duality of hedonic effects in such an addiction. Furthermore, we find that only achievement affordance and immersion affordance have significant and positive relationships with perceived positive mood enhancement and perceived negative mood reduction. Immersion affordance exhibits the strongest relationships. This result can perhaps be explained by the unique nature of MMORPGs, as they present a never-ending immersive virtual world wherein players can role-play and customise their in-game characters, interact with other players and explore a virtual world through their characters. This immersive gaming experience is well recognised as a core element of the MMORPG genre (Barnett & Coulson, 2010).
However, our results show that social affordance does not have significant relationships with either perceived positive mood enhancement or perceived negative mood reduction. We have several possible explanations for these unexpected findings. First, some players might use technologies extraneous to the online games-such as Discord, a free voice and text chat application for gamers (Discordapp.com, 2020)-for social connections and interactions. Second, we suspect that the findings might be attributable to the specific genre of massively multiplayer online games.
For instance, immersive affordance has the strongest relationships with perceived positive mood enhancement and perceived negative mood reduction in MMORPGs that feature role-playing with in-game characters and in which exploring virtual worlds is one of the core activities. In contrast, achievement affordance might assume a more predominant role in massively multiplayer online first-person shooter games that endow players with a sense of achievement and a sense of control over their environment and destiny (Konnikova, 2013 perspective-to produce interactional insights that enrich both (Tarafdar & Davison, 2018).
Second, obtaining a good hedonic tone (ie, states of relative pleasure and euphoria) lies at the root of behavioural addictions (Brown, 1997). As such, the duality of hedonic effects (ie, perceived positive mood enhancement and perceived negative mood reduction) should play a crucial role in MMORPG addiction. The relationships between the duality of hedonic effects and the extent of MMORPG addiction have not been systematically examined in the extant literature. Our study contributes by revealing the previously overlooked importance of the duality of hedonic effects on MMORPG addiction, and invites future studies to systematically examine how the duality of hedonic effects influences addiction to other hedonic technologies.
Third, prior studies of MMORPG addiction focus on its aetiology, pathology and ramification. However, the effects of contextual factors on the extent of MMORPG addiction are poorly understood. The inclusion of technology-or context-specific variables has been consistently called for in general IS research (Hong et al., 2014) and in technology addiction research (Turel, Serenko, & Giles, 2011). We extend the hedonic management model of addiction with the technology affordance perspective to provide a contextualised theoretical contribution to the technology addiction literature. This contribution is particularly important and relevant to IS research. Our model offers an alternative perspective on the mutuality between players and the MMORPG affordances and their roles in MMORPG addiction. In terms of affordance, the specific MMORPG feature is not important in and of itself; rather, it is only important insomuch as it affords the action possibilities of achieving, socialising, and immersing oneselfpossibilities that in turn affect the mood-modifying abilities that players believe are caused by playing MMORPGs.
The affordance approach avoids privileging any single specific component of the MMORPG over any other component in explaining MMORPG addiction, and it forces researchers to consider the mutuality between the action to be taken and the technology's capability. On these merits, we incorporate the technology affordance perspective into our model and advocate its use in future research on technology addiction to better capture how action possibilities afforded by technologies are associated with technology addiction. Finally, although most prior studies associate affordances with positive behaviours (Majchrzak et al., 2013;Strong et al., 2014), there is little understanding of the role affordances play in explaining undesirable IS use behaviours. We expect that our results will offer an alternative perspective on the far-reaching, unintended effects of technological affordances as a potential enabler of addictive technology use.

| Implications for practice
This study has several important implications for practitioners and policymakers. Our findings show that achievement and immersion affordances are positively correlated with mood-modifying abilities, whereas social affordance does not exhibit any significant effect. These findings offer MMORPG developers insights into designing preventive functionalities within MMORPGs. In relation to achievement affordance, MMORPG developers might, for example, consider introducing a voluntary fatigue system, also known as a reward reducing system, that would gradually reduce gained experiences and skill points for players after a certain time limit or prolonged gaming. When players experience some symptoms of MMORPG addiction, they could voluntarily make use of the fatigue system to manage their MMORPG use. The fatigue system might reduce the players' perceived achievement affordance in the gameplay, potentially dissuading them from engaging in potentially dangerous marathon gaming sessions. In relation to immersion affordance, MMORPG developers might, for example, consider introducing alternative login servers that allow players to voluntarily limit the amount of time spent in each gaming episode. Through this functionality, players can log in through a server that limits each gaming episode to 2 hours per day. Such a preventive functionality might reduce the players' perceived immersion affordance from playing MMORPGs. However, we acknowledge that introducing such preventive functionalities to MMORPGs might reduce the players' satisfaction, which in turn could hurt gaming companies' revenue. Game developers are advised to make such preventive functionalities voluntary for players. Thus, players who perceive themselves as vulnerable to MMORPG addiction can make use of such functionalities. Other players, such as those who can regulate their gameplay and/or experience no negative consequences, can continue their usual gaming patterns and derive maximum joy from playing MMORPGs.
Our findings also offer psychiatrists insights into possibilities for developing intervention programmes. As seen in the hedonic management model of addiction, players who regard playing MMORPGs as a desirable, useful activity for obtaining a good hedonic tone might repeatedly play the games. Therefore, the success of intervention programmes hinges on helping players identify alternative hedonic sources and activities that are capable of enhancing their positive mood and/or reducing their negative mood. As MMORPGs are tied to computers and mobiles, they become a key part of our daily lives in the digital era. Therefore, the vector of MMORPG addiction might be difficult or impossible for individuals to avoid. As such, intervention programmes should aim to promote and diversify alternative hedonic sources, rather than to propose abstinence. Intervention programmes should aim to stem MMORPG addiction through reducing the players' reliance on playing MMORPGs for mood management.
Our findings show that age is negatively correlated with the extent of MMORPG addiction. Compared with older players, young players are more susceptible to MMORPG addiction, which might be attributable to younger individuals' relatively lower capacity to self-monitor and self-regulate (Mischel & Mischel, 1983). Policymakers and governments should consider enforcing laws and regulations that limit gaming for these vulnerable groups of players. The South Korean government, for example, implemented the Youth Protection Revision Act, also known as the Shutdown Law or Cinderella Law, which forbids those under the age of 16 from playing online games between the hours of 00:00 and 06:00.

| Limitations and directions for future research
We acknowledge that this study has a few limitations, which might nevertheless lead to other fruitful research avenues.

| Cooperative play vs competitive play
We tested our research model by performing a multiple-group analysis that compared subsamples of cooperative play, competitive play and cooperative play with elements of competitive play, respectively. No significant differences were observed. We suspect that this is because MMORPGs are well blended with a variety of structural characteristics that provide players with a holistically hedonic gaming experience. According to Yee (2006b), in MMORPGs, the achievement component consists of the subcomponents of advancement, mechanics, and competition; the social component consists of the subcomponents of socialising, relationships, and teamwork; and the immersion component consists of the subcomponents of discovery, role-playing, customisation and escapism. It is possible that no single structural characteristic or associated affordance has a dominant role in MMORPG gameplay.
Rather, these characteristics and affordances work together to provide players with a holistic gaming experience.
We believe that types of play would be found to affect addiction if they were tested across different online genres in which cooperative play or competitive play had a dominant role in the gameplay. For instance, massively multiplayer online racing games have a strong focus on competitive play, whereas massively multiplayer online social games have a strong focus on cooperative play. Future studies should examine the differences between cooperative play and competitive play across online game genres, and evaluate their relative effects on addiction.

| Generalisability
This study's results might be generalisable to MMORPG players only. Future research should replicate and validate the theoretical model for other hedonic technologies to improve the generalisability of the model. Future research should also, following the approach adopted in this study, examine context-specific variables to provide a more accurate depiction of the technologies of interest. For instance, the variables of immersion and achievement affordances are specific to MMORPGs and might not apply to other hedonic technologies, such as social networking sites.

| Alternative platforms
MMORPGs, which provide gameplay in three-dimensional and never-ending virtual worlds, have traditionally required players to preinstall software clients on computers that meet certain hardware and software requirements.
In the past, MMORPG players were often restrained by location. However, advances in mobile technology and data services have enabled players to play MMORPGs at anytime and anywhere, increasing the risk of addiction. Future research should explore the influence of additional contextual factors, such as mobility and accessibility, on MMORPG addiction. The range varies because of the assessment method: 3.6% are based on a monothetic assessment method in which all seven diagnostic criteria are met, and 44.5% are based on a polythetic assessment method in which four out of seven diagnostic criteria are met. The MMORPG addiction rate is estimated from a sample of 1420 players from multiple countries, including the United States (46.4%), the United Kingdom (14.8%), Canada (6.3%), Australia (4.2%) and Finland (2.9%). The remainder of the sample (13.2%) includes New Zealand, Greece, Norway, the Netherlands, Germany, Poland, Sweden and Japan (see Hussain, Griffiths, & Baguley, 2012).