Since the appearance of the smartphone, the number of people using smartphones is increasing and, smartphones have become an essential part of our lives. According to data from Korea Communications Commission (2020), 91% of Koreans were reported to own a smartphone. Through various applications on smartphones, people can listen to music, play games, watch videos, use social network services, shop, and even learn. Although smartphones provide convenience to everyday life, excessive use and over-dependence on them can lead to problematic smartphone use or smartphone addiction.
Smartphone addiction is characterized by repetitive failure to resist the impulse to use the smartphone, withdrawal, excessive time spent on smartphone usage, and recurrent physical or psychological problem, negative consequences on daily life caused by excessive smartphone use (Lin et al., 2016). Recently, smartphone addiction has notably increased. In fact, according to a recent systematic review about the prevalence of smartphone addiction (Sohn et al., 2019), approximately one in every four children and young people had smartphone addictions. Especially, the prevalence of smartphone addiction was higher in children and adolescents compared with adults (De-Sola et al., 2017; Haug et al., 2015).
Adolescents can easily be addicted to smartphones than adults for following reasons. First, adolescents can be more vulnerable to addiction due to their high impulsivity and novelty-seeking tendencies (Chambers et al., 2003). In fact, a recent study identified that high levels of impulsivity contributed to smartphone addiction in adolescents (Jo et al., 2018). Also, Kim et al. (2012) found that adolescents tended to use smartphones for entertainment purposes (i.e. listening to music, gaming) than adults. When people use smartphones for hedonic purposes (to gain pleasure), they obtain direct gratifications from the media and are more likely to indulge in the virtual world of smartphones, increasing the danger of addiction (Meng et al., 2020). These findings imply that it is important to examine smartphone addiction focusing on adolescents. Furthermore, according to Cha and Seo (2018), the prevalence of smartphone addiction in Korean adolescents was 30.9%, which is higher than other countries, compared to “10% in England, 21% in the Philippines, and 18% in Hong Kong (Lopez-Fernandez et al., 2014; Mak et al., 2014)” (as cited in Cha & Seo, 2018, p.10). Therefore, Korean adolescents would be an appropriate target when investigating smartphone addiction.
Numerous studies have explored the negative consequences of smartphone addiction. For instance, according to Hawi and Samaha (2016), university students with high risk of smartphone addiction were less likely to have distinctive GPAs. Possible explanation is that smartphone multitasking while studying can impede the cognitive processes required for learning, which in turn can decrease academic achievement (Hawi & Samaha, 2016). Also, studies revealed that smartphone addiction is associated with negative physical health (Kim et al., 2015), lower productivity (Duke & Montag, 2017), and poor mental health (depression, anxiety, suicidal ideation) (Thomée, 2018). Although many studies emphasized the danger of smartphone addiction by stressing the negative consequences, relatively few studies investigated how adolescents become addicted to smartphones. Thus, further work is needed to examine the predictive factors and mechanism of how smartphone addiction is developed in adolescents.
Among various factors that predict smartphone addiction, stress is one of the major factors that is related to problematic smartphone usage and smartphone addiction (Liu et al., 2018; Wang et al., 2015). Individuals with high levels of stress tended to excessively use smartphones to escape from life problems and alleviate stress (Wang et al., 2015). Panova and Lleras (2016) discovered a “security blanket effect” of smartphones among university students. The participants who had access to their mobile phones were more likely to show increased resilience in a stressful situation. Researchers related this effect to the security blanket effect in that it is similar to how children hold on to blankets or other objects to obtain a sense of comfort and safety in a threatening environment. However, the results showed that depending on mobile phones is detrimental to long-term psychological health and thus it may be a maladaptive coping mechanism (Panova & Lleras, 2016). Especially, adolescents in Korea grow in a competitive society, where the academic performance of children is highly valued. Thus, Korean adolescents are more likely to experience greater academic stress than adolescents from other countries, which might have contributed to the high prevalence of smartphone addiction among adolescents in Korea (Cha & Seo, 2018). However, relatively limited studies explored the psychological mechanism of the relationship between stress and smartphone addiction. Thus, the current study focused on how stress influences smartphone addiction among adolescents.
Stress can lead to smartphone addiction through various pathways. For example, according to previous studies, factors such as resilience (Park & Kwon, 2019), self-control (Liu et al., 2018), and grit (Yoo & Choi, 2019) had significant mediating effects on stress and smartphone addiction. Among the various factors that influenced smartphone addiction, this study will be focusing on grit which is a relatively new psychological concept defined as “perseverance and passion for long-term goals” (Duckworth et al., 2007, p.1087). Grit was first introduced as a non-cognitive skill that leads to success (Duckworth et al., 2007). Grit is characterized by the combination of consistency of interest and perseverance of effort. First, consistency of interest refers to the ability to continuously pursue focused interest over a long period of time without frequently changing goals. Second, perseverance of effort refers to the tendency to sustain effort in accomplishing long-term goals even in the face of adversity and challenges (Duckworth et al., 2007). Gritty people sustain effort and pursue consistent interest to accomplish long-term goals even in the face of failure and adversity. Grit has many significant implications, especially for adolescents. Studies have demonstrated that gritty students engaged in deliberate practice than less gritty students and achieved better performance (Duckworth et al., 2011; Lee & Sohn, 2013). In addition to its relevance with academic performance, grit is also related to graduation (Eskreis-Winkler et al., 2014) and peer relationship (Lan, 2020). Thus, grit is an important skill for adolescents in that it benefits not only adolescent’s academic performance but also their overall development.
Although majority of grit studies investigated the predictive power of grit in academic success, recent studies associated grit with mental health and expanded its functions. For instance, gritty individuals experienced less depressive symptoms (Datu et al., 2019) and reported higher life satisfaction and positive affect (Li et al., 2018). Moreover, some studies confirmed the mediating and moderating effect of grit on the relationship between stress and negative outcomes, suggesting that grit could serve as a buffer against negative outcomes of stress (Blalock et al., 2015; Jung et al., 2020; Marie et al., 2019). For instance, Blalock et al. (2015) argued that people with grit are less influenced by stressful situations. They examined the moderating effect of grit on the relation between negative life events and suicidal ideation and revealed that individuals high in grit were less likely to have suicidal ideation in negative situations than individuals low in grit. This may be because gritty people focus more on long-term goals and minimize their attention to stress. Also, grit might enable people to reframe negative situations more positively and use more effective problem-solving strategies during highly stressful situations (Blalock et al., 2015). Similarly, another recent study (Marie et al., 2019) showed that individuals with high levels of grit had a weaker association of posttraumatic stress disorder (PTSD) symptoms and suicidal ideation. The study argued that grit may remediate the impact of PTSD symptoms and reduce the danger of suicide. Furthermore, according to Jung et al. (2020), grit partially mediated occupational stress and burnout among firefighters. This means that high occupational stress leads to lower girt, which in turn increases the occupational burnout. The study implied that high levels of grit could function as a protective factor against the negative consequences of occupational stress. These results suggest that grit might have a mediating effect on stress and various negative outcomes.
Furthermore, several studies have associated grit with maladaptive behaviors. For instance, grittier adolescents were less likely to be involved in alcohol use, drug use, fighting, and delinquent behavior (Guerrero et al., 2016). Although Guerrero et al. (2016) could not precisely determine the mechanism of grit and adolescent’s risky behaviors, they suggested some possible explanations. First, grit can contribute to the confidence and self-efficacy of teenagers, and motivate them to invest in the future through responsible decisions. Also, another possible explanation is that grit is closely associated with self-control, which also pertains to delay of gratification and less engaging in risky behaviors (Guerrero et al., 2016). In addition, Knauft et al. (2019) showed that grit was negatively associated with bulimia and body dissatisfaction, which indicates that grit could serve as a buffer against disordered eating attitudes and behaviors. This might be because the concept of grit is opposite to impulsivity which is a well-known risk factor for eating disorders (Knauft et al., 2019).
Among various maladaptive behaviors, recent studies started to connect grit with addiction such as drug use, internet, and smartphone addiction and broaden the importance of grit (Brozikowsky & Bernhardt, 2019; Griffin et al. 2016; Yoo & Choi, 2019). According to Griffin et al. (2016), grit was related to the recovery of patients with substance use disorder, as patients who were unemployed, diagnosed with a co-occurring psychiatric disorder, or who had used heroin during the past month had lower grit score. Also, Brozikowsky and Bernhardt (2018) examined grit among online gamers. As a result, grittier people were less likely to become addicted to online games, which indicates that grit could be negatively associated with overall addiction and could operate as a protective factor for addiction. More recently, one study (Yoo & Choi, 2019) in South Korea related grit with smartphone addiction and discovered that grit was negatively associated with smartphone addiction. The researchers explained that this might be because smartphone addiction is related to a lack of patience, and the concept of grit encompasses the notion of perseverance (Yoo & Choi, 2019). However, studies about grit and addiction are still limited and therefore, more research in this area is necessary to fully understand how grit is associated with addictive behaviors (Brozikowsky & Bernhardt, 2018).
In addition, while the majority of grit studies used the total score of grit in the past (Eskreis Winkler et al., 2014; Robertson-Kraft & Duckworth, 2014), recent studies argued that two components of grit can cause different consequences (Bowman et al., 2015; Disabato et al., 2019) and therefore should be investigated separately (Datu et al., 2016). For instance, Datu et al. (2016) discovered that the correlation between two factors of grit was very weak, and the perseverance of effort predicted academic engagement, life satisfaction, and positive affect more strongly than consistency of interest. Also, Bowman et al. (2015) separately examined the predictive utility of the two components and revealed that perseverance predicted greater academic adjustment, GPA, and sense of belonging than consistency among college students. Similarly, Disabato et al. (2019) found out that perseverance of effort was associated with goal-directed thinking, meaning in life, subjective happiness more strongly than consistency of interest. These prior findings indicate that positive academic and psychological outcomes are mostly driven by the perseverance of effort component of grit. In fact, consistency of interest dimension of grit is controversial due to its weak predictive function of positive outcomes (Bowman et al., 2015; Datu et al., 2016; Disabato et al., 2019). Also, the items measuring consistency of interest are all negative statements which require the reverse calculation of the scores, reducing the reliability of the measurements (Lim, 2019). However, Knauft et al. (2019) demonstrated that consistency of interest, not perseverance of effort, was related to lower bulimia and body dissatisfaction scores. The study could not identify the specific mechanism but explained that individuals with continued interest in enduring goals would focus on long-term goals even when immediate rewards are absent, which could lead to lower eating disorder-related attitudes and behaviors (Knauft et al., 2019). This result indicates that consistency of interest dimension of grit can also contribute to positive outcomes. Therefore, two components of grit should be analyzed independently to better understand the functions of grit. However, most of the studies used the total score of grit in the past (Eskreis-Winkler et al., 2014; Robertson-Kraft & Duckworth, 2014). Thus, we planned to analyze the two facets of grit separately and complement the previous findings.
In sum, previous findings suggest that grit may operate as a buffer against stressful situations and be negatively related to addictions. Unfortunately, most of the studies associate grit with academic success and mental well-being, and limited studies examine the roles of grit in addictive behaviors. In fact, the study conducted by Yoo and Choi (2019) is the only study that examined the relationship between grit and smartphone addiction, which was done on limited community samples of college students. However, as smartphone addiction is increasing and can lead to detrimental consequences, it is important to identify the factors that contribute to smartphone addiction. Thus, the current study sought to investigate the association between grit and smartphone addiction among adolescents. Particularly, we tried to analyze whether grit has a mediating effect between stress and smartphone addiction. Also, as Yoo and Choi (2019) failed to separately analyze the effect of consistency of interest and perseverance of effort on smartphone addiction, we aimed to investigate how each component of grit is related to smartphone addiction.
As reviewed above, stress appeared to be related to smartphone addiction, and grit may influence the relationship between stress and smartphone addiction. Based on the previous findings, the current study aimed to examine the relationship between stress, grit, and smartphone addiction among Korean adolescents. In particular, this study focused on exploring the mediating effect of grit on the relationship between stress and smartphone addiction. The present study's three research questions are as follows:
Does stress predict smartphone addiction among adolescents?
Does grit predict smartphone addiction among adolescents?
Does grit and components of grit mediate the relationship between stress and smartphone addiction among adolescents?
Based on the previous findings, we expected that stress would positively predict smartphone addiction and grit would negatively predict smartphone addiction among adolescents. Also, we hypothesized that grit would partially mediate the relationship between stress and smartphone addiction. In other words, when levels of stress increase, grit would decrease, which will increase the risk of smartphone addiction. The research model of the current study is presented in Fig. 1.