Relationship between coaching leadership style and young athletes’ social responsibility

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Ye Hoon Lee

Seunghyun Hwang

Youngjun Choi

Cite this article:  Lee, Y. H., Hwang, S., & Choi, Y. (2017). Relationship between coaching leadership style and young athletes’ social responsibility. Social Behavior and Personality: An international journal, 45(8), 1385-1396.


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We investigated the relationship between young athletes’ perception of their leaders’ coaching behavior and the athletes’ level of social responsibility. Participants were 204 high school athletes from the Midwest region in the US. Hierarchical regression analysis results showed that there was a positive relationship between the athletes’ social responsibility and the coaches’ democratic behavior, and a negative relationship between social responsibility and coaches’ autocratic behavior. These results indicate that the athletes who perceived their coaches as behaving more democratically and less autocratically had a higher level of social responsibility than the others had. Our findings signify the importance of using types of coaching behavior that enhance student athletes’ social responsibility.

Sport participation is often considered a vehicle for positive youth development (PYD; Hellison, Martinek, & Walsh, 2008). Indeed, researchers have consistently found a positive association between sport participation and psychological variables such as identity development, initiative, social responsibility, teamwork, and social skills, and also better psychological well-being for school students (Bailey, 2006; Fraser-Thomas, Côté, & Deakin, 2005; Larson, Hansen, & Moneta, 2006). However, the negative impact of sport participation on the psychological development of children has also been reported, for example, aggressive behavior (Burton & Marshall, 2005) and poor moral development (Shields & Bredemeier, 2001).

Thus, there may be a contextual variable mediating the relationship between psychological development and sport participation of children, which, in turn, leads to healthy developmental outcomes during the adolescent years (Carreres Ponsoda, Escarti Carbonell, Cortell Tormo, Fuster Lloret, & Andreu Cabrera, 2012). However, because so many adolescents are likely to participate in sport regardless of the benefits they may or may not gain, sport researchers need to identify opportunities for PYD through continued sport participation, and the ways in which these opportunities can be maximized (Brunelle, Danish, & Forneris, 2007). Therefore, studying which contextual factors may help instill positive values through youth sport can be a key to understanding the psychological development of youth.

Coaches have a critical role in the psychological development of youth sport participants (see, e.g., Benson & Scales, 2009), as they are often considered a significant agent in shaping the character of the young people whom they coach (i.e., identity, goal orientation, and responsibility), and the environment that the young people experience (Côté & Gilbert, 2009). Gould, Collins, Lauer, and Chung (2007) concluded that sport participation provides the context to foster PYD, but the outcome depends on the coaches. Gould et al. found that the coaches’ behavior that led to PYD included treating the young athletes respectfully, setting clear expectations, being flexible, serving as a role model, giving individualized feedback, and making practice fun.

The multidimensional model of leadership (MML) is frequently used in the context of sport (Chelladurai & Saleh, 1980). There are three antecedents of leadership behavior in the MML: leader’s characteristics, members’ characteristics, and situational characteristics, and there are three types of leadership behavior: required, preferred, and actual. Further, organizational outcomes, such as team performance and athlete satisfaction, are affected by the congruence between the three types of leadership behavior and their antecedents. More specifically, when there is congruence between the leader’s actual behavior and the behavior that team members prefer, it is more likely that the team members will be satisfied with their sport and will perform better (Chelladurai, 2014).

To quantify the MML, Chelladurai and Saleh (1980) developed the Leadership Scale for Sports (LLS) to measure leadership behavior of coaches. They identified the following five most meaningful dimensions of leadership behavior in sport: training and instruction, democratic behavior, autocratic behavior, social support, and positive feedback. Training and instruction involves coaching behavior through which the role of each team member is clarified, and intensive training and various skill instructions are provided to improve athletes’ and team performance. Democratic behavior involves the coach providing greater opportunities for the athletes to participate in a group decision-making process, such as practice schedule, game strategies, and team rosters. Autocratic behavior refers to a top-down management style, with the leaders making all the decisions and members being expected to follow those decisions. Social support refers to coaching behavior through which the coach provides each individual athlete with personal care and emphasizes the positive relationship between leader and members. Finally, positive feedback involves the coach recognizing the performance of each athlete and providing team members with positive reinforcement and rewards during practice and competition.

In regard to the interaction between context and youth (i.e., interacting with a sport coach), this raises the question of which developmental variable is strongly related to coaches’ behavior. In this study, we focused on social responsibility, which, in previous studies, adults such as parents, teachers, and administrators, and adolescents have considered to be one of the most desired outcomes of education and development (Wray-Lake, Syvertsen, & Flanagan, 2016). Wray-Lake et al. (2016) defined social responsibility as a set of prosocial values representing personal commitments to improve one’s community and society. It is significantly related to prosocial behavior (Wray-Lake & Syvertsen, 2011) and mental and moral maturity (Kluever & Green, 1998). Thus, the identification of ways to encourage and foster the development of social responsibility among young people has been a matter of great concern among PYD researchers and practitioners (Wray-Lake & Syvertsen, 2011).

Researchers have frequently reported finding a significant relationship between environmental factors and social responsibility in various contexts (see Wray-Lake et al., 2016). For example, a democratic parenting style was found to be positively associated with social responsibility and with engagement—which indicates social responsibility—among the children of those parents (Duke, Skay, Pettingell, & Borowsky, 2009; Gunnoe, Hetherington, & Reiss, 1999; Lenzi, Vieno, Santinello, Nation, & Voight, 2014). In contrast, an autocratic parenting style, whereby the parents attempt to direct their children’s behavior, was found to be negatively related to the children’s social responsibility (Gunnoe et al., 1999). In addition, van Goethem, van Hoof, Orobio de Castro, Van Aken, and Hart (2014) found that community service participation was positively linked to prosocial attitudes toward others.

In the context of sport, Carreres Ponsoda et al. (2012) noted that social responsibility could be affected by factors such as coaches’ leadership style. Smith, Smoll, and Barnett (1995) reported that coaching behavior involving a high frequency of supportive and instructive behavior and low frequency of punitive actions was positively associated with young athletes’ psychosocial development.

In addition, there has been rising interest in the development of more structured methods of instruction in prosocial education to teach responsibility. Hellison (2011) developed a physical activity-based responsibility model, which involves taking personal and social responsibility. According to Hellison’s model, young people will develop social responsibility when staff (a) genuinely care about, respect, and listen to them; (b) gradually shift power and decision making from staff to youth; and (c) integrate life skills and character lessons into physical activities. The first two principles highlight the importance of coaches integrating democratic coaching behavior into their interaction with young people. From the perspective of social learning theory (Bandura, 1986), as coaches are among the significant others who can shape the developmental and contextual processes of youth during practice and competition in sport settings (Gould et al., 2007), it is reasonable to posit that coaches who have a democratic coaching style have the potential to positively influence young athletes’ level of social responsibility. In addition, researchers have identified significant associations between personal characteristics and social responsibility (Wray-Lake et al., 2016). First, Wray-Lake and her colleagues (2016) found gender differences in the level of social responsibility, namely, boys exhibited a lower level of social responsibility than girls did. Researchers have also found a relationship between social responsibility and age (e.g., Nucci & Turiel, 2009; Wray-Lake et al., 2016). For example, Nucci and Turiel (2009) reported that there was a U-shaped pattern in moral development, that is, early and later adolescents displayed more ethical behavior compared to middle adolescents. In addition, Wray-Lake and her colleagues reported that there was a significant decrease in social responsibility from the age of 9 years to 16 years. As previous researchers have clearly demonstrated a significant association between demographic variables and social responsibility (Wray-Lake et al., 2016), we controlled for the variables of age and gender.

In this study, we investigated the relationship between five types of coaching behavior and athletes’ level of social responsibility, and whether or not that relationship was dependent on demographic variables. We hypothesized that the relationship between autocratic behavior and social responsibility would be negative whereas the other types of coaching behavior would be positively related to athletes’ social responsibility.

Method

Participants

Our target sample consisted of high school students (N = 204), who were at five high schools in the Midwest region of the US, and who were playing 1 of 17 different types of sport as university or junior university members. Participants consisted of 79 boys (38.7%) and 125 girls (61.3%), the mean age was 16.10 years (SD = 0.89), and 77.5% were Caucasian.

Procedure

We used the convenience sampling method. After obtaining approval from the Institutional Review Boards at the schools where the data were collected, we sent an invitation email in which the research project was described to two schools in the Midwestern region of USA. When the schools’ athletic directors had approved the data collection procedure, we visited sports teams in the schools and explained the purpose of the project. Each student received a consent form for their parents to sign. One week later, we visited the data collection sites and after the students had submitted the completed parental consent form, they were asked to think about their sport experience in school, and to think of one sport and the coach in that sport. If they had interacted with more than one coach in that sport, the students were encouraged to think about the coach with whom they had been most involved. Anonymity was ensured as participants did not provide any personal identification details.

Measures

Demographic information. We recorded participants’ demographic characteristics of age, gender, sport participated in, level of competition, size of the school, ethnicity, and experience in volunteer activities in the community. Experience in volunteer activities was coded at an ordinal level: (1) not at all, (2) once or twice a year, (3) between 3 and 11 times a year, (4) between 1 and 3 times a month, (5) weekly, or (6) more than once a week.

Leadership Scale for Sports. We measured the types of coaching behavior that participants perceived that their coaches used, with the 40-item LLS (Chelladurai & Saleh, 1980). Responses are rated on a 5-point Likert scale ranging from 1 (never) to 5 (always). A sample item for training and instruction is “Explain to each athlete the techniques and tactics of the sport.” A sample item for democratic behavior is “Ask for the opinion of the athletes on strategies for specific competitions.” A sample item for autocratic behavior is “Refuse to compromise a point.” For social support a sample item is “Help the athletes with their personal problems.” For positive feedback a sample item is “Express appreciation when an athlete performed well.” This scale has satisfactory structural validity and internal consistency (Chelladurai & Saleh, 1980). In this study, the internal consistency (Cronbach’s α) for the five subscales ranged from .70 (autocratic behavior) to .92 (training and instruction).

Social and Personal Responsibility Scale. We used three subscales from the Social and Personal Responsibility Scale (Conrad & Hedin, 1981): the four-item social welfare subscale (having concern for others’ welfare), the three-item duty subscale (feeling responsibility to help others), and the four-item efficacy subscale (perceived ability to be effective when helping others). The items were presented in a structured alternative format: The students were first asked to decide which type of person was most like him or her in two alternative sentences. They were then asked whether this is only sometimes true or almost always true for him or her. A sample pair of two social welfare items is “Some people are interested in doing something about problems in the community” versus “Other people are not that interested in working on problems in the community.” A sample pair of two duty items is “Some people feel obligated to carry out tasks assigned to them by the group” versus “Other people don’t feel that bound by group decisions.” A sample pair of two efficacy items is “Some people think they are able to help solve problems in their community” versus “Other people don’t think that they can do anything about the problems because a few powerful people decide everything.” The anchors for the first two sentences in each of the item pairs were almost always true for me, coded as 4, and sometimes true for me, coded as 3. These anchors were same for the second sentence in each item pair, but were coded as 2 and 1. Finally, the items were coded on a scale of 1 through to 4, with 4 designated as the highest and 1 as the lowest score for each item. The mean of the three subscales was used to represent social responsibility. The original internal consistency (Cronbach’s α) for the total score was .83 (Scales, Blyth, Berkas, & Kielsmeier, 2000), and in this study it was .74.

Data Analysis

We performed descriptive statistical analyses (the mean, standard deviation, and normality of each variable) followed by an analysis of the correlations among the variables. Next, an intercorrelation analysis was performed to examine the relationships among the proposed variables. A dummy code was used for gender and ethnicity: male and white were each coded as 0 and female and other ethnicities were each coded as 1. Finally, we used hierarchical regression analysis (HRA) to test the extent to which coaching behavior was associated with social responsibility. Demographic characteristics of age, gender, and experience in volunteer activities were entered in the first model, because we expected that these variables would be significant predictors of social responsibility (Wray-Lake et al., 2016). In the second model, the five types of coaching behavior were entered as the independent variable along with the demographic variables that we expected to be significant, to examine the relationship between coaching behavior and social responsibility after the demographic variables were controlled for. Statistical significance was set at .05 (Type I error), and we used SPSS version 21.0 for all statistical analyses.

Results

To detect any outliers and invalid data, we calculated the internal consistency, descriptive statistics (scores for means, standard deviations, skewness, and kurtosis), and correlation coefficients for the variables (see Table 1). According to the intercorrelation analysis results, there was a negative relationship between social responsibility and the demographic variable of gender. This indicated that the boys had a lower level of social responsibility than the girls. In coaching behavior, the relationships of autocratic behavior, and positive feedback and social support with social responsibility were all negative, whereas democratic coaching behavior was positively related to social responsibility. These results imply that democratic coaching behavior is more likely to increase social responsibility than is autocratic coaching behavior, which is more likely to decrease social responsibility.

Table 1. Descriptive Statistics and Correlations Among Study Variables

Table/Figure

Note. Reliability coefficients are shown in parentheses on the diagonal. * p < .05, ** p < .01.

We set hypothetical negative and positive relationships to social responsibility of high school student athletes, depending on the type of coaching behavior. Multicollinearity was not detected among the predictors. The range of the variance inflation factor of the predictors was from 1.02 to 1.69. The HRA results with social responsibility (see Table 2) revealed that the first model was significant, F(3, 199) = 4.85, p < .01. However, as age and experience in volunteer activities were found to be nonsignificant, we removed these variables and conducted the second HRA. The full model of gender and the five types of coaching behavior predicting social responsibility (Model 2), was statistically significant, F(6, 196) = 4.80, p < .01. The addition of the five types of coaching behavior to the prediction of social responsibility led to a statistically significant increase in R2 of .078. Of the types of coaching behavior, democratic behavior was positively related to social responsibility, whereas autocratic behavior was negatively related to social responsibility. However, after taking all variables into account, training and instruction, social support, and positive feedback did not have a significant relationship with social responsibility, although social support and positive feedback were negatively associated with social responsibility in the bivariate correlation.

Table 2. Hierarchical Multiple Regression Results Predicting Social Responsibility from Demographic Variables, and Coaching Behavior

Table/Figure

Note. * p < .05, ** p < .01.

Discussion

In this study, we examined the relationship between high school athletes’ perceptions of coaching behavior and their level of social responsibility. The results partially supported our hypotheses, and make an important theoretical contribution to the literature.

First, the results suggested that gender was the only variable that predicted the level of social responsibility among high school athletes. This is consistent with Wray-Lake et al.’s (2016) finding that men reported a lower level of social responsibility level compared to women. Mesch, Brown, Moore, and Hayat (2011) found that women showed greater empathic concern and had more service involvement than men did. The girls in our study also scored higher than the boys did for social responsibility.

Our finding that age did not predict social responsibility was interesting in the light of previous findings. For example, Nucci and Turiel (2009) reported no significant difference in the level of social responsibility during middle adolescence, because there is a U-shaped relationship with social responsibility during the period of adolescence. However, our participants were high school athletes whose ages ranged from 14 to 17 years, which can be considered middle adolescence, whereas Nucci and Turiel examined a broader range of ages. This may account for the absence of a relationship between age and social responsibility in this study.

Our findings contribute to the sports coaching literature by extending the MML (Chelladurai & Saleh, 1980), in which only the outcomes of athlete satisfaction and performance are specified. In this study, the results showed that coaches’ democratic behavior was positively linked, and autocratic behavior was negatively linked, to athletes’ social responsibility. In other words, democratic behavior and autocratic behavior influence the development of positive traits, such as social responsibility, in opposite directions.

Specifically, we found that, after controlling for the demographic variables of age, gender, and experience in volunteer activities, democratic coaching behavior had a positive relationship with social responsibility. This is consistent with Duke et al.’s (2009) and Lenzi et al.’s (2014) results and is also consistent with Hellison’s (2011) discussion on coaches’ democratic style. Hellison’s finding indicated that high school athletes whose coaches engaged in democratic behavior had a higher level of social responsibility.

In addition, democratic parenting behavior creates a family climate of respect and positive bonds by providing a warm and supportive environment (Wray-Lake et al., 2016). Democratic behavior also allows greater participation of children in the discussion of decisions that affect them. This decision-making process leads adolescents to increased decision-making autonomy, which, in turn, results in behavior that is more thoughtful and responsible (Duke et al., 2009). Thus, coaches’ democratic behavior that promotes young athletes’ participation in decision-making processes may contribute to their development of social responsibility.

In contrast, athletes’ perception of autocratic coaching behavior was negatively related to their level of social responsibility, which is consistent with Gunnoe et al.’s (1999) finding. Our result suggests that when young athletes have a coach who controls all the potential of the athletes, makes decisions without asking for the athletes’ opinions, and monitors the athletes’ performance to detect mistakes, they have a lower sense of social responsibility. Duke et al. (2009) reported that controlling behavior of coaches, which often involves harsh discipline and forcing adolescents to obey rules without questioning them, raises the level of anxiety among the young athletes, keeps them dependent on authority, and discourages them from making independent decisions, and becoming mentally and emotionally mature. This may result in a reduced level of social responsibility among high school athletes.

The finding that social responsibility may be influenced by coaches’ behavior has important implications for sport directors and coaches in schools. That is, our results will help coaches and administrators at schools to recognize how they can maximize the benefits of their pupils’ sport experience (Carreres Ponsoda et al., 2012). Our findings imply that the coach is a significant other who can positively influence athletes’ concern for others’ welfare and their sense of effectiveness in helping others. Specifically, coaches should exhibit more democratic behavior and less controlling (autocratic) behavior to develop their young athletes’ social responsibility (Hellison, 2011).

There are several limitations in this study. First, we relied on a self-report survey, which may not have accurately represented the athletes’ coaches’ leadership style. It is possible that self-report data may be affected by social desirability because they are based on the respondents’ perceptions. Future researchers should try to reduce such bias by also collecting data from the coaches’ perception of their own behavior. Second, we used a cross-sectional survey design. Thus, causality and directionality among the variables cannot be inferred. Future researchers should employ experimental or longitudinal designs to examine cause-and-effect relationships. Third, there is a lack of a validated instrument to measure the level of social responsibility of athletes. This lack may be a major reason for an absence of research in this area. Thus, an appropriate scale that reflects the characteristics of athletes should be developed so that the relationship between leadership behavior and the development of social responsibility among young athletes can be reliably measured and assessed.

In conclusion, there has been growing interest in exploring the contribution of both sport participants and coaches to PYD. The potential importance of coaches in athletes’ PYD motivated us to investigate the relationship between coaching behavior and social responsibility among high school athletes. Our results contribute to the literature by providing empirical evidence for the relationships among coaching behavior, PYD, and social responsibility among young athletes, and have implications for the design of coaching programs that will contribute optimally to PYD.

Bailey, R. (2006). Physical education and sport in schools: A review of benefits and outcomes. Journal of School Health, 76, 397–401. https://doi.org/d6stfq

Bandura, A. (1986). Social foundations of thought and action: A social cognitive theory. Englewood Cliffs, NJ: Prentice-Hall.

Benson, P. L., & Scales, P. C. (2009). Positive youth development and the prevention of youth aggression and violence. International Journal of Developmental Science, 3, 218–234. https://doi.org/bsv9

Brunelle, J., Danish, S. J., & Forneris, T. (2007). The impact of a sport-based life skill program on adolescent prosocial values. Applied Developmental Science, 11, 43–55. https://doi.org/c7bzmb

Burton, J. M., & Marshall, L. A. (2005). Protective factors for youth considered at risk of criminal behavior: Does participation in extracurricular activities help? Criminal Behaviour and Mental Health, 15, 46–64. https://doi.org/fqm7h9

Carreres Ponsoda, F., Escartί Carbonell, A., Cortell-Tormo, J. M., Fuster Lloret, V., & Andreu Cabrera, E. (2012). The relationship between out-of-school sport participation and positive youth development. Journal of Human Sport and Exercise, 7, 671–683. https://doi.org/bswb

Chelladurai, P. (2014). Managing organizations for sport and physical activity: A systems perspective (4th ed.). Scottsdale, AZ: Holcomb Hathaway.

Chelladurai, P., & Saleh, S. D. (1980). Dimensions of leader behavior in sports: Development of a leadership scale. Journal of Sport and Exercise Psychology, 2, 34–45. https://doi.org/bswd

Conrad, D., & Hedin, D. (1981). National assessment of experiential education: Summary and implications. Journal of Experiential Education, 4, 6–20. https://doi.org/bt43

Côté, J., & Gilbert, W. (2009). An integrative definition of coaching effectiveness and expertise. International Journal of Sports Science & Coaching, 4, 307–323. https://doi.org/d7kf7w

Duke, N. N., Skay, C. L., Pettingell, S. L., & Borowsky, I. W. (2009). From adolescent connections to social capital: Predictors of civic engagement in young adulthood. Journal of Adolescent Health, 44, 161–168. https://doi.org/bff4zq

Fraser-Thomas, J. L., Côté, J., & Deakin, J. (2005). Youth sport programs: An avenue to foster positive youth development. Physical Education and Sport Pedagogy, 10, 19–40. https://doi.org/cfzm5q

Gould, D., Collins, K., Lauer, L., & Chung, Y. (2007). Coaching life skills through football: A study of award winning high school coaches. Journal of Applied Sport Psychology, 19, 16–37. https://doi.org/d5dfs9

Gunnoe, M. L., Hetherington, E. M., & Reiss, D. (1999). Parental religiosity, parenting style, and adolescent social responsibility. The Journal of Early Adolescence, 19, 199–225. https://doi.org/d98m6g

Hellison, D. R. (2011). Teaching personal and social responsibility through physical activity (3rd ed.). Champaign, IL: Human Kinetics.

Hellison, D. R., Martinek, T., & Walsh, D. (2008). Sport and responsible leadership among youth. In N. L. Holt (Ed.), Positive youth development through sport (pp. 49–60). New York, NY: Routledge.

Kluever, R., & Green, K. E. (1998). The Responsibility Scale: A research note on dissertation completion. Educational and Psychological Measurement, 58, 520–531. https://doi.org/fr5q3x

Larson, R. W., Hansen, D. M., & Moneta, G. (2006). Differing profiles of developmental experience across types of organized youth activities. Developmental Psychology, 42, 849–863. https://doi.org/b5ht43

Lenzi, M., Vieno, A., Santinello, M., Nation, M., & Voight, A. (2014). The role played by the family in shaping early and middle adolescent civic responsibility. The Journal of Early Adolescence, 34, 251–278. https://doi.org/bswf

Mesch, D. J., Brown, M. S., Moore, Z. I., & Hayat, A. D. (2011). Gender differences in charitable giving. International Journal of Nonprofit and Voluntary Sector Marketing, 16, 342–355. https://doi.org/crmkgg

Nucci, L., & Turiel, E. (2009). Capturing the complexity of moral development and education. Mind, Brain, and Education, 3, 151–159. https://doi.org/dprfvk

Scales, P. C., Blyth, D. A., Berkas, T. H., & Kielsmeier, J. C. (2000). The effects of service-learning on middle school students’ social responsibility and academic success. The Journal of Early Adolescence, 20, 332–358. https://doi.org/cwht2m

Shields, D. L., & Bredemeier, B. (2001). Moral development and behavior in sport. In R. N. Singer, H. A. Hausenblas, & C. M. Janelle (Eds.), Handbook of sport psychology (2nd ed., pp. 585–603). New York, NY: Wiley.

Smith, R. E., Smoll, F. L., & Barnett, N. P. (1995). Reduction of children’s sport performance anxiety through social support and stress-reduction training for coaches. Journal of Applied Developmental Psychology, 16, 125–142. https://doi.org/d852vp

van Goethem, A., van Hoof, A., Orobio de Castro, B., Van Aken, M., & Hart, D. (2014). The role of reflection in the effects of community service on adolescent development: A meta-analysis. Child Development, 85, 2114–2130. https://doi.org/bswh

Wray-Lake, L., & Syvertsen, A. K. (2011). The developmental roots of social responsibility in childhood and adolescence. New Directions for Child and Adolescent Development, 2011, 11–25. https://doi.org/dv24c3

Wray-Lake, L., Syvertsen, A. K., & Flanagan, C. A. (2016). Developmental change in social responsibility during adolescence: An ecological perspective. Developmental Psychology, 52, 130–142. https://doi.org/bswg

Table 1. Descriptive Statistics and Correlations Among Study Variables

Table/Figure

Note. Reliability coefficients are shown in parentheses on the diagonal. * p < .05, ** p < .01.


Table 2. Hierarchical Multiple Regression Results Predicting Social Responsibility from Demographic Variables, and Coaching Behavior

Table/Figure

Note. * p < .05, ** p < .01.


Youngjun Choi, Department of Physical Education, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 136-701, Republic of Korea. Email: [email protected]

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