Ergenler Arasında Görülen Siber Zorbalığın ve Mağduriyetin Akran İlişkileri ve Benlik Kavramı ile İlişkisinin İncelenmesi
Year 2022,
, 54 - 64, 14.03.2022
Ezgi Taştekin
,
Pınar Bayhan
Abstract
Bu araştırmanın amacı; ergenler arasında görülen siber zorbalığın ve mağduriyetin, bu dönemde gelişimsel açıdan önemli olan benlik kavramı ve akran ilişkileriyle olan ilişkisini incelemektir. Araştırmanın örneklemini, 14-17 yaş arasındaki 879 ergen oluşturmaktadır. Araştırma kapsamında Piers-Harris’in Çocuklarda Öz Kavramı Ölçeği, Akran İlişkileri Ölçeği ve Yenilenmiş Siber Zorbalık Envanteri veri toplama araçları olarak kullanılmıştır. Araştırma sonucunda siber zorbalığın yaşla birlikte arttığı; siber zorbalığın ve mağduriyetin erkeklerde daha fazla görüldüğü; ergenlerin genel benlik kavramı düştükçe siber zorbalığın ve mağduriyetin arttığı; benlik kavramının davranış ve uyma alt boyutunun siber zorbalıkla ve mağduriyetle negatif yönlü bir ilişkisi olduğu, bu ilişkinin siber zorbalıkta daha yüksek düzeyde ve önemli olduğu; benlik kavramının mutluluk ve doyum alt boyutunun siber zorbalıkla ve mağduriyetle negatif yönlü bir ilişkisi olduğu, bu ilişkinin siber mağduriyette daha yüksek düzeyde ve önemli olduğu; genel akran ilişkileriyle siber zorbalık ve mağduriyet arasında anlamlı ilişki olmadığı; akran ilişkilerindeki sadakatin siber zorbalıkla ve mağduriyetle pozitif yönlü bir ilişkisi olduğu, bu ilişkinin siber zorbalıkta daha yüksek düzeyde ve önemli olduğu; siber mağduriyet ve zorbalık arasında yüksek düzeyde pozitif yönlü bir ilişki olduğu; siber mağduriyetin ve zorbalığın birbirlerinin en önemli yordayıcıları olduğu; siber zorbalığın siber mağduriyeti yordama gücünün daha yüksek olduğu görülmüştür. Araştırma sonuçları, alanyazında yer alan bilgiler ışığında tartışılmış ve öneriler verilmiştir.
References
- Altan, T. ve Eldeleklioğlu, J. (2019). Lise öğrencilerinde siber zorbalığın yordayıcısı olarak siber mağduriyet ve duygusal zekâ. Elementary Education Online, 18(4), 2147-2156.
- Arnarsson, A., Nygren, J., Nyholm, M., Torsheim, T., Augustine, L., Bjereld, Y., ... ve Bendtsen, P. (2020). Cyberbullying and traditional bullying among Nordic adolescents and their impact on life satisfaction. Scandinavian Journal of Public Health, 48(5), 502-510.
- Arslan, S., Savaşer, S., Hallett, V. ve Balcı, S. (2012). Cyberbullying among primary school students in Turkey: Self-reported prevalence and associations with home and school life. Cyberpsychology, Behavior, and Social Networking, 15(10), 527-533.
- Bayhan, P. ve Artan, İ. (2007). Çocuk gelişimi ve eğitimi. Ankara: Morpa Kültür Yayınları.
- Butler, R. J. ve Gasson, S. L. (2005). Self esteem/self concept scales for children and adolescents: A review. Child and Adolescent Mental Health, 10(4), 190-201.
- Butt, S. S., Jamil, F. ve Khalid, R. (2019). Cyberbullying, self-esteem and interpersonal trust in young adults. Pakistan Journal of Social and Clinical Psychology, 17(1), 38-46.
- Chang, Q., Xing, J., Ho, R. T. ve Yip, P. S. (2019). Cyberbullying and suicide ideation among Hong Kong adolescents: The mitigating effects of life satisfaction with family, classmates and academic results. Psychiatry Research, 274(2019), 269-273.
- Charalampous, K., Demetriou, C., Tricha, L., Ioannou, M., Georgiou, S., Nikiforou, M., ve Stavrinides, P. (2018). The effect of parental style on bullying and cyber bullying behaviors and the mediating role of peer attachment relationships: A longitudinal study. Journal of Adolescence, 64(2018), 109-123.
- Cobb, N.J. (2007). Adolescence: Continuity, change, and diversity. New York: McGraw-Hill.
- Cole, D. A., Maxwell, S. E., Martin, J. M., Peeke, L. G., Seroczynski, A. D., Tram, J. M., ... ve Maschman, T. (2001). The development of multiple domains of child and adolescent self‐concept: A cohort sequential longitudinal design. Child Development, 72(6), 1723-1746.
- Corcoran, L., Connolly, I. ve O'Moore, M. (2012). Cyberbullying in Irish schools: An investigation of personality and self-concept. The Irish Journal of Psychology, 33(4), 153-165.
- Çataklı, M. (1985). Transliteral equivalance and reliability of the Turkish version of the Piers Harris Children’s Self Concept Scale. Yayınlanmamış yüksek lisans tezi, Boğaziçi Üniversitesi, İstanbul.
- Dijkstra, J. K. ve Veenstra, R. (2011). Peer relations. B. M. Newman ve M. J. Prinstein (Ed.). Encyclopedia of adolescence-2 içinde (s. 255-259). Londra: Academic Press.
- Englander, E.K. ve Muldowney, A.M. (2007). Just turn the darn thing off: Understanding cyberbullying. Proceedings of Persistently Safe Schools: The 2007 National Conference on Safe Schools and Communities 29-31 Ekim 2007 içinde (s. 83–92). Washington, DC: The George Washington Üniversitesi.
- Erdur-Baker, Ö. ve Kavşut, F. (2007). A new face of peer bullying: Cyberbullying. Journal of Euroasian Educational Research, 27, 31-42
Eroğlu, Y. ve Peker, A. (2015). Ergenlerde akran ilişkileri ile siber zorbalık statüleri arasındaki ilişkinin incelenmesi. Electronic Turkish Studies, 10(11), 593-606.
- Eroğlu, Y., Aktepe, E., Akbaba, S., Işık, A. ve Özkorumak, E. (2015). Siber zorbalık ve mağduriyetin yaygınlığının ve risk faktörlerinin incelenmesi. Eğitim ve Bilim, 40(177), 93-107.
- Estévez, E., Estévez, J. F., Segura, L. ve Suárez, C. (2019). The influence of bullying and cyberbullying in the psychological adjustment of victims and aggressors in adolescence. International Journal of Environmental Research and Public Health, 16(12), 2080.
- Field, A. (2009). Discovering statistics using SPSS. New Delhi: Sage Publications.
- Gradinger, P., Strohmeier, D. ve Spiel, C. (2009). Traditional bullying and cyberbullying: Identification of risk groups for adjustment problems. Zeitschrift für Psychologie/Journal of Psychology, 217(4), 205–213. https://doi.org/10.1027/0044-3409.217.4.205
- Hinduja, S. ve Patchin, J. (2011). Cyberbullying: Identification, prevention, and response. http://cyberbullying.org/Cyberbullying-Identification-Prevention-Response.pdf adresinden erişildi.
- Hinduja, S. ve Patchin, J.W. (2014). Bullying beyond the schoolyard: Preventing and responding to cyberbullying. Thousand Oaks, CA: Sage Publications (Corwin Press).
- Hines, H. N. (2011). Traditional bullying and cyber-bullying: are the impacts on self-concept the same? Doktora tezi, Western Carolina Üniversitesi, Kuzey Carolina.
- Ildırım, E., Çalıcı, C., ve Erdoğan, B. (2017). Psychological correlates of cyberbullying and cyber-victimization. The International Journal of Human and Behavioral Science, 3(2), 7-21.
- Israel, G.D. (1992). Determining sample size (Fact Sheet PEOD-6). Florida: Florida Cooperative Extension Service.
- Kavuk-Kalender, M. K., Keser, H. ve Tugun, V. (2019). Ortaokul ve lise öğrencilerinin siber zorbalık görüşleri, deneyimleri ve müdahale davranışları. Eğitim ve Bilim, 44(198), 183-200.
- Kaner, S. (2000). Akran ilişkileri ölçeği ve akran sapması ölçeği geliştirme çalışması. Ankara Üniversitesi Eğitim Bilimleri Fakültesi Dergisi, 33(1-2), 67-75.
- Kowalski, R., Limber, S. ve Agatston, P. (2012). Cyber-bullying: Bullying in the digital age. Malden, MA: Blackwell.
- Kowalski, R.M. ve Limber, S.P. (2007). Electronic bullying among middle school students. Journal of Adolescent Health, 41(6), 22-30.
- Lee, C. ve Shin, N. (2017). Prevalence of cyberbullying and predictors of cyberbullying perpetration among Korean adolescents. Computers in Human Behavior, 68(2017), 352-358.
- Leung, A. N. M., Wong, N. ve Farver, J. M. (2018). Cyberbullying in Hong Kong Chinese students: Life satisfaction, and the moderating role of friendship qualities on cyberbullying victimization and perpetration. Personality and Individual Differences, 133(2018), 7-12.
- Li, Q. (2008). A cross-cultural comparison of adolescents' experience related to cyberbullying. Educational Research, 50(3), 223-234.
- Livazović, G. ve Ham, E. (2019). Cyberbullying and emotional distress in adolescents: The importance of family, peers and school. Heliyon, 5(6), e01992.
- Mishna, F., Khoury-Kassabri, M., Gadalla, T. ve Daciuk, J. (2012). Risk factors for involvement in cyber bullying: Victims, bullies and bully–victims. Children and Youth Services Review, 34(1), 63-70.
- Öner, N. (1996). Piers-Harris’ in çocuklarda öz-kavramı ölçeği el kitabı. Ankara: Türk Psikologlar Derneği Yayınları.
- Özdemir, S. (2015). Ergenlerde siber zorbalık ve mağduriyetin, anne-baba ve akran ilişkilerine göre incelenmesi.Yüksek lisans tezi, Gazi Üniversitesi, Ankara.
- Peker, A. (2015). Ortaokul öğrencilerinin siber zorbalık statülerini yordayan risk faktörlerinin incelenmesi. Eğitim ve Bilim, 40(181), 57-75.
- Peker, A., Eroğlu, Y. ve Ada, Ş. (2012). Ergenlerde siber zorbalığın ve mağduriyetin yordayıcılarının incelenmesi. Abant İzzet Baysal Üniversitesi Eğitim Fakültesi Dergisi, 12(2), 185-206.
- Piers, E. V. ve Harris, D. B. (1964). Piers-Harris children’s self-concept scale (the way I feel about myself). Nashville, Tennessee: Counselor Recordings and Tests.
- Ramos-Salazar, L. (2017). Cyberbullying victimization as a predictor of cyberbullying perpetration, body image dissatisfaction, healthy eating and dieting behaviors, and life satisfaction. Journal of Interpersonal Violence, 00(0), 1-27.
- Romero-Abrio, A., León-Moreno, C., Musitu-Ferrer, D., ve Villarreal-González, M. E. (2019). Family functioning, self-concept and cybervictimization: An analysis based on gender. Social Sciences, 8(2), 69.
- Salmela-Aro, K. (2011). Stages of adolescence. B. M. Newman ve M. J. Prinstein (Ed.). Encyclopedia of adolescence-1 içinde (s. 360-368). Londra: Academic Press.
- Shavelson, R. J., Hubner, J. J. ve Stanton, G. C. (1976). Self-concept: Validation of construct interpretations. Review of Educational Research, 46(3), 407-441.
- Slonje, R. ve Smith, P.K. (2008). Cyberbullying: Another main type of bullying? Scandinavian Journal of Psychology, 49(2), 147-154.
Steinberg, L. (2003). Adolescence. New York: McGraw-Hill.
- Süslü, D. P. (2018). A study on self-esteem, mother, father, and peer relations as predictors of cyberbullying and cyber-victimization in high school students. Journal of Human Sciences, 15(2), 1381-1393.
- Tokunaga, R.S. (2010). Following you home from school: A critical review and synthesis of research on cyberbullying victimization. Computers in Human Behavior, 26(3), 277-287.
- Topcu, Ç. ve Erdur-Baker, Ö. (2010). The revised cyber bullying inventory (RCBI): Validity and reliability studies. Procedia-Social and Behavioral Sciences, 5(2010), 660-664.
- Vandebosch, H. ve Van Cleemput, K. (2008). Defining cyberbullying: A qualitative research into the perceptions of youngsters. Cyberpsychology&Behavior, 11(4), 499-503.
- Willard, N.E. (2007). Cyberbullying and cyberthreats: Responding to the challenge of online social aggression, threats, and distress. Illinois: Research Press.
- Ybarra, M.L. ve Mitchell, K.J. (2004). Youth engaging in online harassment: Associations with caregiver-child relationships, internet use, and personal characteristics. Journal of Adolescence, 27(3), 319-336.
Examining the Relationship of Cyberbullying and Victimization among Adolescents with Peer Relationships and Self-Concept
Year 2022,
, 54 - 64, 14.03.2022
Ezgi Taştekin
,
Pınar Bayhan
Abstract
The purpose of this research is; to examine the relationship of cyberbullying and victimization among adolescents with the self-concept and peer relationships, which is important developmentally in this period. The sample of the study consisted of 879 adolescents between the ages of 14 and 17. Within the scope of the research, Piers-Harris Children's Self-Concept Scale, Peer Relationships Scale and Revised Cyberbullying Inventory were used as data collection tools. As result of the research, cyberbullying increases with age; cyberbullying and victimization are more common in male adolescents; cyberbullying and victimization increase as adolescents' general self-concept decreases; the sub-dimension of the self-concept that is behavior and compliance has a negative relationship with cyberbullying and victimization, in which this relationship is higher and more important in cyberbullying; the sub-dimension of the self-concept that is self-happiness and satisfaction has a negative relationship with cyberbullying and victimization, and that this relationship is higher and more important in cyber victimization; there is no meaningful relationship between general peer relationships and cyberbullying and victimization; loyalty in peer relationships has a positive relationship with cyberbullying and victimization, in which this relationship is higher and more important in cyberbullying; there is a high level of positive relationship between cyber victimization and bullying; cyberbullying and cyber victimization are the most important predictors of each other; cyberbullying has been found to have a higher power to predict cyber victimization. The results of the research were discussed and recommendations were given in the light of the literature.
References
- Altan, T. ve Eldeleklioğlu, J. (2019). Lise öğrencilerinde siber zorbalığın yordayıcısı olarak siber mağduriyet ve duygusal zekâ. Elementary Education Online, 18(4), 2147-2156.
- Arnarsson, A., Nygren, J., Nyholm, M., Torsheim, T., Augustine, L., Bjereld, Y., ... ve Bendtsen, P. (2020). Cyberbullying and traditional bullying among Nordic adolescents and their impact on life satisfaction. Scandinavian Journal of Public Health, 48(5), 502-510.
- Arslan, S., Savaşer, S., Hallett, V. ve Balcı, S. (2012). Cyberbullying among primary school students in Turkey: Self-reported prevalence and associations with home and school life. Cyberpsychology, Behavior, and Social Networking, 15(10), 527-533.
- Bayhan, P. ve Artan, İ. (2007). Çocuk gelişimi ve eğitimi. Ankara: Morpa Kültür Yayınları.
- Butler, R. J. ve Gasson, S. L. (2005). Self esteem/self concept scales for children and adolescents: A review. Child and Adolescent Mental Health, 10(4), 190-201.
- Butt, S. S., Jamil, F. ve Khalid, R. (2019). Cyberbullying, self-esteem and interpersonal trust in young adults. Pakistan Journal of Social and Clinical Psychology, 17(1), 38-46.
- Chang, Q., Xing, J., Ho, R. T. ve Yip, P. S. (2019). Cyberbullying and suicide ideation among Hong Kong adolescents: The mitigating effects of life satisfaction with family, classmates and academic results. Psychiatry Research, 274(2019), 269-273.
- Charalampous, K., Demetriou, C., Tricha, L., Ioannou, M., Georgiou, S., Nikiforou, M., ve Stavrinides, P. (2018). The effect of parental style on bullying and cyber bullying behaviors and the mediating role of peer attachment relationships: A longitudinal study. Journal of Adolescence, 64(2018), 109-123.
- Cobb, N.J. (2007). Adolescence: Continuity, change, and diversity. New York: McGraw-Hill.
- Cole, D. A., Maxwell, S. E., Martin, J. M., Peeke, L. G., Seroczynski, A. D., Tram, J. M., ... ve Maschman, T. (2001). The development of multiple domains of child and adolescent self‐concept: A cohort sequential longitudinal design. Child Development, 72(6), 1723-1746.
- Corcoran, L., Connolly, I. ve O'Moore, M. (2012). Cyberbullying in Irish schools: An investigation of personality and self-concept. The Irish Journal of Psychology, 33(4), 153-165.
- Çataklı, M. (1985). Transliteral equivalance and reliability of the Turkish version of the Piers Harris Children’s Self Concept Scale. Yayınlanmamış yüksek lisans tezi, Boğaziçi Üniversitesi, İstanbul.
- Dijkstra, J. K. ve Veenstra, R. (2011). Peer relations. B. M. Newman ve M. J. Prinstein (Ed.). Encyclopedia of adolescence-2 içinde (s. 255-259). Londra: Academic Press.
- Englander, E.K. ve Muldowney, A.M. (2007). Just turn the darn thing off: Understanding cyberbullying. Proceedings of Persistently Safe Schools: The 2007 National Conference on Safe Schools and Communities 29-31 Ekim 2007 içinde (s. 83–92). Washington, DC: The George Washington Üniversitesi.
- Erdur-Baker, Ö. ve Kavşut, F. (2007). A new face of peer bullying: Cyberbullying. Journal of Euroasian Educational Research, 27, 31-42
Eroğlu, Y. ve Peker, A. (2015). Ergenlerde akran ilişkileri ile siber zorbalık statüleri arasındaki ilişkinin incelenmesi. Electronic Turkish Studies, 10(11), 593-606.
- Eroğlu, Y., Aktepe, E., Akbaba, S., Işık, A. ve Özkorumak, E. (2015). Siber zorbalık ve mağduriyetin yaygınlığının ve risk faktörlerinin incelenmesi. Eğitim ve Bilim, 40(177), 93-107.
- Estévez, E., Estévez, J. F., Segura, L. ve Suárez, C. (2019). The influence of bullying and cyberbullying in the psychological adjustment of victims and aggressors in adolescence. International Journal of Environmental Research and Public Health, 16(12), 2080.
- Field, A. (2009). Discovering statistics using SPSS. New Delhi: Sage Publications.
- Gradinger, P., Strohmeier, D. ve Spiel, C. (2009). Traditional bullying and cyberbullying: Identification of risk groups for adjustment problems. Zeitschrift für Psychologie/Journal of Psychology, 217(4), 205–213. https://doi.org/10.1027/0044-3409.217.4.205
- Hinduja, S. ve Patchin, J. (2011). Cyberbullying: Identification, prevention, and response. http://cyberbullying.org/Cyberbullying-Identification-Prevention-Response.pdf adresinden erişildi.
- Hinduja, S. ve Patchin, J.W. (2014). Bullying beyond the schoolyard: Preventing and responding to cyberbullying. Thousand Oaks, CA: Sage Publications (Corwin Press).
- Hines, H. N. (2011). Traditional bullying and cyber-bullying: are the impacts on self-concept the same? Doktora tezi, Western Carolina Üniversitesi, Kuzey Carolina.
- Ildırım, E., Çalıcı, C., ve Erdoğan, B. (2017). Psychological correlates of cyberbullying and cyber-victimization. The International Journal of Human and Behavioral Science, 3(2), 7-21.
- Israel, G.D. (1992). Determining sample size (Fact Sheet PEOD-6). Florida: Florida Cooperative Extension Service.
- Kavuk-Kalender, M. K., Keser, H. ve Tugun, V. (2019). Ortaokul ve lise öğrencilerinin siber zorbalık görüşleri, deneyimleri ve müdahale davranışları. Eğitim ve Bilim, 44(198), 183-200.
- Kaner, S. (2000). Akran ilişkileri ölçeği ve akran sapması ölçeği geliştirme çalışması. Ankara Üniversitesi Eğitim Bilimleri Fakültesi Dergisi, 33(1-2), 67-75.
- Kowalski, R., Limber, S. ve Agatston, P. (2012). Cyber-bullying: Bullying in the digital age. Malden, MA: Blackwell.
- Kowalski, R.M. ve Limber, S.P. (2007). Electronic bullying among middle school students. Journal of Adolescent Health, 41(6), 22-30.
- Lee, C. ve Shin, N. (2017). Prevalence of cyberbullying and predictors of cyberbullying perpetration among Korean adolescents. Computers in Human Behavior, 68(2017), 352-358.
- Leung, A. N. M., Wong, N. ve Farver, J. M. (2018). Cyberbullying in Hong Kong Chinese students: Life satisfaction, and the moderating role of friendship qualities on cyberbullying victimization and perpetration. Personality and Individual Differences, 133(2018), 7-12.
- Li, Q. (2008). A cross-cultural comparison of adolescents' experience related to cyberbullying. Educational Research, 50(3), 223-234.
- Livazović, G. ve Ham, E. (2019). Cyberbullying and emotional distress in adolescents: The importance of family, peers and school. Heliyon, 5(6), e01992.
- Mishna, F., Khoury-Kassabri, M., Gadalla, T. ve Daciuk, J. (2012). Risk factors for involvement in cyber bullying: Victims, bullies and bully–victims. Children and Youth Services Review, 34(1), 63-70.
- Öner, N. (1996). Piers-Harris’ in çocuklarda öz-kavramı ölçeği el kitabı. Ankara: Türk Psikologlar Derneği Yayınları.
- Özdemir, S. (2015). Ergenlerde siber zorbalık ve mağduriyetin, anne-baba ve akran ilişkilerine göre incelenmesi.Yüksek lisans tezi, Gazi Üniversitesi, Ankara.
- Peker, A. (2015). Ortaokul öğrencilerinin siber zorbalık statülerini yordayan risk faktörlerinin incelenmesi. Eğitim ve Bilim, 40(181), 57-75.
- Peker, A., Eroğlu, Y. ve Ada, Ş. (2012). Ergenlerde siber zorbalığın ve mağduriyetin yordayıcılarının incelenmesi. Abant İzzet Baysal Üniversitesi Eğitim Fakültesi Dergisi, 12(2), 185-206.
- Piers, E. V. ve Harris, D. B. (1964). Piers-Harris children’s self-concept scale (the way I feel about myself). Nashville, Tennessee: Counselor Recordings and Tests.
- Ramos-Salazar, L. (2017). Cyberbullying victimization as a predictor of cyberbullying perpetration, body image dissatisfaction, healthy eating and dieting behaviors, and life satisfaction. Journal of Interpersonal Violence, 00(0), 1-27.
- Romero-Abrio, A., León-Moreno, C., Musitu-Ferrer, D., ve Villarreal-González, M. E. (2019). Family functioning, self-concept and cybervictimization: An analysis based on gender. Social Sciences, 8(2), 69.
- Salmela-Aro, K. (2011). Stages of adolescence. B. M. Newman ve M. J. Prinstein (Ed.). Encyclopedia of adolescence-1 içinde (s. 360-368). Londra: Academic Press.
- Shavelson, R. J., Hubner, J. J. ve Stanton, G. C. (1976). Self-concept: Validation of construct interpretations. Review of Educational Research, 46(3), 407-441.
- Slonje, R. ve Smith, P.K. (2008). Cyberbullying: Another main type of bullying? Scandinavian Journal of Psychology, 49(2), 147-154.
Steinberg, L. (2003). Adolescence. New York: McGraw-Hill.
- Süslü, D. P. (2018). A study on self-esteem, mother, father, and peer relations as predictors of cyberbullying and cyber-victimization in high school students. Journal of Human Sciences, 15(2), 1381-1393.
- Tokunaga, R.S. (2010). Following you home from school: A critical review and synthesis of research on cyberbullying victimization. Computers in Human Behavior, 26(3), 277-287.
- Topcu, Ç. ve Erdur-Baker, Ö. (2010). The revised cyber bullying inventory (RCBI): Validity and reliability studies. Procedia-Social and Behavioral Sciences, 5(2010), 660-664.
- Vandebosch, H. ve Van Cleemput, K. (2008). Defining cyberbullying: A qualitative research into the perceptions of youngsters. Cyberpsychology&Behavior, 11(4), 499-503.
- Willard, N.E. (2007). Cyberbullying and cyberthreats: Responding to the challenge of online social aggression, threats, and distress. Illinois: Research Press.
- Ybarra, M.L. ve Mitchell, K.J. (2004). Youth engaging in online harassment: Associations with caregiver-child relationships, internet use, and personal characteristics. Journal of Adolescence, 27(3), 319-336.