本論文以政治學及心理學的理論為基礎，探討社會人士的集體行動及政治參與行為及其背後的心理因素，以及網上新聞的普及對這些行為、意向是否具催化作用。根據政治學及社會心理學文獻，團體在社會得到的社會認定「social identity」）及個人對自身的政治功效意識 （「political efficacy」）往往是影響人們集體行動及政治參與（稱「團體參與行動」「intergroup participatory actions」）程度的決定因素。不過，個人/團體對集體行動的參與意向跟媒體使用及社會人士的實際參與之間的關係在文獻中似乎從未提到。然而，這方面的研究在現今數碼時代十分重要。 / 關於網上新聞的影響，主要的文獻論述有二：工具性論述指出網上資訊澎湃、隨手可得，且成本極低，網上新聞的使用對社會人士參與政治有直接影響（本論文將驗證此觀點，是為假設一）；心理學論述指出網上新聞對人們的影響視乎個人既有的心理素質。本文主張個人參與集體行動及參與政治的意向在於人們是否能從這些行動中得到高度的「社會認定」及「政治功效意識」；而這兩方面又可隨著個人接觸的網上資訊增加而得以提昇，因為人們傾向選擇接收那些肯定他們既有看法及態度的資訊（即「選擇性暴露理論」），以及那些提昇他們對某社群歸屬感的資訊（即「使用與滿足理論」）。本文提出下列觀點，並加以驗證：網上新聞的普及提昇「個人功效意識」（假設二）、提昇「集體功效意識」（假設三）、提昇參與團體行動人士得到的「社會認定」（假設四），而個人/團體從社會認定中得到的滿足對他們實際參與團體行動有驅動作用（假設五）。 / 本文對在美國及香港具代表性的民意調查作出分析，分析結果跟上列的假設吻合。然後進行了一項實驗，其結果指出「個人功效意識」或可作為「政治功效意識」內一有效的獨立準則。本人在美國及香港進行民意調查（各地兩項；所涉及的調查相隔一年），並作迴歸分析，以驗證上述有關社會人士參與集體行動及政治意向的假設，研究重點包括人們的投票意向、示威意向、議題參與意向及公民參與意向。研究結果支持假設一（即工具性論述）及假設三（即有關「集體功效意識」的心理學論述）的有效性。假設二（有關「個人功效意識」）及假設四（有關「社會認定」）可作進一步驗證。研究中所有具統計學顯著意義的結果卻否定了假設五（有關「社會認定」對個人/團體帶來的滿足程度）的有效信度。 / 最後，研究局限、結果應用等亦會在文中細述。 / Applying an interdisciplinary and integrative theoretical perspective and framework, this thesis is concerned with the role of Internet news on collective action and political participation, and the important moderating role of certain psychological antecedents on the relationship. The literature shows that identification with a group (social identity) and the feeling that one could make a substantive difference (political efficacy) are two important predictors of such actions (termed “intergroup participatory actions in this thesis). However, the processes that link the antecedents of participatory behaviors to media use and then to actual participation have been neglected. Such an examination is important in the digital age where the Internet provides citizens a media environment where access to information about politics and social causes is easy, cheap and abundant. / Two views of the impact of Internet are prevalent in the literature. The “instrumental“ view argues that Internet use has a direct effect on political participation and typically emphasizes the reduced costs and the relative “informational richness“ associated with Internet news use (Hypothesis 1). The “psychological“ view argues that the effects of the Internet depend to an extent on individual’s preexisting psychological dispositions. It is further hypothesized that two dimensions of political efficacy are important antecedents of participatory actions: ‘individual efficacy’ and ‘collective efficacy’. / The thesis argues that individuals’ willingness to participate in a collective action and participate in politics depends on high levels of social identity and political efficacy, which can be heightened by exposure to Internet news because individuals are likely to consume media content that reinforces their existing attitudes and opinions (as put forward by Selective Exposure Theory) and reinforces their psychological need to feel like a member of a social group (as put forward by Uses and Gratifications Theory). Conceptually, this means that individual efficacy (Hypothesis 2), collective efficacy (Hypothesis 3), and social identity (Hypothesis 4) will accentuate the effects of Internet news use on intergroup participatory actions. Moreover, social identity gratifications will accentuate the effects of social identity on intergroup participatory actions (Hypothesis 5). / Secondary data analyses of national data in the United States and Hong Kong provide initial support for the hypotheses. Moreover, an embedded quasi-experiment provides support for the validity of ‘individual efficacy’ as a unique dimension of political efficacy. Subsequent exploratory and confirmatory factor analyses also showed that both individual and collective efficacy to be unique dimensions of political efficacy, along with internal and external efficacy. / Regression analyses using two Hong Kong and two American samples collected a year apart test the hypotheses for a variety of participatory behaviors, including voting intention, protest intention, issue participation and civic participation. In general, the findings were supportive of the ‘instrumental’ view of Internet effects (H1) and the ‘psychological view’ with respect to collective efficacy (H3). There was less evidence for the effects of individual efficacy (H2) and social identity (H4). All significant interactions for social identity gratifications (H5) were in the opposite direction as hypothesized. / Implications of these findings are discussed and suggestions for further research are specified. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chan, Che Ming. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 232-247). / Abstract also in Chinese. / Acknowledgements --- p.iv / Contents --- p.v / List of Tables --- p.vii / List of Figures --- p.ix / Chapter Chapter 1 --- Introduction --- p.1 / Overview of the Thesis Structure --- p.6 / Contributions to the Literature --- p.9 / Chapter Chapter 2 --- Antecedents of Collective Action and Political Participation --- p.11 / Collective Action and Political Participation as Forms of Intergroup Participatory Actions --- p.12 / Perceived Injustice --- p.15 / Efficacy --- p.19 / Identification --- p.27 / Summary and Way Forward --- p.34 / Chapter Chapter 3 --- The Role of the Internet in Intergroup Participatory Actions --- p.37 / The Mobilizing Potential of the Internet --- p.37 / The Role of Internet News in Political Participation --- p.39 / The Role of Internet News in Protests and Demonstrations --- p.43 / The Internet and Participatory Actions in the Hong Kong Context --- p.45 / Summary and Hypothesis --- p.46 / Chapter Chapter 4 --- The Contingent Effects of Efficacy and Social Identity --- p.48 / Efficacy, Selective Exposure, and Participatory Behaviors --- p.50 / Social Identity, Selective Exposure, and Participatory Behaviors --- p.56 / Social Identity, Uses and Gratifications, and Participatory Behaviors --- p.61 / Summary of Hypotheses --- p.65 / Chapter Chapter 5 --- Secondary Data Analyses of National Survey Data --- p.68 / Theoretical Approach to Analyses --- p.68 / American National Election Studies Survey (2004-2008) --- p.70 / The National Annenberg Election Survey (2008) --- p.97 / The PEW 2009 Values Survey --- p.110 / Hong Kong Survey 2009 --- p.114 / Summary and Way Forward --- p.118 / Chapter Chapter 6 --- Measurement and Validation of Political Efficacy Dimensions --- p.124 / Question Item Selection and Analytic Strategy --- p.125 / Sampling and Operationalization --- p.129 / Results --- p.131 / Summary and recommendations --- p.153 / Chapter Chapter 7 --- Predicting Intergroup Participatory Actions Among Young Adults --- p.156 / Young Adults, the Internet, and Participation --- p.157 / Sampling --- p.166 / Operationalization --- p.166 / Results --- p.174 / Discussion --- p.187 / Chapter Chapter 8 --- Discussion and Future Research --- p.200 / Interdisciplinary Perspective of Intergroup Participatory Actions --- p.201 / Complementary Explanations of Internet News Effects --- p.205 / Expansion and Validation of Political Efficacy Dimensions --- p.212 / Extension of Uses and Gratifications Theory --- p.213 / Contributions to the Hong Kong Literature --- p.214 / Appendices --- p.215 / Chapter Appendix A --- Social Identity Studies in Hong Kong --- p.216 / Chapter Appendix B --- Mass Media and Collective Action in the Hong Kong Context --- p.219 / Chapter Appendix C --- Theoretical Basis for Group-Based Perspective of Uses and Gratifications --- p.222 / Chapter Appendix D --- Questions Items in 2010 Surveys --- p.226 / Chapter Appendix E --- Questions Items in 2011 Surveys --- p.229 / References --- p.232