## 2 Literature Review
### Privacy Fatigue  
Fatigue is originally a concept from medicine, denoting a passive emotion [24]. When the matter people have to decide on and deal with exceeds the range of their ability, the passive response of \"fatigue\" is often engendered. In mobile application environments, obscure and complex system privacy practices and the system's privacy functionalities frequently have such an effect [25]. To tackle the issue of American users being deficient in privacy protection behaviors, [PERSON] and [PERSON] introduced the privacy fatigue concept in their research [26]. Within the connotations of privacy fatigue, cynicism and emotional exhaustion are considered the most prominent features [9]. Emotional exhaustion reflects the user instinctively adopting this emotion-centered response mechanism to raise the adaptive cognitive distance with the privacy issue; then, the sense of discomfort is reduced through privacy fatigue. Cynicism is defined as attitudes of uncertainty, helplessness and distrust towards online services handling personal information [9]. In earlier studies, academics believed users' privacy concern to be a multi-dimensional cognition of risks. Being the key measure of decisions towards privacy protection behaviors, the higher the degree of privacy concern, the stronger the user's sense of risks would be, and thus users become more inclined to adopt privacy protection behaviors [27; 28]. However, as the phenomenon of privacy fatigue appeared, academics discovered changes in user behavioral responses. As an example, [PERSON] and [PERSON] found that when internet users became tired of the issue of network safety, they would loosen defense behaviors towards security risks [29]. Under other situations, fatigue was also shown in users directly skipping the reading of privacy policies and choosing to accept [9]. Hence, there are also academics proposing that, compared to privacy concern, privacy fatigue is a higher influencing factor in privacy decisions and may even be one of the reasons to explain the discrepancy between user privacy concern and privacy behavior decisions, i.e., the privacy paradox [9].  
It is notable that the existing research emphasizes the complexity in terms of the reasons for the privacy paradox and are mainly opinion and behavior oriented, while ignoring the effects of user's emotional cognition and response to the privacy paradox, although some scholars have proposed some possible explanations of privacy fatigue. As far as we can understand, there has not been research deeply discussing how privacy fatigue specifically acts on the privacy paradox and how the two factors of privacy fatigue, namely cynicism and emotional exhaustion, respectively influence behavioral decisions in the privacy paradox. Given the limitations of existing studies, this paper intends to conduct research from the perspective of privacy fatigue to investigate its impacts on the process of the privacy paradox in the mobile social media context. This study also distinguishes the different effects of cynicism and emotional exhaustion, which would be of help to resolve the user privacy issue in the new stage of social media digitization.