文章描述了移动微媒体环境下用户错失焦虑症的内涵与要素，在S-O-R模式下基于认知心理学分析了错失焦虑症用户可能存在的心理状态，构建了由温和诱因诱导、注意聚散更迭、移情机制触发、认知联结需要、认知失调调节、感知控制驱动和正念觉察缺失7个子机理组成的用户错失焦虑症生成机理，并阐释要素与机理及机理之间的逻辑关系。本研究对揭示错失焦虑症用户的内在心理变化及外在非理性、非适应性和问题性媒体使用行为起解释和原因推理作用，有助于用户防御、调节和控制焦虑不安、患得患失等负性情绪，延伸了用户心理和信息行为研究。

This paper describes the connotations and elements of user fear of missing out (FoMO) in mobile micro-media environment. The possible mental state of FoMO users is analyzed based on S-O-R model and cognitive psychology. The mobile micro-media user FoMO generation mechanism is consised by 7 sub-mechanisms such as induction of mild incentives sub-mechanism, shifting of attention sub-mechanism, triggering of empathy mechanism sub-mechanism, need of cognitive connection sub-mechanism, adjustment of cognitive dissonance sub-mechanism, drive of perceptual control sub-mechanism and loss of mindfulness perception sub-mechanism. Finally, the authors explain relationship between elements and sub-mechanisms and analyze logical relationship among sub-mechanisms. This paper interprets the internal psychological changes and external irrational, non-adaptive and problematic media use behavior of FoMO users. It will sever as an explanation and reasoning reason, which will help users to defend, regulate and control negative emotions such as anxiety, suffering and loss. The paper extends the research on user psychology and information behavior.