中文摘要：

任务复杂性是影响用户信息行为的重要因素。本文首先系统梳理客观任务复杂性、主观任务复杂性及其与用户信息搜寻行为关系的文献，构建研究模型。其次，通过专家打分、发声思维、录屏及问卷采集数据，并采用统计方法围绕信息搜寻过程探讨客观任务复杂性对用户认知和导航行为的影响，以及用户认知和导航行为对主观任务复杂性的影响。得出结论：可以从用户认知努力和生理努力角度修正测量客观任务复杂性的指标；任务复杂性的客观属性与主观任务复杂性未发现相关关系，存在调节变量；只有六项认知心理行为指标和两项导航行为指标显著影响用户事后主观任务复杂性的判断。据此，本文用一个具体模型描述客观任务复杂性、主观任务复杂性与用户认知心理和导航行为之间的关系，为分析用户信息搜寻行为的心理机制和行为机制提供研究基础。

英文摘要：

Task complexity is an important component in the studies of users＇ information behavior. This paper firstly gave a systematic review on related literature and provided a research model. Then, an experiment was performed to study the effects of task complexity （ including objective and subjective perspective） on users＇ cognition and web navigating behavior from the whole information seeking process. Experts ranking, think-aloud, screen recording and survey was used to collect the data. Then Spearman and non-parametric test showed：①the current objective task complexity measurements can be modified from the cognition efforts and physical effortS; ② the objective task complexity has no direct significant effects on subjective task complexity while there are mediate effects between them; ③ users＇ perception on subjective task complexity is a rational process as six types of cognitive activities and two types of navigating activities have significant effects on the post-hoc subjective task complexity. Finally, this paper provided a more detailed model to represent the effects of subjective task complexity and objective task complexity on users＇ cognition and web navigating behavior, which can provide more reference value for analyzing user information seeking behavior.