[Objective] This paper investigates the differences of users' search experience between two types of tasks, with and without time constraint, with the goal to understand how various contextual factors influence search behaviors and experience. [Methods] A user experiment is conducted, in which 40 undergraduate students participated, to search for two types of search tasks: Fact Finding (FF) and Information Understanding (IU), under two time conditions: with time constraint, and without time constraint. [Results] The results show that time constraint significantly shorten users' search time, writing time, and the amount of information produced in the notebook, and their new knowledge acquisition; in addition, users speed up the number of words produced in the documents. With respect to the task type effect, users' ratio of time on search and writing, the number of words produced on documents during search are not significantly influenced by task type, no matter whether there is time constraint or not. Very interestingly, when there is no time constraint, users spend longer time to complete the task, longer time on searching to accomplish IU tasks; however, there is no significant difference on the amount of information collected and the level of new knowledge acquisition. When there is time constraint, comparing with FF tasks, users collect more information but think they acquire lower level of new knowledge. [Limitations] This study is conducted in a lab environment, and the time constraint is manipulated by experimenters, which may not be the same as it is in real settings, so the results of this study may not be generalizable to various conditions. [Conclusions] This study has implications for understanding how time and search task type influence search behaviors for information search research.
刘畅, 张璐. 时间限制和搜索任务类型对搜索体验的影响分析[J]. 现代图书情报技术, 2015, 31(9): 1-8.
Liu Chang, Zhang Lu. Effect of Time Constraint and Task Type on Search Experience. New Technology of Library and Information Service, DOI：10.11925/infotech.1003-3513.2015.09.01.
 Li Y L, Belkin N J. A Faceted Approach to Conceptualizing Tasks in Information Seeking [J]. Information Processing & Management, 2008, 44(6): 1822-1837.
 Savolainen R. Time as a Context of Information Seeking [J]. Library & Information Science Research, 2006, 28(1): 110-127.
 Slone D J. The Impact of Time Constraints on Internet and Web Use [J]. Journal of the American Society for Information Science and Technology, 2007, 58(4): 508-517.
 Crescenzi A, Capra R, Arguello J. Time Pressure, User Satisfaction and Task Difficulty [C]. In: Proceedings of the 76th Annual Meeting of the Association for Information Science and Technology (AIST2013), Montreal, Canada. 2013.
 Fujikawa K, Joho H, Nakayama S. Constraint can Affect Human Perception, Behaviour, and Performance of Search [C]. In: Proceedings of the 14th International Conference on Asia-Pacific Digital Libraries (ICADL 2012), Taipei, Taiwan, China. 2012: 39-48.
 Maule A J, Hockey G R J, Bdzola L. Effects of Time-pressure on Decision-making Under Uncertainty: Changes in Affective State and Information Processing Strategy [J]. Acta Psychologica, 2000, 104(3): 283-301.
 Topi H, Valacich J S, Hoffer J A. The Effects of Task Complexity and Time Availability Limitations on Human Performance in Database Query Tasks [J]. International Journal of Human-Computer Studies, 2005, 62(3): 349-379.
 Weenig M W H, Maarleveld M. The Impact of Time Constraint on Information Search Strategies in Complex Choice Tasks [J]. Journal of Economic Psychology, 2002, 23(6): 689-702.
 Byström K, Järvelin K. Task Complexity Affects Information Seeking and Use [J]. Information Processing & Management, 1995, 31(2): 191-213.
 Gwizdka J, Spence I. What can Searching Behavior Tell Us About the Difficulty of Information Tasks? A Study of Web Navigation [C]. In: Proceedings of the 69th Annual Meeting of the American Society for Information Science and Technology (ASIST), Austin, US. 2006: 1-22.
 Kellar M, Watters C, Shepherd M. A Field Study Characterizing Web-based Information-seeking Tasks [J]. Journal of the American Society for Information Science and Technology, 2007, 58(7): 999-1018.
 Wu W C, Kelly D, Edwards A, et al. Grannies, Tanning Beds, Tattoos and NASCAR: Evaluation of Search Tasks with Varying Levels of Cognitive Complexity [C]. In: Proceedings of the 4th Information Interaction in Context Symposium.
ACM, 2012: 254-257.
 Anderson L W, Krathwohl D R. A Taxonomy for Learning, Teaching and Assessing: A Revision of Bloom's Taxonomy of Educational Objectives [M]. Pearson, 2001.
 刘畅, 赵瑜, 杨帆.信息检索用户实验设计中时间限制和任务次序的影响研究[J].图书情报工作, 2015, 59(1): 99-105. (Liu Chang, Zhao Yu, Yang Fan. Examination of the Effects of Time Constraint and Task Order in User Experiment [J]. Library and Information Service, 2015, 59(1): 99-105.)
 Nickles K R, Curley S P, Benson P G. Judgment-based and Reasoning-based Stopping Rules in Decision Making under Uncertainty [R]. Wake Forest University, 1995.