The Construction of Mental Models of Information-rich Web Spaces: The Development Process and the Impact of Task Complexity Yan Zhang A dissertation submitted to the faculty of the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the School of Information and Library Science Chapel Hill 2009 Approved by: Barbara Wildemuth Gary Marchionini Paul Solomon Diane Kelly Javed Mostafa Peiling Wang UMI Number: 3387797 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI 3387797 Copyright 2010 by ProQuest LLC. All rights reserved. This edition of the work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106-1346 © 2009 Yan Zhang ALL RIGHTS RESERVED ii Abstract YAN ZHANG: The construction of mental models of information-rich web spaces: The development process and the impact of task complexity (Under the direction of Barbara Wildemuth) This study investigated the dynamic process of people constructing mental models of an information-rich web space during their interactions with the system and the impact of task complexity on model construction. In the study, subjects’ mental models of MedlinePlus were measured at three time points: after subjects freely explored the system for 5 minutes, after the first search session, and after the second search session. During the first search session, the 39 subjects were randomly divided into two groups; one group completed 12 simple search tasks and the other group completed 3 complex search tasks. During the second search session, all subjects completed a set of 4 simple tasks and 2 complex tasks. Measures of the subjects’ mental models included a concept listing protocol, a semi-structured interview, and a drawing task. The analysis revealed that subjects’ mental models were a rich representation of the cognitive and emotional processes involved in their interaction with information systems. The mental models consisted of three dimensions (structure, evaluation and emotion, and (expected) behaviors); the structure and evaluation/emotion dimensions consisted of four iii components each: system, content, information organization, and interface. The construction of mental models was a process coordinated by people’s internal cognitive structure and the external sources (the system, system feedback, and tasks) and a process distributed through time, in the sense that earlier mental models impacted later ones. Task complexity also impacted the construction of mental models by influencing what objects in the system were perceived and represented by the user, the specificity of the representations, and the user’s feelings about the objects. Based on the study results, recommendations for employing mental models as a tool to assist designers in constructing user models, eliciting user requirements, and performing usability evaluations are put forward. iv Dedication To my father. v Acknowledgements The writing of a dissertation could be a solitary journey. But many people made mine an enjoyable process. I want to first thank my advisor, Barbara Wildemuth, for being positive, encouraging, and inspiring. This work would not have been possible without her guidance. My genuine appreciations also go to other members of my dissertation committee, Gary Marchionini, Paul Solomon, Diane Kelly, Javed Mostafa, and Peiling Wang for their input and support. In shaping my research questions, I benefited a lot from the discussions with Dr. Peter Ornstein in the Department of Psychology at UNC, and John Schumacher at IBM Lotus Software Group. They helped me see the meaning and significance of this research from other perspectives. I also want to express my appreciation to the SILS community, the faculty, staff, and students. My journey of pursuing a PhD would be less rewarding without your company. For many kinds of support that I have received for crafting my dissertation, I am particularly grateful to Deborah Barreau, Rachael Clemens, Jane Bahnson, Sanghee Oh, Sarah Redeem, Cassidy Sugimoto, Amber Cushing, Weimao Ke, Dana Hanson-Baldauf, Carolyn Hank, Dihui Lu, Jungsun Oh, Songphan Choemprayong, Laura Sheble, and Leo vi Cao. Finally, I am grateful that I have a loving and supportive family. My mom and dad shared with me their persistence, courage, and humbleness, and my husband was unconditional in his support of my work. vii Table of Contents LIST OF TABLES .................................................................................................. XIV LIST OF FIGURES .............................................................................................. XVIII CHAPTER 1 INTRODUCTION ................................................................................ 1 CHAPTER 2: LITERATURE REVIEW ..................................................................... 5 2.1 Mental models in psychology .............................................................................................................. 5 2.1.1 Mental models in logical reasoning and language comprehension ............................................. 5 2.1.2 Mental models in representing domain knowledge ..................................................................... 8 2.1.3 Schemata, Scripts, and Frames .................................................................................................. 10 2.1.4 Mental models and schemata .................................................................................................... 13 2.1.5 Mental imagery: the form of mental models ............................................................................. 14 2.1.6 Situated cognition: alternative approaches to mental models .................................................... 15 2.2 Mental models in HCI ........................................................................................................................ 16 2.2.1 Mental models defined in HCI .................................................................................................. 16 2.2.2 Types of mental models in HCI ................................................................................................. 18 2.2.3 Characteristics of mental models in HCI ................................................................................... 21 2.2.4 Utility of mental models ............................................................................................................ 24 2.3 Mental models in IR ........................................................................................................................... 31 2.3.1 Content and structure of mental models .................................................................................... 32 viii 2.3.2 Factors affecting mental models of IR systems ......................................................................... 35 2.3.3 Construction of mental models of IR systems ........................................................................... 37 2.3.4 Characteristics of mental models of IR systems ........................................................................ 38 2.3.5 Mental models’ effects on information searching behavior ....................................................... 40 2.3.6 Mental models and IR system design ........................................................................................ 42 2.3.7 Summary ................................................................................................................................... 43 2.4 Methods for studying mental models ................................................................................................ 44 2.4.1 Mental models elicitation methods ............................................................................................ 44 2.4.2 Experimental studies of mental models ..................................................................................... 52 2.5 Task complexity and spatial ability ................................................................................................... 54 2.5.1 Task complexity ........................................................................................................................ 54 2.5.2 Spatial ability............................................................................................................................. 59 CHAPTER 3: THEORETICAL FRAMEWORK & RESEARCH QUESTIONS ....... 63 3.1 Theoretical framework ...................................................................................................................... 63 3.1.1 Rationale for the framework ...................................................................................................... 63 3.1.2 The research framework ............................................................................................................ 65 3.1.3 Utility of the framework ............................................................................................................ 68 3.2 Research questions and rationale ..................................................................................................... 69 3.2.1 Construction of mental models of an information-rich