Copyright 2011 Alexandra L. Bartell

260 Pages·2012·8.19 MB·English

©Copyright 2011
Alexandra L. Bartell

The Effect of Linguistic Explicitness and English Language Proficiency on the
Credibility of Online Medical Information
Alexandra L. Bartell
A dissertation,
submitted in partial fulfillment of the
requirements for the degree of
Doctor of Philosophy
University of Washington
2011
Program Authorized to Offer Degree:
Department of Human Centered Design & Engineering
UMI Number: 3501499
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Abstract
The Effect of Explicitness and English Language Proficiency on the
Credibility of Online Medical Information
Alexandra L. Bartell
Chair of the Supervisory Committee:
Professor Jan Spyridakis
Department of Human Centered Design & Engineering
Perceived credibility is important to consumers of online medical information because
it frequently forms the basis for making treatment choices. While credibility is important to
users around the globe, most medical Web sites have been designed primarily for
audiences within specific cultural contexts. Many medical Web sites created by low-context
Western institutions may lack the graphics or interactivity that users from high-context
Eastern cultures expect, forcing these users to depend on the words of a site for meaning
rather than the context of the communicative situation.
The Formality/Contextuality continuum model suggests that communicative situations
with less context have a greater need for linguistic precision. Moreover, the preference for
the level of explicitness has been shown to differ among nonnative users of a second
language where those with less proficiency prefer more explicit communications and those
with greater proficiency prefer more implicit communications.
This exploratory study analyzed the effect of linguistic explicitness in an experimental
medical text on the credibility of 102 Japanese Internet users who had different levels of
English language proficiency. The participants were randomly assigned to one of two
experimental conditions where they read a medical text with one of two levels of explicitness
and then answered a survey designed to measure their credibility perceptions.
This study added to the theory and practical applications of credibility research by
showing that style in the form of explicitness does affect the credibility judgments of online
medical information for high-context readers. Participants found the explicit text significantly
more credible than the implicit text; however, their English proficiency levels did not appear
to affect their credibility perceptions. These results suggest that increasing the explicitness
level by increasing the frequency of nouns, adjectives, prepositions, and articles may enrich
the context of a text and fill in the communicative gap for nonnative English readers who
come from high-context cultures, thus improving their credibility perceptions. More studies
should be conducted with larger samples, different types of readers, and other
communication media to ascertain how the credibility of online medical information can be
enhanced by increasing the explicitness of texts and reducing extraneous cognitive load.
TABLE OF CONTENTS
Page
Chapter 1. Introduction 1
Credibility of Online Medical Information 2
The Influence of Socio-Cultural Contexts on Credibility 3
Chapter 2. Literature Review 5
Cultural Dimensions of Communication 5
High-Context/Low-context Theory 5
Comparative Studies of Low-Context/High-Context Web Sites 6
Relationship of Explicitness to Communication Contexts 7
The Formality/Contextuality Continuum Model 7
Cognitive Processes Involved in Credibility Judgments 14
Elaboration Likelihood Model Theory 14
The Concept of Credibility 15
Credibility Research for the World Wide Web 16
Credibility Research for Online Health Web Sites 17
Cognitive Load in Online Environments 19
Cognitive Load Theory 19
The Effects of Cognitive Load in Online Environments 20
Problem Summary 22
Research Question and Hypotheses 23
Chapter 3. Methods and Materials 25
Methods 25
Research Design 25
Participants 36
Participant Requirements 37
Participant Recruiting 37
Informed Consent 38
Materials 38
Baseline Texts 39
Experimental Texts 44
Survey Content and Delivery 46
Survey Procedures 47
i
Comprehension Article and Test 48
Rationale for Remote-Based Administration and Delivery 49
Readability Statistics 57
Data Collection and Analysis 57
Chapter 4. Results 59
Demographic Composition 60
Computer and Web Use 60
Education 61
Participant Involvement with Topic 61
Experience in Medical Professions 61
Analysis of Ancillary Credibility Variables 61
Analysis of Participant English Comprehension Levels 62
Principal Components Analysis of Credibility Ratings 63
Chapter 5. Discussion and Conclusions 71
Discussion 71
Demographic Data 72
Reader Attribute Data 73
Participant Proficiency and Perceptions of Credibility 75
Credibility Results and Hypotheses 76
Study Limitations 77
Conclusions and Recommendations for Future Work 82
Appendix A - Recruiting Material 87
Appendix B - Baseline Texts 103
Appendix C - Scoring Instructions and Guidelines 109
Appendix D - Manual Deconstruction of Baseline Texts 116
Manual Deconstruction Results (Researcher) 116
Manual Deconstruction Results (Second Coder) 126
Appendix E - Modified Penn Treebank Set 136
Appendix F - Infogistics Natural Language Processor Results
for Baseline Texts 138
Appendix G - Experimental Texts 160
Credibility Perceptions Article (Explicit Version) 160
Credibility Perceptions Article (Implicit Version) 166
Appendix H - Manual Deconstruction of Experimental Texts 170
ii