Towards a discourse theory of abstracts and abstracting. PhD thesis, University of Nottingham.

416 Pages·2017·17.95 MB·English

by  Christine Middleton

Towards a Discourse Theory
of Abstracts and Abstracting
by
Timothy Robin Gibson, M.A., M.Phil.
Thesis submitted
for the degree of
Doctor of Philosophy
University of Nottingham
May 1992
Abstracts
Readers are invited to judge which abstract they prefer
Abstract 1
This Ph.D. thesis investigates the extent to which certain linguistic variables
affect the perceived success of an abstract. In his opening chapter, the author
situates the work as a contribution to discourse theory and formulates a set of
seven basic research questions the study seeks to answer. Chapter 2 considers
the most satisfactory design for the research. Part Two provides a survey of the
relevant source material, consisting of reviews of: the Linguistics and
Psychology literature; Artificial Intelligence computational summarising
systems; and standards and guidelines taken from Information and Library
Science. Part Three discusses the data collection: first, the collection of
naturally occurring abstracts from a teaching establishment; second, the
collection of judgements elicited by means of a set of questionnaires. The
remainder of the thesis constitutes an attempt to reconcile these two types of
data, words and opinions. The author draws a distinction between the·
qualitative and quantitative opinions of the judges (which he refers to as
'external measures') and the linguistic features present in the different
abstracts ('internal measures') which determine these subjective opinions.
Part Four discusses the data analysis, which draws on grammatical
techniques from Systemic-Functional theory. In Part Four, hypotheses are
investigated which relate the success of the different abstracts as perceived by
the judges to the linguistic features present in the texts. Five different types of
analysis are piloted using a small number of texts; three of these analyses are
taken further and applied to all the abstracts. Part Five consists of two
chapters. The first details the conclusions to be drawn from the study and
explicitly answers the seven basic research questions introduced in Chapter 1.
The second provides some suggestions for further research, chiefly concerning
the collection of further external and internal measures. Finally, techniques
from multivariate statistics are briefly sketched as a means of reconciling the
two types of measure in the future.
.
1
Abstract 2
This Ph.D. thesis investigates the extent to which certain linguistic variables
affect the perceived success of an abstract. More specifically, answers to seven
basic research questions are sought. These include: what reasons do readers
give for preferring one abstract over another?; is 'success' better explained by
correlation with one, or with many, linguistic variables?; to what extent do
readers agree with each other in their various preferences? and which
linguistic features can help to explain readers' preferences? In order to
answer these questions, a total of 42 naturally occurring abstracts were
collected from 29 second year Library and Information Science students at
Brighton Polytechnic. 26 of these abstracts summarised General Knowledge
source texts. 17 summarised Information Science (I.S.) source texts of three
different types: journal articles, newspaper items and book chapters. The
shortest I.S. abstract consisted of 111 words, the longest 651. Subjective data in
the form of opinions of these abstracts were elicited by means of a set of six
questionnaires. These questionnaires were administered to the students, to
their two lecturers, and to 14 judges representing model consumers of such
abstracts. The questionnaires elicited both quantitative and qualitative data.
The 8 I.S. judges, for example, were asked to rank up to five different abstract
versions summarising the same source text according to how helpful they
believed them to be. They were also asked to provide reasons for their
preferences. Different grammatical analyses from Systemic-Functional theory
were employed to discover to what extent certain linguistic features in the
abstracts determine their overall quality as perceived by the judges. Although
some suggestions were made to overcome problems with the descriptive
frameworks, analyses of generic structure and of cohesive harmony were
found to be insufficiently reliable to enable precise hypothesis testing. However,
the following linguistic phenomena were investigated more extensively and
yielded interesting results: lexical texture; grammatical intricacy and choice
of Theme. The answers to the above research questions are as follows. The
reasons judges provide for preferring one abstract over another are many and
varied; the two most common concern content and what might be termed
'reader-friendliness'. Success in text is a multivariate notion; anyone
linguistic measure cannot explain all the variation in judges' preferences.
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Judges hold widely differing views of what constitutes a successful abstract:
scores for Kendall's Coefficient of Concordance, a measure of inter-judge
W,
agreement, range from 0.109 to 0.597, suggesting that there are different
drivers of success and that judges prioritise the importance of these drivers
differently. In answer to the question, which linguistic features can help to
explain readers' preferences?, the following results were obtained from the
various hypotheses tested. Counter-intuitively, it was found that the more
successful abstracts were characterised by lower levels of lexical density and
were described as being 'clear'. Low levels of lexical density and lexical
variation seem to be more the mark of 'reader-friendly' abstract writing,
whereas higher levels of lexical density and lexical variation characterise
abstracts y.rhich contain more information, but are correspondingly harder to
process. In contrast to what is claimed in the literature, the hypothesis which
stated that abstracts with a larger amount of clause level complexity would be
generally preferred over abstracts with a smaller amount of clause level
complexity was generally supported. Also, some clause combining strategies
were noticeably preferred by the judges~ while others were noticeably
dispreferred. However, these preferences were not shared across the different
abstract sets. Judges were found to be particularly sensitive to choice of
Theme. A new type of Theme was identified to complement the two already
existing sub-types of topical Theme, interactional and informational: Themes
are to be regarded as discoursal if they refer to aspects of the source material,
or to studies which are themselves discussed by the source material. Eight
hypotheses concerning choice of Theme were investigated. For example,
hypothesis 8 claimed that abstracts with more informational Themes would be
preferred over abstracts with fewer informational Themes. This was
supported for the Tanzanian set (H8c), but falsified for the other three. The
judges seem to be indicating that they deem an informational style to be more
appropriate for the Tanzanian source text. The three different types of topical
theme serve different functions: informational themes primarily reflect the
writer's desire to enlighten, by presenting the raw facts of the message for
readers' consideration; discoursal themes primarily reflect the writer's desire
in orient their readers, by providing a way of navigating through the various
channels in which the information is presented; interactional themes
primarily reflect the writer's desire to make it easy for readers to integrate the
knowledge, by showing readers how the information relates to the various
people involved in its transfer.
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AcknowledgelDents
First and foremost, I would like to thank my supervisor, Margaret Berry,
for all the help she has given me since I started as an undergraduate in the
University of Nottingham. Margaret is the best supervisor one could wish for;
I consider myself very lucky indeed to have had so many opportunities to
benefit from her sound advice, clear teaching and unwavering support.
Ron Carter, Hilary Hillier, Gerald Parsons and many other friends in the
Department of English Studies have also been a constant source of
encouragement. lowe a special debt of gratitude to Caroline Stainton, who has
been an enormous help throughout the different stages of the work.
One of the nicest things about trying to work out why some texts are
perceived as being more successful than others is that inevitably one gets to
meet lots of people. I should like to thank the students (some of whom may
even now be writing abstracts professionally) and the other respondents to my
various questionnaires. I think all these people would be surprised if they
knew how much time I have spent deliberating over their work. I hope this
may in part compensate them for the fact that I cannot thank them all by
name.
Without Chris Turner, the Head of Department of Library and Information
Studies, there would have been no field study at Brighton Polytechnic. I would
also like to acknowledge the good-natured help and enthusiasm of Sharon Hall
and Alex Simpson, the two lecturers referred to in Part Three below.
I am happy to acknowledge the encouragement of Chris Butler, Mark
Caldicott, Andrew Hockley, Michael Hoey, Carol Maxwell, Nigel Pirie,
Annabel Pollock, Rachel Ruffle, John Seton, Peter Thomas, Andrew and
Stephen Thompson and Mark Velody, who provided support of a different kind
which also helped to keep me going throughout the research. lowe special
thanks to Sandra Williams and Dawn Wright, who worked with me on the
automatic text summarisation project. I would also like to thank my parents
for their patience and support.
.
IV
I carried out this work while employed by BT firstly as an Artificial
Intelligence programmer, and, more latterly, as a Human Factors engineer
investigating quality of service, the measurement of customer satisfaction and
other marketing concepts. Although at first sight these responsibilities do not
seem to have very much to do with textlinguistics, I think they have all shaped
the way I have carried out the research reported in this thesis. I should
therefore like to thank BT not just for supporting this Ph.D., but also for
providing me with such interesting and challenging work.
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Table of Contents
.
Abstracts .................................................................................................
1
Acknowledgements .........................................................
IV
II ••••••••••••••••••••••
Part One: Introduction
Chapter 1: Research Questions .......................... 1
II' ••••••••••••••••••••••••••••• II II ••••
1.1 Why abstracts and abstracting '? .................................................1
I
1.2 Why a discourse theory ? ....................................................... 2
II. '
1.3 'Wb.y , Towards . ? ........................................................................4
II '
1.4 Orientation of this Thesis .................................................................5
1.5 Research Questions .........................................................................8
1.6 Organisation of this Thesis ...............................................................9
Chapter 2: General Research Design ........................................................ 11
2.1 Introduction ................................................................................. 11
2.2 The Multimethod Approach ............................................................ 13
2.3 Data Collection ...................................... " ,., ... , ............................... 18
2.3.1 Fieldwork ............................................................................. 18
2.3.2 Surv-eys ................................................................................ 2:)
2.3.3 Nonreactive Methods ............................................................. 22
2.4 Data Analysis ............................................................................... 23
2.5 Conclusions .................................................................................. 2,4.
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Part Two: Reviews of the Literature
Introduction ............. I .................. I......................................................... 27
Chapter 3: Review of the Psychology and Linguistics Literature ...................
~
3.1 Introduction ................................................................................. ~
3.2 Some Brief Remarks Concerning Cognitive Psychology ......................
~
3.3 Review of Work Relevant to Summarisation
in Experimental Psychology ................................................................ :J)
3.3.1 Sherrard 1986 ........................................................................ 31
3.3.2 Johns 1985 ............................................................................ 33
3.4 Review of Work Relevant to Abstracting
in Linguistics .................................................................................... ::JE)
3.4.1 Nwogu and Bloor 1989 ............................................................ :II
3.4.2 Drury 1989 ............................................................................ 00
3.5 Conclusions .................................................................................. 42
Chapter 4: Review of Automatic Summarising Systems .............................. 44
4.1 Introduction ................................................................................. 44
4.2 Introduction to the Shallower 'Spotting' Systems ............................... 44
4.2.1 An Example: Hoey's Lexical Connectivity Nets ........................ .45
4.3 Introduction to the Deeper 'Understanding' Systems ......................... 4B
4.3.1 An Example: FRUMP ........................................................... 49
4.4 Conclusions ................................................................................. 52
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Chapter 5: Review of the Library and Information Science Literature ........... 53
5.1 Introduction ..................... 53
II ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••
5.2 Why Write Abstracts? ..................................................................... 53
5.3 What are Abstracts? ...................................................................... 54
5.3.1 What Sorts of Abstract are there? ............................................. 55
5.3.1.1 The Needs of Readers ..................................................... 56
5.3.1.2 Type of the Original .......................................................
f{/
5.4 How does One Write an Abstract? ....................................................
f{/
5.4.1 Rules ................................................................................... 58
5.4.1.1 The Topical Sentence ..................................................... 58
5.4.1.2 Structural Elements ...................................................... 58
5.4.1.3 Miscellaneous Recommendations ................................... 59
ro
5.4.2 Procedures
II II II. II •• II II •• II' •••• II. II •• II ••••• II •• II' II •• II ••••• 1,." •• I" II •• II. II
5.5 Conclusions .................................................................................. 61.
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Part Three: Data Collection
Introduction ... I. ..... I. ............. I.............................. ..... 62
e ••••••••••••••••••••••••••••
Chapter 6: Fieldwork Data ....................................................................... 64
6.1 Introduction ....................................................................................... 64
6.2 Objectives of the Fieldwork. ............................................................. 64
6.3 Planning the Fieldwork .................................................................. 65
6.3.1 Planning the Ideal Site for the Fieldwork ................................. 65
6.3.2 Planning an Appropriate Role for the Fieldworker .................... 67
m
6.3.3 Planning the Duration of the Fieldwork ...................................
m
6.3.4 Planning the Focus of the Fieldwork ........................................
6.4 The Brighton Polytechnic Case Study ............................................... '70
6.4.1 The Abstract Writers ............................................................. 71
6.4.2 The Source Texts ................................................................... 72
6.5 Conclusions .................................................................................. '73
n
Chapter 7: Surv-ey Da"ta. ............................................................................
n
7.1 Introduction .................................................................................
7.2 Survey Data Requirements ............................................................. 78
7.2.1 The Requirement to Collect Source Material Process Da"ta. .......... 8)
7.2.2 The Requirement to Collect Source Material Product Data. ......... 81
7.2.3 The Requirement to Collect Abstracts Process Data ................... 81
7.2.4 The Requirement to Collect Abstracts Product Data ................... 82
7.3 Collecting the Data: Questionnaire Design and Administration .......... 83
7.3.1 Selecting the Most Appropriate Informants to Question ............. 84
7.3.2 Selecting the Most Appropriate Questions to Ask. ...................... 85
7.3.3 Selecting the Most Appropriate Layout
and Means of Administration ........................................ 94
e •••••••••••••••
7.3.4 Pilot Survey Da"ta. Collection .................................................... 95
7.4 Conclusions .................................................................................. 00
.
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