Abstract
Cognitive overload and disorientation limits the
effectiveness of hypertext for learning. By cognitively
adapting a hypertext system to the user and by
providing instructional cues, the effects of these
problems might be reduced. A quasi-experimental
evaluation study is reported, with a view to testing the
efficacy of this theory.
Keywords:
adaptive hypertext, hypertext based
learning, conceptual modelling, learning styles.
Introduction
Disorientation and cognitive overload are two problems
that may ultimately limit the usefulness of hypertext for
learning. Learners fail to gain an overview of the
material and have difficulty in locating information
known to be available. It is clear that the navigational
access offered by hypertext, is not by itself, sufficient.
Research into navigation and orientation has tended to
focus on graphical representations of the information
structure. Attempts are however, being made to
augment basic node and link hypertext by incorporating
AI knowledge representation schemes into the model
[1].
With hypertext, student's explore and follow paths that
are not dictated by outside sources, and as such, permits
learning in a whole new fashion. By allowing students
to use the material presented in their own way,
hypertext brings freedom to the educational process.
However this freedom to learn is not a sufficient
condition to assume effective learning. There is the
danger of 'hyperchaos', whereby students can miss
relevant points or form wrong interpretations of the
information. Advocates of hypertext-based learning
acknowledge that letting the learner sink or swim in a
sea of links and nodes has its problems, and talk
increasingly of tools for navigation and guidance, of
more directed support for learning activities, of
adaptive links and of AI-based advising tools. It is also
clear that there is currently little empirical support
favouring hypertext based instructional systems over
traditional systems - the efficacy of hypertext for
learning has not yet been established.
CONCEPTUALLY ADAPTED HYPERTEXT
This study assessed the relationship between
presentation techniques and learning styles, and their
effects on learning outcome. The major research issue
investigated is whether learning outcome can be
enhanced by conceptually adapting hypertext and by
providing instructional cues to the learner.
Two hyperdocuments containing the subject material to
be learned were developed. One document conceptually
adapts to the user and provides instructional cues to aid
exploration of the information space. The other
document is a conventional static hypertext, providing
the learner with a parsimonious set of links to facilitate
exploration. Both systems contained the same
information. A conventional lecture formed the third
presentation method. Before developing the hypertext
systems and putting together the material for the
lecture, a knowledge handbook of the domain was
produced, to ensure consistency across the three
presentations methods. The knowledge handbook was
also used whilst developing a conceptual model of the
domain, based on established instructional design
techniques [3]. This model was explicitly incorporated
into both hyperdocuments and provided the theoretical
basis for adapting the hypertext and providing the
instructional cues in the knowledege-based
hyperdocument. Adaptivity was achieved by attaching
rule-sets to nodes, which inferred what links to provide,
depending on the nodes previously visited by the
learner and the conceptual model.
A total of 85 students participated in the study. Students
completed an elementary structured programming test
(to ascertain their prior knowledge level of the domain
to be taught), and were categorised into one of four
learning styles [2] - Activists, Reflectors, Theorists and
Pragmatists. The students were sequentially assigned to
one of three treatment groups, each using a different
treatment method (a lecture, a cognitively adapted
hypertext or a static hypertext). Those students
allocated to the lecture group were given a presentation
and guided through some worked examples, lasting a
total of one hour. Students in the cognitively adapted
hypertext and the static hypertext groups spent one
hour learning as much of the information in the systems
as possible. Upon finishing their respective sessions,
students completed a test to ascertain the amount of
material learned. The learning outcome was measured
by a fourteen question post-test, which resulted in a
single score. Questions were developed to test
understanding of the key concepts and basic
procedures.
RESULTS
Three research questions where addressed: (1) Does
Learning Style affect learning outcome? (2) Does the
Presentation Method (Lecture, Cognitively Adapted
Hypertext or Static Hypertext) affect learning outcome?
(3) Are there interaction effects between learning styles
and method of presentation that affect learning
outcome?
The dependent variable used in the study was an
objective measurement of learning outcome. The
independent variables include: (a) the learning style of
the learner and (b) the method of presentation of the
material. Univariate analyses of variance were used to
test for significant differences in the means of the
learning outcome scores between the different methods
and the learning styles. Specifically, a two-factor
ANOVA was used to investigate interactions effects
between presentation method and learning styles.
Learning Outcome Scores
The learning outcome score means for each of the study
design groups are presented in table 1, along with the
number of subjects in each group and the standard
deviation.
TABLE 1.
