ALN Magazine Volume 4, Issue 2 - December 2000
Don Lehman
Department of Medical Technology
University of
Delaware
Newark, DE 19716
E-mail: mdlehman@udel.edu
Before undertaking the creation of hyperlinked educational multimedia, the author needs to have a design plan. Creating without a design plan is like building a house without blueprints. Besides considering the content, the author must make decisions on the user interface, the type of media used (e.g., text, pictures, audio, video), and when and where to apply hyperlinks. The cognitive processes and experiences of the user should also be considered. The author has control over the content and the links, but the user's discretion determines the sequence. This article discusses issues of designing to facilitate the user's access to the content in educational software.
A. Historical Context
In advanced courses,
students are expected to master complex concepts and transfer acquired knowledge
to new situations. Understanding must go beyond the presented information. In
order to comprehend text or a concept, students must construct the meaning
in terms they personally understand. The presented information must be combined
with other information (most prominently the prior knowledge of the learner) to
form an adequate representation of the meaning. Extra cognitive processing to
integrate new information with prior knowledge is sometimes called elaborative
processing. Different instructional media can encourage elaborative processing,
but because hyperlinked multimedia incorporates a variety of media, it can
facilitate elaborative processing [1].
What is hypertext? Theodore Nelson, the man who coined the term
hypertext, was quoted as saying, "By hypertext, I mean nonsequential writing -
text that branches and allows choices to the reader, best read at an interactive
screen" [2].
Landow adds that hypertext is a medium linking verbal and nonverbal information.
Hypertext is more reader-driven than printed text: readers are able to access
information that is relevant to themselves.
In traditional textbooks,
learners are expected to read through the information in a manner designated by
the author. With hypertext, learners have more control on how the information is
presented. Learners can follow links and navigation buttons created by the
author. It is up to the author to create these links in a logical organized
fashion to prevent the user from getting distracted and confused.
It has
been assumed that learner control is an important aspect of effective learning,
and that is the purported benefit of hypertext. Studies have found that students
with larger quantities of learner control rate the instruction more favorably
[3],
[4].
However, the more favored instruction does not necessarily translate into more
efficient learning. In addition, empirical findings yield mixed results with
respect to the learning benefits of learner control compared to
programmed-control instruction [5], [6], [7]. The
majority of these studies were done several years ago; in the meantime, computer
technology has become more powerful and made it easier to create hypertext
applications. New learning theories have been presented to guide authors in
creating hypertext applications, and thus new studies should be conducted to
evaluate the contributions of these theories.
Do multimedia and computer
assisted instruction (CAI) improve learning? When compared to traditional
instruction, CAI improved student scores and attitudes toward learning, and
decreased learning time [8], [9]. In
addition, computer technology may improve academic achievement, motivation, and
time on task [10]. If
a program is well designed, students will want to spend time learning, and their
scores should improve.
However, not everyone feels CAI is an effective
teaching medium. Clark [11], [12]
claims that media do not influence learning. He feels any perceived advantage of
CAI can be explained by other hypotheses: 1) content differences between
instructional methods with different media were not controlled and, therefore,
the medium was not necessarily the cause of any significant effect; 2) because
the learning method was new, it will automatically be more exciting and the
novelty effect will only temporarily improve learning, and; 3) it is the method
of instruction that fosters learning, not the medium.
B.
Learning Theories
Spiro [13] uses
the word "ill-structuredness" to describe conceptual complexity and case-to-case
irregularity in knowledge domains. In order for students to understand a
difficult case, they must appreciate the complex interaction among several
concepts. Spiro argues that all domains involving the application of knowledge
to unconstrained naturally occurring situations, or cases, are substantially ill
structured.
Many learning theories stress the importance of retrieving
organized packets of knowledge, or schemas, from memory to organize presented
information. Spiro argues that conceptualization of ill-structured domains
renders the use of prepackaged schemas inadequate. Knowledge will have to be
used in too many different ways for them all to be anticipated in advance.
Therefore, emphasis must be shifted from the retrieval of intact knowledge
structures to the construction of new understandings, to the situation-specific
assembly of prior knowledge drawn from diverse pre-existing mental
representations. In other words, instead of retrieving a previously packaged
solution from memory, one must bring together from various knowledge sources an
ensemble of information needed to understand or solve the problem at
hand.
Cognitive Flexibility Theory (CFT) was developed to teach
ill-structured domains. It refers to a particular constructivist theory that
integrates learning theory, mental representation, and instruction. The basis of
CFT is allowing students to revisit the same material at different times, in
rearranged contents, for different purposes, and from different conceptual
perspectives. For full understanding, content must be covered more than once. A
single explanation of a complex concept would miss salient knowledge facts that
could be important in a different context. Thus, simply repeating a process is
not sufficient; that would be oversimplification. However, re-examining a case
in the context of comparison to another case can lead to new
insights.
CFT recommends the use of "landscape criss-crossing" for
instruction [14], [15]. The
content is re-edited to produce a particular kind of criss-crossing of the
conceptual landscape. The conceptual landscape needs to present a large
set of case examples of a particular conceptual structure being taught. In this
way, the learner can see a range of conceptual applications of the case.
Hypertext and multimedia can support the use of the CFT.
A. User Interface
The user interface controls
how the user interacts with the software. Ebersole [16]
defines the interface as where two worlds meet--in this case humans and
computers. The Windows and Macintosh operating systems have a graphical users
interface (GUI). Multimedia with hyperlinks can produce an interactive
interface, requiring the user to be more active than traditional media such as
books and television.
Cognitive overhead for users requires keeping
track of hyperlinks, where they are in the software, and how to get back to a
place they have been. Too much cognitive overhead can have a negative effect on
learning. Thus, for example, navigation should appear effortless to the user.
Hyperlinks can make educational software appear fragmented, adding to user
confusion. To increase coherence, some authors recommend placing links at the
end of blocks of texts or in side bars [16].
Another way to minimize the appearance of fragmentation is to provide the user
hints or clues as to where hyperlinks will lead. This will give users more
information before they decide to follow a link, so they can decide if following
the link is worth the journey.
It is important to provide users with a
variety of easy-to-use and understandable navigational buttons to prevent them
from getting lost and to minimize cognitive overhead. Consistency can help
accomplish this. Authors should place similar buttons or links in the same
location on different screens. In addition, the same actions should result in
the same effect. Other techniques to minimize cognitive overhead include the use
of back buttons, maps, and bookmarks.
To increase the user's
understanding of the interface and navigational tools, an appropriate metaphor
for navigation should be incorporated. Commonly used metaphors are books, a
desktop, travel, and stack of cards [16].
These metaphors bring familiar real-world concepts to the complexity of
hyperlinks.
B. Dual Coding
Multimedia has
the advantage of presenting material in different ways, and some media
communicate specific information better than others. For example, text appears
better than sound for communicating verbal information [1].
Pictures generally help people learn more effectively than text, except when
items are conceptually similar or if items are presented too fast for learners
to create verbal labels. However, pictures may be limited when communicating
abstract ideas.
Multimedia combinations may help users learn by
processing information through more than one channel. This is termed
dual-coding. For example, encouraging learners to use both verbal and pictorial
channels appears to be an effective instructional design. Evidence exists that
verbal and picture information should be presented together [1].
Students seem to perform better when textual annotations were combined with
drawings.
Some multimedia authors believe that pictures improve learner
interest and therefore learning; however, authors must avoid the indiscriminate
use of images. It appears that adding unrelated pictures does not improve
learning, and may in fact decrease learning [1].
Unrelated pictures may be a distraction from the content and intended
curriculum.
C. Hypertext Structure
As
mentioned above, the overall structure of hypertext can affect learner outcomes.
In fact, disorientation may be the major limiting factor of hypertext [17], [18]. The
problem seems to result in a measurable decline in performance. Disoriented
users may encounter problems deciding where they want to go and how to get
there.
McDonald and Stevenson [19]
examined the effects of different hypertext topologies and prior knowledge on
navigation performance and user disorientation. They examined hierarchical,
nonlinear, and mixed topologies. In hierarchical text, the information nodes are
linked in a hierarchical fashion in which a node at one level can access only
the nodes directly above and below it. In nonlinear (network) text, the nodes
form a complex network of connections based on a large number of referential
links. Mixed text is basically a hierarchical structure with a number of links
allowing users to jump to other branches of the hierarchy.
In both
browsing and navigation, mixed hypertext produced the best results, followed by
hierarchical, with nonlinear producing the poorest. Overall, knowledgeable
participants performed better than nonknowledgeable participants; however, there
was no difference between knowledgeable and nonknowledgeable participants with
mixed hypertext. Navigation results suggested that mixed hypertext provided the
best mixture of freedom and constraint.
The advantages of nonlinear
structure are claimed to be 1) information is more readily available to the
reader, and 2) network structure allows nonlinear access to information [19].
Readers, therefore, have increased control over the sequence of information.
However, this increased control may have negative consequences if users are
unable to navigate around unfamiliar and complex information without
experiencing disorientation.
Disorientation with hypertext structure may
be decreased if a user has prior knowledge of the subject matter. Conversely,
disorientation may be heightened in novices [20].
Compared to novices, more knowledgeable users may experience fewer navigational
problems in hypertext environments because they have a greater understanding of
the conceptual structure of the subject matter, allowing them to impose
structure on the hypertext [19].
D. Random Access Instruction
The
instructional theory derived from the CFT is termed Random Access Instruction.
Hypertext computer applications are well suited for the criss-crossed
instruction of the CFT. However, implementing CFT is not just using the computer
to connect everything with everything else. The learner could become lost in a
confusing labyrinth of incidental connections.
It is important that only
those cases and parts of cases pertinent to the focal conceptual structure be
presented. Students need to see these examples in a close time frame. Examining
cases separated by long time periods is not an efficient way to learn complex
concepts. The computer with hypertext is well suited for this task. Numerous
examples can be programmed for students' immediate access.
Providing
background information on the contexts being explored is another important
aspect of CFT. This information needs to be functional and context sensitive.
Just providing dictionary definitions, which are subtypes of a word's meaning,
is not adequate. Particularized definitions providing supplemental guidance
about the way meaning is used in a particular situation are needed.
Particularized definitions are functional and context (case) sensitive
representations of a concept. Abstract definitions fail to cover conceptual
meanings used in ill-defined domains; therefore, supplemental guidance about the
way meaning is used in a particular situation is required.
E. Supported Text
It has been estimated that between 10 and
12 percent of students in English-speaking countries cannot read sufficiently to
successfully acquire content-area information [21].
Content literacy is the use of reading and writing to acquire new knowledge in a
given domain. Reading environments are needed that support content literacy.
Electronic text designed to promote improved comprehension (usually by inserting
a variety of text enhancements or electronic resources) is called supported
text.
There are three major components to supportive text: presentation,
keys, and resources. Presentation is the content and the system that presents
it. The system consists of the physical artifacts and the interface that
operates them. With electronic documents, the system is the computer monitor,
mouse, and keyboard. Computer-based text presentations reproduce and transform
or expand the function of printed text. The computer version has the advantage
of giving students more control over their learning. They can proceed in a
nonlinear fashion in a manner that best suits their learning style.
Keys
are problematic words, phrases, sentences, or paragraphs that students encounter
as they read the text. Keys may be embedded in other keys. Students with
different prior experiences and reading ability will find different parts of the
text problematic. Authors must try to anticipate keys and provide students with
resources in comprehending their meaning. The keys need to be identified in some
manner so students know when resources are available. In computer software, keys
can easily be underlined, or displayed in a different color.
The
resources may be translational, where the text is rewritten into simpler
language. They may be content vocabulary, where crucial technical terms and
phrases are defined. They may also be references to other text, figures and
materials. Resources should be readily accessible so that they do not disrupt
the learning process. The use of hypertext and mouse-overs can meet the
requirements of resources in supported text.
F. Using
Learning Objectives with Hypertext and Multimedia
Effective use of
hypertext systems requires a sense of purpose--that is a goal or focus--while
reading the hypertext. Posing a question or problem to be solved by learners can
help focus learning in environments with large amounts of learner-control.
Alternatively, the addition of questions at the end of content nodes can get
students to think about what they have just seen.
Research suggests that
getting users engaged in problem solving tasks make hypertext systems more
efficient [22]. In
the absence of learning objectives that encourage readers to organize the text,
readers using unstructured hypertext may not put forth the effort necessary to
create a complete representation of the content.
The constructive processing of knowledge for transfer must be taken beyond
the retrieval of knowledge structures from memory to include flexible
situation-specific assembly of the background knowledge by the learners
themselves. In addition, flexible learning environments are required for
learners to develop problem-solving skills. Hypertext computer systems are ideal
for creating these types of environments.
Authors must be careful when
designing hypertext applications. Learner control is a double-edged sword. As
the complexity of a program increases (such as more navigational links), so does
the potential for confusion or disorientation of the learner. This can leave the
learner lost in a maze of information. Authors must be consistent, provide
clearly defined navigational tools, and focus the learner, for example with a
problem to be solved.
Don Lehman, MSc, MT(ASCP), SM(AAM) is Assistant Professor, Dept. of Medical Technology, University of Delaware, Newark, Delaware. His interests include medical microbiology, parasitology