Part 1:
The Instructional Role of Illustrations
Illustration Functions
One of the more useful ways of approaching instructional illustrations is by
examining their functions (Duchastel, 1978). In this discussion, we will examine
how illustrations can attract attention, aid retention, enhance understanding, or
create context. For example, showing a photo of a dramatically beautiful cloud
image at the opening of a presentation on climatology does more to attract
attention than explain the content. Providing a table of cloud type images
organized according to the cloud classification scheme might be seen as primarily
aiding retention. Drawing a diagram illustrating the processes in the formation of
a particular cloud type will help explain these processes for increased
understanding. If we want to place weather forecasters in an instructional scenario
where they are asked to practice making forecast decisions, we might create
context by providing a user interface that resembles a forecast office with a
window revealing storm clouds growing outside.
Illustrations don't always fall neatly into one of these categories. Often they will
serve two or more of these functions. Opening with a dramatic cloud image may
grab attention and at the same time help explain or make memorable the cloud
structure you are discussing. For this section, we will use the categories of
attention, retention, understanding, and context creation to organize a general
discussion of the benefits to using illustrations in instruction.
This module title
graphic serves
mainly to be
attractive and
gain attention (in
addition to
identifying the
instructional
module, of
course). This is
an important
role, however.
One could argue
that it also
begins to
establish a
context by
introducing
abstract images
of the ice crystal
and pilot report
codes.
Using the simple
shape of a cone,
this illustration
memorably
represents the
relative times
spent by a
weather
forecaster with
the various
scales of data.
Such a device
can aid
tremendously in
a student's
retention.
This illustration
helps learners to
better
understand
various
processes of
cloud formation.
When we are considering illustrations as aids to retention and understanding, we
also need to look at how illustrations can provide performance support. While the
use of illustrations as performance support is not the focus of this discussion, it is
appropriate to touch on those aspects in this section as well. After all, task
practice (with performance aids) is obviously a valid part of instruction. And if we
blur the definition of instruction a bit to include the long path toward gaining
expertise that follows formal instruction, then performance aids can also be seen
as instructional.
Attention
Gaining the attention of students is a precondition to any kind of learning. It
appears first in most lists of events in the instructional process (e.g., Gagné &
Briggs, 1979) both because it is a precondition and because it can be too easily
slighted among the more "constructive" aspects of instruction. In the terms of
cognitive psychology, gaining attention is critical because of the limited capacity
and duration of the "short-term" or "working" memory (which has a capacity of
five to nine items and a duration of 10 seconds, according to most researchers).
Working memory is the place where conscious mental work is performed. If new
items need to be brought into working memory, others must be dropped. If items
are not used or rehearsed, they tend to be forgotten. If they have been used
sufficiently, they will be stored in long-term memory for later recall.
According to cognitive theory, only a small fraction of all sensory stimuli that
reach the brain actually make it to the working memory, a process known as
selective perception (Gagné, 1985). Considering the limitations of working
memory, it is easy to understand why such a process is necessary. Without it we
would be inundated with stimuli in an instant. With all the stimuli that are vying
for attention, it is a challenge to keep learners focused on the intended message or
task. Using illustrations can help because they can be complex to the senses, and
because they can provide novelty in the probably more plentiful stream of spoken
words or written text.
Complexity
Complexity draws and holds attention (Fleming & Levie, 1978). Illustrations,
because they can display varieties and interrelationships of lines, shapes, colors,
spaces, and text, tend to be more complex to the senses than lectures or text alone,
and so they will stand out to the learner. It should be added, however, that there
are limits to the benefits of complexity. If complexity exceeds the processing
capabilities of learners, they may withdraw attention in self-defense. There is an
optimal level of complexity that varies with the age and ability of learners that
must be taken into consideration.
Our attention is
drawn to the
circle on the
right because of
the higher
complexity
introduced by
multiple colors.
Novelty
Novelty is also one of the keys to gaining attention (Fleming & Levie, 1978). Our
attention is drawn to what is new or unexpected in our sensory field. This is the
reason police and other emergency sirens use rapidly changing pitches rather than
sheer volume to announce the need for caution. Even though the ideas you present
may be quite interesting or complex, a long, uninterrupted lecture or pages of text
may introduce sensory monotony. Judicious use of illustrations within such
presentations will introduce novelty and help hold the attention of learners. As
with complexity, however, instructors should not over emphasize novelty as a
strategy. Anything that is originally novel and attention-getting can become
monotonous with overuse.
One of the
benefits of using
illustrations is
simply the visual
variety they
produce. The
lower screen is
much more
inviting than the
one above and is
more likely to
engage students.
The attention
gained by the
more complex
circles is now
lost due to
overuse. The
more simple,
solid color circle
now stands out
because of its
novelty.
Retention
Retention usually refers to keeping information available in the long-term
memory, but the ability to retain needed information in working memory is
equally important to learning and performance. Problem solving, for instance,
requires keeping many factors of a situation in mind while analyzing them for a
solution. Illustrations provide assistance for both kinds of retention.
Long-Term Retention
One of the basic ways that illustrations aid retention relates to the well-researched
(but not undebated) dual-coding theory of memory (Paivio, 1971). This theory
proposes that information is stored in long-term memory both as verbal
propositions and as mental images. It suggests that when information is presented
verbally and visually it has a better chance of being remembered. Corroborating
research shows that concrete words are remembered better than abstract words,
and that pictures alone are remembered better than words alone (Fleming &
Levie, 1978). From the dual-coding perspective, an explanation is that concrete
words help us generate associated mental images, and that pictures alone help us
to generate associated words, in addition to detailed mental images. The
combination of verbal proposition and mental image establishes multiple
pathways by which the information can be retrieved from memory.
The fact that we
can store the
concept "frog" as
both a verbal
proposition and a
mental image
increases the
likelihood that
we will
recognize one
when we see or
read about it.
Simultaneous verbal and visual representation probably does not completely
account for the memorable nature of images, though. It may be that, because they
are concrete, images are intrinsically more durable in memory than verbal
propositions. The extraordinary aberration of photographic (or idetic) memory, in
which people retain incredibly detailed images in memory after a single viewing,
has no corresponding aberration in verbal memory. (Extraordinary "aural"
memory has been noted, however, in people such as Mozart.) Feats of seemingly
remarkable verbal memory, such as Greek and Roman orators and storytellers
reciting lengthy speeches or enormous epic poems from memory, actually use
visualization strategies (linking words to mental images) to enhance recall.
Obviously, illustrations can help learners retain information by stimulating the
mental images to facilitate dual-coding. They can be of special value when
teaching abstract information by providing images that learners might not
generate on their own. Charts showing trends, diagrams of processes, and visual
metaphors of abstract ideas are all ways of providing images for abstract ideas.
The complex
relationships of
the atmospheric
properties and
processes that
determine
thunderstorm
types are
memorably
illustrated in this
"concept map."
These
relationships are
difficult to sum
up as succinctly
in words.
Illustrations can
help generate
associated
mental images
for abstract
information.
Learners may
remember the
primate
taxonomy better
if they can call
up this spatial
arrangement
from memory.
Another way of looking at how illustrations help students retain abstract
information is their ability to assist in building well-structured "schemas."
Cognitive theory proposes that we store knowledge in networks of interrelated
propositions called schemas (Norman, 1982). Recall is achieved by following a
path of related propositions until the desired information is encountered. Complex
and accurately structured schemas facilitate recall by providing many alternate
and efficient paths to reach information.
Psychologists
prefer to think of
our knowledge
as stored in
multidimensional
proposition
networks, or
schemas, rather
than using the
more linear "file
cabinet"
metaphor.
Graphic organizers are diagrams that explicitly reveal a useful schema (Jonassen
& Hawk, 1984). Presenting these organizers to students, either in advance of
instruction or as summaries, facilitates the process of "organization," the
structuring of a schema. Several studies also show the advantages of having
students finish incomplete graphic organizers, or requiring students to create their
own (e.g., Geva, 1983). Because participatory graphic organizers require the
additional involvement of students, this strategy may have an even more positive
effect on recall than instructor-generated organizers (as long as feedback is
provided to correct possible misconceptions). Other related graphical tools for
building schema include pattern notes (usually student-generated), concept maps,
and all varieties of diagrams.
This is an
example of a
graphic
organizer for a
unit on rock
classification in a
geology class.
Using graphic
organizers may
help structure
useful schemas
in the minds of
students. They
can provide the
scaffolding from
which to build
more detailed
knowledge.
"Participatory"
graphic
organizers,
which students
must complete
themselves, may
work best of all
in helping
students build
resilient memory
structures.
Retention in Working Memory
Illustrations can also be seen as assisting the short-term or working memory by
making more information readily available. Illustrations can present
simultaneously all the information needed to explain a topic or perform a task.
Where a linear string of words must use a series of semantic cues to its
organization over the course of its passage, an illustration can use lines, boxes,
arrows, space, color, typefaces, and the relative distance between elements to
communicate information about the relationships of those elements. Because the
reader can see this information at a glance or with minimal study, graphical
presentation can be more efficient than words alone (Winn, 1987). For example,
charts with multiple columns and rows can reveal the complex relationships
between large amounts of information. Such information would be difficult to
present and even more difficult to comprehend in words alone. When students
read prose or hear exposition, they have to hold information in working memory
long enough to relate it to information presented later– a difficult task in a long
passage. Simultaneous presentation can reduce the processing load on the
working memory and thus help students better see relationships within the
information.
Illustrations also assist working memory by helping to create hierarchies of
information. Since the capacity of working memory is so limited, the mind uses
hierarchies to reduce the numbers of necessary details it has to keep in store. A
visual representation or a label of a subset of information can act as a pointer.
This pointer can be stored in working memory instead of all its elements to reduce
the mental workload, yet the pointer can keep the elements readily available for
quick reference if needed (Gagné, 1985). Because illustrations can present a large
amount of information simultaneously, and can use various visual cues to suggest
hierarchical groups, they can become powerful pointers. The Greek and Roman
speakers mentioned above sometimes used a strategy that involved associating
passages of the poem or speech with images of objects and rooms in a real house.
When reciting the poem, they would imagine themselves exploring that house,
and would recall passages into working memory as they "visited" each room filled
with reminders (Cicero, On the Good Life, as cited in Hilts, 1995). This type of
strategy is so effective that even when the elements within a subgroup are only
tenuously, or even artificially related, the visual pointer can solidly link them.
Heirarchies help
learners retain
information by
"chunking" it. A
heirarchy
illustration
provides a big
picture, but one
that is
conveniently
broken into
categories.
Recall the
category and you
may recall the
details more
easily.
Distributed Cognition
Illustrations sometimes aid retention, or even circumvent the need for retention,
by substituting for it. "Knowledge in the world" (Norman, 1988) is information
that we can refer to in outside sources (reference materials, instructions, control
labels) rather than commit to memory ("knowledge in the head"). When practical,
it is more efficient to leave knowledge in the world, temporarily or permanently,
rather than to exert effort to memorize it.
The concept of "distributed cognition" (Norman, 1993) suggests that we not think
of ourselves as isolated minds. Rather, we should consider how teams of people
function together to perform tasks, and how our tools and work environment act
as extensions of our cognition and contribute to our ability to perform. In other
words, we should consider how knowledge in the world and in the head work
together and work to improve the relationship. Illustrations play a key role in our
distributed cognition.
For example, "job aids" are sometimes illustrations of procedural steps or physical
layouts that are designed to be read while performing a procedure. Common
examples are the step-by-step assembly instructions included with products sold
unassembled. In this case, the procedure is intended to be performed only once
and never memorized, but job aids are also useful for learning procedures that
eventually must be performed automatically. Decision trees (see example
immediately below) and flow charts of decision-making procedures help us apply
a decision-making strategy by reminding us what questions to ask and what data
to pay attention to. After time, we may internalize the process and no longer need
to refer to the decision tree.
Students must first learn the steps of a complex procedure as verbal knowledge
(facts and rules that are recalled explicitly, achievable via rote learning) before
they become capable of performing it automatically. Yet repeated practice is the
most effective way to learn to perform the steps and their subtleties (learning by
doing). Referring to job aids can help students through the initial stage by letting
them practice complex procedures without committing large amounts of data to
memory (which at first may seem meaningless). When they have performed the
procedure many times, the data begins to acquire meaning, making it more easy to
remember. In other words, the memorization can take place when it is most
effective.
Understanding
We’ve discussed how illustrations gain attention and make information more
memorable, but how do they make information easier to understand? One answer
seems to lie in the ability of illustrations to make the abstract more concrete, and
to make the concrete more abstract. Another answer has to do with calling upon
alternative, under-utilized mental skills.
Illustrations for Concrete Information
Illustrations are obviously valuable in teaching concrete concepts and how to
work with concrete objects. It would be nearly impossible to teach students how
to classify cloud types without showing illustrations of each type and pointing out
their differences. It would be equally difficult to teach medical students human
anatomy without illustrations. It may be stating the obvious, but illustrations are
also critical for showing those things that can’t normally be seen, such as the
interiors of things and the microscopic and macroscopic. Illustrations are
important for teaching principles that have spatial determinants. An illustration
would be especially appropriate for showing that different species of trees
dominate the ecosystem at different altitudes.
Illustrations are
especially
important for
teaching spatial
concepts and
principles.
Illustrations can
make the
invisible visible.
Cross sections
are important for
showing internal
structure (in this
case, a
hurricane).
Arrows can serve
a lot of purposes,
such as revealing
the paths of the
wind.
Colors are a
useful tool for
showing
temperature
differences.
Illustrations for teaching concrete information are, in most cases, more effective if
they are somewhat abstracted. Overly realistic illustrations, including
photographs, may present too many unnecessary details that can obscure the
critical elements. Line drawings or other simplifications, which suggest the real
object but highlight the critical elements in an unrealistic way, are usually more
effective than realistic illustrations. Of course, realism may be necessary for the
later stages of developing expertise, where objectives require students to identify
or manipulate objects in the real world. Proponents of situated learning
approaches also warn us not to abstract learning excessively from real world
experiences.
Weather
forecasters must
work with data
and imagery that
can be cryptic to
them (let alone
the rest of us)
because it is so
abstracted from
reality.
Instructional
illustrations can
provide a
somewhat more
realistic
depiction of what
they see in that
data, helping
them visualize its
physical
implications.
While they can't
rely on such
images on the
job, use of more
realistic
illustrations
during training
can be a stepping
stone to better
use of the data.
Illustrations for Abstract Information
Illustrations prove valuable in teaching abstract information by providing spatial
metaphors for logical structure. Using space, lines, boxes, arrows, color, and the
relative distance between elements, an illustration can provide a concrete
equivalent of abstract ideas. Many writers have outlined methods of making
graphic representations of the common structures of information, such as
comparison and contrast, procedural steps, description, causation, and chronology
(e.g., Jones, Pierce, & Hunter, 1989). For example, column charts are efficient for
comparing or contrasting the characteristics of items; time lines are good at
showing chronological relationships; flow charts can show causation clearly.
Here are some
examples of
common
templates that
can be used for
structuring
information
graphically.
This is a nice
example of an
illustration that
uses the
continuum
template.
This series of
very simple
graphics
provides a
tangible
expression of the
statistical
concept of
"correlation."
There are
advantages in
averaging an
ensemble of
computer model
runs rather than
relying on a
single run based
on a best guess
of the initial
state. This
abstraction
makes the point
clear by reducing
the problem to
lines and points.
Data graphics are a special case of illustration that provide spatial representations
of numeric data. Data graphics, such as bar graphs and pie charts, are
indispensable for revealing trends or other relationships of data that would not be
easily discerned if the data were presented only numerically.
Data graphics
help reveal
trends,
comparative
quantities, or
areas of overlap
indicated, but not
made obvious, in
the raw
numerical data.
It can be beneficial at times to combine data graphics and
conceptual graphics. The conceptual graphic can provide a
physical representation of the principle revealed in the data.
Here we see that at particular wavelengths, surface
temperatures, as indicated by energy emitted by water
molecules near the earth's surface, are not seen by weather
satellites.
The omnipresence of data graphics in research papers, newspapers, corporate
reports, etc., shows that illustrations are important not only in learning abstract
information, but also in the ongoing effort to manipulate it. We all use
illustrations as performance aids. It has been said that "solving a problem simply
means representing it so as to make the solution transparent" (Simon, 1981). We
draw organizational charts, process maps, Gantt and PERT charts, etc. to help us
manage information and see what courses of action are necessary.
Using graphic
vectors we can
explain how you
can estimate the
orientation and
speed of groundrelative wind
gusts from a
storm outflow as
they interact with
the
environmental
winds--a
confusing
problem
otherwise.
Alternative Mental Skills
Another advantage to using illustrations is that they address alternative mental
skills or learning styles of students. In our culture we tend to stress verbal over
visual learning. Because the written text and the lecture are the primary modes of
instruction, students have fewer chances to use and develop visual learning
abilities. Tapping these abilities with illustrations may reinforce learning in ways
that verbal learning alone would not.
This idea recalls "whole-brain learning," which some researchers have advocated
(Toth, 1980). Left-brain/right-brain theory proposes that the left hemisphere of
the brain is best at verbal and other symbolic processes, and that the right
hemisphere is better at visual and creative processes. By tapping both
hemispheres in whole-brain learning, each hemisphere can contribute its own
strengths, and more thorough learning may take place. The idea that it is
beneficial to address multiple learning styles (visual vs. aural, etc.) is based on a
similar concept, although here it is proposed that each learner has a predisposition
to a particular style. If we use only one teaching mode, such as lecture, we may be
leaving behind those students with equal ability, but an alternate preferred, and
presumably optimal, learning style.
Creating Context
Situated Learning
When theorists speak of "situated cognition," they are referring to the way our
ability to perform is closely tied to how well we become enculturated in the social
and physical environment of practice. They suggest that "communities of
practice" create their own situation-specific meanings, and that cognition in any
specific "community of practice" is intertwined with one's interactions with
colleagues and the tools-of-the-trade (Lemke, 1997). This point-of-view suggests
that knowledge cannot be effectively objectified and taught isolated from the
environment in which we want learners to perform. Instead, we need to offer
opportunities for practice in those environments, or at best, in close
approximations of them.
Creating "case-based learning" (Schank & Cleary, 1995) materials, through
computer-based instruction or some other medium, can fulfill the need for situated
learning. Someone who has been exposed to a rich variety of cases (such as an
experienced expert) will be able to draw from them when they face analogous
situations. Examples of case-based or scenario-based learning tools can range
from collections of stories culled from experts to highly interactive instructional
simulations. Illustrations within such materials can play an important role in
establishing a realistic context. They can provide representations of the
environment and tools of practice, adding realism to the cases or simulations that
can act as stepping-stones to actual performance. For example, providing a
computer interface whose look simulates the actual data-display system of a
weather forecaster may facilitate the transfer of computer-based forecaster
training to the job by creating the proper mindset for its application.
Lessons that use
illustrations to
suggest the work
environment
may aid in
"situating" the
learning
appropriately.
These graphics
were used in
various stages of
a simulation
created for
emergency
managers. They
help to create an
increasingly
stressful
atmosphere and
make the
simulation more
realistic (in
addition to
adding a touch of
humor).
If we want
meteorologists to
be able to better
transfer training
to their jobs, it is
important that at
least a portion of
the instructional
graphics
represent the
type of data
graphics that are
used on the job.
We should resist
always trying to
"improve" the
data by making it
more readable,
or we risk not
improving
performance.
Instructional Metaphors
Useful instructional contexts can be metaphorical or analogical as well as
realistic. These types of contexts may also help make information better
understood by linking new knowledge to existing knowledge that has an
analogous relationship, or simply by providing a mnemonic device. Illustrations
can make effective mnemonic devices.
The stretching of
vorticity is a
difficult physical
concept, but
comparing it to a
skater's
conservation of
momentum helps
to clarify what
we mean.
This content
menu is
constructed in
the form of a
jigsaw puzzle.
The content of
this instructional
module
(Numerical
Weather
Prediction) has
no relationship to
a puzzle except
that it is often
puzzling to its
users. The puzzle
metaphor may be
attention-getting
and memorable
nonetheless.
References
Duchastel, P.C. (1978) Illustrating Instructional Texts, Educational Technology,
Nov. 1978.
Fleming, M. & Levie, W. H. (1978) Instructional Message Design, Englewood
Cliffs, N.J.: Educational Technology Publication.
Gagné, R.M. & Briggs, L.J. (1979) Principles of Instructional Design (Second
Edition), New York: Holt, Rinehart, and Winston.
Gagné, E. (1985) The Cognitive Psychology of School Learning, Boston: Little,
Brown, and Company.
Geva, E. (1983) Facilitating reading comprehension through flowcharting.
Reading Research Quarterly, 18, 384-405.
Hilts, P.J. (1995) Memory's Ghost: The Strange Tale of Mr. M. and the Nature of
Memory, New York: Simon & Schuster.
Jonassen, D. & Hawk, P. (1984) Using graphic organizers in instruction.
Information Design Journal, 4, 58-68.
Jones, B.F., Pierce, J., & Hunter, B. (1989) Teaching students to construct graphic
representations. Educational Leadership, Dec. 88/Jan. 89, 20-25.
Lemke, J.L. (1997) Cognition, Context, and Learning: A Social Semiotic
Perspective. In D. Kirshner & J. A. Whitson (Eds.) Situated Cognition: Social,
Semiotic, and Psychological Perspectives, Mahwah, NJ: Lawrence Erlbaum
Associates.
Norman, D. A. (1982) Learning and Memory, San Francisco: Freeman.
Norman, D.A. (1988) The Psychology of Everyday Things, New York: Basic
Books, Inc., p. 55-80.
Norman, D. A. (1993) Things That Make Us Smart, Reading, MA: AddisonWesley.
Paivio, A. (1971) Imagery and Verbal Processes, New York: Holt, Rinehart, and
Winston.
Schank, R.C., & Cleary C. (1995) Engines for Education. Hillsdale, NJ: Lawrence
Erlbaum Associates.
Simon, H.A. (1981) The Sciences of the Artificial (2nd Edition), Cambridge, MA:
MIT Press.
Toth, M.A. (1980) Figures of thought. The use of diagrams in teaching sociology.
Teaching Sociology, 7, 409-424.
Winn, W. and Holliday, W. (1982) Design Principles for Diagrams and Charts.
The Technology of Text, (Jonassen, D.H., Ed.), Volume 1, 277-299.
Winn, W. (1987) Charts, Graphs, and Diagrams in Educational Materials, The
Psychology of Illustration (Volume 1), New York: Springer-Verlag, 152-198.