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Nine Ways to Reduce Cognitive Load in Multimedia Learning
Richard E. Mayer; Roxana Moreno
Online publication date: 08 June 2010
To cite this Article Mayer, Richard E. and Moreno, Roxana(2003) 'Nine Ways to Reduce Cognitive Load in Multimedia
Learning', Educational Psychologist, 38: 1, 43 — 52
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URL: http://dx.doi.org/10.1207/S15326985EP3801_6
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MAYER AND MORENOWAYS TO REDUCE COGNITIVE LOAD
Nine Ways to Reduce Cognitive Load in Multimedia Learning
Richard E. Mayer
Department of Psychology
University of California, Santa Barbara
Roxana Moreno
Educational Psychology Program
University of New Mexico
First,weproposeatheoryofmultimedialearningbasedontheassumptionsthathumanspossess
separate systems for processing pictorial and verbal material (dual-channel assumption), each
channel is limited in the amount of material that can be processed at one time (limited-capacity
assumption), and meaningful learning involves cognitive processing including building con
-
nections between pictorial and verbal representations (active-processing assumption). Second,
basedonthecognitivetheoryof multimedialearning,weexamine theconceptofcognitive over-
load in which the learner’s intended cognitive processing exceeds the learner’s available cogni-
tive capacity. Third, we examine five overload scenarios. For each overload scenario, we offer
one or two theory-based suggestions for reducing cognitive load, and we summarize our re-
search results aimed at testing the effectiveness of each suggestion. Overall, our analysis shows
that cognitive load is a central consideration in the design of multimedia instruction.
WHAT IS MULTIMEDIA LEARNING AND
INSTRUCTION?
The goal of our research is to figure out how to use words and
pictures to foster meaningful learning. We define multimedia
learning as learning from words and pictures, and we define
multimedia instruction as presenting words and pictures that
areintended tofoster learning.The wordscan beprinted (e.g.,
on-screen text) or spoken (e.g., narration). The pictures can
bestatic(e.g., illustrations,graphs,charts, photos,or maps)or
dynamic (e.g., animation, video, or interactive illustrations).
An important example of multimedia instruction is a com
-
puter-based narrated animation that explains how a causal
system works (e.g., how pumps work, how a car’s braking
systemworks, how the human respiratory system works,how
lightning storms develop, how airplanes achieve lift, or how
plants grow).
We define meaningful learning as deep understanding of
the material, which includes attending to important aspects of
the presented material, mentally organizing it into a coherent
cognitive structure, and integrating it with relevant existing
knowledge. Meaningful learning is reflected in the ability to
applywhatwas taughtto newsituations, sowe measurelearn
-
ing outcomes by using problem-solving transfer tests (Mayer
& Wittrock, 1996). In our research, meaningful learning in
-
volves the construction of a mental model of how a causal
system works. In addition to asking whether learners can re
-
call what was presented in a lesson (i.e., retention test), we
also ask them to solve novel problems using the presented
material(i.e., transfertest). Allthe resultsreported inthis arti
-
cle are based on problem-solving transfer performance.
In pursuing our research on multimedia learning, we have
repeatedly faced the challenge of cognitive load: Meaningful
learning requires that the learner engage in substantial cogni
-
tive processing during learning, but the learner’s capacity for
cognitiveprocessingis severelylimited. Instructionaldesign
-
ers have come to recognize the need for multimedia instruc
-
tion that is sensitive to cognitive load (Clark, 1999; Sweller,
1999; van Merriënboer, 1997). A central challenge facing de
-
signersofmultimedia instructionis thepotential forcognitive
overload—in which the learner’s intended cognitive process
-
ing exceeds the learner’s available cognitive capacity. In this
articlewe present a theoryof how peoplelearnfrom multime
-
dia instruction, which highlights the potential for cognitive
overload. Then, we describe how to design multimedia in
-
EDUCATIONAL PSYCHOLOGIST, 38(1), 43–52
Copyright © 2003, Lawrence Erlbaum Associates, Inc.
Requests for reprints should be sent to Richard E. Mayer, Department of
Psychology, University of California, Santa Barbara, CA 93106–9660.
E-mail: mayer@psych.ucsb.edu
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struction in ways that reduce the chances of cognitive over
-
load in each of five overload scenarios.
HOW THE MIND WORKS
We begin with three assumptions about how the human mind
works basedonresearch in cognitive science—the dual chan
-
nel assumption, the limited capacity assumption, and the ac
-
tive processing assumption. These assumptions are summa
-
rized in Table 1.
First, the human information-processing system consists
of two separate channels—an auditory/verbal channel for
processing auditoryinput and verbal representations and a vi
-
sual/pictorial channel for processing visual input and picto
-
rial representations.
1
The dual-channel assumption is a
central feature of Paivio’s (1986) dual-coding theory and
Baddeley’s (1998) theory of working memory, although all
theorists do not characterize the subsystems exactly the same
way (Mayer, 2001).
Second, each channel in the human information-process
-
ing system has limited capacity—only a limited amount of
cognitive processing can take place in the verbal channel at
any one time, and only a limited amount of cognitive process-
ingcantake placein thevisualchannel atanyonetime.This is
the central assumption of Chandler and Sweller’s (1991;
Sweller, 1999) cognitive load theory and Baddeley’s (1998)
working memory theory.
Third, meaningful learning requires a substantial amount
of cognitive processing to take place in the verbal and visual
channels. This is the central assumption of Wittrock’s (1989)
generative-learning theory and Mayer’s (1999, 2002) select-
ing–organizing–integrating theory of active learning. These
processes include paying attention to the presented material,
mentally organizing the presented material into a coherent
structure, and integrating the presentedmaterialwithexisting
knowledge.
Let us explore these three assumptions within the context
of a cognitive theory of multimedia learning that is summa
-
rized in Figure 1. The theory is represented as a series of
boxes arranged into two rows and five columns, along with
arrows connecting them. The two rows represent the two in
-
formation-processing channels, with the auditory/verbal
channel on top and the visual/pictorial channel on the bottom.
This aspect of the Figure 1 is consistent with the dual-channel
assumption.
The five columns in Figure 1 represent the modes of
knowledge representation—physical representations (e.g.,
words or pictures that are presented to the learner), sensory
representations (in the ears or eyes of the learner), shallow
working memory representations (e.g., sounds or images at
-
tended to by the learner), deep working memory representa-
tions (e.g., verbal and pictorial models constructed by the
learner), and long-term memory representations (e.g., the
learner’s relevant prior knowledge). The capacity for physi-
callypresenting wordsand picturesis virtuallyunlimited, and
the capacity for storing knowledge in long-term memory is
virtually unlimited, but the capacity for mentally holding and
manipulating words and images in working memory is lim-
ited. Thus, the working memory columns in Figure 1 are sub-
ject to the limited-capacity assumption.
The arrows represent cognitive processing. The arrow
fromwords toeyesrepresentsprintedwords impingingon the
eyes; the arrow from words to ears represents spoken words
impinging on the ears; and the arrow from pictures to eyes
represents pictures (e.g., illustrations, charts, photos, anima
-
tions, and videos) impinging on the eyes. The arrow labeled
selecting words represents the learner’s paying attention to
some of the auditory sensations coming in from the ears,
whereas the arrow labeled selecting images represents the
learner’s paying attention to some of the visual sensations
coming in through the eyes.
2
The arrow labeled organizing
words represents the learner’s constructing a coherent verbal
representation from the incoming words, whereas the arrow
labeled organizing images represents the learner’s construct
-
ing a coherent pictorial representation from the incoming im
-
ages. Finally, the arrow labeled integrating represents the
mergingof theverbalmodel,thepictorial model,and relevant
prior knowledge. In addition, we propose that the selecting
44
MAYER AND MORENO
1
Based on research on discourse processing (Graesser, Millis, & Zwaan,
1997), it is not appropriate to equate a verbal channel with an auditory channel.
Mayer(2001)providedanextendeddiscussion of thenatureofdualchannels.
TABLE 1
Three Assumptions About How the Mind Works in Multimedia
Learning
Assumption Definition
Dual channel Humans possess separate information processing
channels for verbal and visual material.
Limited capacity There is only a limited amount of processing capac
-
ity available in the verbal and visual channels.
Active processing Learning requires substantial cognitive processing
in the verbal and visual channels.
FIGURE 1 Cognitive theory of multimedia learning.
2
Selecting words refers to selecting aspects of the text information rather
thanonlyspecificwords.Selecting images referstoselectingparts of pictures
rather than only whole pictures.
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and organizing processes may be guided partially by prior
knowledge activated by the learner. In multimedia learning,
active processing requires five cognitive processes: selecting
words, selecting images, organizing words, organizing im
-
ages, and integrating. Consistent with the active-processing
assumption, these processes place demands on the cognitive
capacity of the information-processing system. Thus, the la
-
beled arrows in Figure 1 represent the active processing re
-
quired for multimedia learning.
THE CASE OF COGNITIVE OVERLOAD
Let us consider what happens in multimedia learning, that
is, a learning situation in which words and pictures are pre
-
sented. A potential problem is that the processing demands
evoked by the learning task may exceed the processing ca
-
pacity of the cognitive system—a situation we call cogni
-
tive overload. The ever-present potential for cognitive
overload is a central challenge for instructors (including in
-
structional designers) and learners (including multimedia
learners); meaningful learning often requires substantial
cognitive processing using a cognitive system that has se-
vere limits on cognitive processing.
We distinguish among three kinds of cognitive demands:
essential processing, incidental processing, and representa-
tional holding.
3
Essential processing refers to cognitive pro-
cesses that are required for making sense of the presented
material, such as the five core processes in the cognitive the-
ory of multimedia learning—selecting words, selecting im-
ages, organizing words, organizing images, and integrating.
For example, in a narrated animation presented at a fast pace
andconsisting of unfamiliar material, essentialprocessing in
-
volves using a great deal of cognitive capacity in selecting,
organizing, and integrating the words and the images.
Incidental processing referstocognitive processesthat are
not required for making sense of the presented material but
are primed by the design of the learning task. For example,
adding background music to a narrated animation may in
-
crease the amount of incidental processing to the extent that
the learner devotes some cognitive capacity to processing the
music.
Representational holding refers to cognitive processes
aimed at holding a mental representation in working memory
over a period of time. For example, suppose that an illustra
-
tion is presented in one window and a verbal description of it
is presented in another window, but only one window can ap
-
pear on the screen at one time. In this case, the learner must
hold a representation of the illustration in working memory
while reading the verbal description or must hold a represen
-
tation of the verbal information in working memory while
viewing the illustration.
Table 2 summarizes the three kinds of cognitive-process
-
ing demands in multimedia learning. The total processing in
-
tended for learning consists of essential processing plus
incidental processing plus representational holding. Cogni
-
tive overload occurs when the total intended processing ex
-
ceeds the learner’s cognitive capacity.
4
Reducing cognitive
load can involve redistributing essential processing, reducing
incidental processing, or reducing representational holding.
In the following sections, we explore nine ways to reduce
cognitive load in multimedia learning. We describe five dif
-
ferent scenarios involving cognitive overload in multimedia
learning. For each overload scenario we offer one or two sug
-
gestionsregardinghowtoreduce cognitiveoverload basedon
thecognitivetheoryofmultimedialearning,andwereviewthe
effectiveness of our suggestions based on a 12-year program
of research carried out at the University of California, Santa
Barbara (UCSB). Our recommendations for reducing cogni
-
tive load in multimedia learning are summarized in Table 3.
Type 1 Overload: Off-Loading When One
Channel is Overloaded With Essential
Processing Demands
Problem: One channel is overloaded with essential
processing demands.
Consider the following situation:
A student is interested in understanding how lightning works.
She goes to a multimedia encyclopedia and clicks on the entry
for lightning. On the screen appears a 2-min animation depict
-
ing the steps in lightning formation along with concurrent
on-screen text describing the steps in lightning formation. The
on-screentext ispresented atthebottom onthe screen,so while
the studentis reading she cannot view the animation, and while
she is viewing the animation she cannot read the text.
This situation creates what Sweller (1999) called a
split-attention effect because the learner’s visual attention is
split between viewing the animation and reading the
WAYS TO REDUCE COGNITIVE LOAD 45
3
Essential processing corresponds to the term germane load as used inthe
introduction to this special issue. Incidental processing corresponds to the
term extraneous load as used in the introduction to this special issue. Finally,
representational holding is roughly equivalent to the term intrinsic load.
4
To maintain conceptual clarity, we use the term processing demands to
refer to properties of the learning materials or situation and the term process
-
ing to refer to internal cognitive activity of learners.
TABLE 2
Three Kinds of Demands for Cognitive Processing in Multimedia
Learning
Type of Processing Definition
Essential processing Aimed at making sense of the presented ma
-
terial including selecting, organizing, and
integrating words and selecting, organiz
-
ing, and integrating images.
Incidental processing Aimed at nonessential aspects of the pre
-
sented material.
Representational holding Aimed at holding verbal or visual represen
-
tations in working memory.
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on-screen text. This problem is represented in Figure 1 by the
arrow from picture to eyes (for the animation) and the arrow
from words to eyes (for the on-screen text); thus, the eyes re
-
ceivea lotofconcurrentinformation,but onlysome ofthat in
-
formation can be selected for further processing in visual
workingmemory(i.e., thearrow fromeyes toimages can only
carry a limited amount of information).
Solution: Off-loading.
One solution to this problem is
to present words as narration. In this way, the words are pro
-
cessed—at least initially—in the verbal channel (indicated by
the arrow from words to ears in Figure 1), whereas the anima
-
tion is processed in the visual channel (indicated by the arrow
from picture to eyes in Figure 1). The processing demands on
the visual channel are thereby reduced, so the learner is better
able to select important aspects of animation for further pro
-
cessing (indicated by the arrow from eyes to image). The pro
-
cessing demands on the verbal channel are also moderate, so
thelearneris betterable toselectimportant aspectsof thenarra
-
tion for further processing (indicated by the arrow from ears to
sounds). In short, the use of narrated animation represents a
method for off-loading (or reassigning) some of the processing
demands from the visual channel to the verbal channel.
In a series of six studies carried out in our laboratory at
UCSB, students performed betterontests of problem-solving
transfer when scientific explanations were presented as ani
-
mation and narration rather than as animation and on-screen
text (Mayer & Moreno, 1998, Experiments 1 and 2; Moreno
& Mayer, 1999, Experiments 1 and 2; Moreno, Mayer,
Spires, & Lester, 2001, Experiments 4 and 5). The median ef
-
fect size was 1.17. We refer to this result as a modality effect:
Students understand a multimedia explanation better when
the words are presented as narration rather than as on-screen
text. A similar effect was reported by Mousavi, Low, and
Sweller (1995) in a book-based multimedia environment.
46
MAYER AND MORENO
TABLE 3
Load-Reduction Methods for Five Overload Scenarios in Multimedia Instruction
Type of Overload Scenario Load-Reducing Method Description of Research Effect Effect Size
Type 1: Essential processing in visual channel > cognitive capacity of visual channel
Visual channel is overloaded by
essential processing demands.
Off-loading: Move some essential
processing from visual channel to
auditory channel.
Modality effect: Better transfer when words
are presented as narration rather than as
on-screen text.
1.17 (6)
Type 2: Essential processing (in both channels) > cognitive capacity
Both channels are overloaded by
essential processing demands.
Segmenting: Allow time between
successive bite-size segments.
Segmentation effect: Better transfer when
lesson is presented in learner-controlled
segments rather than as continuous unit.
1.36 (1)
Pretraining: Provide pretraining in
names and characteristics of com
-
ponents.
Pretraining effect: Better transfer when stu
-
dents know names and behaviors of sys
-
tem components.
1.00 (3)
Type 3: Essential processing + incidental processing (caused by extraneous material) > cognitive capacity
One or both channels overloaded by
essential and incidental processing
(attributable to extraneous material).
Weeding: Eliminate interesting but
extraneous material to reduce pro
-
cessing of extraneous material.
Coherence effect: Better transfer when ex
-
traneous material is excluded.
0.90 (5)
Signaling: Provide cues for how to
process the material to reduce
processing of extraneous material.
Signaling effect: Better transfer when sig
-
nals are included.
0.74 (1)
Type 4: Essential processing + incidental processing (caused by confusing presentation) > cognitive capacity
One or both channels overloaded by
essential and incidental processing
(attributable to confusing presenta-
tion of essential material).
Aligning: Place printed words near
corresponding parts of graphics to
reduce need for visual scanning.
Spatial contiguity effect: Better transfer
when printed words are placed near cor
-
responding parts of graphics.
0.48 (1)
Eliminating redundancy: Avoid pre-
senting identical streams of
printed and spoken words.
Redundancy effect: Better transfer when
words are presented as narration rather
narration and on-screen text.
0.69 (3)
Type 5: Essential processing + representational holding > cognitive capacity
One or both channels overloaded by
essential processing and representa-
tional holding.
Synchronizing: Present narration
and corresponding animation si-
multaneously to minimize need to
hold representations in memory.
Temporal contiguity effect: Better transfer
when corresponding animation and nar-
ration are presented simultaneously
rather than successively.
1.30 (8)
Individualizing: Make sure learners
possess skill at holding mental
representations.
Spatial ability effect: High spatial learners
benefit more from well-designed instruc
-
tion than do low spatial learners.
1.13 (2)
Note. Numbers in parentheses indicate number of experiments on which effect size was based.
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