An Empirical study of Attending and ComprehendingMultimedia Presentations
Pete Faraday & Alistair Sutcl@e
The Centre for HCI Design
City University,
Northampton Square
London, EC1 OHB, UK+44-171-477-8994
P.M, [email protected]
ABSTRACT
The paper reports two studies concerning attention to and
comprehension of Multimedia presentations. The MM
sequence used was taken from a commercially produced
CD-ROM, ‘The Etiology of Cancer’. First, an eye tracking
study of the presentation is reported. A second study was
then cortductekl ml the memorisation of the materials used in
the eye tracking study. The results of the studies are used to
propose guidelines to improve design of MM presentations.
KEYWORDS
Eye Tracking, Comprehension, Presentation Design.
INTRODUCTION
One of the problems in the design of Multimedia (MM)
interfaces is knowing whether the presentation will
successfully deliver its content to its audience. For a user,
understanding a multimedia presentation requires a series of
cognitive processes composed of visual and auditory
attention, comprehension into a proposition, and integration
into a mental model. This paper outlines two studies we
performed on these cognitive processes, and attempts to use
their results to provide design advice for MM presentations.
The studies made use of a commercially produced MM
presentation, ‘The Etiology of Cancer’ ( figure 1).
Our first study examined visual attention to thepresentation. Unlike auditory attention, in which speech is
processed in a linear manner [19]; visual attention
processing is more complex. Visual attention is required to
extract still and moving visual objects [7, 14], and text label
or caption elements from the presentation [12]. It can
process only a limited amount of visual information at any
one time, since it can only take visual input from a
Permission to rneke dlgitrd/hard copies of all or patt of this material forpersonal or classroom use is granted without fee provided that the copiesare not made or distributed for profit or commercial advantsge, the. copy-right notice, the title of the publication and its date appear, and notice isgiven that cop yright is by permission of the ACM, lnc. To copy otherwise,
to republish, to post on servers or to redlatribute to tists, requires specific
permission and/or fee.ACM Multimedia 96, Boston MA USA01996 ACM ()-89791_S71_l/9tj/11 ..$3.50
relatively small area, around 2 degrees of angle from the
eye [12, 14]. Processing is serial, fixation has to be shifted
each time to process the next piece of visual information
[9]. Whilst processing, attention is locked and the eye is
held still in a fixation, toward the point being attended to
[4,12, 21].
In order to investigate visual attention we examined the
order in which visual information is processed by the
viewer using an eye tracking system. We were interested in
the attentional processing of different visual presentation
elements, such as text captions, labels and still and moving
objects; and in how the serial nature of visual attention
would cope with processing a complex and rapidly
changing MM presentation. Few studies have made use of
eye tracking equipment to look at animated materials [4,21],
and none have attempted to track subjects viewing a
complex multimedia presentation. However, visual attention
is vital if visual information is to be successfully processed
from the presentation.
Our second study examined comprehension of the
presentation. The comprehension process acts upon the
elements processed by attention, and combines them
together with the user’s existing long term memory (LTM)
knowledge [1]. The outcome of this is a proposition, or unit
of meaning, built from the presentation elements [10, 22].
For instructional presentations the proposition will be one
of the following types, based on [3] : (i) object proposition,
defining object descriptors or identifiers; (ii) action
proposition, defining the role(s) of objects in the action,
together with path or state change produced by the action;
(iii) procedure proposition : giving sequence or cause-effect
relationships between a group of actions
These proposition types may be built fkom the speech, still
or moving visual objects, label or caption text elements
attended to. The individual propositions are then combinedtogether to form a mental model [10], representing the
meaning across the presentation.
processed, the mental model will
objects, actions and procedures.
As the presentation is
contain a hierarchy of
265
Figure la Figure lb
Despite significant improvements in diagnosis and ... the major cause of death in most cases of cancer is
treatment ... metastasis ...
Figure lC Figure Id
.. the spread of tumour cells fkom the primary neoplasm ... where secondary growth occurs,to distant organs .,.
Figure 1e Figure 1f
266
In our second study, we investigated the comprehension
process by testing free recall, in which subjects wrote down
what they could remember of the presentation. We were
interested in the information types recalled from the
presentation and in relating then to the type of presentation
elements shown. We also investigated the effects of the
users existing LTM knowledge upon comprehension by
using two subject groups, one with and one without
background knowledge of the subject area,
STUDY ONE
The first study investigated the pattern of fixations and
attention upon the MM presentation,. using a Pupilometer
eye tracking system. The objectives of the study were to
attempt to match the shifting of fixations to the visual
presentation elements shown, and to investigate any
common patterns.
Study Materials
A 27 second animation was taken tlom the ‘Etiology of
Cancer’ showing the spread of cancer, termed metastasis. It
is illustrated as a series of screen shots in figure 1. The
speech track which accompanied the presentation is given
under the relevant screen shots.
In figure la,b the malignant tumour object in the centre of
the screen is shown moving down toward the bottom edge
of the screen. The scene ends as shown in figure 1b. A new
scene begins in figure 1c with the tumour breaking up into a
series of tumour cells which move in a diagonal from the
tumour across to the blood vessel. Figure 1d shows the next
scene in which turnour cells move from the top right of the
screen in a diagonal following the blood vessel to the
bottom left of the screen. The final scene is shown in figure
1e,f in which the tumour cells proliferate from the small
cluster shown in figure 1e to the secondary tumour shown in
figure 1f.
Figure 2: Single subject scan path on figure 1c
Study method & Procedure
Eight subjects were drawn flom research students within
City University. A pupilometer system was fixed upon the
subjects eye, whilst they viewed the MM presentation. Due
to equipment problems, two subjects had to be discarded.
The tracker produced an x,y location of the pupil every 50
msec and filtered out spurious data from subject blinks.
Subjects used a bite clamp avoid head movement and were
held approximately 50cm from a 17 inch VGA CO1OW
monitor.
Data AnalysisThe raw data of pupil location was time sliced into five
second parts for each subject to ease analysis. A PC based
tool was built to plot the data for each subject as a scan
path, The data for the six subjects was synchronised over
time to build up a composite trace for each part. This was
placed upon a 32 by 24 grid so that it could be mapped to
the 640x480 VGA screen resolution and compared with the
MM presentation. An example of the data analysis is shown
in figure 2.
ResultsThe fixation maps were compared with the presentation
sequence to produce a pattern for fixation clusters against
the presentation across the six subjects. Whilst it is known
that pupil location and attention may not always coincide, in
general a fixation, or pause, of the pupil at a location will
indicate attentional processing [21]. The parts of the
presentation fixated were analysed to produce an aggregate
of the shitls in fixation between each. The parts were then
ordered in directed graphs, shown on the screen shots and
graphs as a circled number (figure 3,4,5,6). The arrows in
the directed graphs show the direction of fixation, whilst the
number at the end of each arrow shows how many subjects
shifted from one part to another; if subjects shifted back and
forth between parts, the number will be larger. The entry
and exit points are shown on the graphs as bold numbers.
Figure 3a : Fixations on figure 1a
267
(1) All subjects initially produced orientation fixations,
beginning by transversing over the large central tumour
object presentation (figure 3a)
(2) Five of the subjects then shifted to fixate upon the
region of the ‘Metastasis’ title caption (figure 3a)
(5) Revealed caption ‘Cells break through basal Lamina’
concurrent with animation. Subjects tended to fixate upon
this and the motion of tumour cells (4). They also refixated
between the other labels (3a), (3b) (figure 3b)
(3a, 3b, 3c) Shift to the labels ‘malignant tumour in
bronchial epitheliums’, ‘connective tissues’. No particular
order was found across the subjects. The ‘basal lamina’ label
(3c) was not fixated upon. This may be because it was
removed shortly after the start of the presentation and
replaced with label (5) during the animation (4) (figure 3a)
Figure 4a : Fixations on figure lC
,--3
Figure 3b : Fixations on figure lb
J(.=--~@T”mO”’”biect 2 q
(
(
(2~Metast~s;label ~--.,_=@ tvldignantt.fnourl abel
, (2 ‘!)l-l;$
* ia Connective tissue label A— 5 Cells breakthrough label
,> ‘$23: y \2
4 Tumour path~>,
Figure 3C : Directed graph for figure 3a, 3b
(4) Animation of the malignant tumour cell spreading
downwards. The motion caused a general shift of fixation to
the centre of the presentation; but the shift did not happen at
the start of the motion for most subjects. This could be due
to attention still being locked on the labels (3a), (3b) at thestart of the motion. Once attention shifted, subjects did nottrack the motion, but tended to fixate upon its general area
and edges. This may be because the animation was internal,changing the shape, but not the position of the object as a
whole so did not require tracking. (figure 3b)
Figure 4b : Directed graph for figure 4a
(6) The scene was changed. Subjects produced orientation
fixations and then generally shifted to the title ‘Metastasis’
or directly to the tumour path. The tumour path showed the
tumour object partly broken up as a still, before animating it
in (8). (figure 4a)
(7) Subjects shifted to caption ‘Cells break away’ (figure 4a)
(8) Animation of the tumour cells moving in a diagonal
f?om top-middle to bottom-right. All subjects showed an
alignment upon the tumour cells, with subsequent fixations
tracking their path of motion. (figure 4a)
(9) Shift to revealed caption ‘Cells invade capillary’ at the
end of the path of(8). Several subjects then shifted fixations
back and forth between the tumour cell objects and labels
‘Cells break away’ and ‘Cells invade capillary’. (figure 4a)
268
Figure 5a : Fixations on figure 1c
Figure 5b : Directed graph for figure 5a
(lOa, 10b) The scene was changed. Subjects produced
orientation fixations and then shifted to the title ‘Metastasis’(lOa) or to the tumour object itself (lOb) (figure 5a)
(1 la) Animation of the tumour cells moving in a diagonal
from top-right to bottom-left. Only two subjects fixated
upon the start of the motion. The other subjects fixations
tended to be either still on (1 O), or on (1 lb), before picking
up the path about l/4 way through (figure 5a)
(1 lb) Static label ‘Cells travel through blood stream’.
Subjects in general shifted from (1 O) to (1 lb), and then to
the animation (11 a). (figure 5a)
(12a, 12b) Shift to secondary tumour object at the end of
the path (11 a) and then to revealed label ‘Cells adhere to
capillary wall’; subjects shifted fixations back and forth
between the tumour cells and label. (figure 5a)
Figure 6a : Fixations on figure 1e
(13a, 13b) The scene was changed. Subjects produced
orientation fixations and then generally shifted to the
secondary tumour object (13a) or cells escape label (13b).
Subjects shifted fixations back and forth between the object
and label. (figure 6a)
(14) Several subjects switched from the secondary object
or cells escape label to the metastasis label. (figure 6a)
Figure 6b : Fixations on figure lf
Figure 6C : Directed graph for figure 6a, 6b
(15a) Animation of secondary tumour cell growth; subjectstended to fixate upon its general area and edges. The
269
animation was internal, changing the object shape, and
again did not produce tracking fixations (figure 6b)
(15b) Revealed label ‘Cells proliferate to form liver
metastasis’; subjects shifted fixations back and forth
between the secondary tumour growth object and label
(figure 6b)
Discussion
The study provided some evidence for the effect of design
techniques upon fixation and attention within presentations.
Several tentative conclusions are proposed :
● Animation has a strong effect on attention. This follows
the previous results of [7,12,21]. The onset of an
animation will generally produce a shift of attention to
the object in motion. Evidence for this can be found in
animations (8) and (15a).
However, in animations (4) and (11a) the start of the
animations were generally not shifted to immediately. In
animation (4) subjects did not seem to shift to the
downward spread of the tumour cells until late in their
motion; whilst in (1 la) the path of the tumour celk was
not tracked by any subjects until the animation was
around 1/4 complete. Instead attention may have been
locked on the title ‘Metastasis’ (2), (10) and labels (3a, 3b,
3c) and (11 b) in the two frames. If the start of the motion
is important, then ensure that attention will be free, not
processing labels or captions.
. Attention will generally be locked when processing
motion, making it unavailable to shift to other elements
which change or are revealed. This is inkeeping with [7].
In (4) the animation of the tumour cells moving
downwards may have locked attention before it could
process the label ‘basal lamina’ (3c). Using animation may
be unwarranted if the object is not important; trackingmay prevent other fixations.
● Animation which shows an object moving as a whole
along a path produces fixations which will track the
motion of the object and will be directed toward the end
point of the path [8]. Tracking fixations are clearly shownin animation of turnour cells in (8) and (11a). Subsequentelements to be processed should be placed at the end of
path of the motion. Animation which shows an objectchanging state, in which the object remains as a whole but
it shape alters, produces dispersed fixations over the area
and edges of the object. In animation (4) and (15a)
fixations are spread over the tumour and its edges whilstit changed shape.
● Changing scenes causes attention to re-orientate.
Reorientation fixations were found after scene changes in
(2), (6), (10) and (14). Each time attention seemed to
process the scene from fi-esh, eg refixating on the
previously attended title ‘Metastasis’ afier each scene
change. Similar results are given by [11, 16], who suggest
that using a cut in film tends to enhance attention to the
material following the cut. Avoid revealing labels or
object motion to allow re-orientation to take place after
changing to a new scene.
. By gradually revealing labels, symbols and objects,
fixations can be shifted eg between the tumour and labels
in (5), (9). Reveal may be used to order attention fi-om
one part of the topic to the next. Revealing several
presentation elements simultaneously may obscure any
ordering effects; reveal important elements singularly.
● Static presentation elements are not attended to
uniformly. Those which are Iabelled, which are bright in
colour, or appear to be different from their surroundings
will be attended to in preference to other objects. Use
strong colours or labels to draw attention. Avoid using
multiple labels, such as in (3a, 3b, 3c) which may lead to
unpredictable shifting of attention. .
. Reading captions and labels will lock attention [12],preventing other elements being processed, Reading also
requires longer fixation time than for identifying objects.
Attention may have been locked on the title ‘Metastasis’
(10) and caption (1 lb), preventing processing of the start
of animation (11a). Allow time for text elements to be
processed : this may range from a 1/5 second for a simple
word to several seconds if the word is unfamiliar [12].
● Labelling an object will produce shifts of fixations
between the object and label eg (13a,b) and (15a,b), The
findings of [6] are similar suggesting that switches of
attention are used to integrate information from the label
with the object. Ensuring that an object and its label areboth available together may aid this process.
STUDY TWO
The results of study one gave some insight into how visual
attention would process an MM presentation. However, it
did not address what was extracted fi-om the presentation by
comprehension. Study two investigated recall of theinformation content of the original presentation. The issues
of interest here were what types of proposition would berecalled from the presentation; and how the different
presentation elements, such as speech, still and moving
objects, label and captions would influence what wasrecalled. The effect of the subject’s existing domain
knowledge upon comprehension was also tested by
comparing a group of low knowledge subjects with a
second group of subjects who had expert knowledge of
biochemistry.
270
Problem
i) Metastasis is problem despitesignificant advances in diagnosis
Cause
Ii) Metastasis is thespread of cancer
E&d
xiii) Major causeof Death
Seauence
iii) Tumour cells break awayfrom primary tumour
i ‘----- ._Obiect state Acfion
iv) Cells m v) CellsBronchial breakthroughEpithehum Basal Lamina
._.r–--—-—
vii) Tumour cells travelthrough blood stream
I~..
—-~
vi) Cells break viii) Cells Invade ix) Cells Adherethrough Connectwe Capillary to Capillarytissues
Figure 7: Graph of propositions
Study Method & Procedure
Study two used two groups of eight subjects. The first
group was drawn from research students within City
University, who had low background knowledge of the
presentation domain. The second group of subjects was
recruited from biochemistry post-graduates who had high
background knowledge, but were pretested to ensure that
they had no specific knowledge of the subject matter itself.
This provided low ‘v’ high background knowledge
conditions. Both groups of subjects were shown the
presentation once and were then instructed to write down
what they could recall of the presentation.
Materials
The same materials were used as for study one (figure 1).
Data Analysis
In order to score the accuracy of subject recall the MM
presentation was analysed into a set of thirteen propositions,
representing the main ideas was created, The propositions
were further grouped into either high level organizing
concepts of sequence, problem or cause-effect, or into
lower level actions or object states within each part of the
sequence. This is shown as a graph in figure 7, with higher
level concepts at the top and lower level actions at the base.
The recall transcripts were analysed and categorised into
these propositions.
Results
Recall was scored for each of the thirteen propositions for
the two groups of subjects. These are shown in the table 1.
DiscussionThe background knowledge of the subjects appeared to
make little difference to their recall performance. Thissuggests that performance was based on what was given in
I,Seauence
x) Secondary tumourgrowth is formed
/vdQL1 mxi) Cells escape xii) Ceilsfrom Capillary invade
another organ
the presentation, rather than what was already known by
subjects from their existing long term memory.
Recall of higher level sequence propositions iii), vii), xii),
representing a group of actions, was good for both expert
and novice groups. Most of these sequence propositions
were given as animations. Animations are known to
improve comprehension of general action information
[15, 17]. The use of extra animations may have improved
recall performance for eg the tumour breaking through
the basal lamina, tumour adhere and extravisation actions.
Recall of specific action, object state and object role
propositions v), vi), ix), x) was poor. Most of these
propositions were given in text caption or label elements.
Comprehension difficulties may be in part due to
attentional problems with the use of multiple labels and
animations, discussed earlier. Others problems may be
related to poor synchronisation of the text labels with the
speech track, see below.
Recall of propositions which were only given in the
speech track was generally poor. The high level problemproposition i) and effect proposition xiii) were both
poorly recalled. However, the speech ‘metastasis spread
of cancer’ proposition ii) was well recalled. This may
have been because it was reinforced with the title
‘Metastasis’ in each fi-ame of the presentation. Generally,
if the speech information is complex or important then it
may be best to also concurrently present it in a caption. It
may also be useful to use captions or labels which take
the exact wording given in the speech track, to ensuretight linking. It is concluded by [5] that ‘only exact
duplicates on the screen of what is being said in thenarration appear to allow it to be processed unimpeded’.
271
●
●
Proposition type
Problem
Cause
Sequence
Object state
Action
Action
Sequence
Action
Action
Action
Action
Sequence
Effect
Proposition Low Domain High Domain Total (/1 6)
knowledge (/8) knowledge (/8)
i) Metastasis is a problem despite 1 0 1
significant improvements in diagnosis
and treatment
ii) Metastasis is the spread of cancer. 6 7 13
iii) Tumour cells break away from 6 4 10
primary tumour.
iv) Malignant tumour cells are in 1 1 2
bronchial epitheliums
v) Tumour cells breakthrough basal o 2 2
Iamina
vi) Tumour cells break away through o 1 1
the basal lamina and connective tissue
vii) Tumour cells travel through the 7 5 12blood stream.
viii) Tumour cells invade the blood 4 5 9
vessel capillary
ix) Tumour cells adhere to the o 2 2
capillary wall in liver
x) Tumour cells escape from capillary 2 4 6
xi) Tumour cells invade another 6 5 11organ.
xii) A secondary tumour is formed. 8 5 13
xiii) Metastasis is major cause of 3 1 4death
Table 1: Recall results for low ‘v’ high domain knowledge
Linking of the speech track to visual elements of the
presentation was generally poor. The speech track rarelyprimed or re-inforced the propositions presented visually.
Where speech did prime the animation toward the end of
the presentation in propositions xi) and xii) describing the
secondary tumour, it improved comprehension. Mostly
however, the speech propositions i), ii), xiii) did not
directly relate to the visual elements being shown. It is
noted by [2, 5] that it is important that speech and text
captions, labels, animation or objects combine to form asingle composite proposition. Comprehension may fail ifdifferent propositions are presented by the two media. A
study by [5] found that if speech and visual informationwere unrelated, subjects would generally ignore one ofthe media, usually the speech track. [2] also notes that itis vital that speech describing object or actions should
coincide with the object or action being shown.
The structure of the mental model formed from the
propositions can be supported by the use of advanced
organisers and summaries [13, 22], The use of a the
general title ‘Metastasis’ improved recall for proposition
ii). Titles, advanced organisers and summaries may help
to structure the mental models formed by the user from
the individual propositions, keeping high levelpropositions active in the mental model.
IMPROVING DESIGN
We have used these conclusions to produce a re-authored
version of the first part of the presentation (figure 1a, b),which showed the tumour breakthrough the basal lamina
and enter the connective tissue.
We began by providing an advanced organiser for the
sequence, using a caption and speech track whichintroduced the main topic of Metastasis (figure 8). The
caption was tightly linked to the speech track to reinforce
the propositions given. The organiser will form the top level
of the mental model for this part of the presentation, below
which other propositions could then be integrated,
272
Metastasis is the spread of cancer from the primary tumour
to a secondary tumour...
Figure 8
In the first scene itself, the title ‘Metastasis’ was removed
and placed in the organiser as any unnecessary titles may
distract attention following orientation. The original
presentation also used three other labels, which were shown
concurrently. These may cause attention to shift
unpredictably between objects. Instead a single central label
was used to direct attention to the central tumour mass;
other labels were then revealed as required. The tumour
mass had a different colour to its background, this was left
as-is, since objects which stand out against their ground will
usually attract attention (see figure 9).
,,, The malignant primary tumour shown is in the patients
bronchial epitheliums.
Figure 9
Following a pause to allow reading time, a revealed captionwas then used to shift attention to the basal lamina (figure
10). The basal lamina was
basal lamina object wasnot brightly coloured, so a newdrawn which stood out more
clearly, to make it easier to attend to. Again reading time
was allowed for the caption.
In order to spread, the cells of the primary tumour must
break through the basal lamina ...
Figure 10
Next an animation was added to show the basal lamina split
apart. To improve comprehension of the action for the
proposition ‘Tumour cells break through basal ku-nina’ the
next frame (figure 10) used an additional animation of the
basal Iamina splitting. The speech track was also changed to
reinforce the text captions, Using the same phrases in
speech and captions will tightly link what is processed into
a single proposition. The start of the animation was then
synchronised to the speech track, so that the spread of the
tumour began as it was introduced by the speech. This may
again help to produce a single unified proposition.
.,. and then enter the surrounding connective tissues.
Figure 11
The animation will shift attention to the basal lamina and
bottom of the tumour. As the animation will also lock
attention, it was placed prior to the existing animation of the
273
tumour spreading down into the connective tissue which
otherwise might have competed for attention.
After the end of the new animation, the existing animation
was then used to shift attention to the tumour spreading
down into the connective tissue. With attention shifted to
the spreading tumour, this animation was then paused half
way through and a label revealed describing the animation,
figure 11. By pausing the animation, it should allow
attention to move to the revealed label. After leaving time
for the label to be read, the end of the animation was
completed.
MetastasisThe spread of cancer from Primary Tumour .
(i)TumourCells in Bronchial Epilhelium cross Basal
Lamlna and enter connective Tissues
Figure 12
The final frame (figure 12) returned to the advanced
organiser and gave a summary of the previous animations
and captions to provide a high level proposition to ensure
the mental models fi-om the captions and animations were
correctly integrated with the organiser.
EVALUATION OF RE-AUTHORED VERSION
Our current work is to evaluate the re-authored presentation
with a further group of subjects. Preliminary results indicate
that comprehension is improved by the design changessuggested. However, we are also seeking to clarifi whether
changes in the content of the verbal information provided,
or the addition of visual elements such as animations and
captions are responsible for these improvements, To
investigate these issues, we intend to produce a third
presentation, which will be a text and speech only condition
based upon the re-authored presentation. By comparing thiswith the re-authored presentation, we will be able to judge
how effective our visual against verbal changes have been.
CONCLUSIONS
Little current work on MM has addressed the evaluation
and successful design of MM presentations. It is believedthat the issues of attention and comprehension are strongly
interlinked with producing ‘good’ MM presentations : a
‘good’ presentation is one which can understood by the userin the manner intended by the designer. The two studies
reported have shown some of the dangers of attempting to
design MM presentations without concern for attention and
comprehension.
Our eye tracking results explored the potential problems
that using captions, labels, animations and scene changes
may cause, Attention can easily be overloaded, resulting in
presentation elements being missed. Attentional design
should take into account the need to order shifts of attention
according to the content being shown. It should allow for
attention being locked by animation and reading, such as
providing time to read captions and labels and to pause for
re-orientation when scenes are changed. Where the
presentation is complicated it may also be useful to guide
attention to important elements using animation, reveals,
colouring or labels.
Our second study of subject’s recall of the presentation
showed that design problems may lead to difficulties incomprehension. We suggested comprehension may be
improved by ensuring that the elements of the presentation
could be formed together into unified propositions. This
may be achieved by scripting the speech track to more
tightly reference and synchronise with the visual elements
of the presentation; and by using animations and captions to
support the propositions being formed. We also proposed
that the formation of the subject’s mental model could be
supported by applying titles, organisers and summaries.
This work provides some tentative steps toward placing
MM design and evaluation within a firmer theoretic
framework. Several problems remain for future research. As
noted, the re-authored version of the presentation is
currently being tested with firther subjects. We also feel it
is important to address how design advice can be integrated
into the life cycle of MM production, following our work in
[20]. Because of the costs of producing MM presentations,
leaving evaluation until the product is complete is not
practical. Design advice needs to be given during the
formative processes of authoring, such as when scriptingand choosing media.
ACKNOWLEDGMENTS
The Etiology of Cancer CD-ROM is produced by and
copyright of American Medical Television and Silver
Platter,
REFERENCES
1. Baddeley, A. Human Memory. LEA, 1990.
2. Baggett, P. The Role of Temporal overlap of Visual and
Auditory Material in Forming Dual Media Associations.
Journal of Educational Psychology 76,1984,408-417
3, Bieger, G.R. & Glock, M.D. The Information Content
of Picture-Text Instructions. Journal of Experimental
Education 53 (1984), 68-76.
274
4. Brandt, H. The Psychology of Seeing. New York : The
Philosophical library (1954)
5. Grimes, T. Mild Auditory-Visual dissonance in TV
News may exceed viewer attention. Human
Communication Research 18,2 (1991), 268-298
6. Hegarty, M. & Just, M.A. Constructing mental models
of machines fi-om text and diagrams. Journal of Memory
& Language, 32,717-742, 1993.
7. Hillstrom, A.P. & Yantis, S. Visual motion and
attentional capture. Perception & Psychophysics, 55(4),
(1994), 399-411.
8. Hochberg, J & Brooks, V. The Perception of Motion
Pictures. In Handbook of Perception and Human
Pe~formance X
9. Johnson, W .A. & Dark, V..J. Selective Attention.
Annual review ofpsychology, 37,43-45.
10. Johnson-Laird, P. Mental Models. Harvard Press, 1983.
11. Kraft, R. The role of cutting in the evaluation andattention of film. Journal of Experimental Psychology :
Learning, Memory & Cognition, 12, 1 (1986), 155-163.
12. Loftus, G.R. Eye Fixations on Text and Scenes. In EyeMovements in Reading, Pet-ception, and Language
Processes. Academic Press, 1983, pp.359-376.
13. Mayer, R. E. Aids to text comprehension. Educational
Psychologist, 19(1 984), 30-42
14. Nelson, W.W. & Lotlus, G.R. The functional field
during Picture Viewing. Journal of Experimental
Psycholo~ : Human Learning& Memoq, 6(4), (1980),
391-399.
15. Park, O. & Hopkins, R. Instructional conditions for
using dynamic visual displays : a review. Instructional
Science 21 (1993), 427-449
16. Reeves, B. The effects of scene changes and semantic
relatedness on attention to television, Communication
Research, 20(2), 1993, 155-175
17. Rieber, L. P. Animation in Computer Based Instruction.
Educational Technology Research & Development 38
(1990), 77-86
18, Rollins, H.A. & Thibadea, R. The effects of auditory
shadowing on recognition of information received
visually. Memory & Cognition, 1(2), (1973), 164-168
19. Salame, P. & Baddeley, A. Disruption of STM by
unattended speech : Implications for the structure of
Working Memory. Journal of Verbal Learning &
Verbal Behaviour,21, (1982), 150-164
20. Sutcliffe, A.G. & Faraday, P.M. Designing Presentation
in Multimedia Interfaces. In Proceedings CHZ’94
Human Factors & Computer systems. ACM, 1994, pp.
92-98
21, Yarbus A. Eye Movements& Vision. Plenum. 1967.
22. Van Dijk, T.A. & Kintsch, W. (1983) Strategies of
Discourse Comprehension. New York: Academic Press.
275
Top Related