1) The study examined whether comprehension of a multimedia presentation with text and pictures could be improved by increasing the cohesion and coherence of the text. 2) Participants read an original or revised version of a text on lightning formation and were tested on their recall. The revised text made implicit information explicit and required no bridging inferences. 3) Recall of causal connections was significantly better for those who read the revised text, supporting the hypothesis that a more cohesive text improves comprehension. No differences were found using a scoring system for isolated propositions.

1. Text coherence and
multimedia
comprehension
Lucia Lumbelli, Gisella Paoletti,
Maurizio Boscarol

2. Research question
Can the comprehension of a
multimedia with static pictures and
written text be improved by only
increasing the cohesion and
coherence of the text component?

3. Premises (1): Text cohesion and
comprehension
• Studies about text comprehension highlighted the
importance of the quality of a text which is called
cohesion or cohesiveness (Ozuru et al.2009).
• It refers to the extent to which ideas conveyed in a
text are made explicit.
• It is considered as an objective text feature which
determines the coherence as a subjective state of
readers, as a feature of a text representation.
• Text cohesiveness and the corresponding
coherence of text representation have been shown
to significantly affect the comprehension process
outcomes (Mc Namara et al.1996;Graesser, Mc
Namara, Louwerse & Cai 2004; O’Reilly & Mc
Namara, 2007; Ozuru et al. 2009).

4. Premises (2): Coherence in
multimedia learning
• The definition of the coherence of internal
representation as a consequence of text
cohesiveness seems to complete the definition
of coherence chiefly adopted in the research on
multimedia learning.
• A coherent document only presents the
information items necessary to build the causal
chains to be learned: every detail which is not
related to these chains has to be eliminated if
learning has to be facilitated (Mayer 2001,
2005). Relationship between ideas or concepts
is considered rather than between sentences.

5. Premises (2): Multimedia
coherence and length
• Comparisons between coherent versus
incoherent multimedia are thus
comparisons between shorter versus
longer documents.
• The outcome is that more coherent and
shorter multimedia give rise to better
learning than less coherent and longer
ones (Mayer, Heiser & Lonn, 2001;
Moreno & Mayer, 2001; Mayer& Moreno,
2002; Harp & Mayer, 1997, 1998).

6. Premises (3)
Two main features of text cohesiveness are
assumed to contribute to an accurate definition of
coherence as a subjective state or as an attribute
of internal representation:
• all information items necessary to reconstruct the
causal connections are made explicit; no inference
from prior knowledge is required,
• connectives like conjunctions and anaphors which
have the function of connecting two adjacent
sentences are integrated with information; this
frees readers from the need to draw bridging
inference.

7. Hypothesis
• If learning as establishing connections between
ideas can be assumed also as the outcome of
text comprehension,
• and if text cohesion is assumed to improve text
comprehension by helping readers construct
coherent internal representation,
• then by manipulating the text component of a
multimedia so as to make it as much cohesive as
possible by making all information necessary to
understand explicit,
• we will give rise to an easier and better
comprehension of the text and consequently of
the whole multimedia.

8. Text revision as germane load
• Our revision might increase the ‘germane
cognitive load’ related to the
comprehension process, so adjusting to
text comprehension a concept which has
been defined as regards the learning
process:
• explicitation of information which readers
have to necessarily infer is an addition
which should facilitate text comprehension
although it makes the text longer.

9. The experiment
• Thirty-four participants read on a computer screen
a multimedia presentation on lightening formation
already used in many investigations (Mayer,
2001).
•
Two text versions were compared:
- the original version with information items only
partially explicit and some connectives requiring
integration;
- the revised version with all information
items explicitly stated and no integration required.

10. Participants
Two groups of 17 participants matched on a standardised
reading comprehension test scores
• Mean age= 24
• Females 30, Males 12.
• Low specific prior knowledge no ‘expertise reversal effect’
expected
• Good reading comprehension ( MT scoring : Mean=
16.47619; St. Dev.= 2.987224, range= 0-20) no negative
effect of the greater length of text expected

11. Material for the experiment
The experimental material
has been already used in
many published
experiments (Mayer,
2001, 2005).
It included 14 static Warmed moist air near
pictures depicting the the earth’s surface rises
rapidly.
main steps of the process
of lightening formation,
each integrated with a
brief written description.

12. Characteristics of manipulations
We only added information which was
implicit in the original text and/or which
had to be necessarily inferred from it in
order to form a coherent representation.
• No redundancy in the sense of repeated
words and sentences
• No unnecessary details
• No learning measures (Effects are
expected on the online comprehension
process rather than on learning).

13. First type of addition: improvement
of cohesion
By facilitating the connection between two adjacent sentences
either by making the use of a connective (e.g. anaphora)
easier, more effortless, or by making explicit an information
item which in the original text should be inferred in order to
link the new sentence with the previous one.
In this case the text manipulation has effects on the readers’
representation of text-base, while accepting the definition of
text-base according to which it includes the information item
which should be necessarily inferred from the explicit one.

14. An example of the first type of
addition
Warmed moist Warmed moist
air near the air near the
earth’s earth’s surface
surface rises rises rapidly
rapidly. so forming an
updraft.
....
As this updraft
As this updraft
cools...
cools...

15. Comment on the example
In the original version we find an anaphora (‘in
this updraft’) which has to be connected to
the phrase ‘rises rapidly’ by means of the
following bridging inference:
since the air rises rapidly an updraft is formed
The completed text of the revised version:
Warmed moist air near the earth’s surface rises
rapidly so forming an updraft

16. Second type: improvement of coherence
By explicitly stating a causal sequence which otherwise
readers should infer from their prior knowledge in order
to obtain a coherent representation of the text.
In this case the text manipulations should directly affect
the readers’ representation of situation model.

17. An example of the second type of
addition
Warmed moist
Warmed moist air near the
air near the earth’s surface
earth’s rises rapidly so
surface rises forming an
rapidly. updraft.
This updraft is
formed because
the warmer air is
As the air in this lighter and
updraft therefore tends
cools... to rise.
As the air in this
updraft cools.....

18. Comment on the example
This integration should help readers use
their prior knownledge to build the
relationship between:
becoming warmer and becoming higher
which explains why the updraft builds

19. Procedure
• Participants were asked to pay a special attention to the
chain of cause-and-effects described in the presentation.
• After reading the multimedia presentation, the
participants were asked to write what they remember
about the process described there with a new instruction
in which the invitation to pay attention to the link between
the events described was repeated.
• Recall was coded through two systems of analysis:
– the one described by Mayer (2001) with 8 isolated propositions,
– the second one produced ad hoc for the experiment.

20. The scoring system
Since comprehending a text means establishing
and maintaining coherence between sentences
(Oakhill, Cain & Bryant, 2003; van den Broek
1994), the scoring has to reflect the extent to
which the consequential connections which are
always explicit in the revised text and only
partially explicit in the original one have been
comprehended/written by participants.

21. An example of the scoring system
The example corresponds to the initial one of Mayer’s scoring items (‘air
rises’):
The consequential connections into which the updraft formation (first
moment of the lightening formation) is articulated:
1. Cool air becomes warmer when it draws Near to the ground warmer
near to the ground
Warmer lighter
2. since the air becomes warmer, it becomes
lighter Lighter tends to rise
3. the air tends to rise because it is lighter
4. since the air rises, it brings about an Air rises updraft
updraft.
The participants’ protocols about this initial event of the process described in
the multimedia were scored from zero to 4 (score 1 to each correct answer,
score 0 to each incorrect one).

22. Examples of scoring written
protocols
• N.1. When cool and moist air meets warm
ground, it tends to become warmer(1) and
therefore becomes lighter(2) and tends to rise(3)
forming an updraft(4).
score: 4
• N.2. Cool and moist air becomes warmer by
nearing to a warm surface(1).It tends to rise and
so becomes cooler(updraft).
score: 1

23. Instructions
Instruction 1
You will be presented with a text which describes the lightning
formation. The text is accompanied by pictures about the
same subject. You should carefully read the text and look at
the pictures so as to understand how and why the successive
events there described occur (take place, happen)
Instruction 2
Now you should write down what you can find into your mind
about the text you read and the pictures you looked at. You
should explain as exhaustively as possible all stages of
lightning formation.

24. Results
• The recall performance was analyzed in a one-
way ANOVA with text-version as between subject
factor.
• A significant main effect of text revision on
comprehension of consequential connections
(F=1,32= 4,8346, p<0.05) was found in a direction
consistent with our expectation, with a significant
improvement of the performance for the
participants who examined the revised version of
the text (mean score=6,6; d.s.=2,45) vs. those
who had the original version (mean score=4,6;
d.s.=2,69).

25. Comparison between original vs
revised text comprehension

26. Results (2)
• No effect of the revision on the recall
analysed by means of Mayer’s list of
isolated propositions (Fig. 4) was found:
the increase in the amount of items of
information, which might be expected to
be a source of extrinsic cognitive load,
was counterbalanced by the enhancement
of text coherence.

27. Comparison according to Mayer’s
scoring system