8. EXPERIMENT 2
8.4 Results
8.4.2 Mean section time
the effect of experimental conditions on the learning time should be better uncovered by the time that subjects spent in learning each single instructional section (section time).
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general guard elephant chariot horse cannon soldier
Instructional section
Mean section time (seconds)
simp-visu simp-audi med-visu med-audi comp-visu comp-audi ani-visu ani-audi
Figure 10: Mean section time as a function of experimental condition, by instructional sections
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general guard elephant chariot horse cannon soldier
Instructional section
Mean section time (seconds)
Figure 11: Mean section time as a function of instructional section
There were significant differences in the learning time between the instructional sections (F(6; 673) = 10.689; p < 0.001). According to the Bonferroni tests, the mean section time of the Section ‘soldier’ was significantly longer than that of the other sections, whereas the mean section times of the Sections ‘guard’ and
‘chariot’ were significantly shorter than those in relation to the Sections ‘horse’,
‘cannon’, and ‘soldier’. The cause of the differences in the mean section time could be the number of propositions, which will be analyzed subsequently.
In addition to picture complexity and text mode, other factors such as the number of propositions in the texts and the number of objects in the pictures may also influence the section time. Since the number of objects comprises the number of visual distractors as well as the number of relevant objects, and each of them might have a different influence, it is better to examine the effect of the two different object types separately. I, therefore, first give an overview of how the quantity of those factors was distributed in the instructional sections. Tables 1 to 4 depict the number of propositions, objects, visual distractors and relevant objects in each of the corresponding sections.
Chinese-chess pieces general guard elephant chariot horse cannon soldier Number of
propositions 11 9 11 9 14 11 13
Table 1: The number of propositions in the corresponding instructional section
Conditions
(simp-visu/-audi) (med-visu/-audi) (comp-visu/-audi) (ani-visu/-audi)
Chinese-chess pieces
number of objects
number of objects
number of objects
number of objects
general 2 10 15 11
guard 2 10 15 11
elephant 4 10 16 12
chariot 2 10 15 11
horse 5 15 20 12
cannon 4 11 16 13
soldier 3 15 16 9
Table 2: The number of objects in the respective instructional section
Conditions
(simp-visu/-audi) (med-visu/-audi) (comp-visu/-audi) (ani-visu/-audi)
general 0 5 10 10
guard 0 5 10 10
elephant 0 5 10 10
chariot 0 5 10 10
horse 0 5 10 10
cannon 0 5 10 10
soldier 0 5 8 8
Table 3: The number of visual distractors in the relational instructional section
Conditions
(simp-visu/-audi) (med-visu/-audi) (comp-visu/-audi) (ani-visu/-audi)
Chinese-chess pieces
number of relevant objects
number of relevant objects
number of relevant objects
number of relevant objects
general 2 5 5 1
guard 2 5 5 1
elephant 4 6 6 2
chariot 2 5 5 1
horse 5 10 10 2
cannon 4 6 6 3
soldier 3 10 8 1
Table 4: The number of relevant objects in the respective instructional section Again, I adopted the same definitions of propositions developed by Kintsch (1974) as the criteria to count the number of propositions. Word categories regarded as predicates are verbs, adverbs, adjectives, conjunctions, prepositions, and quantifiers. The number of objects includes figures that refer to the positions of the relevant and the non-relevant (visual distractors) chess pieces on the chess board.
The relevant objects are the objects that carry relevant meaning for elucidating the movement rules. On the contrary, the visual distractors represent some other chess
pieces which are irrelevant to the movement rules. In the diagrams that are of
‘simple’ and ‘medium’ complexity, for instance, the figures regarded as objects consist of blue and gray dots as well as black circles. The blue arrows and the red crosses are included in the number of objects.
8.4.2.1 The effect of the number of propositions
The data are given in Figure 12. According to the ANOVA, the effect of the number of propositions on the mean section time was significant (F(3; 676) = 20.465; p <
0.001). The results indicated that the mean section time was positively related to the number of propositions.
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9 11 13 14
Number of propositions
Mean section time (seconds)
Figure 12: Mean section time as a function of the number of propositions On the other hand, the effect of the number of objects, the number of visual distractors, and the number of relevant objects on the mean section time was also examined. It should be mentioned that I used ‘quantity’ instead of the absolute number of visual distractors as well as of relevant objects because the amount of them was varied regularly between the levels of picture complexity. Accordingly, the absolute number in this case is not important but it is only the variation in the amount that is of interest. For the sake of convenience, I distinguished three levels of the quantity of visual distractors and the quantity of relevant objects. For the quantity of visual distractors, the three levels were ‘no’ (0), ‘medium’ (5), and ‘high’ (10). As to the quantity of the relevant objects, the ‘low’ quantity corresponded to 1 to 3 objects, ‘medium’ contained 4 to 5, while ‘high’ consisted of 6 to 10 objects.
Moreover, it should be noted that the picture mode (static vs. animated) will influence the effects of the number of objects, the quantity of visual distractors as well as the quantity of relevant objects. The number of objects in animation, for
example, affects section time in a different way than it does when static pictures are used. Since subjects’ visual attention is attracted or guided by the motion, the effect of the number of objects or the visual distractors, respectively, on the mean section time is probably much weaker than that in static pictures. Thus, to avoid contamination of the data analysis, it is better to distinguish the effect of static-picture conditions from that of the animation conditions. In this experiment, I have mainly evaluated the effects of these factors in relation to the static-picture conditions. This principle is also employed with regard to the ongoing evaluations of the effects concerning those factors. In addition, if there is an interaction between the effects of text mode and picture complexity, there is also probably an interaction between text mode and the number of objects to be expected, because picture complexity is partly defined by the number of objects. This should also be taken into account when analyzing the effects of the number of objects, the quantity of visual distractors, and the quantity of relevant objects.
8.4.2.2 The effect of the number of objects
Figure 13 depicts the mean section time as a function of the number of objects. The results showed that the effect of the number of objects on the mean section time for static-picture conditions was significant (F(8; 516) = 5.852; p < 0.001): the mean section time was positively related to the number of objects. Due to the large variance between the values, the relationship between the mean section time and the number of objects was not linear. According to the Bonferroni tests, significant differences were found to exist between the 2/3, 2/16, 3/4, 3/10, 3/11, 3/15, 10/16 objects. In order to roughly estimate the general effect of the number of objects on the mean section time, the number of objects was divided into two conditions at the median (=10). A t-test (t(523) = -1.747, p = 0.081) showed that the mean section time of the sections with few objects (< = 10) (mean = 15.508 sec) tended to be shorter than that of the sections with many objects (> 10) (mean = 17.124 sec).
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2 3 4 5 10 11 15 16 20
Number of objects
Mean section time (seconds)
Figure 13: Mean section time as a function of the number of objects in the static-picture conditions
The quantity of the visual distractors had no effect on mean section time, whereas the effect of the quantity of relevant objects was significant (F(2; 522) = 3.697; p < 0.5). The data relating to the quantity of the relevant objects are shown in Figure 14. When the text mode was considered, the effect of the quantity of relevant objects was only significant when auditory text (F(2; 260) = 9.142; p < 0.001) was presented. The Bonferroni tests pointed out that the difference between ‘medium’
and ‘high’ was significant.
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low medium high
Quantity of relevant objects
Mean section time (seconds)
Figure 14: Mean section time as a function of the quantity of
relevant objects, when text was presented auditorily
8.4.2.3 The effect of the number of visits to the same section
The factor ‘the number of visits to the same section’ was also investigated in connection with the mean section time. Figure 15 depicts the mean section time as a function of the number of visits to the same section. It stands to reason that mean section time was inversely related to the number of visits to the same section.
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1 2 3 4 5 6 7 8 9
Number of visit to the same section
Mean section time (seconds)
Figure 15: Mean section time as a function of the number of visits to the same section