3 experiments were carried out to assess a model for designing multimedia manuals that explain how machines work. Results show that animated and hypermedia instructions provide a significant advantage over static text and diagram presentations when both text and diagram are designed according to the model.
Machine comprehension from text and diagram involves the following processes
:
- machine decomposition by diagram parsing
- constructing a static mental model by making representaional connections (between
text document and text representation, and graphic doc and graphic representation)
- making referential connections between the digrams and text information
- determining the causal chain of events in the machine
- constructing a dynamic mental modelby mental simulation and rule-based inference
- Section 1 : facilitating decomposition and referential connections by proving
schema with labeled parts
- Section 2 : facilitating the decomposition into to functional units by an
exploded view that spatially separate the two units
- Section 3 : facilitating the construction of a static mental model of the
machine, by proving users with information on units in the real world, and its
linkages with other components
- Section 4 : encourage users to reason about the causal chain of events before
viweing the animation, since self-generated explanations improve learning (Chi,
deLeeuw, Chiu & LaVancher, 1994). Means : multiple choice questions with
appropriate feedback
- Section 5 : explanantion to help understand the propagation of causality,
with auditory comments and changing highlights on a static schema
- SEction 6: animation of the whole machine
- Section 7 : explanation of underlying physics principles
Comparison between hypermedia manual, full text (equivalent in text and diagrams
without hyperlink nor animation), and causal text condition (about 50% correct)
Results : No difference on any learning outcomes, not even for mental animation
or causal questions
3 conditions on paper : full text, causal text and diagram only
Results : people in the full text condition no more able to animate the system
that users in the causal text condition. No difference either with these two
conditions and diagram only, except for the bicycle tire pump, for which the
text was giving an unvisible information.
Expe 3 : replicates expe 2 with open ended questions instead of multiple choice
Same results
Explanation of why is animation not better than static instructions : when
the machine has several causal chains that merge, subjects repeatedly animate
components near the merging point. Animations that continuously run from strat
to end prevent people to do so.
Faraday & stuttclife (1997) : using eye movement recording, they found that
it was necessary to draw users'attention to part of the diagram by highlighting
components that were going to animate.
Animation should not been used when people could easily infer the information from static diagram and text. Similarly, text is useful only when the information can is not visible and can not be inferred from the diagram .