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and presenting levels of the OET outperformed students who merely viewed a visualization. The relative
impact of the higher levels has been little studied within CER, however. For more information on the
evaluations covered by Urquiza-Fuentes and Velázquez-Iturbide’s survey, see their article and references
therein.
Lauer (2006) used the OET to compare the performance of three groups of students using the MA&DA
AV system for viewing, changing, andconstructing visualizations, respectively. He found no significant
differences between the groups’ performance, which he suggests may be due to the interfering effects of
other factors in the experimental setup.
Myller, Korhonen, and Laakso have compared the controlled viewing and changing levels in the EET in
the TRAKLA2 AV system. Myller et al. (2007b) found no significant difference between a group that used
the system in a controlled viewing mode and another group which engaged with the tool on the changing
level as well. The authors conclude, however, that “students without previous knowledge seem to gain
more from using visualizations on [a] higher engagement level”. Continuing the study, Laakso et al. (2009)
also found no statistically significant differences between a controlled viewing group and a changing group.
They report that this may be in part due to the fact that the students in the changing group did not use
the tool as intended. Korhonen et al. (2009b) found that when AV users who work in collaboration are
engaged on a higher level of the EET, they also communicate more and discuss the topic of the lesson
on more levels of abstraction than when engaged on a lower level. Myller et al. (2009) got similar results
with the Jeliot 3 PV system.
To summarize, it can be said that empirical work to date does tentatively support various claims
behind the engagement taxonomies, but a solid general validation of the taxonomies does not exist at
present. In Section 11.4, I will return to what is known about learner engagement in the specific context
of the PV tools for visualizing notional machines that are the focus of my review.
11.2.3 I prefer a new two-dimensional taxonomy for describing modes of interaction
In Section 11.3 below, one of the aspects that I describe for each of the tools that I review is its support
for different modes of learner engagement. I might have used the OET or EET for this purpose, but have
decided instead to use my own adaptation of them. I will briefly explain the reasons for this before I
outline the framework that I used.
Comments on the OET and EET
The constructing category in the OET seems crowded. Creating a visualization from scratch or from
primitive components is a cognitively demanding task, which requires a kind of reflection on the properties
of the visualization that is distinct in nature from what is required to manipulate a given visualization or
to add annotations (of given kinds) to source code. 5
The EET splits the activities originally placed in the changing and constructing categories variously into
entering input, changing, modifying, andconstructing. The reasoning behind the order of the categories
in the EET is not clear, and some specific choices seem questionable. For instance, is directly changing
a visualization necessarily less engaging than modifying the visualization’s input set? Does entering input
during viewing belong three levels lower than providing an input set before viewing (which counts as
modifying)?
The EET’s introduction of additional categories seems reasonable and potentially helpful. However,
the EET (especially) conflates two dimensions that might best be analyzed separately: how the learner
engages with the visualization itself, and the relationship that the learner has with the software being
visualized.
Finally, the responding category in both taxonomies is somewhat troublesome, as there are many
different kinds of questions that may be asked, some of which demand rather more cognitive effort than
others. This concern does apply to other levels as well, but responding is arguably the vaguest. (Cf. the
criticism of Bloom’s taxonomy at the beginning of Section 2.2.)
The following is my analytical attempt to improve on the taxonomies.
5 A similar criticism has been made by Lauer (2006).
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