area is not formed correctly, then the playground element will not appear and
the participant will be prompted to reconsider her actions. In addition to these
methods of control over the environment, the system provides intrinsic
feedback concerning placement of the blocks onto the playground tiles. For
example, the system will not allow the participant to place a block next to the
fence, near the benches, on the yellow-brick footpath or next to a block of a
different colour. Visual and audio cues enhance these restrictions.
Figure 4. A view of the Virtual Playground, in which children re-design the layout of the
playground based on rules provided by expressive virtual characters. The owl is the main
character that greets each participant and provides the general rules before the participant
starts the design game. Coloured birds speak out the rule for each area that needs to be
changed.
It is important to note here that the Virtual Playground is not designed as an
instructional environment following specific pedagogical models for teaching
fractions, but as a tool for the evaluation of our research question concerning
interactivity and learning. Hence, the characters (owl and birds) are neither
avatars nor autonomous agents that respond intelligently to the participant’s
actions and questions. They are merely “rule providers”, meaning that they
simply state the rules of the tasks that must be performed (in place of a
written instruction sheet, for example).
5. Evaluation
Empirical work was carried out with a total of 57 primary school students
between the ages of 8 and 12, in different between-group experiments: an
exploratory study, a pilot study, and a large-scale experiment. The exploratory
study, as already described, aimed at defining the evaluation methodology
and framework for analysis. The pilot study, which was carried out a few
months prior to the main experiment, aimed at improving the usability of the
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