Anais do IHC'2001 - Departamento de Informática e Estatística - UFSC

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Anais do IHC’2001 - IV Workshop sobre Fatores Humanos em Sistemas Computacionais
Figure 3: A snapshot of the RDCM HCI style in ST
The main findings of empirical studies carried out using ST indicated that a shift from
object manipulation to concept manipulation had a positive effect on the learning of
geometrical concepts by 6 th -grade children from 2 classes of an upper middle-class school
in Canada (for details see previous publications by Sedig [Sedig, 1998; Sedig et al., 2001]).
In particular, the DCM version was more effective than the DOM one and the RDCM
version was most effective in promoting domain learning. Children interacting with the
DOM version of ST were sometimes confused with translation, for instance, missing the
point that this operation is achieved along a linear vector path and not along an arbitrary
curvilinear one (which is typically observed in drag-drop interactions available in DOM).
Differences in understanding between children from these two groups were also observed
with respect to the concepts of rotation and reflection.
The relatively superior efficacy of the RDCM style for learning was attributed to the
progressive fading of visual clues that served as scaffolding for the children’s reasoning. In
the absence of such clues, they had to make more inferences about the causal relations
between on-screen manipulations and the desired final state of the operation. These
relations should have been acquired in previous stages of the game, when the visual
scaffolding was available.
These findings led to the conclusion that further investigations about the use of direct
manipulation for learnware were necessary. Discarding DM as an inappropriate style
altogether would have prevented these children from the experience of having access to the
causal relations between variations on vector coordinates, angles and arcs, and certain
patterns of spatial configurations of polygons in 2D space. A well designed mechanism for
leading learners from visual to algebraic representations of abstract concepts thus seemed
to have the potential to become a new metaphor for DM interfaces for learnware [Sedig et
al., 2001]. However, some open issues could be immediately raised.
1. “what visual representations to use to facilitate development of proper conceptual
models;
2. what elements of the representation of a concept should be allowed to be
manipulated—i.e., what controls (or handles) to manipulate, how to embed these
controls in the visual structure, and in what order, if necessary, they should be
manipulated; and,