When a child uses a Boolean query in a category browser with different hierarchical
branches, the child has to focus on a specific topic and navigate top-level categories
sequentially; this process is perhaps too abstract for a child to operate (Hutchinson
et al., 2007). Koshman (2006) analyzes the placement of the icons that are associated
with document representation in a visualized information system through the lens of
the Gestalt theoretical constructs of pattern perception, which are involved in
interpreting a graphical display. A good information interface structure gives users a
clear understanding of what they perceive, although there is no perfect structure for all
users. As the structures of virtual environments have become increasingly complex,
there has been considerable interest in the question of “depth cues” and whether a
3D visualization will reveal more useful information to the searcher than a
2D visualization (Westerman and Cribbin, 2000).