Should the Elements of Diagrams Be Rendered in 3D?

To some extent the utility of a diagram depends on how effectively the information can be perceived. We have applied the structural object recognition theory of Biederman to the problem of constructing node-link diagrams. According to geon theory, as objects are perceived they are decomposed into 3D primitives called geons, together with the skeleton structure connecting them. This work evaluates diagrams using geon-like primitives. Results of two experiments are reported. These show that diagrams constructed of 3D components can be visually analyzed more rapidly, with fewer errors, and can be remembered better in comparison with equivalent 2D silhouette diagrams.