A consistent spatial model reduces navigation confusion
Aliases: spatial model · navigational space · location expectation
What it is
Detail always to the right, filters always from the bottom, dialogs in place — once those three contracts are predictable, someone who took a wrong level can find the path by direction. A consistent spatial model cuts the search for “where is next,” not the prettiness of a single clip. The model is a stable map from kind to location: this class of surface lives on this side.
Why it happens
People build a coarse spatial map of a product: collections on the left, detail on the right, tools from below, interruptions from above. Motion is how the map is drawn; repetition turns it into expectation. When the bet is right, the next jump is prepared with the right posture and return can retreat along the map. When the bet is wrong, every jump is a fresh search. Confusion shows up as extra saccades, a wrong back gesture, and “how did I get here?”
A locally correct direction with an unstable kind-to-location map still fails to build the model. Filters from the bottom today and from the right tomorrow mean a kind has no fixed address. That is related to swapping axes mid-task, but sits one level up: even if each task is internally coherent, kinds without a product-wide address cannot transfer across tasks.
Studying it
Before the next transition is seen, ask people to draw where that kind of UI will appear, then actually run several kinds of navigation. Match between prediction and outcome is the index of whether a model was built. Also measure erroneous returns and time to reopen the same surface. Independent variable: stability of the kind-to-location map. Dependent variables: prediction accuracy, erroneous gestures, reopen time.
Where it stops holding
- A small tool with only one or two surface kinds does not need a full map; over-classifying invents fake coordinates.
- A kind the user has never visited has no address yet; the first appearance cannot violate a model that does not exist.
- When static layout already parks split panes in fixed places, motion only has to avoid fighting the panes; it need not invent a third axis.
Applying it
- List the product’s surface kinds, give each a default appearance location, and make motion obey that table.
- Fold a new kind into an existing address; do not open a new edge for one new component.
- Check: name a kind aloud and ask people to point at where it will come from. Scattered pointing means the map is not built.