Information Technology Reference
In-Depth Information
Table 12.1 The Cognitive Dimensions
1. Hidden dependencies: how visible the relationships between components are
2. Viscosity: how easy it is to change objects in the interface
3. Role-expressiveness: how clear the mapping of the objects are to their functions
4. Premature commitment: how soon the user has to decide something
5. Hard mental operations: how hard are the mental operations to use the interface
6. Secondary notation: the ability to add extra semantics
7. Abstraction: how abstract the operations and system are
8. Error-proneness susceptibility: how easy it is to err
9. Consistency: how uniform the system is (in various ways, including action mapping)
10. Visibility: whether required information is accessible without work by the user
11. Progressive evaluation: whether you can stop in the middle of creating some notation and
check what you have done so far
12. Provisionality: whether you can sketch out ideas without being too exact
13. Diffuseness: how verbose the language is
14. Closeness of mapping: how close the representation in the interface (also called notation) is to
the end results being described
Fig. 12.1 The Word Style editor (left) shows the parent of the ref style, but cannot show the
children of the Normal style. The spreadsheet (right) shows what cells the formula is dependent
on (and can show those that appear as the line on the graph), but does not show where a given cell
is used
The implications of considering hidden dependencies are that all dependencies
that may be relevant to the user's tasks should be represented. Or, as a minimum,
tools should be provided which enable them to be represented. This is consistent
with the notion we saw earlier in the topic of recognition being easier than recall.
For example, spreadsheets would be easier to use (for certain tasks anyway) if they
could show forward relationships (e.g., this cell's value is used in all these other
places). Recognizing this fact (the need for visibility) is quite separate from
designing a solution to the problem—one option would be to use color coding
(e.g., child cells could be shown in the same color; ancestor cells could be shown
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