Descriptive v.s. Predictive Theories
–Descriptive: Object/Action Interface Model
–Predictive: GOMS (Goals, Operators, Methods & Selection rules)
and keystroke-level model to predict execution time or error rates
Object-Action Interface Model
–Understand Task in terms of objects & actions
–Metaphoric Representations of interface objects & actions
–Visible Representation of
interface actions
–Task and Interface
Hierarchies
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Observation: Menu Interface reflects Task Analysis
Disappearance
of Syntax
–Syntactic knowledge is system and application dependent
Shift to Direct-Manipulation Systems