2000 Franz Kurfess Cognitive Models 1 Normans Cognitive

© 2000 Franz Kurfess Cognitive Models 1

Norman’s Cognitive Model © 2000 Franz Kurfess [Seffah] Cognitive Models 2

Cognitive Design Principles Bridging the Gulf of Evaluation feedback about the system status utilize knowledge the user has already provide explanations, mental model Bridging the Gulf of Execution exploit affordances and automatic cognitive processes don’t astonish the users! use icons and widgets, but keep them consistent and make them easy to use © 2000 Franz Kurfess Cognitive Models 3

Aspects of Design Principles Affordances Causality Visible Constraints Mapping Transfer Effects Population Stereotypes Conceptual Models © 2000 Franz Kurfess Cognitive Models 4

Mapping: Stove Controls Arbitrary - 24 possibilities - Requires visible labels and memory (e. g. back/right, front/left, back/left, front/right © 2000 Franz Kurfess Paired - 2 possibilities per side = 4 possibilities - Requires label (e. g. back, front) [Seffah] Full Mapping - 4 possibilities - Requires no visible labels and memory Cognitive Models 5

Mapping and Causality good example: Netscape preferences not so good: Clip Art Gallery © 2000 Franz Kurfess [Seffah] Cognitive Models 6

Transfer Effects © 2000 Franz Kurfess [Seffah] Cognitive Models 7

Good Conceptual Model affordances holes for fingers constraints big hole: several fingers small hole: thumb transfer learned when young applies to all kinds of scissors © 2000 Franz Kurfess [Seffah] Cognitive Models 8

Bad Conceptual Model affordances four buttons, functions unclear constraints and mappings unclear, no visible relations between objects and effects transfer must be learned explicitly different for different models conceptual model is not intuitive © 2000 Franz Kurfess [Seffah] Cognitive Models 9