Understanding Gulf of Execution & Evaluation in Cognitive Engineering - Prof. Francois V. , Study notes of Computer Science

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Questions?

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Project

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HW#4 due today

Cognitive engineering

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Gulfs of execution and evaluation [Norman 86]

Gulf of evaluation: statistical analysis (2)

Real world:

Gulf

(^1) 0.5 0 0

0.^

1

X

Y

Evaluation

Conceptual model:

x,y correlated?

Gulf of evaluation: statistical analysis (3)

Real world:

Gulf

Evaluation

Conceptual model:

x,y correlated?

Gulf of execution: Drawing a rectangle (2)

Real worldDraw a rectangleRotate the shape

Conceptual model:Draw a rectangle

Execution

Gulf

Gulf of execution: Drawing a rectangle (3)

Conceptual model:Draw a rectangle

Execution

Gulf

Real world

Cognitive engineering example

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Move “paper.tex”

from

~/conferences/CHI_

to

~/conferences/UIST_

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Using a Unix shell (current directory is ~)

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Using a GUI (starting from the desktop, no window open)

Direct manipulation

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Central ideas–

Object understood by their visual characteristic

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Using good affordances

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Using a good conceptual model and convincing metaphors

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Actions understood in term of their effects on the screen

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Rapid and incremental

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Immediate visual feedback

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Easily reversible

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Outcome–

Direct engagement

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the feeling of working

directly

on the task

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No need to know the implementation details

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The display becomes reality: the WYSIWYG interface

Interface metaphors

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Definition–

Use of one kind of object or idea in place of another to suggest a likenessor analogy between them

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Purposed–

Leverages our knowledge of familiar, concrete objects/experiences

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Transfer this knowledge to abstract computer and task concepts

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Examples–

Desktop, files, folders, trash can…

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Paintbrush in a painting program

Metaphors caveats

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Too limited–

The metaphor restricts interface possibility

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Too powerful–

The metaphor makes believe that the system can do things it can’t

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Too literal or cute–

Make it difficult to operate

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Mismatched–

The metaphor makes it difficult to carry out the task