cognitive elements of menu selection 조 성 식조 성 식. 1/20 contents menu selection process...

Cognitive Elements of Menu Selection

조 성 식

2/20Contents

Menu Selection Process

Problem Solving & Search Strategies

Cognitive Layouts of Mental Models

Summary

- Information Acquisition and Search- Choice Process and Time

- Response Process

- Evaluation and Error Detection

- Heuristics- User Strategies and Styles

- Menu Selection as a Metaphor

- Schemata and Scripts

- Cognitive Layouts of Menus

3/20Menu Selection Process

Information Acquisition and Search

Choice Process and Time

Evaluation and Error Detection

Response Process

-Information Processing Models

-Models of Visual Search

-Stopping Rules

-Searching Time

-The Number of Alternatives

-The Difficulty of the Choice

-Luce’s Choice Axiom

4/20Information Acquisition and Search (1/5)

Information Processing Models

- The way in which a user scans a menu frame for information depends on the task and the user's prior knowledge about the frame.

- Explicitly known target

* The user engages in a visual matching process.

* Menus which use visually and semantically distinct alternatives

will result in faster response times and fewer error.

- Partially specified target

* The user engages an encoding and evaluation process.

* subjective likelihood & subjective utility

* optimizing rule & satisficing rule


5/20

Information Processing Models


Information Acquisition and Search (2/5)

6/20

Models of Visual Search



Stopping Rules

- Self-terminating Search

- Exhaustive Search

- Redundant Search

7/20

Searching Time

- S = E(A)t + k + c where E(A) is an expected number of alternatives that will be inspected t is the time required to read one alternative k is the key-press time c is the computer response time

- P(k) = 1 - (1 - p)k

where p is the probability of finding the target on a single saccade k is the number of saccades required to find the target



- S = t / p where t is the time to be taken by a saccade

- S = n t where p = 1/n , n is the number of alternatives

8/20

Searching Time



unpracticed

Highly practiced

9/20Choice Process and Time


S = a + b log2(n)S = a - b log2(pi)

The number of Alternatives : Hick-Hyman Law

Axiom 1 : p(a1| a1, a2)/p(a2| a1, a2) = p(a1| a1, a2, ..., an)/p(a2| a1, a2, ..., an)

The Difficulty of the Choice

Luce’s Choice Axiom

Axiom 2 : pij =0 then ai may be neglegible

1

n

i i jj

p v v

10/20Response Process

Enter a code


Pointing to the Alternative

- Analogue pointing devices : Fitts’Law, R = a log2(d/w) + b

- Discrete pointing using arrow keys : R = a (dx + dy) + b

11/20Evaluation and Error Detection

The feedback may be receipt of some information, the location of a target item, the execution of a function, or the presentation of subsequent menu frame.

Consequently, feedback engages another decision making processin hierarchical menu search. How this affects the search strategy will be discussed in the next section.


12/20Problem Solving & Search Strategies

Heuristics

- Generate-Test

- Hill Climbing

- Test-Operate-Test-Exit

- Means-Ends Analysis

User Strategies and Styles

- Pathiness

- Ringiness

- Loopiness

- Spikiness

- NV/NT

- NV/NS

- Scanning

- Browsing- Searching

- Exploring

- Wandering

- Shallow and broad- Narrow and deep- Progressive deepening

13/20Heuristics (1/2)

Generate-Test

Hill Climbing

- Generate a candidate -> Test to see if it is actually a solution.


- 4 difficulties * difficult to generate candidates * hard to test see if it is actually a solution * a large number of candidates -> unlikely to work * the correct solution has a low probability of being selected - Problem reduction approach

14/20Heuristics (2/2)

Test-Operate-Test-Exit

Means-Ends Analysis

Goal –> subgoal –> sub-subgoal


Ex) Viewing file A –> find file A –> run directory program

15/20User Strategies and Styles (1/2)

Shallow and broad


Progressive deepening

Narrow and deep

- likely to survey a wide number of possible solutions but explore them only superficially.- appropriate for placing pieces in a jigsaw puzzle.

- likely to limit his or her search to only a few alternatives and explore them in depth. - appropriate for solving the Tower of Hanoi puzzle or playing chess.

- a mixture of upper two strategies - particularly useful when there are a fair number of possible solutions and it is not clear.

16/20User Strategies and Styles (2/2)

- Pathiness

- Ringiness

- Loopiness

- Spikiness

- NV/NT

- NV/NS

- Scanning

- Browsing

- Searching

- Exploring

- Wandering

Canter, Rivers, Storrs (1985)


17/20Cognitive Layouts of Mental Models

Menu Selection as a Metaphor

Schemata and Scripts

Cognitive Layouts of Menus

18/20Menu Selection as a Metaphor

Example : Restaurant menus Computer menus


Metaphor

a literary device is to transfer the reader's concrete knowledge about a familiar thing to an unfamiliar subject being written about.

- Norman and Chin (1989) provide a comparison between restaurant menus and computer menus.- The restaurant menu generates a powerful metaphor for human/computer interaction.

19/20Schemata and Scripts

Schema

- A diagrammatic outline of something that conveys its essential characteristics.


Script (called an event schema)

- An expected or stereotypical sequence of actions and events.

- Most information fits somewhere in between perfect conformity and total chaos.

20/20Cognitive Layouts of Menus

Road Map Tree

Smorgasbord


21/20Summary

The user must search for information, encode the meaning of alternatives, assess the alternatives, make a choice and effect a response.

Good menu design takes into consideration such human factors to increase speed and reduce errors.

Good user interface design should convey a sense of meaning and engage schemata that lend themselves to solutions of the tasks being performed.

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