metaphor and mental models

8/11/2019 Metaphor And Mental Models

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Last time

Conceptual models

To what is it similar? What metaphors do they

bring to bear?

What actions can one perform on or with a webpage?


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Last time

Conceptual models

What will the users be doing when carryingout their tasks?

How will they think about the task? What concepts and metaphors will they bring

with them to the system?

What interaction modes will be most useful?


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Conceptual models based on

activities

Giving instructions issuing commands using keyboard and function keys

and selecting options via menus

Conversing interacting with the system as if having a

conversation (e.g., AskJeeves)

Manipulating acting on objects and interacting with virtual objects

(e.g., pong, MS Word)

Browsing Looking through lists, poking around, etc.


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Conceptual models based on

objects

Usually based on an analogy withsomething in the physical world

Examples include books, tools, vehicles Classic: Star Interface

based on office

objects

Johnson et al (1989)


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Interface metaphors

Interface designed to be similar to a physical entity butalso has own properties

Can be based on activity, object or a combination of both

Exploit users familiar knowledge, helping them to

understand the unfamiliar


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W W W


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Another Internet metaphor

WWW as planet earth

The superhighway

An atlas Web sites are:

Towns Points of interest

Links are roads

There are vacation spots and places we go to work

Every site has an address

Sites like Yahoo! provide a yellow pages for locatinggoods and services

Search engines are somewhere between a yellow pagesand visitor center or information desk


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Benefits of interface metaphors

Makes learning new systems easier

Can expand the audience

Helps users understand the underlyingconceptual model


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Problems with interface metaphors

Break conventional and cultural rules

e.g. recycle bin placed on desktop

Can constrain designers in the way they conceptualize a

problem space Forces users to only understand the system in terms of

the metaphor

Designers can inadvertently use bad existing designs

and transfer the bad parts over Limits designers imagination in coming up with new

conceptual models


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However, for the most part, metaphor is an

extremely useful tool in constructing user

interfaces.


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Metaphor is fundamental to how we

think

- George Lakoff & Mark Johnson


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Argument is War

Your claims are indefensible

He attacked every weak point in my argument

Her criticisms were right on target

I demolished his argument.

Ive never won an argument with her.

You disagree? Okay, shoot!

If you use that strategy, shell wipe you out.

He shot down all of my arguments.


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More is up/good is up

Im feeling up. That boosted my spirits.

Get up. Wake up. She rises early.

Hes at the peak of health. I am on top of the situation. He is under

my power.

My income rose last year.


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Future is forward, past is back

In the weeks ahead of us

Thats all behind us


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The conduit metaphor (contd)

Its difficult to put my ideas into words.

Its hard to get that idea across to him

Youre reasons came through to us. His words carry little meaning.

Your words seem hollow.

The idea is buried in terribly denseparagraphs.


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If youre interested

Metaphors We Live By, George Lakoff and

Mark Johnson

Women, Fire, and Dangerous Things,

George Lakoff


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A conceptual modelis what we target as

designers

Metaphoris useful in building conceptual

models

A mental model is how an individual in

our audience actually perceives what we

have built.


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Mental models

Users develop an understanding of a system

through learning & using it

This type of understanding is often described as

a mental model

How to use the system (what to do next)

What to do with unfamiliar systems or unexpected

situations (how the system works)

People make inferences using mental models of

how to carry out tasks


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Mental models

Craik (1943) described mental models asinternal constructionsof some aspect of theexternal world enabling predictions to be

made Involves unconscious and conscious

processes, where imagesand metaphorsare activated

Deep versus shallowmodels (e.g. how todrive a car and how it works)


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Everyday reasoning & mental

models

(a)You arrive home on a cold winters night to

a cold house. How do you use the

thermostat to get the house to warm up as

quickly as possible?


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Everyday reasoning & mental

models

(b) You arrive home very hungry. You look in

the fridge and find all that is left is an

uncooked pizza. Do you set the oven to

bake at 375 degrees (as specified by the

instructions) or turn the oven up higher to

try to warm it up quicker?


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Heating up a room or oven that is

thermostat-controlled

Many people have erroneous mental models

(Kempton, 1996)

Why?

General valve theory, where more is more principle

is generalized to different settings (e.g. gas pedal,

tap, radio volume)

Thermostats based on model of on-off switch model


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Heating up a room or oven that is

thermostat-controlled

Same is often true for understanding how

interactive devices and computers work:

Poor, often incomplete, easily confusable, based on

inappropriate analogies and superstition (Norman,1983)

e.g. frozen cursor/screen - most people will bash all

manner of keys


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How does Google work?

Write down the steps you believe Google

follows in finding and ranking search

results for a query you submit.


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Now answer the following

questions

What will be the characteristics of the topresult for the query?

dog food

Does your mental model predict adifference in top results for the queries:

dog food organic

food dog organic organic dog food

organic dog food


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Exercise: ATMs

Write down the steps you believe an ATM(cash machine) goes through in order toenable you to get money.


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Exercise: ATMs

Answer the following:

How much money are you allowed to take out?

If you took this out and then went to another machineand tried the same what would happen?

What denominations are allowed?

What information is on the strip on your card? How isthis used?

What happens if you enter the wrong PIN?

Why are there pauses between the steps of a

transaction? What happens if you try to type duringthem? Can you type ahead?

Do you count the money? Why?


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How did you fare?

Your mental model How accurate?

How similar?

How shallow?

Payne (1991) did a similar study and found

that people frequently resort to analogies to

explain how they work

Peoples accounts greatly varied and were

often ad hoc

metaphor and mental models

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