a developer: design of everyday things

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Design of everyday things - fundamental principles of interaction - Presentation

Got a chance to introduce my favorite book to team

DesignOfEverydayThings - What I learned as a developer

In this series of notes: https://twitter.com/ajavadeveloper/status/1145615948277112833

I only notes part of "Fundamental Principles of Interaction"

It's just a small unit of this book, but already help me A LOT.

Whenever I'm confused of designing, I re-read this book to get more ideas.

Because I'm a developer, so the most important thing it taught me is:

Why we need write clean code, how a clean code look like? How to know a design is good or bad.

Affordance and Signifier: That's why we need good naming.

Ex. visible signifier

StringUtils.trimToEmpty

StringUtils.substringBetween

Ex. Invisible

String dateString = PrivateDateUtils.toDateString( date ); // What is the format?

@SuperAnnotation // Things become invisible when there are many decision made at runtime, developer won't know.

public class NormalClass {}

Mapping and Conceptual Models: Developers always handling mapping and conceptual models

PersonDao.persist( person ); // Clear model, dev expect it will persist

Person.save(); // May be a little confuse

personService.find( id ); // When a find method persist data due to other reason such as queue full or statistics, it become confusing

Feedback: We need many feedback, no matter in code or in performance tunning or monitoring

personService.find( id ); // It's better to response quickly

personService.find( id, timeout, TimeUnit ); // It's better to provide timeout when things may become long

public void find(String id) {

    try {

        personDao.someErrorMayHappen(); 

    } catch (Exception ex) {
        // Eveything is find, treat as no data

    }

}

When there are too many error, we even unable to know the feedback is valid or not

DesignOfEverydayThings - Conceptual Models

A conceptual model is an explanation, usually highly simplified, of how something works.
Ex. There are folders in screen, but it doesn't means there is really a folder in disk
Ex. User browse data in PC and think it's a data in PC, but data is in cloud actually.
Ex. User browse a page and think there is a real page, but it's runtime generated
A product has many kinds of conceptual models

Ex. User's conceptual model
Ex. Advanced driver's conceptual model
Ex. Engineer's conceptual model
Ex. Designer's conceptual model

Conceptual models are often inferred from the device itself. Some models are passed on from person to person. Some come from manuals.
Some conceptual models come from experience, so wrong conceptual models let devices hard to use
How things work come from user perceived structure

Signifier
Affordance
Mappings

Ex. Scissors

The number of actions are limited
Holes for putting something into
Only fit for finger(s)
Only accept possible fingers
Only one thing can do after putting fingers
Actions are visible

Anti-Ex. Digital Watch

Many buttons, unable to know conceptual models
Not visible, need read manual
Sometimes click longer time, sometimes need press more than one button at the same time

Conceptual models provide a way to predicate what things will going to behave and what will not happen
A bad conceptual model let user can only try to remember what will happen in every actions
Anti-Ex. Freezer control. It shows deepfreeze and fresh food are separated when it's not.

It may provided wrong conceptual model when freezer may affect refrigerator

DesignOfEverydayThings - Feedback

Anti-ex. or repeatedly push the pedestrian button at a street crossing? => Because user doesn't know whether system got his request or not.
Feedback—communicating the results of an action—is a well-known concept from the science of control and information theory.
You can't hit a ball without seeing the target
You can't pick up a glass with hand without the feedback.
Feedback must be immediate: even a delay of a tenth of a second can be disconcerting. If the delay is too long, people often give up, going off to do other activities.
It wastes resource to do one thing that user doesn't wait for it anymore.
Too much feedback become annoying.
Ex. When performance tuning, we need major number to alarm. It will be useless if we alarm everything
Backseat driver: too much feedback to driver. May distract people or just turn it off
Use one simple signal producer to reduce cost, let people not easy to remember (Beep code)
Beep code definition may be different in different machines. We'll be confused when those machines beep together.
Feedback has to be planned and prioritized.
Feedback is essential, but it has to be done correctly. Appropriately.

DesignOfEverydayThings - Mapping

Mapping is the relationship between the elements of two sets of things
Ex. Switch mapping Lights in office
Mapping the layout of controls and displays
Ex. Steeling a car, rotate the steering wheel clockwise to cause the car to turn right.
Ex. Tank is different,its designed to control wheel speed because it uses track
It doesn't matter whether these conceptual models are accurate: what matters is that they provide a clear way of remembering and understanding the mappings.
Natural mapping leads to immediate understanding.
Ex. to move an object up, move the control up.
Ex. Make light control mapping same as lights in room
Ex. Automobile Seat Adjustment control
Note the "natural" is specific to a particular culture.

DesignOfEverydayThings - Signifier

Need separate to 7 posts, because image become huge base64 in Blogger, unable to upload.... Orz

DesignOfEverydayThings - Signifier - 7

When facing a device, we seeking for clue about how to use. Designer need provide it.

Otherwise, we need use our own creativity and imagination.
Misleading signifier: a row of vertical pipes across a service road in a public park

Pipes blocks cars
Park vehicle go through the pipes

Affordances: possible interactions between people and environment.
Perceived affordance often acts as signifier, but they can be ambiguous
Signifiers signal things, indicate what actions are possible and how to be done. Signifier must be visible.

DesignOfEverydayThings - Signifier - 6

Ex. The sink that would not drain

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