More on Design of Everyday Things

Designer and user models Goal: user model and design model should be identical Design Model User Model Communication from designer to user is via the system image So system image must lead user to acquire a user model equal to the design model Designer User System System Image

So how does a designer help users acquire the right model? Visibility Affordances Mappings Constraints Feedback

So how does a designer help users acquire the right model? Visibility - Don’t hide things. Make the status visible Affordances Mappings Constraints Feedback

So how does a designer help users acquire the right model? Visibility - Don’t hide things. Make the status visible Affordances - the design aspect of an object which suggests how the object should be used Mappings Constraints Feedback

So how does a designer help users acquire the right model? Visibility - Don’t hide things. Make the status visible Affordances - the design aspect of an object which suggests how the object should be used Mappings - Take advantage of physical analogies Constraints Feedback

Constraints Limit the range of possible actions Physical Constraints Only some possibilities are physically possible (only one way the battery in my camera) Semantic Constraints Only some possibilities make sense Cultural Constraints Only some possibilities are acceptable Logical Constraints General principles: e.g., every part should be used

Feedback Remember that people will build models And feedback leads to causal models: “if Y happened after X, then X caused Y” So provide the proper feedback immediately: respond to user actions – don’t hide the results! Did I press the button? (visual and/or audio feedback) All actions should have effects Promote exploration Provide meaningful error messages

Wii I recently bought a used original Wii. While trying to setup the device to use my wireless I received: Wii Error Code 51330 What does that mean?

Wii It turns out that it means I had entered my password incorrectly. BUT, I had to search the internet (see the catch 22 on this) to learn that. Say what you mean and mean what you say

Dr. Diesburg’s TV Say what you mean and mean what you say. Make sure that end users don’t see error messages that they can’t understand (and arguably shouldn’t see).

White House Form

Last resort - standardization Fewer things to memorize Quicker to learn Clocks should run clockwise But note that standards are culture-dependent!

“Standards” and cultures What does the color red mean? US – danger, warning, … India – purity What color should a wedding dress be? US – white India – red & yellow How do you turn on a faucet? US – counter-clockwise UK – clockwise Problems with icons – mailboxes, trashcans, …

Applying the principles

A usable design - scissors Affordances Holes for something to be inserted Constraints Big hole for several fingers, small hole for thumb Mappings Between holes and fingers suggested and constrained by appearance A cultural standard Conceptual model Implications of actions clear – feedback is immediate

How do I pump the gas?

“Push To Start”

Design Principle Problems Visibility Affordances

When does the bottom light go on?

Design Principle Problems Conceptual Model Feedback

Setting Options in MS Word

Design Principle Problems Conceptual model – “What happened?!?”

Which string turns on the fan, which turns on the light?

Design Principle Problems Mappings

What’s that thing in the corner?

It’s a mop sink!

Design Principle Problems Affordances Conceptual Model Standardization

How do you raise/lower this screen?

Design Principle Problems Conceptual Model Mappings

Next Steps For next time Upcoming Assignments DOET Chapters 5 and 6 Begin to talk with others about teams Upcoming Assignments Friday, September 8 – Team Formation