Design of Everyday Things Don Norman on Design & HCI

Summary Darn these hooves! I hit the wrong switch again! Who designs these instrument Panels, raccoon?!

Don Norman Professor at Northwestern and Principal of Nielsen Norman group Previously Professor at UCSD, senior positions at Apple & HP ACM/CHI Lifetime Achievement Award Prolific author http://www.jnd.org/

Discussion What did you take away from DOET book so far?

Here are some Affordances are important Minimize the gulf of interpretation and gulf of execution Use natural mappings Make state visible Use a conceptual model that makes sense Provide feedback

Daily Challenges How many of you can use all the functionality in your VCR Digital watch Copy machine Stereo system Plumbing fixtures

Hall of Shame Example Leitz slide projector To move forward, short press To move backward, long press What happens when you get frustrated?

Fun Examples Phones How do you - transfer a call - change volume - store a number - ...

Changing Ringer Volume Press “Program” Press “6” Set volume Low - Press “1” Medium - Press “2” High - Press “3”

Much better…

Important Concepts Affordances Visibility Conceptual models Mapping Feedback Constraints

Affordances Perceived and actual properties of an object that determine how it could be used Chair is for sitting Button is for pushing Door handle is for …. Scroll arrow is for … Icon is for …

Door Opening Affordances 1 2 3 4 5 Which doors are easy to open? Which doors are hard to open? Why? 6 7

Affordances in interfaces Interfaces are virtual and do not have ‘real’ affordances like physical objects Interfaces have ‘perceived’ affordances Learned conventions of arbitrary mappings between action and effect at the interface Some mappings are better than others

Mantra Complex things may need explanation, but simple things should not If a simple thing requires instructions, it is likely a failed design

Designing for People Norman’s 2 main principles Provide a good conceptual model Make things visible Affordances is part of this

Conceptual Models People build their own systems of how things work Example - thermostat Designer can help user foster an appropriate conceptual model Appearance, instructions, behavior...

Conceptual Models Mental models are not always right Two Classes: Functional model Stimulus - response “Press the accelerator once, then turn the key” At surface or superficial level Structural model Deeper sense of why it happens, not just what happens “Press the accelerator to engage the automatic choke on a carburetor”

Visibility When functionality is hidden, problems in use occur Occurs when number of functions is greater than number of controls When capabilities are visible, it does not require memory of how to use Recognition over Recall in the world vs. in the head

Simple Example Bathroom faucets Two functions Hot/cold Flow

Bathroom Faucets 1 Can you figure out how to use it? Are two functions clear and independent?

Bathroom Faucets 2 Can you figure out how to use it? Are two functions clear and independent?

Bathroom Faucets 3 Can you figure out how to use it? Are two functions clear and independent?

My parent’s microwave 5:45

My microwave

About that VCR… That old joke - “how many of you have a VCR that is blinking 12:00?” :-) Still true today :-(

Which is Faster for Setting Time?

Two Important Principles Mapping Feedback

Mapping Relationship between control and action/result in the world Take advantage of physical analogies or cultural understandings Good: Car, various driving controls Mercedes Benz seat adjustment example Bad Car stereo - Knob for front/back speakers

Which is better? or

Mapping Example: Euros Size::value

Mapping Example: Stove Which controls which?

Why not this?

Yikes!

Why Not Design Better Stove Speakers Physical, monetary, convenience, etc., constraints dictate otherwise

Feedback Sending information back to the user about what has been done Includes sound, highlighting, animation and combinations of these e.g. when screen button clicked on provides sound or red highlight feedback: “ccclichhk”

Example Scissors Affordances - Insert something into holes Constraints - Bigger hole for several fingers, small for thumb Mapping - How to insert fingers into holes suggested by visible appearance Conceptual model - Suggested by how parts fit together and move Scissors

Execution-Evaluation cycle Norman (DOET, p. 46) Gulf of Execution User Goals Physical System Gulf of Evaluation

Goals, Execution, Evaluation What we want to happen Execution What we do to the world Evaluation Comparing what happened with what we wanted to happen (Gulf of Execution) (Gulf of Evaluation) Physical System

Execution Physical System Goals What we want to happen An intention to act so as to achieve the goal The actual sequence of actions that we plan to do The physical execution of that action sequence Physical System

Evaluation Physical System Goals What we want to happen Evaluation of the interpretations with what we expected to happen Interpreting the perception according to our expectations Perceiving the state of the world Physical System

Seven Stages - All Together Goals What we want to happen An intention to act so as to achieve the goal Evaluation of the interpretations with what we expected to happen The actual sequence of actions that we plan to do Interpreting the perception according to our expectations The physical execution of that action sequence Perceiving the state of the world Physical System

Implications – Which Gulf does these Address? Make current state and action alternatives visible Need good conceptual model with consistent system image Interface should include mappings that reveal relationships between stages User should receive continuous feedback Provide affordances

Goal: Minimize Gulfs Gulf of Execution Gulf of Evaluation Conceptual model Affordances Natural mappings Gulf of Evaluation Make state visible Feedback

Try and Try Again Norman thinks that it often takes 5 or 6 tries to get something “right” Simply may not have that luxury in a competitive business environment