April 19, 2004“Design of User-Friendly Systems” DLC, Design of User Friendly Systems Joel Clawson Genevieve Hudak Brock LaMeres Kitty Turner

April 19, 2004“Design of User-Friendly Systems” DLC, Introduction Topic: –Design Objective: –To understand good and bad design practices as pertained to the psychology of users

April 19, 2004“Design of User-Friendly Systems” DLC, Agenda The dysfunction of everyday things The psychology of everyday actions Knowledge in the head and in the world Knowing what to do To err is human User-centered design Overview of Things That Make Us Smart

April 19, 2004“Design of User-Friendly Systems” DLC, Characteristics of Objects Easy to understand Easy to interpret Contain visible clues to operation Difficult to Use Frustrating No clues/False clues Get in the way of normal thought processes on operation Well DesignedPoorly Designed

April 19, 2004“Design of User-Friendly Systems” DLC, Frustrations of Everyday Life Poor Visibility Lack of Natural Signals Poor Mappings Poor Instructions Poor Relations between old, known functions and similarly named new ones

April 19, 2004“Design of User-Friendly Systems” DLC, Psychology of Everyday Things Affordances –Plates → Pushing –Knobs → Turning –Slots → Inserting False Causality Conceptual Models

April 19, 2004“Design of User-Friendly Systems” DLC, Principles of Design for Understanding and Usability Provide a good Conceptual Model Make things Visible –Provide good mappings –Provide natural relationships –Don’t overload a control Provide Feedback

April 19, 2004“Design of User-Friendly Systems” DLC, The Psychology of Everyday Actions “Humans will try to figure it out” A user sits down at an interface with a goal. The user… 1) Observes what functionality is available. 2) Forms a conceptual model of how the system works. 3) Takes an action to achieve the goal. 4) Observes the outcome of the action, was it right or wrong? 5) Either Reinforces or Discredits his conceptual model. 6) Continues until the goal is accomplished.

April 19, 2004“Design of User-Friendly Systems” DLC, The Psychology of Everyday Actions This is good if ??? - The interface understands how the user approaches the system. - Allows the user to explore the system risk free. - Provides only necessary functionality at the top level. - Handles Errors. This is bad if ??? - Inappropriate actions result in no or incorrect feedback. - There is no forgiveness for mistakes. - The model of the system varies from the conceptual model of the user.

April 19, 2004“Design of User-Friendly Systems” DLC, The Psychology of Everyday Actions A good system understands how users get lost…. - Can the user build a conceptual model of the system from the interface? (false models, misconceptions) - Does the feedback of actions discredit the model? (Falsely Blaming yourself, Blaming the wrong cause) - Does the system reinforce misconceptions? (Learned Helplessness, Taught Helplessness)

April 19, 2004“Design of User-Friendly Systems” DLC, The Psychology of Everyday Actions A good example: Delete Confirmation - Confirmation that an action was taken. - A correlation of the action and observation. - A way out of a dangerous situation. A bad example: MS Word Auto Format - no relationship between action and outcome. - no consistency between the outcomes. - not always possible to reverse action and get back to where we started.

April 19, 2004“Design of User-Friendly Systems” DLC, The Psychology of Everyday Actions -Design Aids to Compliment the User’s Thought Process… 1) Visibility The user will see what is available and act accordingly. 2) A Good Conceptual Model The user will form a simple model, does the system allow models to be formed? 3) Good Mapping Is there a correlation between the action and the outcome? 4) Feedback Users reinforce/discredit their model according to the reaction they get from an action. If there is no action, the user is lost.

April 19, 2004“Design of User-Friendly Systems” DLC, Knowledge in the Head and In the World “Digital Media Offers Overwhelming Information” 1)There is too much information for the user to remember. 2)Designers must Decide which information will be memorized and which will be stored in the system.

April 19, 2004“Design of User-Friendly Systems” DLC, Knowledge in the Head and In the World What are the Tradeoff ??? Knowledge in the WorldKnowledge in the Head Retrievability:Available when visible/audibleRequires Memory Search Learning:Not RequiredRequired Efficiency:SlowFast once Retrieved First Encounter:EasyDifficult

April 19, 2004“Design of User-Friendly Systems” DLC, Knowledge in the Head and In the World What do we do ??? - Exploit the Nature of Human Thought - Humans want to form a “conceptual model” of all things. - Information without a model is difficult to remember. - Try to communicate Concepts instead of Raw Information Ex)1) Where do you find the information vs. What is the information? 2) How Features Alter the System vs. What Specifically do the features do?

April 19, 2004“Design of User-Friendly Systems” DLC, Knowledge in the Head and In the World Mappings Can Help “Knowledge in the World” “Stove Control Example” No Mapping Natural Mapping This exploits the human need for a conceptual model through “mappings”

April 19, 2004“Design of User-Friendly Systems” DLC, Knowledge in the Head and In the World Understanding Memory Can Help “Knowledge in the Head” 1) Memory for Arbitrary Things (difficult, standardization helps) 2) Memory for Meaningful Relationships (efficient) 3) Memory through Explanation (conceptual models)

April 19, 2004“Design of User-Friendly Systems” DLC, Physical and Logical constraints Physically constrain possible operations Rely upon properties of the physical world Examples: –Large peg cannot fit into small hole –Keys can have only one of two orientations when inserted into a vertical slot Logical constraints take advantage of natural mappings and relationships Location and operation should follow these natural mappings: –Two switches to controls two lights: left switch should control left light and right switch should control right light –Last piece of a jigsaw puzzle, naturally constrained to go in the empty hole

April 19, 2004“Design of User-Friendly Systems” DLC, Cultural and Semantic constraints Cultural constraints: Knowing how to act in cultural situations such as at a restaurant Culturally acceptable behavior frames –Notice these when they are violated, such as standing in an elevator facing the rear –Differ from culture to culture Semantic constraints rely on –the meaning of the situation –the user’s knowledge of the situation and the world Example: –How to sit in a chair with arms, sit with legs over open edge

April 19, 2004“Design of User-Friendly Systems” DLC, Visibility and Feedback Visibility: “Making relevant parts [or the correct action] visible”– easier said than done Doors –Unclear design of many doors as to which side of the door opens Switches –Many switches controlling different things –Natural mapping of switches often not exploited; which direction of the switch is on/off Feedback: “Give each action an immediate and obvious effect.” Use sound to make things visible –Whistle of tea kettle when water boils –Click when toast pops up –Change in pitch when vacuum is clogged Having a good display – visual feedback –Lets the user know what effect their actions have

April 19, 2004“Design of User-Friendly Systems” DLC, Capture and Data-Driven Errors Capture error: When “a frequently done activity suddenly takes charge instead of (captures) the one intended.” Occurs when two different action sequences have initial stages in common, where one is well practiced and the other unfamiliar Examples: Going to change your clothes for dinner and finding yourself in bed Get in your car on Sunday to go to the store and end up going to work instead Data-driven error: Occurs when sensory data interferes with the current action sequence. Automatic actions are data-driven.

April 19, 2004“Design of User-Friendly Systems” DLC, Description and Mode Errors Description error: When the intended action has a lot in common with other actions that are possible. Comes from imprecise internal descriptions. Occurs when the wrong and right objects are physically near each other. Example: Flipping the wrong switch in a long row of switches Mode error: When controls must perform more than one action, depending on the mode Errors occur when the mode is not made visible Especially prevalent on computer systems and digital watches

April 19, 2004“Design of User-Friendly Systems” DLC, Associative activation and Loss-of-activation Errors Associative activation error: When internal thoughts and associations trigger actions. Examples: Thinking something you shouldn’t say and then saying it. Answering your telephone ‘come in’ Loss-of-activation error: Plainly, forgetting. Can happen in the middle of doing something, such as walking into a room and forgetting why you went there.

April 19, 2004“Design of User-Friendly Systems” DLC, To Err is Human Types of errors Visibility of Errors Conceptual models that lead to error Structure of tasks: Wide and deep Shallow Narrow Explaining away errors Social Pressures Forcing Functions

April 19, 2004“Design of User-Friendly Systems” DLC, More Info Flanders, Vincent. “Web Pages that Suck”. ker/

April 19, 2004“Design of User-Friendly Systems” DLC, User-Centered Design Good design The user says “Yes, I see” or “Of course”. A simple explanation is sufficient. Bad design The user says “How am I going to remember that?” after the explanation.

April 19, 2004“Design of User-Friendly Systems” DLC, principles of good design OR 7 principles for transforming difficult tasks into simple ones 1. Use both knowledge in the world and knowledge in the head. 2.Simplify the structure of the tasks. 3. Make things visible: bridge the gulfs of Execution and Evaluation. 4. Get the mappings right. 5. Exploit the power of constraints, both natural and artificial. 6. Design for error. 7. When all else fails, standardize.

April 19, 2004“Design of User-Friendly Systems” DLC, Use knowledge in the world and knowledge in the head Users are more comfortable and learn better when the knowledge they need to perform a task is readily available in the world or through constraints. Users perform faster and more efficiently when they can synthesize the knowledge needed for their task. So it should be easy to go back and forth – to combine knowledge in the head with knowledge in the world. The designer must develop a conceptual model for the user that captures the important parts of the device and that is understandable by the user.

April 19, 2004“Design of User-Friendly Systems” DLC, Simplify the structures of tasks The amount of planning and problem solving for a task should be minimized.

April 19, 2004“Design of User-Friendly Systems” DLC, Make things visible On the execution side of an action: So that users know what actions are possible and how the actions can be done. On the evaluation side of an action: So that users know what the results of the actions are and the current state of the system.

April 19, 2004“Design of User-Friendly Systems” DLC, Get the mappings right Make sure the user can understand the relationship between intentions and possible actions, actions and their effects on the system, the actual system state and what is reflected in the interface, and the perceived system state and the needs, intentions and expectations of the users.

April 19, 2004“Design of User-Friendly Systems” DLC, Exploit the power of constraints, both natural and artificial Use natural and artificial constraints to make users feel that there is only one possible action.

April 19, 2004“Design of User-Friendly Systems” DLC, Design for error Assume that any error is possible and plan for it. Allow users to recognize errors and recover from them. Make it easy to reverse operations and hard to do irreversible actions.

April 19, 2004“Design of User-Friendly Systems” DLC, When all else fails, standardize When the above principles cannot be put into place, standardize the actions, layout, display, and results. With standardization, users only have to learn it once but they must be trained to the new standard.

April 19, 2004“Design of User-Friendly Systems” DLC, Knowing what to do Constraints Physical and Logical: Good: Cultural and Semantic: Good: Bad: Visibility and Feedback Visibility: Good: Bad: Feedback: Good: Bad:

April 19, 2004“Design of User-Friendly Systems” DLC, Human Centered Technology Aimed at aiding cognition –Often interferes and confuses –Should be aimed at the needs of people Two Kinds of Cognition –Experiential –Reflective

April 19, 2004“Design of User-Friendly Systems” DLC, Kinds of Learning Accretion –Accumulation of Facts Tuning –Practice to make reflective tasks become experiential Restructuring –Acquiring new concepts

April 19, 2004“Design of User-Friendly Systems” DLC, Representation Cognitive Artifacts –What make us smart –Provide abstract representations –Represent the important ideas Match the Artifact to the Task Naturalness Principle: –Experiential cognition is aided when the properties of the representation match the properties of the object/idea being represented

April 19, 2004“Design of User-Friendly Systems” DLC, Fitting the Artifact to the Person People are better at Perception than Abstraction and Symbolism Appropriateness Principle: –The representation used by the artifact should provide exactly the information acceptable to the task: neither more nor less. People seek understandings, causes, purpose

April 19, 2004“Design of User-Friendly Systems” DLC, The Human Mind Machines use different principles than people –They complement each other –Details vs. Representation

April 19, 2004“Design of User-Friendly Systems” DLC, Distributed Cognition Distributed Intelligence –Knowledge is in the world Impossible means Impossible –Properties of the world Accuracy is not always important

April 19, 2004“Design of User-Friendly Systems” DLC, Organizing Knowledge Hierarchical Spatial Temporal

April 19, 2004“Design of User-Friendly Systems” DLC, Conclusion User-centered design –About the USER –Thinking –Interaction with world

April 19, 2004“Design of User-Friendly Systems” DLC, Questions ?