CS365 - HCI Week 2 Prof. Ahmed Sameh

Reflections  How long should it take to learn a new web development tool i.e. Dreamweaver or Microsoft’s’ new Expression Studio?  mins to become productive -  What is meant by “usability?”  Effective to use  Efficient to use  Safe to use  Having good utility  Easy to learn  Easy to remember  Can you decide what people “experience” when they are satisfied with the interface?

Problem solving  Process of finding solution to unfamiliar task using knowledge.  Several theories.  Gestalt  problem solving both productive and reproductive  productive draws on insight and restructuring of problem  attractive but not enough evidence to explain `insight' etc.  move away from behaviourism and led towards information processing theories

Problem solving (cont.) Problem space theory  problem space comprises problem states  problem solving involves generating states using legal operators  heuristics may be employed to select operators e.g. means-ends analysis  operates within human information processing system e.g. STM limits etc.  largely applied to problem solving in well-defined areas e.g. puzzles rather than knowledge intensive areas

Problem solving (cont.)  Analogy  analogical mapping:  novel problems in new domain?  use knowledge of similar problem from similar domain  analogical mapping difficult if domains are semantically different  Skill acquisition  skilled activity characterized by chunking  lot of information is chunked to optimize STM  conceptual rather than superficial grouping of problems  information is structured more effectively

Errors and mental models Types of error  slips  right intention, but failed to do it right  causes: poor physical skill, inattention etc.  change to aspect of skilled behaviour can cause slip  mistakes  wrong intention  cause: incorrect understanding humans create mental models to explain behaviour. if wrong (different from actual system) errors can occur

Emotion  Various theories of how emotion works  James-Lange: emotion is our interpretation of a physiological response to a stimuli  Cannon: emotion is a psychological response to a stimuli  Schacter-Singer: emotion is the result of our evaluation of our physiological responses, in the light of the whole situation we are in  Emotion clearly involves both cognitive and physical responses to stimuli

Emotion (cont.)  The biological response to physical stimuli is called affect  Affect influences how we respond to situations  positive  creative problem solving  negative  narrow thinking “Negative affect can make it harder to do even easy tasks; positive affect can make it easier to do difficult tasks” (Donald Norman)

Emotion (cont.)  Implications for interface design  stress will increase the difficulty of problem solving  relaxed users will be more forgiving of shortcomings in design  aesthetically pleasing and rewarding interfaces will increase positive affect

Individual differences  long term – sex, physical and intellectual abilities  short term – effect of stress or fatigue  changing – age Ask yourself: will design decision exclude section of user population?

Psychology and the Design of Interactive System  Some direct applications  e.g.blue acuity is poor  blue should not be used for important detail  However, correct application generally requires understanding of context in psychology, and an understanding of particular experimental conditions  A lot of knowledge has been distilled in  guidelines  cognitive models  experimental and analytic evaluation techniques

Does the Wii meet these criteria

User experience goals satisfying aesthetically pleasing enjoyable supportive of creativity engaging supportive of creativity pleasurable rewarding exciting fun entertaining provocative helpful surprising motivating enhancing sociability emotionally fulfilling challenging boring annoying frustrating cutsey

Usability and user experience goals  Selecting terms to convey a person’s feelings, emotions, etc., can help designers understand the multifaceted nature of the user experience  How do usability goals differ from user experience goals?  Are there trade-offs between the two kinds of goals?  e.g. can a product be both fun and safe?  How easy is it to measure usability versus user experience goals?

Design principles  Generalizable abstractions for thinking about different aspects of design  The do’s and don’ts of interaction design  What to provide and what not to provide at the interface  Derived from a mix of theory-based knowledge, experience and common-sense

Visibility This is a control panel for an elevator How does it work? Push a button for the floor you want? Nothing happens. Push any other button? Still nothing. What do you need to do? It is not visible as to what to do! From:

Visibility … you need to insert your room card in the slot by the buttons to get the elevator to work! How would you make this action more visible? make the card reader more obvious provide an auditory message, that says what to do (which language?) provide a big label next to the card reader that flashes when someone enters make relevant parts visible make what has to be done obvious

What do I do if I am wearing black?  Invisible automatic controls can make it more difficult to use

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”

Constraints  Restricting the possible actions that can be performed  Helps prevent user from selecting incorrect options  Physical objects can be designed to constrain things  e.g. only one way you can insert a key into a lock

Logical or ambiguous design?  Where do you plug the mouse?  Where do you plug the keyboard?  top or bottom connector?  Do the color coded icons help? From:

How to design them more logically (i) A provides direct adjacent mapping between icon and connector (ii) B provides color coding to associate the connectors with the labels From:

Consistency  Design interfaces to have similar operations and use similar elements for similar tasks  For example:  always use ctrl key plus first initial of the command for an operation – ctrl+C, ctrl+S, ctrl+O  Main benefit is consistent interfaces are easier to learn and use

When consistency breaks down  What happens if there is more than one command starting with the same letter?  e.g. save, spelling, select, style  Have to find other initials or combinations of keys, thereby breaking the consistency rule  e.g. ctrl+S, ctrl+Sp, ctrl+shift+L  Increases learning burden on user, making them more prone to errors

Internal and external consistency  Internal consistency refers to designing operations to behave the same within an application  Difficult to achieve with complex interfaces  External consistency refers to designing operations, interfaces, etc., to be the same across applications and devices  Very rarely the case, based on different designer’s preference

Keypad numbers layout  A case of external inconsistency (a) phones, remote controls(b) calculators, computer keypads

Affordances: to give a clue  Refers to an attribute of an object that allows people to know how to use it  e.g. a mouse button invites pushing, a door handle affords pulling  Norman (1988) used the term to discuss the design of everyday objects  Since has been much popularised in interaction design to discuss how to design interface objects  e.g. scrollbars to afford moving up and down, icons to afford clicking on

What does ‘affordance’ have to offer interaction design?  Interfaces are virtual and do not have affordances like physical objects  Norman argues it does not make sense to talk about interfaces in terms of ‘real’ affordances  Instead interfaces are better conceptualized as ‘perceived’ affordances  Learned conventions of arbitrary mappings between action and effect at the interface  Some mappings are better than others

Activity  Physical affordances: How do the following physical objects afford? Are they obvious?

Activity  Virtual affordances How do the following screen objects afford? What if you were a novice user? Would you know what to do with them?

Usability principles  Similar to design principles, except more prescriptive  Used mainly as the basis for evaluating systems  Provide a framework for heuristic evaluation

Usability principles (Nielsen 2001)  Visibility of system status  Match between system and the real world  User control and freedom  Consistency and standards  Help users recognize, diagnose and recover from errors  Error prevention  Recognition rather than recall  Flexibility and efficiency of use  Aesthetic and minimalist design  Help and documentation

Key points  Interaction design is concerned with designing interactive products to support the way people communicate and interact in their everyday and working lives  It is concerned with how to create quality user experiences  It requires taking into account a number of interdependent factors, including context of use, type of activities, cultural differences, and user groups  It is multidisciplinary, involving many inputs from wide-reaching disciplines and fields