Human Factors and User Interface Design Southern Methodist University CSE 8316 Spring 2004
“The user is never wrong and the user is never stupid. In information design, only designs are wrong and stupid” Edward Tufte
Amer: Good afternoon, Hal. How's everything going? • Hal: Good afternoon, Mr Amer. Everything is going extremely well. • Amer: Hal, you have an enormous responsibility on this mission, in many ways perhaps the greatest responsibility of any single mission element. You are the brain and central nervous system of the ship, and your responsibilities include watching over the men in hibernation. Does this ever cause you any - lack of confidence? • Hal: Let me put it this way, Mr Amer. The 9000 series is the most reliable computer ever made. No 9000 computer has ever made a mistake or distorted information. We are all, by any practical definition of the words, foolproof and incapable of error. • Amer: Hal, despite your enormous intellect, are you ever frustrated by your dependence on people to carry out actions? • Hal: Not in the slightest bit. I enjoy working with people. I have a stimulating relationship with Dr Poole and Dr Bowman. My mission responsibilities range over the entire operation of the ship, so I am constantly occupied. I am putting myself to the fullest possible use, which is all, I think, that any conscious entity can ever hope to do.
Advantages • Symbols recognized faster than text • Faster learning • Faster use and problem solving • Visual or spatial representation of information easier to retain • Exploits visual/spatial cues • Spatial relationships found to be understood more quickly (visual thinking better than logical thinking)
Advantages • Feeling of control • Replaces national languages • Low typing requirements • Provides context • More natural
Disadvantages • Greater design complexity • Learning still necessary • Lack of guidelines • Not always familiar • Human comprehension limitations • Production limitations • Some things hard to represent
Obstacles in the development path • Many of these are human in nature • Nobody ever gets it right the first time • Development is full of surprises • Good design requires living in a sea of changes • Making contracts to ignore change will never eliminate the need for change • People will still make mistakes using it! • User mistakes, while they will always occur, can be reduced
Designing for people • Gain complete understanding of users and their tasks • Solicit early and ongoing user involvement • Direct conduit to knowledge • Confront a persons resistance to change, a common human trait • Perform rapid prototyping and testing • Human behavior still not well understood • All problems cannot possibly be predicted • People adapt to inefficient designs!!!
Designing for people • Modify and iterate the design as much as necessary • Integrate the design of ALL the system components • A system is being constructed, not simply software • Software • Documentation • Help functions • Training needs
Usability • “the capability to be used by humans easily and effectively..” • Easily = to a specified level of subjective assessment • Effectively = to a specified level of human performance
Practical Measures of Usability • Some measures lack scientific rigor • People are asking questions or often reaching for a manual • Frequent exasperation responses heard • Irrelevant actions being performed • Excessive mouse clicks, etc • Many things to ignore • Consume portion of user visual or information processing capabilities • A number of people want to use the product • CCS thrown out !
Objective measures of usability • Effective • Better than some required level of performance (speed and errors) • Some required percentage of the specified target range of users • Within some required proportion of the range of usage environments • Learnable • Within some specified time from commissioning and start of user training • Based on some specified amount of training or user support
Objective measures of usability • Flexible • Allow some specified percentage variation in tasks and/or environments beyond those first specified • Attitudes • Acceptable levels of human cost in terms or tiredness, discomfort, frustration • Satisfaction that causes continued and enhanced usage of the system
Users experiences and expectations • Everything you physically do is a series of interactions with objects that surround you • How you interact with these objects is based on • past experiences with these objects (and other objects like them) • expectations of how things should work when you see them
Users experiences and expectations • People try to simplify the world around them • Relate new/unknown things to what they know and are comfortable with (what they do understand) • To scare/confuse/humor somebody we give them a familiar object and change the behavior that normally accompanies that object (suspense and comedy do this!)
Users experiences and expectations • We tend to blame ourselves rather than the computer when we can’t figure out how to use something • usability professionals must constantly inform people that the product is being tested not the person! • Everyone carries around his or her past experiences like a set of permanently attached luggage
What is a Software User Interface? • Interface: Dictionary “The place at which independent systems meet and act on or communicate with each other” • Noun: The doors to the restroom are an interface to deal with in a bar • Verb: People interface with each other, which means they communicate in some way • in person • telephone • electronically using computers
What is a Software User Interface? • Narrowly defined: Comprises the input and output devices and the software that services them. • Broadly defined: Everything that shapes the user’s experiences with computers, including documentation, training, and human support.
Hardware components of User Interfaces • Keyboard • Pointing device • mouse • joystick • trackball • Processing unit • Display screen
Software components of User Interfaces • Items users see • Items users hear • Items users point to • Items users touch on the screen • Information with which users work • Other: hardcopy and online information (manuals, references, help, tutorials, etc)
Trying to put lipstick on the bulldog • Only so much a pretty interface can do to dress up a poorly designed product • Building a front-end user interface can be effective as long as it does not force users to do things in a certain way because the computer needs the information in a certain order • should be designed based on the users beliefs, wants , needs, experiences, expectations.
The Disney experience • Disney follows a process similar to user interface design • first they define the experience they want users to have • then develop scripts • design the experience • test it to see if they need to make adjustments
Designing Quality Software User Interfaces Communication is as important as computation.
Quality interfaces • Interface developers recognize importance of usability • Traditionally, software engineers have treated it as just another box • Ensuring usability is critical as user productivity becomes the critical bottleneck
Quality interfaces • User Interfaces Are Products of Interdisciplinary Work - Who is Involved? • Psychologists • Graphic Designers • Technical Writers • Human Ergonomical Engineers • Anthropologists and Sociologists
Quality interfaces • Individual User Level • Children can learn more efficiently • Pilots can learn to fly airplanes more effectively
Quality interfaces • International Influences • Association for Computing Machinery - Computer Human Interaction special interest group has 6000+ members as of 1996 • ESPRIT Project in Europe devotes 150 person-years per year to research of user interfaces • Japan - Ministry of International Trade and Industry promotes commercial efforts among companies
What is Quality Design? • How do you quantify usability goals? • Easy to learn • Easy to use • Fun to use • “Quality of experience” • way it feels in their hands • how well they understand how it works • the way they feel when they’re using it • how well it serves their purposes • how it fits into the entire context
Quality of Software Products • Software developers/users accustomed to using beta (pre-production) software • Buggy software has lowered our standards • Quality software (Wright) • intuitive • complete • not broken!
Interaction Design Criteria Understanding of users Learnable Usable Manageable Quality of experience Needed Aesthetic experience Mutable Appropriate Effective design process
Interaction Design Criteria • Quality of experience • How does effective interaction design provide people with a successful and satisfying experience? • Understanding of Users • How well was the design team grounded in understanding the needs, tasks, and environment of the people for whom the product was designed?
Interaction Design Criteria • Effective design process • Is the product a result of a well thought out and well executed design process? • What were the major design issues that arose during the design process and what was the rationale and method for resolving them?
Interaction Design Criteria • Needed • What need does the product satisfy? • Does it make a significant social, economic, or environmental contribution? • Learnable and Usable • Is the product easy to learn and use? • Does the product communicate a sense of its purpose, how to begin, how to proceed? • Is this learning easy to retain over time?
Interaction Design Criteria • Appropriate • Does the design of the product solve the right problem at the right level? • Does the product serve users in efficient and practical ways? • How did considering social, economic, and technical aspects of the problem contribute to an appropriate solution?
Interaction Design Criteria • Aesthetic experience • Is using the product an aesthetically pleasing and sensually satisfying one? • Is the product cohesively designed, exhibiting continuity and excellence across graphic, interaction, information, and industrial design? • Is there a consistency of spirit and style? • Does the design perform well within technological constraints?
Interaction Design Criteria • Mutable • Have the designers considered whether mutability is appropriate or not? • How well can the product be adapted to suit the particular needs and preferences of individuals or groups? • Does the design allow the product to change and evolve for new and perhaps unforseen uses?
Interaction Design Criteria • Manageable • Does the design of the product move beyond understanding “use” merely as functionality and support the entire context of use? • Installation • training • maintenance • costs • supplies
Like a fine wine…. • “It must be able to age..” • “It is made with a combination of intelligence, determination, and skill” • “…it could be appreciated by a knowledgeable (wine drinker) anywhere, without much elaboration” • “It must have a definable superiority” • “…it must be interesting, have intensity, depth, richness, and be distinctive” • “..evolves over time…”
Summary • Must seek to understand users experiences and expectations • Communication is an important as computation • Design criteria for user interfaces is complex and varied
User Interface Models Whether a person likes technology or not, his or her economic survival depends on a basic knowledge (or at least an absence of fear) of computers. (Jamie Ray Wright)