Goals of Human Computer Interaction PDF

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Goals of Human Computer Interaction...

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8/26/2020

Goals of HCI Usability Goals User Experience Goals

Imagine that you just put your document into the photocopier and set the photocopier to make 15 copies, sorted and stapled. Then you push the big button with the "C" to start making your copies. What do you think will happen? (a) The photocopier makes the copies correctly. (b) The photocopier settings are cleared and no copies are made. If you selected (b) you are right! The "C" stands for clear, not copy. The copy button is actually the button on the left with the "line in a diamond" symbol. This symbol is widely used on photocopiers, but is of little help to someone who is unfamiliar with this.

Specific usability goals: • Effective to use (effectiveness) • Efficient to use (efficiency) • Safe to use (safety) • Easy to learn (learnability)

Usability Goal

Why is usability important?

• Is a key concept in HCI with a primary concern to make systems easy to learn and use. • Is generally regarded as ensuring that interactive products are easy to learn, effective to use, and enjoyable from the user’s perspective.

Many everyday systems and products seem to be designed with little regard to usability. This leads to frustration, wasted time and errors. This list contains examples of interactive products: mobile phone, computer, personal organizer, remote control, soft drink machine, coffee machine, ATM, ticket machine, library information system, the web, photocopier, watch, printer, stereo, calculator, videogame etc¦. How many are actually easy, effortless, and enjoyable to use? For example, a photocopier might have buttons like these on its control panel.

Disciplines contributing to HCI

Factors in HCI Organisation Factors Training, job design, politics, roles, work organisation Environmental Factors Noise, heating, lighting, ventilation Health and Safety Factors The User Cognitive processes and capabilities Motivation, enjoyment, satisfaction, personality, experience Comfort Factors Seating, equipment, layout. User Interface Input devices, output devices, dialogue structures, use of colour, icons, commands, navigation, graphics, natural language, user support, multimedia, Task Factors Easy, complex, novel, task allocation, monitoring, skills Constraints Cost, timescales, budgets, staff, equipment, buildings System Functionality Hardware, software, application Productivity Factors Increase output, increase quality, decrease costs, decrease errors, increase innovation Credit to: Matt Jones

Effectiveness - Effectiveness is the capability of producing a desired result. - The goal is referred to how good a system in doing what it is supposed to do.

The field of HCI covers a wide range of topi cs, and its development has relied on contributions from many discipli nes. Some of the mai n discipli nes which have contributed to HCI a re:

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Computer Science o technology o software design, development & maintenance o User Interface Management Systems (UIMS) & User Interface Development Environments (UIDE) o prototyping tools o graphics Cognitive Psychology o information processing o capabilities o limitations o cooperative working o performance prediction Social Psychology o social & organizational structures Ergonomics/Human Factors o hardware design o display readability Linguistics o natural language interfaces Artificial Intelligence o intelligent software Philosophy, Sociology & Anthropology o Computer supported cooperative work (CSCW) Engineering & Design o graphic design o engineering principles Credit to: Matt Jones

Efficiency • Is measured as the resources expended by the user in relation to the accuracy and completeness of goals achieved. • A way of supporting users in performing tasks.

• Easy to remember how to use (memorability)

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To prevent confusion with efficiency in HCI • In computer science terms efficiency is the ratio of useful work to resources (processor and storage) expended. In other words, the ratio of the output to the input of a given system. If for example an algorithm is said to be efficient, if it does a good job of economising on the computer resources to achieve its objective.

Safety . For example, where there are hazardous conditions---like x-rays machines or chemical plants---operators should be able to interact with and control them using computer-based system remotely. . Preventing the user from making serious error by reducing the risk of wrong keys/buttons being mistakenly activated (an example is not placing the quit or delete-file command right next to the save command on a menu.)

Providing users with various means of recovery in case they made some errors or mistakes. Other safety mechanism include undo facilities and confirmatory dialog boxes that give users another chance to consider their intentions

Safety and Disaster • Nuclear power plant (The Meltdown at Three Mile Island 1979) –“As alarms rang and warning lights flashed, the operators did not realize that the plant was experiencing a loss-ofcoolant accident. They took a series of actions that made conditions worse by simply reducing the flow of coolant through the core.”

• 1988 • USS Vincennes shot down an Iran Air A300 Airbus with 290 people aboard

How did it happen? • USS weapon system had sophisticated software to identify potential threats • But, lead to confusion since some data was not displayed on the large screen but on other side; a less noticeable display screen. • The Airbus which leveled off at 12,500 feet was taken to be an F-14 fighter descending to attack!

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Learnability • It refers to how a system is easy to learn how to use.

Memorability • e.g. • Desktop metaphor • Command lines vs GUI (mouse) vs Touch

It is well known that people do not like spending a long time learning how to use a system.

• Better representation of icons and menu names for example. • “Don’t Make me THINK, is the key to a usable product”

e.g. interacting with TV, writing emails, even using computers.

Memorability, cont. • e.g. Check any remote controls pause button. Can you easily figure out where it is located?

User experience goals . Satisfying . Enjoyable

• - Opening a file? (Opening a recent work?)

. Fun

• - Command line history • Browser bookmarks, Save password?

. Entertaining

• - Searching in Google

e.g. Apple vs Android (You can easily find clunky android based phones. But, not with iPhone.) (Steve Jobs doesn’t want bad hardware designs on top of their product/software.)

. Helpful

. Aesthetically pleasing . Supportive of creativity . Rewarding . Emotionally fulfilling

. Motivating

Apple’s introduction of their PC with mouse had only one button so users would not figure out what the second button does? They even had a computer that doesn’t look like a normal computer. To conquer the fear of users who are afraid of computers. e.g. computer with handle. fun looking colors.

Thank You.

Same thing with Windows?

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