Human Computer Interaction

1. 1
HumanComputerInteraction
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2. Chapter1
Introduction:
 What is HCI?
Human computer Interaction
 Study of howHumaninteracts with a Computer.
 “HCIistheneitherthestudyofhumansnorthestudyof
technology,butratherthebridgingbetweenthosetwo.”
Preece
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3. Cont’d…
• Association for Computing Machinery (ACM):
 “HCI is a discipline concerned with the design,
evaluation and implementation of interactive computing
systems for human use and with the study of major
phenomena surrounding them.”
 Dix: “HCI is study of people, computer technology and the
ways these influence each other. We study HCI to determine
how we can make this computertechnology more usable by
people” (1998)
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4. Cont..
 Carroll: “HCI is the study and practice of usability. It
is about understanding and creating software and
other technology that people will want to use, will be
able to use, and will find effective when used.”
(2002)
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5. H… C… I…
Human:
 Individual user, a group of usersworking together,a sequenceof
usersin an organization
Computer:
 the machine the program runs on
 PC,mobile phones,embedded system (photocopier, microwave oven
…), software (search engine, word processor …)
Interaction:
 The user tells the computer what they want
the computer communicates results
(userclicks “print” and theninterface replies with a dialog box)
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6. Cont…
 HCI helps usto understand why some software products
are good and other software is bad.
 Thestudy of our interface with information.
 It is not just ‘how bigshould I make buttons’ or
‘how to layout menuchoices’
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7. Cont…
 It can affect
 Effectiveness
 Productivity
 Morale
 Safety
 Example: a car with poor HCI
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8. Example
• iPod by Apple Computers
• Pros:
– portable
– power
– ease of use
– # of controls
• Cons:
– scratches easily
– no speech for car use
– proprietary
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9. HCI importance result of:
 Cheaper/available computers meant people more important than machines
 Excellent interface ideas should be modeled after human needs instead of
system needs (user centered design)
 Evolution of ideas into products through several generations
 Pioneer systems developed innovative designs, but often commercially
unviable/ impracticable
 settler systemsincorporated (many years later) well-researched designs
 People no longer willing to accept products with poor interfaces
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10. In general
 In the past, the main concern of HCI was ‘usability’ to ensure that
technologies are easy to learn and easy to use.
 More recently, HCI has begun
🞑 Todevelop techniques for inventing things that are not just
usable but useful.
🞑 Toinvestigate the relationships between people that
computers and computer networks enable.
suchas patterns of behavior between people and within
social groups.
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11. HCIGoals
 is to improve the interactions between users and
computers by making computers more usable and
receptive to the user's needs.
 to produce usable and safe systems, as well as
functional systems
 These goals can be summarized as ‘to develop or
improve the safety, utility, effectiveness,
efficiency and usability of systems that include
computers
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12. Usability Goals…
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More specifically, usability is broken down into
the following goals:
 Effective to use (effectiveness)
 Efficient to use (efficiency)
 Safe to use(safety)
 Have good utility (utility)
 Easy to learn (learnability)
 Easy to remember how to use (memorability)

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 Effectiveness: It is a very general goal and refers to how
good a system at doing what it is supposed to do.
 Efficiency: It refers to the way a system supports users in
carrying out their tasks.
Safety: It involves protecting the users from dangerous
conditions and undesirable situations.
 In relation to the first ergonomics aspect, it refers to the
external conditions where people work.
 For example, where there are hazardous conditions---like x-
rays machines or chemical plants---operators should be able
to interact with and control computer-based system
remotely.

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 Utility: It refers to the extent to which the system
provides the right kind of functionality so that user can
do what they need or want to do.
 Learnability: It refers to how easy a system is to learn
to use.
 It is well known that people do not like spending a long
time learning how to use a system.
 A key concern is determining how much time users are
prepared to spend learning a system.
 Memorability: It refers to how easy a system is to
remember how to use, once learned.

15. User experience goals…
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 Satisfying
 Enjoyable
 Fun
 Entertaining
 Helpful
 Motivating
 Supportive of creativity

16. Disciplines contribute to HCI
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• Psychology and cognitive science: to give her/his
knowledge of the user’s perceptual, cognitive and problem-
solving skills;
• Ergonomics: for the user’s physical capabilities; .
• Sociology: to help her/his understand the wider context of the
interaction;
• Computer science and engineering: to be able to build the
necessary technology;
• Graphic design: to produce an effective interface presentation;
• Technical writing: to produce the manuals, and so it goes on.

17. HCI Scope
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18. Con’t…
 Use & Context: Find application areas for computers
 Human: Study psychological & physiological aspects
 e.g., study how a user learns to use a new product, study
human typing speed
 Computer: Hardware & software offered
 e.g., input & output devices, speed, interaction styles,
computer graphics
 Development: Design, implementation & evaluation
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19. Questions?
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