Part A - Introduction

Everyday Things

Introduce the Streams of Human Computer Interaction

"Human-computer interaction (HCI) is the study, planning and design of the interaction between people (users) and computers. It is often regarded as the intersection of computer science, behavioral sciences, design and several other fields of study." Wikipedia (2011)

History | Technological Change | Norman | Usability | Exercises

This course is about human communication with computers.  For the most part, we focus on the human side of the communication and the effects that software design can have on that communication.  The course itself is an introductory course that surveys many of the aspects of human-computer communication that are currently prominent.  The accepted name for this field of study is Human-Computer Interaction or HCI for short. 

Computers are just one of the 20,000 or so everyday things that we encounter daily.  These everyday things meet our needs and requirements in various ways and to various degrees.  Some are central to our activities, while others are peripheral.  We communicate with these everydays things on many, and in some cases quite complex, levels.  The design of each everyday thing - be it a light switch, an appliance, an automobile, or a computer - influences the quality of our interaction with it, and hence the quality of our daily lives.

General knowledge on how to design everyday things is well advanced.  We could apply this knowledge to the design of new everyday things, but we tend to start from scratch with each new thing.  In other words, we tend to repeat many of the same mistakes that we have made in our earlier designs of other things.  This pattern has held equally true with the design of software.

HCI is a multi-disciplinary field and in this sense does not work with its own, well-defined set of principles.  The HCI designer draws on quite a few and quite diverse fields on knowledge:

  • psychology
  • sociology
  • physiology
  • ergonomics
  • cognitive science
  • graphic design
  • computer science
  • electrical engineering

We touch on aspects of each of these fields in this course. 

History of HCI

The history of HCI reveals three relatively independent streams:

  • human factors (HF)
  • information systems (IS)
  • computer-human interaction (CHI)

Human Factors is the eldest.  HF has studied how humans relate to the world around them, particularly with respect to the tools that they use.  Information Systems, the second eldest, has has management issues and has also been referred to as data processing or management information systems.  Computer-Human Interaction has focused on the hard science issues and has been directly associated with computer science proper. 

HCI Timeline

Human Factors dates back to a 1911 theory of management known as Taylorism (Grudin 2008).  Fredrick Taylor published his ideas on the science of management in two books: Shop Management and the Principles of Scientific Management.  He developed his labour productivity concepts based upon scientific principles and focused on the efficiency of operations.  The World Wars accentuated the need for proper use and reliability of tools, which gave further impetus to Human Factors.  In 1957, the Human Factor Society (HFS) was formed to improve the efficiency of skilled performance and to train people to achieve skilled performance.  Experts in HF authored the first HCI papers on how to improve designs for operators.  In 1972, the HFS formed the Computer Systems Technical Group (CSTG), which soon became the largest technical group in the society itself.  In 1992, HFS changed its name to the Human Factors and Ergonomics Society (HFES).  In 2007, the HFES created the Journal of Cognitive Engineering and Decision Making (CEDM).  HFES now has 23 technical groups, including the Human Performance Modelling Group (HPM), which develops engineering style approaches to problems in goal-directed activities that are centered on quantitative models. 

Information Systems originally focused on processing information within business enterprises and only recently shifted into its present form with commercial acceptance of the Internet.  Organizations began creating web pages and e-commerce sites.  The Association for Information Systems, founded in 1994, established the Special Interest Group in Human-Computer Interaction (SIGHCI) in 2001.  IS was the stream least prepared for the acceptance of the Internet.  It experienced the most fundamental shift of the three HCI streams. 

Computer-Human Interaction made discretionary hands-on use its focus.  CHI grew out of the development of new hardware and programming languages by experienced programmers.  In 1980, the Association for Computing Machinery (ACM) created a "Human Aspects" department for its communications.  As personal computers appeared commercially, ACM formed the Special Interest Group on Computer-Human Interaction (SIGCHI).  Contributors to SIGCHI were largely programmers who had set aside paper coding sheets in favor of text-editing at interactive terminals.  They were neither operators who had been using terminals in their more basic forms as tools for many years not managers focused on the efficient flow of information.  CHI has distinguished itself from HF and IS by adopting terms such as cognitive engineering and usability engineering.  CHI researchers have viewed themselves as hard scientists and have sought to distance themselves from the cognitive science developed by the HF practitioners and researchers.

Both HF and CHI, with their different focii, were well-prepared for the rise of the Internet.  Neither HF nor CHI experienced any fundamental shift with the acceptance of the Internet compared to the shift that IS experienced. 

Both HF and IS had existed well before discretionary hands-on use became widespread.  Both were well-established streams when CHI surfaced.  CHI evolved differently along the path of innovation, discarding technologies as they became routine and has now drifted from its original focus on science and engineering towards aesthetics, marketing, and non-rational persuasion. 

Technological Change

Different everyday things change at different rates.  Technology in general changes quite rapidly.  If technological change demands that we change in directions different from those in which we will be comfortable, the demand stresses us.  Some of us react by rejecting the change.  Some of us react by accepting the challenge and absorbing the stress. 

Moore's Law

Moore's law states that:

"Since the invention of the integrated circuit in 1958, the number of transistors that can be placed inexpensively on an integrated circuit has increased exponentially, doubling approximately every two years. The trend was first observed by Intel co-founder Gordon E. Moore in a 1965 paper. It has continued for almost half a century and in 2005 was not expected to stop for another decade at least." (Wikipedia, 2009).

Moore's law has applied to computer hardware for over four decades. 

Pace of Change

The automobile industry is one industry that has kept pace with technological change and met human requirements and desires to an admirable degree.  Because of this, the automobile itself serves as a benchmark for the evolution of design. 

Compare the usability of an automobile with the usability of an operating system:

At a recent computer expo (COMDEX), Bill Gates reportedly criticized the auto industry stating that,

"If GM had kept up with technology like the computer industry has, we would all be driving $25 cars that got 1,000 miles to the gallon."
In response to this comment, General Motors issued a press release stating that:

If GM had developed technology like Microsoft, we would all be driving cars with the following characteristics:
  1. For no reason whatsoever, your car would crash......... Twice a day.
  2. Every time they repainted the lines in the road, you would have to buy a new car.
  3. Occasionally your car would die on the freeway for no reason. You would have to pull to the side of the road, close all of the windows, shut off the car, restart it, and reopen the windows before you could continue. For some reason you would simply accept this.
  4. Occasionally, executing a maneuver such as a left turn would cause your car to shut down and refuse to restart, in which case you would have to reinstall the engine.
  5. Macintosh would make a car that was powered by the sun, was reliable, five times as fast and twice as easy to drive - but would run on only five percent of the roads.
  6. The oil, water temperature, and alternator warning lights would all be replaced by a single 'This Car Has Performed An Illegal Operation' warning light.
  7. The airbag system would ask 'Are you sure?' before deploying.
  8. Occasionally, for no reason whatsoever, your car would lock you out and refuse to let you in until you simultaneously lifted the door handle, turned the key and grabbed hold of the radio antenna.
  9. Every time a new car was introduced car buyers would have to learn how to drive all over again because none of the controls would operate in the same manner as the old car.
  10. You'd have to press the 'Start' button to turn the engine off.

Limits of Technological Change

Although many of us find many of the technological changes attractive, there are limits to what technology can reproduce.  One prominent example is in the field of robotics.  As we produce human replicas that start to look and act more like humans, these designs generate responses of revulsion alongside those of attraction.  The intellectual uncertainty can lead us to reject the design outright. 

No matter how sophisticated technology gets, a gap exists between the tools and the humanoids that we create and how we ourselves evolve in light of our own creations.  We call this persistent gap the Uncanny Valley

Donald Norman

"I just found a Norman door. It's really difficult to open."

'Norman' does not refers to a door from the Norman period of British history.  Instead, 'Norman' refers to a door that works in a way that Donald Norman has popularized.

Donald Norman is currently

  • co-founder and consultant with the Nielsen Norman Group
  • co-director of the joint MBA and Engineering program at NorthWestern University
  • Distinguished Visiting Professor at the Korea Advanced Institute of Science and Technology
  • Emeritus Professor of Cognitive Science at the University of California, San Diego

Professor Norman started his career as a cognitive scientist interested in how the human mind works.  He focused on perception, attention, and memory.  When he visited Cambridge, England on a sabbatical to the Applied Psycholgy Unit at the Medical Research Centre, he became quite frustrated with the building in which he had to work.  This was neither the first time nor the last time.  Out of these frustrations and those before, he wrote a book entitled "The Psychology of Everyday Things".  His friends liked his book, but the book didn't sell particularily well.  The first sentence in his book (quoted above) is about the design of doors.

Norman's publisher had a problem with the book and convinced Norman to change the title of the second edition to "The Design of Everyday Things".  The editor explained to Norman that visitors to bookstores read the spines of books as they browse and that bookstores often shelve their stock according to keywords in the title.  Changing "Psychology" to "Design" had two important effects:

  • the new title more accurately expressed the contents of the book
  • bookstore staff shelved the book in the design section rather than the psychology section (a user primarily interested in design seldom browses the psychology section)

Evidently, Norman had committed the same error that many designers of unusable everyday things commit: self-centeredness.  The change of title by the publisher corrected this shortsightedness.  Norman's book is now a best-seller and one of the classical works of HCI.

In his book, Norman highlights three points:

  1. "it's not your fault" - it's the fault of the designer
  2. "design principles do exist" - they speak to
    • conceptual models - we continually try to find meaning in the events around us - we need conceptual models of how things work - the conceptual model associated with any thing has to come about by the appearance of the thing itself - the thing, whatever it is, must explain itself to us
    • feedback - it is important to show immediately the effect of an action on a thing - if the thing does not show the effect immediately we are left wondering if our action has had any effect
    • constraints - constraints make a thing easier to use - the more constraints that exist, the less the chance of error
    • affordances - all appropriate options must be perceptible, while inappropriate options should be invisible.
  3. "observation matters" - learn to watch, learn to observe - observe yourself, observe others.

Donald Norman is one of the major contributors to CHI.  He defined "user satisfaction functions" in the first CHI 83 paper.  Most recently, he has published a new book stressing the role of aesthetics in our response to objects.  His new book is entitled "Emotional Design: Why We Love (or Hate) Everyday Things". 

Here is Donald Norman's 2003 talk on Emotional Design:

at Technology, Entertainment and Design (TED).


Notwithstanding CHI's refocusing on aesthetics, marketing, and non-rational persuasion, usability remains one of the most important properties of good design.  Cognitive engineering treats usability as central. 


Consider the Vincennes tragedy:

"In 1988, the USS Vincennes guided missile cruiser shot down an Iranian airliner over the Persian Gulf with almost 300 people aboard. There were two failures in this incident. The radar operator interpreted the airliner as an F-14, descending as if to attack, rather than (in reality) a civilian plane that was climbing after takeoff. Both failures seemed to be caused by user interface. The IFF system was reporting the signal from an F14 on the ground at an airport hundreds of miles away, not the signal from the airliner; and the plane's altitude readout showed only its current altitude, not the direction of change in altitude, leaving to the operator the mental comparison and calculation to determine whether the altitude was going up or down." (Peter Neumann, "Aegis, Vincennes, and the Iranian Airbus", Risks v8 n74, May 1989).

The absence of an indicator showing whether an aircraft was ascending or descending was an error in the software design process.  The contractor focused not on good design or what is needed, but on cost and giving the Navy what is said it needed.  The IFF mode error was a user-interface design error.  While the operator was tracking the flight with his cursor, the IFF system was reporting the result from the last location.  (Luke Swartz)

Usability Studies

Usability studies evaluate how good a system is, how well users can use its functionality.  They measure:

  • learnability
  • efficiency
  • memorability
  • error rate/severity
  • subjective satisfaction

Usability dimensions are NOT uniform for all users and are NOT uniform across all applications.  In usability studies, we try to understand the different classes of users:

  • novices
  • infrequent users
  • experts
    • domain experts
    • application experts
    • feature experts

Interface Design is Hard

User interface design can take 50% of total development effort.  Certain principles are well-accepted in HCI. 

  • The developer is not the user.  Users are always right.
    • Software engineering is about communicating with other developers, typically like ourselves
    • Usability engineering is about communicating with users who are typically unlike ourselves

  • Users change:
    "Users aren't oracles. They don't always know what they want, or what would help them. In a study conducted in the 1950s, people were asked whether they would prefer lighter telephone handsets, and on average, they said they were happy with the handsets they had (which at the time were made rather heavy for durability). Yet an actual test of telephone handsets, identical except for weight, revealed that people preferred the handsets that were about half the weight that was normal at the time." (Klemmer, Ergonomics, Ablex, 1989, pp 197-201).


One of the most common reasons for poor designs is an out-of-balance focus that neglects the user's needs and goals.  Kevin Scoresby (2004) has listed seven excuses for poor design:

  • We have to be first to market (Translation: We don't have time to make sure the product meets our customer's needs)
  • Our budget doesn't allow for design specialists (Translation: We can't invest what's needed to maximize long-term company revenue)
  • The requirements make it clear what has to be done (Translation: Simply including certain features is more important than how those features are implemented)
  • Well, it makes sense to me (Translation: I'm a representative sample of our customer base)
  • It will be so cool if we do it this way (Translation: My personal target audience is my co-worker (or resume) rather than the customer)
  • Customers will get used to it (Translation: Customers will continue using the product long enough to lose touch with how difficult it is)
  • That's what the help desk is for (Translation: The design issues will soon be someone else's problem)

Hall of Shame

Here are a few examples of poor designs that have been published on the Internet:


  • Read Norman's book
  • Check out this web site