Category Archives: Foundation to Human Computer Interaction

Discussions and study research on foundations to Human Computer Interaction. Covering topics like Interface efficiency, KLM, GOMS, The Human Processor Model, Fitts’ Law, Feedback, Errors, Forcing, Gestalt laws, Responsiveness, Seven Stages of Action, Visibility, Affordances, Mapping, Constraints & Conceptual models, State Transition Diagrams, Petri Nets and so on.

Human Computer Interaction – Future and History

Human Computer Interaction Future
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Self Notes:
This lesson is quite interesting as it did not just explain the history of human computer interaction – it also explained the future applications of the HCI field.

  • The future of human computer interaction dated back even before the term ‘human computer interaction’ or ‘interaction design’ was coined. In the 1960’s Doug Englebert created the first pointing device interface. The first mouse demonstrated how easily humans could interact with computers.
  • Anything the involves an interaction between a computer and a human being can be considered within the subject of human computer interaction.
  • The key focus of human computer interaction now is the end user and designing interactions that create a usable experience for this user.
  • The concept of human computer interaction future be a shift from ‘average user centered’ design artifacts to ‘people centered’ design.
  • Adoption of technology has 3 phases: Enthusiast Phase – The enthusiast use it, Professional Phase – It is used in work environments, Consumer Phase – Used in daily phase.
  • For a product to reach the consumer phase it must designed in such a way that it can be used without any special effort and can pass most severe usability tests. This is where experts in field of human computer interaction will help companies and organizations to make the shift in phases of technological adoption.
  • Human computer interaction future: Everything learned in the perceptual, emotional, social and cognitive processes of the human mind will be applied to create a silent and invisible computing.

State Transition Diagrams, Petri Nets

State Transition Diagrams, Petri Nets
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Self Notes:

  • State Transition Diagrams (STD) is a modelling tool that helps developers and designers understand the interaction and operation between a computer and user.
  • STDs is used to describe the behavior of a system
  • A system can have only one initial state but can have many final states
  • States are dependent of time and attributes of the system.
  • Petri nets consists of nodes and arcs. They are used to model distributed systems


Book Review: The Design of Everyday Things by Donald Norman

by Jinesh Parekh,
Masters in Human Computer Interaction (Student)

The design of everyday things - Donald Norman

Overview: About the book and the Author

After reading ‘The Design of Everyday Things’ I have come to believe that it wouldn’t be an exaggeration when people address Donald Norman man as the father of usability and design. Published in 1988, ‘The Design of Everyday Things’ has revolutionized the functioning of several industries, businesses and scientific disciplines like industrial design, user interface design, user experience, interaction design and of course human computer interaction.

A bible for designers, developers, innovators and project managers? I have been thoroughly impressed by this Donald Norman’s work and his ideologies on design. It’s been pointed out over and over again in this book that good design can be the solution. The book illustrates several different examples of how good design can be a game changer for many organizations and how bad design can completely murder the effectiveness (and usability) of a product no matter how sound the science is behind the workings of the product. What makes Norman’s work extraordinary is his easy-go styled narration and sharp observations on the psychology of usage. He provides a deep insight on how people use everyday objects. The ‘end user’ and his/her experience is made the center of focus in his study. He talks about the different emotions felt and the experiences gained by the user while operating everyday devices.

There are many designers around the world that have read this book. After all, it’s been in circulation for over 24 years and is still far ahead of its time. The book was written in 1988 and I strongly believe that the designers who implemented the learnings from this book have created better products, services and experiences for users around the world. Donald Norman is a visionary and any person who loves creative thinking will enjoy reading this book.

Ideologies and Learning: Lessons learned from this book

As mentioned before, the central focus of this book is the user and how everyday objects should be designed in way that it is easy to learn, easy to use and is functionally fast. Norman does this by emphasizing on the psychology of tasks and actions. He fruitfully manages to make designers change their ‘task oriented philosophy’ to a ‘goal oriented philosophy’. Objects are used to achieve goals, not tasks – he points out. This marks a substantial shift in philosophy of design – no matter how experienced or new the designer may be, it makes him/her reconsider the style, method and process of design.

“Design is really an act of communication, which means having a deep understanding of the person with whom the designer is communicating.”

– Donald Norman
He explains that a designer should aim to the correct mental model of how a user would behave to achieve his goals through a series of actions and how it can be done if the design has the right amount visibility, affordances and constraints. To put it simply, affordances are what functionalities or actions the design should/can offer to the user and constraints are what functionalities or actions the design should not / can’t offer the user.

The book contains a series of scientific-psychological study references presented in a short, precise and easy to understand manner. Two such exquisitely explained phenomenon, that I thoroughly enjoyed reading the most, are the structures and workings of (short term and long term) memory within the brain and the function of knowledge that could be embedded within the brain, a design or in the environment. Prior to this book, designers never accounted for this – which is why most them did not know how human beings use knowledge and memory in accomplishing simple tasks. This is reason why we have bulky manuals. To Norman, manuals and instructions kill usability.

“Any time you see signs or labels added to a device, it is an indication of bad design: a simple lock should not require instructions.”

― Donald A. Norman
The design itself should signal the appropriate actions. He repetitively signifies the importance of how intuitive designs, that do NOT require special efforts to perform tasks, lead to the success of the artifact and how it distresses the user. This is imperative in understanding how a good piece of equipment needs to be designed. Personally, I would love to see a world without manuals.

He fundamentally inspects how often and why users feel confusion, anger, frustration, guilt or shame simply by their inability to use or learn how to use a particular device. He eases the reader, through systematic explanations and examples, by telling them that it’s only human to make mistakes and their inability of usage arises from poor design decisions made by the designer/manufacturer and not due to a fault of their learning capacity. According to Norman, devices can be made easy to use or learn if the designer follows a few simple design strategies at the stage of development. The most important strategy of this sort such is: Good Design = Natural Mapping (i.e. account for all possible user actions/goals and errors) + Natural Design/Interface. He mentions that users crave for visibility of crucial elements, simplicity in use and appropriate feedback after every action they take in the design of their product or service.

“Principles of design:
1. Use both knowledge in the world and knowledge in the head.
2. Simplify the structure of tasks.
3. Make things visible: bridge gulfs between Execution and Evaluation.
4. Get the mappings right.
5. Exploit the power of constraints.
6. Design for error.
7. When all else fails, standardize.”

― Donald A. Norman, The Design of Everyday Things

He urges people (his readers) to test products before buying them and keep usability an important criteria for purchase. This makes sense. Most of the times, when we buy things, we look at the price, features or the quality of the product in our mind while making our purchase decision. Keeping ease of everyday use in mind while buying a product would not only change the way we buy products it would also force manufacturers to rethink their designs. The cumulative effect of this approach could do wonders to the world.


I cannot think of any complaints or criticisms from this book. I enjoyed reading it thoroughly. The book has had several revisions and it seems that Norman has really gone through a lot of trouble to make sure readers from any background can understand this book. However, for experts within the field of design, usability engineering or psychology – the examples and illustrations in the book may seem a bit repetitive. A colleague of mine, who has also read this book, mentioned –

“I like this book but after a while I just quickly browse through some of the paragraphs like it’s a magazine article without paying much attention to the illustrations or examples. I understand what he is saying and I don’t need so many examples to get his message. The entire book could be made more concise!”

Conclusion: How can this book help you?

It doesn’t matter if you are an experimental scientist or an electrical engineer, a computer programmer or telephone operator, an entrepreneur or a software designer, this book is highly recommended for individuals who appreciate forward thinking, creativity and logic. The applications of the knowledge/lessons derived from this book are endless. The ideas presented in this book 24 years back are now being used (or under development process).

With numerous well explained examples he really makes the reader re-think the world. It certainly made me rethink the way I interact with everyday objects like tea-makers, ovens, maps, laptops, elevators, phones etc. From opening locks to your door to using a calculator for making some calculations, from switching the radio on your car to listen to music to handling a projector to make presentations, this book will create a storm of thoughts and will make you change the way you have interacted with objects and the emotions you must have felt while doing so.

Movie Review and Reflections: Objectified

By Jinesh Parekh and Thea Schrenk

DISCLAIMER: Most of the subject matters in this film are closely related to the field of human computer interaction and our opinions and reflections will be based on this perspective

movie review objectified
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“When you see an object, you make so many assumptions about that object in seconds. What it does, how well its going to do it, how much do you think it should cost? The object testifies to the people that conceived it, developed it, manufactured it…Anything that is touched by man is transformed by man is by its very nature of design.”

–Objectified Film

Objectified, a movie made in 2009 by Gary Hustwit, talks about the creation and thought process behind the everyday objects that we use and interact with. It primarily focuses on the important relationship between an object and its design by making us more aware of subjects like industrial design, mass production, design sustainability, interaction design, human computer interaction and their ancillary fields. This is the second part of a 3-part series called Design Trilogy that gives us an insight on the role of everyday objects in our life and the people who use and design them.The discussions in the movie provokes the watcher with interesting ideas, trends and awareness about designs and objects, the production and usage of objects by human beings and the future of planning and creation.

After watching this 75 minute film, we were invoked with all sorts of different questions like
‘Why is this chair made of metal?’,
‘Why does this bagpack look like this?’
‘Why are most cups round and now square?’
‘Why do shower heads have holes in a particular way?
‘Why does wood create a feeling of warmth in us but the feeling of sand paper irritates us?’
‘Why does a telephone have a notification light?’
‘Why don’t we have reusable sticks in a toothbrush?’
‘Why aren’t things built to last?’
‘Why aren’t clothes waterproof?’
‘Why do we have icons?’
‘Why book cover have to be hard and the pages so soft?’
‘Why is this property about these small capsular pills that makes us perceive it as medicine?’
‘How to make things more efficient?’

Questions like these and many more made this film an interesting watch as even after you finish watching the movie, you don’t stop thinking about it. The movie contains many interviews and talks from renewed old and young designers from around the world on their ideas and philosophies behind the design of an object.

As mentioned in the movie several times, every object has a story of its own and a purpose to our human lives. From the time it was created to the time it was reached the market and from the time it was bought and used to the time its was discarded . Different objects have different meanings to our lives. On one of your busiest days something as unimportant as a coffee maker could be your best helping friend. On a forgetful day, a reminder on your smart phone can save you, reminding you on your grandparents anniversary. On a sad day playing a music instrument like the violin can help you unwind and relax. What is it about objects that trigger emotions?How can a designer give objects a character to create the desired experience?

A well designed object is capable of communicating with its user just by its function or form. It enables us to create memories. It is no wonder that people have spent years perfecting a simple tool like a coffee cup or a telephone. The movie illustrates scenarios on how to design well and what should a good design be made of. Well designed objects do not just look pretty, they are meant to serve and fulfill a function. Good design is not produced in the studio, it occurs by observing behaviour and needs. Good design is natural design where unnecessary things are taken away. Good design is under designed. It’s almost as if it wasn’t designed! An object can be well designed only if designers are intellectually and emotionally involved in the process of problem solving through innovation in design.

Gutes Design sollte Innovatives sein.
(Good design should be innovative.)
Gutes Design macht ein Produkt brauchbar.
(Good design should make a product useful.)
Gutes Design ist esthetisches Design
(Good design is aesthetic design.)
Gutes Design macht ein Produkt verständlich.
(Good design will make a product understandable.)
Gutes Design ist ehrlich.
(Good design is honest.)
Gutes Design ist unaufdringlich.
(Good design is unobtrusive.)
Gutes Design ist langlebig.
(Good design is long-lived.)
Gutes Design ist konsequent bis ins letzte Detail.
(Good design is consistent in every detail.)
Gutes Design ist umweltfreundlich.
(Good design is environmentally friendly.)
Gutes Design is so wenig Design wie möglich.
(Good design is as little as possible.)

Dieter Rams, Former Design Director, Braun Kronberg, Germany

The evolution of design has always been centered around this very idea. How can things be made better, faster, lighter, simpler, more functional, aesthetically pleasing and affordable that can truly improve the users’ experience. A user centered focus on design has lead rapid development in the fields of industrial design, interaction design, human computer interaction and universal design. Experts from various fields like these spend their life studying what it means for an object to have a good design and an artefact can solve a human problem.

The tools and objects we use everyday are not just affected by the thoughts of the designers, they are also affected by our choices. The relationship between price and design, modern day marketing, logistics, availability and policies also govern what we use and the way it is being used. The movie therefore appeals to designers to consider the economical, social and practical side of things while creating a product design that will be used by millions.

The movie raises awareness on the challenges faced by designers. Designers spend maximum of their time designing for the 10% of the world population that already own too much while 90% don’t have even basic products and services to lead a subsistent life. The mass production of goods and their wastage speaks volumes about how design, as of today is not made to last. The life cycle of a product is not just from the time it was bought to the time it was used. Designers need to think beyond product experience and need to think about what will happen to the product after its been designed? Why do most designed objects end up in landfills? Design should be forever. Design should be as such that it increases value over time and use. Objects should wear in instead of wear out. We don’t need to create new objects but we need to create new systems. We need to rethink processes and design systems that reduce consumption instead of increasing it.

Lastly, this movie throws a light on interaction design and human computer interaction. As trends have shown, Objects do not just exist in the physical world, they also exist in the digital world. the virtual e-card was very real communicating your emotion to your loved one. That conversation you had with your uncle through a VOIP application on your laptop was very real. The knowledge you got from that book you read on your plastic, glass and metal tablet is very real. The study of industrial design is now integrating with the field of interaction design and human computer interaction. Its no longer about creating hardware or software. It’s about designing for interaction.

To conclude, we recommend every person within the design or development industry watch this movie. Although the movie can be a bit irritating when some of the designers appear as nassarcists when the talk about the future of design how they will be recognized as cultural generators, we believe design will be a significant element in decision making and that the overall ideas discussed by the interviewers are often ignored by us. Design will create scenarios that shape people’s lifestyles. It’s not the designer who will be a crucial part of the design process, its the people will be a part of the design process in the future.

“Design needs to be plugged into human behavior. Design dissolving in behavior”

Naoto Fukasawa, Industrial Designer, Former Head of IDEO.

Interface efficiency, KLM, GOMS

Interface Efficiency
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Self Notes:

Interface efficiency helps quantify whether a design is functional or not. It is a fantastic technique to design better interfaces. It also tells us when you can stop looking for better design. Efficiency is usually measured as time on task, one of the quintessential usability metrics. It does not tell us how easy the interface is. It does not help us determine how fast the user will be and it certainly cannot detect beauty.

Can a new design make things faster? Sometimes. But by the time usability is measured it’s too late to change the interface!

Interface efficiency helps us determine when is the right time to stop looking for a new design.

KLM: The KLM requires that you describe how the user would do the task in terms of actions at this keystroke level. Basically, you list the sequence of keystroke-level actions the user must perform to accomplish a task, and then add up the times required by the actions. KLM helps us determine the time taken for various key stroke level tasks.

A few key stroke level tasks can sum up everything we do with a computer within the metrics of time:

  • Homing: Moving Hand to Keyboard or Mouse: 360ms
  • Clicking: the Mouse: 230 ms
  • Pointing: with the Mouse: 1100ms
  • Mental Operations: (Deciding what to Do): 1350 ms

GOMS is a modelling technique for Human Computer Interaction is based on the CMN model. It is a design method based on cognitive psychology. It takes into account 4 levels of cognitive activities:

  • Goals: What the system user wants to accomplish
  • Operators: Are actions available to user. Can by physical or mental.
  • Methods: What methods can the system user use to accomplish his/her goals
  • Selection Rules: What methods will the system user select to accomplish his goals.

Understanding Interface Efficiency through Aza’s blog was very interesting. However, KLM and GOMS took me a lot of time to understand. I understood the concepts thoroughly and its applications, however I must revise this again after a few weeks as many new terms were introduced in this lesson and this was possibly one of the most intensive one so far!

I have started playing around with CogTools. So far, I do not understand much. Will need to read their documentations.


The Human Processor Model & Fitts Law

Fitts Law
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Self Notes:


This tool is probably one of the best ways to learn the fundamentals of Fitt’s law. It’s a fantastic way to understand the different variables that make up this law.

The Fitt’s law depends on 3 factors:

  • T is the average time taken to complete the movement.
  • D is the distance from the starting point to the target’s center.
  • W is the width of the target (measured along the axis of motion).

What are the implications of this?

  • While designing a UI, the designer needs to makes sure the buttons are large enough and close proximity for the action to be completed quickly.
  • If the actionable object has been put far away, it would be important to compensate it by making the object larger.
  • It helps us determine which is the best pointing device that be used in order to achieve tasks quickly and efficiently.
  • While we are using pointers – the edge of the screens are the easiest to target. This is because they have infinite width and height. While designing a UI, if the user needs quick access to something, one should make sure that  the quick access icons/menus should be towards the edges for quick access.
  • Although the right click menu is effective – the pie menu can be more effective than the right click menu.
  • The pixel you are pointing at is the easiest to click. But the corners of the screen are almost as easy to point.

Disadvantages of FITTs Law:

  • Predicts only one dimensional movement. Doesn’t account for z axis.
  • Absence of a consistent technique to deal with errors

Is an attempt to understand the goals of task analysis, calculation and approximation. It enables us to predict user performance to a certain degree.
The model works on two principles:

  1. Set of processors, memories and their interconnection
  2. Set of principles of operation

Once complete, the calculations can then be used to determine the probability of a user remembering an item that may have been encountered in the process. The probability could then be used to determine whether or not a user would be likely to recall an important piece of information they were presented with while doing an activity.

Factors affecting the Principles of Operation:

  • P1: Variable Perceptual Processor Rate Principle: The Perceptual Processor Cycle Time varies inversely with stimulus intensity i.e. Th Perceptual Processor Cycle Time will be lesser if the stimulus intensity will be high and vice-versa.
  • P2: Encoding Specificity Principle: Specific encoding operations performed on what is perceived determine what is stored, and what is stored determines what retrieval cues are effective in providing access to what is stored. The principle states that memory is most effective when information available at encoding is also present at retrieval.
  • P3: Discrimination Principle: The difficulty of memory retrieval is determined by candidates that exist in the memory, relative to retrieval cues.
  • P4: Variable Cognitive Processor Rate: The cognitive processor cycle time is shorter for greater task demands and increased information loads; it also diminishes with practice
  • P5: Fitts Law: The time (t) to move the size of the target (s) which lies at a distance (d).
  • P6: Power Law of Practice: The power law of practice states that the logarithm of the reaction time for a particular task decreases linearly with the logarithm of the number of practice trials taken.
  • P7: The uncertainty Principle: Decision time increases with uncertainty of decision or judgement to be made.
  • P8: Rationality Principle: A person acts to attain his goals through rational actions, given the structure of the tasks and his inputs of information and bounded by his limitations on his knowledge and processing ability. Goal + Task + Operators + Input + Knowledge + Process Limit  = Behaviours
  • P9: The Problem Space Principle: The rational activity in which people engage to solve a problem can be described in terms of 1) a set state of knowledge, 2) operators for changing one state to another, 3) constraints on operator movement and 4) control knowledge for deciding which operator to apply next.

Some applications of CMN Model:

  • Moving Picture Rate
  • Determining Perceptual Causality
  • Reading Rate
  • Reaching a button


Feedback, Errors, Forcing, Gestalt laws, Responsiveness

Feedback, Errors, Forcing, Gestalt laws, Responsiveness
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Examples of Various Errors:

  • Capture errors: While coding in HTML, I double click on the file icon instead of right-click and open with Notepad++. By double clicking it opens the file in Google Chrome.
  • Description errors: While using public transport in Tallinn, I have often scanned my loyalty card from co-market (a super market close to my house) because the cards look the same.
  • Data-driven errors: When I am on the go and I have to take quick notes like a phone number for a pizza place, and if my facebook on my smart phone is open, I usually use the text editor in the ‘messages’ to type the number. I tend to forget that FB text editor does not allow copy of text while typing a message.
  • Associative activation errors: To save money on international calling I use an app called Localphone. Localphone creates separate routing numbers with local extensions for international calls i.e. for every contact I have, there are two possible numbers. I usually call on the actual number instead of the routing number.
  • Loss-of-activation errors: When I am composing an email on my smart phone and I get interrupted by a facebook message notification. When I try to go back on ‘display all apps’ I forget what I started.
  • Premature conclusion errors: Shutting my PC when the display goes off but not the processing light. Always happens with Windows 8.
  • Mode errors: Trying to listen to music on my smart phone while it’s on silent mode.

Self Notes:

This is probably one of the best lectures so far. Whilst I enjoyed studying Feedback, Errors, Forcing and Responsiveness, I thoroughly enjoyed the concept of Gestalt Laws. It’s amazing how these set of rules have changed the way I look at information, systems, objects and design. I look at my past work experience and I believe my quality of output would be so much better if I knew what I know now because of these simple and fascinating set of laws.

Seven Stages of Action

Seven Stages of Action
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Self Notes:

The second module gives an insight on how a good interface designer should consider the seven stages of action. Doing so, shifts the focus from designing to achieve tasks to designing to achieve goals. It’s important to understand how humans achieve goals through the a series of actions that are wonderfully explained using this diagram:

Seven Stages of Action
Seven Stages of Action

This module also explains that the usage of a device or tool should have information embedded into the environment instead of the brain. Knowledge is gathered through experience.  The tool should demand minimal cognitive effort by the user thereby reducing the gulf of execution. Feedback should be instant in order to minimize gulf of evaluation.