While wandering through the Gangaram’s , one of the largest book stores in the city, I stumbled upon this book and was immediately stimulated by the fact that it was written by Norman. I decided to plunge to this book as my fascination of design was pretty evident after the usage of i-pod, a product which to my knowledge has an immaculate design.
The book as the title states is about the understanding of the every day things and the importance of design element in each of them.
First a word on the cover page – , the picture of a coffee pot invented by the French artist Jacques Carelman ."Coffeepot for masochists" is what he called it, and it is quite unusable, for the handle is on the same side as the spout. Just goes to show that hitec things become so unusable.
In the first chapter of the book, the basic philosophy of POET (Psychology of everyday things) is revealed, where it states the design of any thing should be based on the needs and interests of the user with an emphasis on making the products usable and understandable.The author takes us through a number of everyday examples which lack some of the elements of good design.Swinging glass doors where people get trapped, telephone with innumerable functions but poor design, cooling unit of refrigerator, seat adjustment in Benz car, floppy drive etc. In all these examples there lies a common thread of presence / lack of core design principles.
As per POET, there are 7 design principles that need to be followed:
1. Good Conceptual Model: Usage of Knowledge in the head and Knowledge in the World. Providing a model to the user which has a consistency in presentation of operations and results, besides providing a coherent system image.The designer’s mental model and user’s mental model should be in synch with the system’s conceptual model.
2. Simplify the structure of tasks- Use Affrodances: Affordance refers to the perceived and actual characteristics, properties of the product. These decide the way the device would be used.These provide strong clues to the usage of the devices
3. Make things Visible : By Looking , the user should be able to tell the state of device and the alternatives for action.Bridge the gulf of execution and gulf of evaluation
4. Get the Mappings Right : Relationship between action and control.Make sure that user can determine the relationships
Between intentions and possible actions
Between actions and their effects on the system
Between actual system state and what is perceivable by sight, sound or feel
Between the perceived system state and the needs, intentions and expectations of the user
5. Exploit the power of constraints:The usage of constraints in the design such as Physical, Semantic, Cultural and Logical helps the user know, use, experiment and ultimately become convenient with the device.
6. Feedback (Design for error): Full and continuous feedback of the actions.
7. When all else fails, standardize
The above design principles become all the important in this increasingly technological world where we seem to confront with the paradox of technology, a time when the things provide a whole host of functions in a device , however it also results in complicating the usage of the whole product.The end result is gulf of execution ( difference between intention and allowable action) and gulf of evaluation(amount of effort required to know the state of the system and determine how well the expectations and intentions have been met) . It should be designer’s endeavor to reduce both the gulfs to minimum.
One way to dissect and start analyzing a device in its design rigor is to look at the following framework of action. The author describes the 7 steps of action as
Forming a goal + Forming an Intention +Specifying an action + executing the action + Perceiving the result of the action + Interpreting the state of the world + evaluate the outcome
The combination of 2 factors i.e Knowledge in the World and Knowledge in the Head are used by users to work with devices efficiently. In most of the situations , there is a trade-off between 2 factors where the knowledge in the world is structured in such a way by the user that knowledge in head is minimized.
Incorporating error element in the design:
Errors come in 2 forms. Slips and mistakes. The fundamental difference between the two is this : Slips are a result of a wrong execution of a activity which has been done so many times that it forms part of sub conscious mind. User typically has the right goal in his mind as far as the slip is concerned. When a user committs a mistake, it is usually to do with the wrong goal in mind.
Slips can be classified in to 6 categories :
1. Capture slips:When two different action sequences have the same initial tasks but have a different sequence towards the end, the most commonly used activity sequence is carried out for all the similar activities thus causing a slip
2. Description slips: These tend to happen when the wrong and the right object , are at a close proximity
3. Data Driven errors: These are automatic reactions to some events and can intrude in to the action sequence of a user
4. Associative Action error: When 2 activities take place at the same time and user needs to attend to both the events, it is possible that he makes a wrong association between the event&what’s he supposed to do.
5.Loss-of-activation error :Forgeting something
6.Mode errors: This happens when devices have different modes of operation. Action appropriate to one mode has a totally different implication to another mode.Time devices and computers are some examples where users can come across mode errors
Why do we need to know the kinds of slips and how does it help in the design?
It helps in design in 2 ways. One is try to design in such a way that these slips/mistakes do not happen.Secondly,incase a slip/mistake happens, provide feedback readily, easily and accurately and in a form consistent with user’s goals.
One way that is commonly used to reduce errors is to have forcing functions which will stop the effect of one error to produce a cascading effect. Lock-in(Automatic switchoff of device), Lock-out(seal the cellar during fire mishap) and Interlock (ovens)are typically the forcing functions used in various devices.These help narrow the gulf of execution and evaluation.
What is the design challenge?
From a designer’s perspective, the needs of his clients are different from the needs of the end consumer. Clients are typically from the purchase department and other non-user department of the company, where the cost and fast deployment is all a client looks for.Hence usability does not figure in the scheme of things in the mind of the designer. Besides, the hunger of extra features and worshiping false images(placing hi-tech gadgets in the office to show off that the firm is high tech) also are driving the designers to incorporate more and more features and thus making the usability a lesser priority item.Hence most of the designers put aesthetics first , cost second and somewhere a distant third comes usability.
Typically the best design is the one which arises out of evolutionary design, i.e design that comes out of various experiments and tests. Examples include telephone, type writers which have evolved over a certain period of time and people have become quite comfortable with the design.However because of the factors mentioned previously, it is difficult for the device to take its path of evolutionary design. In such situations it is better for the designer to build a lot of experimentation in to the product. This invite to experiment must be built using the same principles like visibility, mapping, lesser cost to experiment , feedback so that the evolutionary period for each user is shortened.
Final thoughts on User-Centered Design :
Make it easy to determine what actions are possible at any moment of time (Constraints)
Make things visible, including the conceptual model of the system, alternative actions and results of the action(Visibility)
Follow natural mappings between intentions and the required actions, between actions and resulting effect and between the information that is visible and interpretation of the system(Mappings)
Make it easy to evaluate the current state of the design(Conceptual Model, Feedback)
If the design involves big instruction manuals, or makes user think" How am I going to use remember this ?" – It is a clear sign of a bad design.
This book has truly enhanced the way I look at the world. In the past days itself , I have started noticing various products and appreciate / critique the design that went in to it. I can relate a lot of principles mentioned in the book to a mundane activity like a website design. I think this book serves a good primer for me to go on to the book that I wanted to read "Emotional Design". Planning to lay my hands on it asap.