Normans+Principles

Donald A. Norman is the author of the book "The Design of Everyday Things", where he illustrates the psychology behind 'good' and 'bad' designs. Norman has come up with a few basic principles that will help designers design better products. By using these design principles and taking them into consideration when designing everyday products, it can help prevent simple but often overlooked design problems with everyday products. Norman's design principles include: Visibility, Feedback , Constraints , Mapping , Consistency and Affordances.

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Visibility
The visibilty principle simply states that the basic functions of the system or product easy enough for a user to understand and use. All performance aspects of the product or system should be relatively obvious to the user. The user should not find it difficult to understand the product or system if the visibilty principle is followed. The functions of the system or product should be evident just be looking at the device.

Feedback
The feedback principle states that while using the product or system there should be some immediate and obvious kind of signal to let the user know that there was a response or a result. Some sort of system feedback should let the user know that they have done something. These signals could be audio or visual cues or something that is obvious to the user and it will let them know that did something. The response must aslo make sense and let the user know if what they are doing is correct or incorrect.

Constraints
The constraints principle is useful in stopping users form taking certain actions that are not suppose to be taken with certain devices. There are physical, semantic, logical, and cultural contraints. Some constraints are put into place because some actions should never be executed on some products or devices. Perhaps a certain action would destroy the product and a contraint is put in to prevent this from happening. Examples of physical constraints: seat belt, locking mechanism, USB-port (only one way to insert the USB key). Examples of logical constraints: speed limit, log-in system. Examples of cultural constraints: language, keyboard for different languages.

Mapping
Mapping principle also known as 'natural mapping' means that there should be a logical and/or cultural spatial/temporal relationship on how the product is used and displayed. There should be a relation between actions and intentions on using the product or system. The more clear the relationship is the easier it is for users to become accustomed to the product or device. One problem that exists with mapping is that the more complex the system or device is the harder is it to make it easy to use. If you do not take into account previous relations, users will become confused on your random mapping. For example, the cursor keys on the keyboard.

Consistency
The consistency principle allows users to 'get used to a product or system' and therefore once they learn how to use it, they can continue to use it because given actions produce the same results so it is consistent every time. Consistency must also be taking into consideration as to other similar products or systems in the market, e.g. VCR, the key pad of cellular phones, and the layout of retail chains such as Home Depot and Starbucks.

Affordances
"Does the design provide intuitive clues on what can or should be done?" e.g. to push or pull a door.

Works Cited Professor Jones Lecture Two and Three
 * http://www-static.cc.gatech.edu/classes/cs6751_97_fall/projects/follow_me/exam/alexandre.html**