So, what does the term ‘constraints’ mean in web design?
By definition, this term refers to the restrictions placed on the number of user actions allowed which results in reduction of the chances of operator error while also increasing the usability of the design.
If one must understand constraints, in terms of web design, it’s important to comprehend both psychological as well as physical constraints too.
#1: Physical Constraints
This aspect of constraints deals with restricting the user from performing action on a particular object, whether they can be defined as virtual or actual. Usually there are three types of physical constraints used, and they are axes, barrier and paths.
Paths restrict users from performing linear or curvilinear actions (such as the iTunes volume bar) while axes allow users to perform rotary action (such as the Illustrator CS6). Barriers, on the other hand, either deflect, prevent or slow down certain user actions that are detrimental to the overall experience with a common example being a dialog box that ask “Are you sure you want to continue?” which you will find on e-commerce interfaces.
#2: Psychological Constraints
This type of constraint limits user actions by taking advantage of how users view and understand the environment. Symbols, conventions and mapping are three methods by which psychological constraints are applied.
Symbols use text, sounds and icons which categorize, clarify and caution users about certain actions, with an error sound made by the PC when an incorrect entry is made being an excellent example.
Conventions create restrictions based on previously learned exercises and customs and the use of both a red and green button can clue the user as to what purpose each of these buttons serve.
Finally, mapping is able to manage user behavior by creating a relationship between two elements of a design. One example of this is the placement of radio buttons next to choices that a customer has to make.