Fundamental Principles of Design Part-3
In the first two parts of this series we have discussed about Affordances and Signifiers in part-1 and about Mapping and Feedback in part-2. In this last part of the Fundamental Principles of Design series, we will be discussing about the remaining three fundamental principles which are Constraints, Discoverability and the Conceptual Model.
Constraints
Constraints are clues that limits the number of possible actions for a user thus simplifying its use and interaction for them. It helps them take appropriate action on the basis of the constraints present.
There are four classes of constraints which seems to be universal and are being applied to numerous different scenarios.
Physical Constraints
Physical constraints is about providing limitations using the physical properties for executing the possible set of actions.
In order for the physical constraints to be more effective and useful, it’s necessary that the constraints provided are easily visible and interpretable hence preventing any incorrect action beforehand. It happens many times that the physical constraints provided prevent wrong action from succeeding but only after it’s tried by the user.
Cultural Constraints
Cultural constraints are the allowable actions for social situations which can be universal or particular to any specific culture. These are restrictions which have resulted in what is considered to be appropriate and correct within that culture. Some cultural constraints are uniform everywhere while many are specific to particular cultures.They likely change with time.
Conventions are also a kind of cultural constraints.
Universally accepted interface convention is the concept of windowing for displaying information. A window with a basic set of possible actions is universal convention for displaying any kind of information. The position of the icons inside the window might change like icons on the top left in linux based operating systems whereas it being on top right side in windows operating system but the basic structure remains same.
Another universally accepted convention is the use of icons and it’s label beneath for the apps on the phone. This convention remains same disregard of the different operating systems be it android or ios.
Semantic Constraints
Semantic constraints are described as those that rely on the meaning of the situation to control the possible set of actions. It depends on the user’s knowledge of the situation and of the world for the usage of the product/service.
Semantic constraints can change with time.
Logical Constraints
Logical constraints are the one which makes use of reasoning and logical relationship to determine the possible actions.
For example after reassembling any device, if there is a part left, it gives clue to the user that the device is not assembled properly and there has to be a place where this remaining part will fit.
Conceptual Model
A conceptual model is basically an explanation of how something works. Conceptual Models need not be complete or accurate but they should provide clear and easy way for the users to understand and remember the functioning of the device.
Conceptual model helps enhance the discoverability and helps evaluate the results of the action taken. It helps the user predict the possible outcome for the action taken by them.
Quite often there are multiple conceptual model of the same product/service. We will be discussing about the conceptual model that a user has in mind about the product they are using. These conceptual models are known as mental models because they reside in a user’s mind about their understanding of how something works. There are multiple mental models of the same product/service. Each of this model is based on the operations they do with the product/service.
Someone using Macbook for programming purpose will have different mental model than the one using it for design purpose which again will be different from a person using it for photography and video editing. All the way from using different softwares to knowing and using different key shortcuts which would help them in getting their work done faster can be different.
A social media influencer might have different conceptual model of the social media platforms in comparison to someone using for personal purpose.
Usually the conceptual model is inferred from the product itself, while there are some which are communicated from one person to the other. Some are learned from the manuals provided. When the device provides insufficient information for a conceptual model, it is built on the basis of the experience of the user of using that and similar products. Such models are mostly error prone and leads the user into difficulty while using the product.
It is important to have good conceptual model because when things go wrong or unplanned without the presence of a good conceptual model user doesn’t know how to rectify the error and handle the situation.
The user’s conceptual model can be different from that of the designer’s. The designer expects both of them to be the same. For that to happen it’s necessary to have a good system image as the user’s conceptual model is based on the system image and interaction with the concerned product/service. System image is the information perceived on the basis of combined information like the structure of the device, affordances and signifiers present, documentation and information available.
Discoverability
Discoverability is referred to figuring out what a product does, how it works and what all actions are possible with it. Discoverability and understanding results from the appropriate application of the other six fundamental principles of design.
The sites that the users interact with, all of them have some common features that help the user figure out how to use them. What makes one site better from the other is it’s discoverability on the basis of how the other principles are applied. It should be easy for a user to understand the operating of any product/service by interacting with it.
Facebook has received criticism over the years because of it’s privacy controls that keeps on changing and it’s not that straightforward to find and apply privacy setting on it.
This was our three part series about Fundamental Principles of Design. Have examples to share with us? Comment them in the comment section below. Also keep checking this space for more articles related to Human Centered Design!