week 5 post 1: design principles and heuristics

  

 

The sets  

• four sets of design principles---> These aren't the only four sets but are the ones that are referenced most often, 

15 principles 

Discoverability 

Discoverability--> when the user doesn't know what to do, they should be able to easily figure out what to do. 

• want to make functions discoverable, but that doesn't mean just throwing everything on the screen.  

• We want to walk a line between discoverability, and simplicity 

 
Simplicity 

• the design should make simple common tasks easy, communicating clearly and simply in the user's own language and providing good shortcuts. 

• Their principle of simple and intuitive use advocates the use of design easy to understand regardless of the user's experience, knowledge, language skills, or current concentration level. 

• in this principle you can see universal design's special concern with appealing to users of a variety of different levels of expertise, ages, disabilities etc. 

 

Affordances 

• One way to keep design both simple and usable is to design interfaces that by their very design tell you how to use them. 

• Affordances---> The design of the thing affords or hints at the way it's supposed to be used. an object with an affordance, basically tells the user by its very design, how it's meant to be used." 

• Signifiers are in-context instructions like arrows to indicate which way to swipe for a particular action, or in this case, a button labeled menu to indicate how to pull up a menu. 

• In this way, we can kind of create our own affordances by creating an intuitive mapping between controls and their effects in the world being consistent with what others have done in the past. 

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Mapping  

• Norman and Nielsen both talk about the need for a mapping between interfaces and their effects in the world. 

• Norman notes that mapping is actually a technical term coming from mathematics that means a relationship between the elements of two sets of things. 

• In this case, our two sets are the interface and the world. 

• Nielsen describes mapping by saying the system should speak the users' language, with words, phrases, and concepts that are familiar to the user, rather than system-oriented terms. 

• Follow real-world conventions, making information appear in a natural and logical order. 

• Example, is the fact we call cut, copy, and paste, cut, copy and paste. 

• But using cut, copy, and paste forms a natural mapping between our own vocabulary and what happens in the system. 

• these two principles are subtly different, but they're actually strongly related. 

• Nielsen's heuristic describes the general goal, while Norman's principle describes one way to achieve it. 

• Strong mappings help make information appear in natural and logical order. 

 

Perceptibility 

• Perceptibility refers to the user's ability to perceive the state of the system. 

Consistency 

• using controls, using visualizations, using layouts, using anything we use in our interface design consistently, across both the interfaces that we design and what we design more broadly as a community. 

• The general idea across all of these is we should be consistent both within and across interfaces to minimize the amount of learning the user needs to do to learn our interface. 

• In this way, we create affordances on our own, unlike traditional physical affordances, there's no physical reason for the interface to be designed a certain way. 

• But by convention, we create expectations for users and then fulfill those expectations consistently. 

Flexibility 

• Wherever possible, we should support the different interactions in which people engage naturally, rather than forcing them into one against their expertise or against their preference. 

Equity 

• The principle of flexibility in some ways appears to clash with the principle of equity. 

• But both come from the principles of universal design. 

• The principle of flexibility said the design should accommodate a wide range of individual preferences and abilities. 

• But the principle of equity says the design is useful and marketable to people with diverse abilities, and it goes on to say we should provide the same means for all users, identical whenever possible and equivalent when not. 

• And we should avoid segregating or stigmatizing any users. 

• In reality, these are actually complementary of one another. 

• Equity is largely about helping all users have the same user experience, while flexibility might be a means to achieve that. 

Ease and Comfort 

• The ease principle is the design can be used efficiently and comfortably and with a minimum amount of fatigue. 

• The comfort principle notes that appropriate size and space is provided for approach, reach, manipulation and use regardless of the user's body size, posture or mobility.’ 

• areas like wearable computing and virtual reality, issues of ease and comfort become more and more pertinent. 

Structure 

• we should organize our user interfaces in ways that helps the user's mental model match the actual content of the task. 

• Organizing things in intuitive ways that group together similar parts, separate dissimilar parts, and help the user navigate what they're consuming. 

 
Constraints 

• Constraining the user to only perform the correct actions in the first place. 

• Norman's Four Types of Constraints 

• Add image 

Tolerance 

• Tolerance means that users shouldn't be at risk of causing too much trouble accidentally. 

• make sure that the system prevents the user from doing too much damage accidentally--> Either by constraining them away from making those mistakes or allowing an easy way to recover once those mistakes have been made. 

Feedback 

• the system should give plenty of feedback so that the user can understand why the error happened and how to avoid it in the future. 

• Poor feedback can be worse than no feedback at all--> Because it's distracting, uninformative, and, in many cases, irritating and anxiety-provoking. 

• (No codes), precisely indicate the problem, and constructively suggest a solution. 

• tight relationship with recoverability. 

• Not only should it be possible to recover from an error, but the system should also tell you exactly how to recover from an error. 

• That's feedback in response to errors. 

Documentation 

• one goal of usable design is to avoid the need for documentation altogether---> We want users to just interact naturally with our interfaces.