Understand that UI/UX is closely linked to human psychology and tendencies
Aesthetic-Usability Effect
An aesthetically pleasing design nets a positive response about usability and makes the UI design appear better even in the absence of any other differences.
- This is a low-hanging fruit for FreeCAD’s GUI as the default themes presented can be carefully curated for a visually pleasing effect.
Visually pleasing design masks usability problems and keeps problems from being discovered.
While this is a benefit when considering the end-user, it can also pose a problem when seeking feedback from users about problems and proposed solutions.
Testing UX design improvements a simplified and bland theme/stylesheet should be used.
People are more tolerant of usability issues when the design aesthetic is appealing
“During usability testing, one user encountered many issues while shopping on the FitBit site, ranging from minor annoyances in the interaction design to serious flaws in the navigation. She was able to complete her task, but with difficulty. However, in a post-task questionnaire, she rated the site very highly in ease of use. “It’s the colors they used,” she said. “Looks like the ocean, it’s calm. Very good photographs.” The positive emotional response caused by the aesthetic appeal of the site helped mask its usability issues.”
(The Aesthetic-Usability Effect)Takeaway: Aesthetically pleasing interfaces are worth the investment. Visual designs that appeal to your users have the side effects of making your site appear orderly, well designed, and professional. Users are more likely to want to try a visually appealing site, and they’re more patient with minor issues.
Doherty Threshold
Summarized as user interactions and software response time hits a psychological ‘addictive’ state when response is roughly 400ms or slightly less.
In the case of FreeCAD, appears to be less relevant, and is incredibly difficult to quantify.
Fitt’s Law
The time to acquire a target is a function of the distance to and size of the target.
The bigger the distance to the target, the longer it will take for the pointer to move to it. In other words, closer targets are faster to acquire.
The larger the target, the shorter the movement time to it. In other words, bigger targets are better.
Complements the concepts of the “Two Component Model”
Initial movement fast, imprecise
Final movement slower for precision
Takeaways
Size matters, interactive/clickable elements should be large enough to reduce errors/miss-clicks.
Minimizing travel distance to relevant targets also reduces the incidence of errors.
Goal-Gradient Effect
This effect implies that giving users a sense of progress through visual indicators increases productivity.
Seems to apply to linear task type applications and is not likely to be applicable to most work done in CAD.
Hick-Hyman Law
Hick’s Law is a simple idea that says that the more choices you present your users with, the longer it will take them to reach a decision. It’s common sense, but often neglected in the rush to cram too much functionality into a site or application.
“The time it takes to make a decision increases with the number and complexity of choices.”
Minimize choices to decrease and simplify decision making and increase efficiency
Reducing displayed options increases efficiency and keeps users engaged in their task.
Avoid Overwhelming Users by highlighting recommended options
Be careful not to simplify to the point of abstraction
Takeaway: K.I.S.S. - Keep it Simple, Stupid
Jakob’s Law
Effectively states users spend most of their time using other software (or websites/web apps) This means that users prefer to work within established conventions that they are already used to.
Closely related to “The Power Law of Learning”
- Repetition and consistency improve and reduce learning curves
Takeaways:
Common functions found in most other software should work generally the same way new users can reasonably expect based on preexisting experiences.
Consistency in behavior and element location is paramount to good UI/UX design
When making major changes, minimize discontent by empowering users to continue using a familiar version for a limited time.
Law of Common Region
UI elements tend to be perceived into groups if they are sharing an area with a clearly defined boundary
Humans naturally perceive objects as organized patterns.
Gestalt laws organize based on the following categories:
Proximity
Similarity
Continuity
Closure
Connectedness
Law of Proximity
Proximity helps to establish a relationship with nearby objects.
Elements in close proximity are perceived to share similar functionality or traits.
Proximity helps users understand and organize information faster and more efficiently.
Law of Pragnanz
The human eye likes to find simplicity and order in complex shapes because it prevents us from becoming overwhelmed with information.
Research confirms that people are better able to visually process and remember simple figures than complex figures.
The human eye simplifies complex shapes by transforming them into a single, unified shape.
Takeaway: Icons should be reviewed with this principle in mind.
Law of Similarity
Elements that are visually similar will be perceived as related
Color, shape, size, orientation and movement can signal that elements belong to the same group and likely share a common meaning or functionality.
Ensure that links and navigation systems are visually differentiated from normal text elements.
Law of Uniform Connectedness
Elements that are visually connected are perceived as more related than elements with no connection
Group functions of a similar nature so they are visually connected via colors, lines, frames or other shapes.
Use uniform connectedness to show context or to emphasize the relationship between similar items.
Use tangible connecting reference (line, arrow, etc) from one element to the next to also create a visual connection
Miller’s Law
The average person can only keep 7 (+/- 2) items in their working memory
Takeaways
Don’t impose unnecessary design limitations just for the sake of hitting ‘7’
Organize content into smaller chunks to help users process, understand and memorize more easily.
Short Term memory capacity will vary per individual based on prior knowledge and contextual understanding
Occam’s Razor
Among competing hypothesis that predict equally well, the one with the fewest assumptions should be selected
Takeaways:
The best method for reducing complexity is to avoid it in the first place
Consider completion only when no additional items can be removed
Analyze each element and remove as many as possible, without compromising the overall function
Pareto Principle
For many events, roughly 80% of the effects from 20% of the causes.
Takeaways:
Inputs and outputs are commonly not distributed evenly
A large group may contain only a few meaningful contributors to the desired outcome
Focus the majority of effort on the areas that will be the largest benefits to the most users.
Parkinson’s Law
Any task will inflate until all of the available time is spent
Takeaways:
Limit the time it takes to complete a task to what users could reasonably expect it will take.
Reducing the actual duration to complete a task from the expected duration will improve the overall user experience
Leveraging types of features such as autofill to save the user time allows for quick completion of tasks
Peak-End Rule
People judge an experience largely based on how they felt at its peak and at its end rather than the total sum or average of every moment of the experience.
Takeaways:
Pay attention to the most intense points and final moments of the user ‘journey’
Identify the moments when your product is the most helpful, valuable or entertaining and design to delight the end user.
Remember that users recall negative experiences more vividly than positive ones