Foundations of User-Centered Design through the book “The Laws of UX” by Jon Yablonski — Part 2

Credit: Hai Thang (UI/UX Designer)

We now dive into the next chapter. Part 2 introduces us to Miller’s Law, which simplifies information processing, Postel’s Law, emphasizing adaptability and user-friendliness, and the Peak-End Rule, highlighting the importance of strong moments and final impressions. These principles, like the earlier laws, provide essential insights into user behavior and psychology, guiding us toward crafting resonant experiences. In “Foundations of User-Centered Design through the book ‘The Laws of UX’ by Jon Yablonski,” we further explore these laws, enhancing our ability to design interfaces that seamlessly align with user cognition and emotions.

Miller’s Law

The average person can only keep 7 (plus or minus 2) items in their working memory.

Miller’s Law talks about how our short-term memory has limits. It suggests that we can remember things better when we group them into smaller parts that make sense. The exact number of these parts can be different for each person, based on what they know and understand. You might have heard about the “magic number 7,” but it’s not always true for everyone. Some studies say it could be even fewer.

So, instead of following strict rules like having exactly seven navigation items, it’s smarter to think about how our memory works. Designing things that fit how our minds actually remember stuff is much better than just sticking to a fixed number.

1. Don’t use the “magical number seven” to justify unnecessary design limitations.
2. Organize content into smaller chunks to help users process, understand, and memorize easily.
3. Remember that short-term memory capacity will vary per individual, based on their prior knowledge and situational context.

For example:

Phone number is a long sequence of numbers that can be tough to remember. By breaking it into three parts like in the longer sequence, it becomes shorter segments, making it easier to remember.

By breaking information into sections, adjusting the size of headings and text content, highlighting important details, users can easily grasp the hierarchy of information. This helps reading and finding information become simpler.

Postel’s Law

Be liberal in what you accept, and conservative in what you send.

1. Users will transfer expectations they have built around one familiar product to another that appears similar.
2. By leveraging existing mental models, we can create superior user experiences in which the users can focus on their tasks rather than on learning new models.
3. When making changes, minimize discord by empowering users to continue using a familiar version for a limited time.

An example of Google applying Jacob’s Law in UX is when they introduced a new version of YouTube in 2017, allowing desktop users to access the new Material Design interface without any constraints easily.

Users were given a choice to preview the new design, get acquainted with it, provide feedback, and even revert back to the old version if they preferred. Dissonance in mental models was minimized by empowering users with the option to switch when they were ready.

Youtube UI

Imagine an email client where users are composing messages. Postel’s Law implies that the email client should be able to handle various input formats, even if they aren’t perfectly formatted according to email standards. For instance, if a user forgets to include a subject line or doesn’t follow specific formatting conventions, the email client should still try to send the email successfully. However, when displaying received emails, the client should strictly follow formatting rules to ensure the messages are presented consistently and professionally.

Postel’s Law can help bridge the gap between humans and machines through flexible designs. By welcoming various types of input, adapting and transforming them into machine-friendly data, this principle reduces the burden on users. This approach brings about a more “human” experience by narrowing the divide between people and technology.

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

1. Pay close attention to the most intense points and the final moments (the “end”) of the user journey.
2. Identify the moments when your product is most helpful, valuable, or entertaining and design to delight the end user.
3. Remember that people recall negative experiences more vividly than positive ones.

This principle implies that if an experience has a particularly positive or negative moment that stands out, or if it ends on a high note, users are more likely to remember the overall experience as positive. For example, a frustrating process that ends with a satisfying resolution might still be seen in a positive light due to the strong ending.

For example, you’re using a news reading app on your mobile phone. Throughout your usage, you come across several articles that are somewhat repetitive and not very engaging. However, as you reach the very end of the app, you encounter a screen summarizing the most important news updates and notable topics.

According to the Peak-End Rule, users will particularly remember the feeling at the very end of the experience (the screen summarizing important news) and the highest point of the experience (the important and notable news articles). Despite encountering less engaging content earlier, your final impression of the app will be more positive, based on your recognition that the app provided valuable and relevant information.

This example demonstrates how creating a strong ending and a peak moment within the user experience can enhance user perception, even when encountering less remarkable elements along the way.

Another example, in a digital fitness app, imagine a user completing a workout routine. Throughout the workout, there are intense intervals and rest periods. The workout ends with a motivating message congratulating the user on their effort. The user remembers the challenging intervals and the uplifting conclusion. These peak moments and the positive ending strongly influence their overall perception of the workout’s effectiveness and satisfaction. This exemplifies the Peak-End Rule in digital products, where emotionally impactful peaks and a favorable conclusion shape users’ impressions.

Conclusion

The principles of Miller’s Law, Postel’s Law, and the Peak-End Rule provide us with invaluable insights into the psychology behind user behavior and perception. They guide us in creating interfaces and experiences that resonate with users, making interactions smoother and more memorable.

As we wrap up this exploration, we eagerly anticipate the next chapter in our journey through user-centered design principles. In Part 3, we will delve into the Aesthetic-Usability Effect, Von Restorff Effect, Tesler’s Law, and the Doherty Threshold. These principles offer fresh perspectives on the relationship between aesthetics, usability, attention, and functionality. Join us as we continue to unravel the layers of design wisdom, drawing from “The Laws of UX” by Jon Yablonski, to craft experiences that captivate and engage users on a whole new level.