UX Design Principle #006: Peak-End Rule

William Brodlo
Marketing & Design Associate
Read Time
5 min read
Published On
September 8, 2023

In the field of User Experience Design, certain principles from psychology can greatly influence the overall user experience. These principles help create more intuitive and human-friendly experiences.

UX Design involves not only creating visually appealing interfaces but also interfaces that are easy to use and understand. Designers use psychological principles to ensure that interfaces meet users’ needs and tendencies; we’ve already presented Hick’s Law, Fitts’s Law, Jakob’s Law, Miller’s Law, and Postel’s Law. The next principle in our series is the Peak-End Rule.

What is the Peak-End Rule?

The Peak-End Rule, initially proposed by Nobel laureate Daniel Kahneman and his colleagues in the field of psychology, is a concept that emphasizes the significance of specific moments in an experience as well as the way they conclude.

In essence, people tend to judge an experience primarily based on two factors: the most emotionally intense point (the "peak") and how the experience concludes (the "end"). In UX Design, the "peak" moment corresponds to the high point of the user's interaction with a product or interface. Designers should strive to create these peak moments intentionally. Applying this principle to UX Design can yield remarkable results in terms of user satisfaction and overall usability. By understanding the Peak-End Rule, UX designers can optimize user experiences and leave a lasting, positive impression, ultimately benefiting the product or service.

Examples of the Peak-End Rule in Practice

Online Shopping

Image Source: Amazon

In the context of online shopping, the Peak-End Rule manifests as e-commerce websites prioritize providing a seamless and enjoyable shopping experience (the peak) through user-friendly interfaces, product recommendations, and smooth checkout processes. As we see here with Amazon, they ensure a positive end by sending order confirmation emails, offering transparent shipping and return policies, and providing efficient customer support for any post-purchase inquiries, thereby leaving customers with a satisfying and memorable shopping experience. By focusing on both the peak and the end, online retailers aim to build trust, loyalty, and repeat business among their customers.

Onboarding Gamification

Image Source: Duolingo (screenshots pulled from GoodUX)

Introducing gamification elements, such as rewards, badges, or achievements, can make the user's experience more interactive. This may distract from less desirable tasks (like onboarding) or encourage increased participation in actions desired by admins. Duolingo has mastered gamification for their app and spoke about it at the most recent Config conference! As you can see here, Duolingo uses gamification to make the setup portion of their app a fun experience that also collects information on your language proficiency level. In this case, the principle functions like a usability testing tool during onboarding. It helps you learn about your users, uncover issues, and identify improvement opportunities through gamification. The onboarding process can serve as a peak moment that enhances the overall enjoyment of using the interface and inspires users to continue engaging with the platform.

Personalization

Image Source: Grammarly

Tailoring the user experience by personalizing content or recommendations based on user preferences is a powerful way to apply the Peak-End Rule. Providing users with content that resonates with them can create a peak moment as they feel understood and valued. They feel a sense of relevance and connection, which can be emotionally rewarding and memorable. Grammarly uses the data from how you interact with their platform to send personalized email check-ins, giving you personal statistics about your productivity, accuracy, and vocabulary. This personalization not only enhances engagement but also fosters a sense of being understood and valued by the platform or service, resulting in increased user satisfaction and the likelihood of return visits. Effective personalization relies on data-driven insights and algorithms that continuously adapt to users' behaviors and preferences, ensuring that the peak moments are consistently positive and reflective of users' evolving interests.

Applying Postel's Law in UX Design

When designing user experiences, leveraging the Peak-End rule can help create more memorable and positive experiences. Find some UX examples of how the peak-end rule can be applied below.

Error Messages

Craft error messages that are not only informative but also prioritize user understanding and satisfaction. Use language that is precise and guides users toward a resolution. By using user-friendly language devoid of technical jargon and ambiguity, designers ensure that even when users encounter errors, the end of their interaction with the system leaves them with a sense of guidance and support rather than frustration, ultimately enhancing their overall user experience. Moreover, error messages should be designed to prevent users from feeling like they made a mistake, emphasizing that the system is there to assist them in achieving their goals, thus reinforcing a positive end to their interaction.

Visual Impact

Incorporate visually striking elements or animations during critical interactions within your interface. These eye-catching features can create memorable peaks in the user's journey, leaving a lasting impression. For example, dynamic transitions between screens or interactive elements that respond to user inputs can serve as peaks that capture the user's attention and engagement. However, it's equally important to ensure that the visual elements do not overwhelm or distract users; they should follow design best practices and enhance the user experience by conveying information or guiding users effectively. By carefully orchestrating these visually impactful moments, UX designers can capitalize on the Peak-End rule to enhance user satisfaction and the overall usability of the product or service.

End Workflows on a Positive Note

Once an error is resolved or a workflow is completed, ensure the user's journey concludes on a positive note. Express gratitude for their patience and encourage them to continue exploring the interface. Consider adding a fun animation or a congratulatory message that reinforces their successful completion of the task, providing a peak moment. You can also offer further assistance or additional resources that may enhance their experience, leaving users with a sense of accomplishment and value, which aligns with the principles of the Peak-End rule and fosters a positive overall impression of the interface.

Takeaways

Introducing the Peak-End Rule into your digital products can elevate user experiences to new heights. By intentionally crafting peak moments and ensuring a positive conclusion, designers can leave a lasting impression on users, fostering satisfaction, engagement, and loyalty. While delving deeper into UX Design principles, we find psychology maintaining its pivotal role in shaping interfaces that resonate with users. As a top UX Design agency, we strategically embed these UX Design principles into our research and design to ensure the best digital products possible for our clients. Stay tuned for more insights into the world of UX Design, and explore how these principles can transform your design approach.

If you would like to learn more about the Peak-End Rule, we recommend these further readings:

If you haven't read the other five installments in our UX Design Principle series, take a look at Hick’s Law, Fitts’s Law, Jakob’s Law, Miller’s Law, or Postel’s Law.