How to apply behavioral psychology to UX

How to apply behavioral psychology to UX

Understanding behavioral psychology is essential for creating meaningful user experiences. Far too often ignored or underutilized, it nevertheless forms an essential foundation for designing products and services that truly meet human needs. In this article, we explore key ideas shared by two UX design experts during an in-depth discussion: Chris, founder of UX Playbook, and Ben McCarthy Jones, product design leader at Experian and founder of UXologist.

Through this guide, you will learn why psychology is at the core of design, what are the key psychological concepts to integrate into your work, and how to leverage them to improve your products. If you are a designer, developer, or simply curious to better understand why we use interfaces as we do, read carefully.

Why psychology is crucial in UX?

Design is fundamentally a human-centered process. Understanding users goes beyond knowing how to interact with them within a product. Behavioral psychology helps grasp their motivations, emotions, and cognitive biases. Ben McCarthy Jones explains: " Psychology expands our understanding beyond what the user does in a product. It helps us understand why they do what they do in their daily lives. "

In short, psychology in UX is the art of connecting human behaviors to concrete solutions, while considering their cognitive, emotional, and contextual needs.

Concrete example: Duolingo

Duolingo is a fascinating case illustrating the (sometimes extreme) use of psychology. Its design is based on principles like gamification, loss aversion bias, and habit formation. However, by pushing some principles too far (such as sarcastic or insistent notifications), the app risks frustrating users and losing them.

The challenge is to find a balance: using psychology to maximize engagement without compromising ethics or the overall experience.

Fundamentals of behavioral psychology in UX

1. Limit information overload

Key principle: Too much information at once overwhelms users, leading to confusion or disengagement.
Solution: Use progressive disclosure. This concept involves presenting data hierarchically and displaying only essential elements at each step.

Example: During onboarding, instead of showing a long and intimidating form, divide the process into clear steps, each accompanied by concise and helpful explanations.

2. Framing and priming effect

Framing effect: How you present information influences the user's perception.
Priming effect: Prepare the user by setting expectations before an important step.

Practical example: When a user signs up, explain why you are asking for their email address. For example: " By providing your email, you will receive personalized recommendations. "

Proper framing of information reduces doubt while enhancing trust.

3. Completion effect (Zeigarnik effect)

Humans dislike leaving tasks unfinished. The Zeigarnik effect exploits this intrinsic need for completion.

How to apply it: Include clear progress bars or checklists to encourage users to complete an action. For example, an indicator "75% registration completed" motivates users to finish the process.

4. Decoy effect

This bias leads users to choose a specific option by presenting less attractive alternatives. In UX, this principle is often used in pricing structures.

Example: SaaS pricing pages: an "intermediate" plan is highlighted as the most reasonable, surrounded by a cheaper option and a more expensive option to guide the choice.

Designing around biases and behaviors

Prioritize cultural context

Designing a universal product requires considering cultural differences. For example, Japanese web interfaces are often filled with text and images, while Western designs prioritize white space and clarity. What may seem cluttered in one culture can be perceived as familiar and reassuring in another.

Advice: Before designing, research the expectations and behaviors of users in each market.

Collaborate with developers

Small changes can have major impacts on the user experience, but convincing developers can be a challenge. To do this:

1. Build a trusting relationship. Involve them from the early stages, even before having concrete solutions.
2. Propose iterations. If an idea seems too complex to develop, explore simpler alternatives.
3. Explain the benefits. Connect the proposed changes to measurable results, such as improving conversion rates.

Examples of small adjustments for maximum impact

• Make CTAs (call-to-action buttons) more visible: Place them strategically and associate them with a clear value proposition.
• Simplify content: Reduce the number of words on each screen and prioritize visuals and icons.
• Use motivating elements: Add progressive messages or encouragements ("You're almost there!").
• Test colors and placements: A simple change in button color or position can significantly increase clicks.

How to get started with behavioral psychology

• Inform yourself before acting. Rely on existing resources (studies, competitive analyses) to identify relevant psychological biases for your project.
• Conduct targeted research. Ask open-ended questions to understand users' motivations and frustrations.
• Quantify results. Once hypotheses are established, use quantitative data to validate your approaches.

Key takeaways

• Psychology is a key tool in UX. It helps create experiences tailored to users' real needs.
• Simplify and guide. Cognitive overload is a major obstacle. Reduce unnecessary information and structure your interfaces into clear steps.
• Draw inspiration from everyday life. Psychological principles like the decoy effect or framing are ubiquitous in advertising, pricing, and human interactions.
• Test and learn. Data and user feedback are essential to validate your hypotheses.

In conclusion, integrating psychology into your design processes is not just about improving your products. It's a way to better understand humans in all their complexity. With the right strategies, you can not only design engaging experiences but also ethical and respectful of your users' needs. Behavioral psychology, when used effectively, is a true lever for transformation in the world of UX design.

Source: "How To Use Behavioural Psychology In UX AMA with Ben McCarthy-Jones" - Chris from UX Playbook, YouTube, Sep 18, 2025 - https://www.youtube.com/watch?v=RrPSW87UWXw

Use: Embedded for reference. Brief quotes used for commentary/review.