As a UX designer with a passion for psychology at CBTW, Mokhtar El Moden brings a unique lens to the intersection of design and human behavior. In this post, he reflects on the nuanced relationship between user experience (UX) and conversion rate optimization (CRO), exploring how these two disciplines-often seen as opposites-can coexist to create meaningful, effective digital experiences. Dive into his insights on how cognitive psychology and ethical design influence user satisfaction and business outcomes.
We can define user experience (UX) in many ways, but we also often mistakenly assume that successful user experience equals successful usability. Like many people, you may think that allowing users to complete an order in 3 clicks instead of 5 defines a good user experience. This is often true, so let’s build on this definition: User experience improves when a site is easy to use and helps users achieve their goals effortlessly.
CRO, or Conversion Rate Optimization, focuses more on the end result. It involves developing strategies to encourage users to take desired actions. This discipline uses cognitive psychology and user biases to understand what piques interest and drives users to action. CRO emphasizes these elements to achieve its goals. It’s a flexible discipline that allows for a wide range of methodologies.
For example, A/B testing is commonly used in CRO. In this method, we make a hypothesis and the goal is to test it. Over a period of time, we divide users between two versions of a website: Version A and Version B, where Version B reflects the hypothesis.
Where UX and CRO intersect
Focusing on the means rather than the end, one might initially think that the two disciplines might be at odds from an epistemological standpoint. But this is not necessarily the case.
In a digital checkout, for instance, providing clear information about shipping options or return policies can improve conversion rates (who hasn’t abandoned a purchase because the return policy was unclear?). These improvements also contribute to a better user experience by ensuring that relevant information is available at the right time and place. In other words, a good user experience is about providing the right information at the right time, which positively influences users’ willingness to continue their journey and convert.
Another example is optimizing micro-interactions within a product interface. For example, when adding a product to a shopping cart, a subtle yet engaging visual confirmation – such as a smooth animation or instant confirmation – can reassure users that their action was successful. For CRO, this reduces potential abandonment due to uncertainty about the effectiveness of the action. In UX, it improves navigation fluidity and satisfaction, making the overall experience more enjoyable and intuitive.
The two can be at odds
It is also true that, in many situations, a results-oriented perspective can be in direct conflict with a journey-oriented perspective. Everyone has heard the divisive phrase “the end justifies the means,” and there can often be some truth to it.
Indeed, if the CRO’s goal is to achieve conversion goals, you can easily rely on cognitive psychology and established patterns of human behavior. Cognitive biases, for example, are mental shortcuts that typically help us make quick decisions in a complex world. While these biases are useful in many situations, they can also be exploited, making individuals more susceptible to manipulation when used unethically.
Let’s explore some of the most common ones:
Scarcity Bias / Fear of Missing Out (FOMO)
Who hasn’t visited Booking.com and been consciously or unconsciously influenced by messages like “3 people are currently looking at the same listing as you“? Or been nudged by websites that say the product you’re looking at is almost out of stock? Not very ethical, is it? But it works! And there’s a good reason: as humans, we’re wired to respond to contextual information. When something seems to be in short supply, it signals to us that it’s valuable or desirable. While this is often true, companies have become aware of this tendency and now use it to their advantage – sometimes at the expense of users.
Anchoring bias
Both the movie theater and Starbucks use a simple system to drive conversions and increase average order value: S, M, L. These businesses or industries offer three size categories, not to give you more choices, but to guide your decision. Take a look at the pricing below – do you see a problem?
Exactly! The price difference between each size is not proportional, leading you to believe that size L is the best deal. “For just 50 cents more, I’d rather get the large,” you might think. However, if only the S and L sizes were offered initially, you might have had a 50% chance of choosing one or the other. Here, the M size is almost fictitious; it exists only to steer you toward the L.
Exploiting these cognitive biases in UX is also referred to as dark patterns. If you want to know more about how these influence conversions, read our previous article “Dark Patterns in UX: Short-Term Wins, Long-Term Business Risks“.
Does the end justify the means? A CRO Perspective
Humans are naturally influenced by cognitive biases (as mentioned earlier), but we also have our own tendencies and flaws-like hesitating before making a purchase or struggling to make decisions. Now consider a designer or company that subtly influences your choices, confident that you’ll ultimately appreciate the product you receive, even if some manipulation was involved.
To illustrate this, imagine a progress bar indicating that you need “€20 more to get free shipping“. This creates psychological tension and makes you feel slightly manipulated. But what if the experience of owning and using the additional products you purchased outweighs the unexpected expense? In such a scenario, how should we evaluate this? Could the ultimate satisfaction of using the products redefine the initial sense of manipulation?
Behavioral science suggests that it might, thanks to concepts like the Peak-End Rule.
The Peak-End Rule (Daniel Kahneman’s Theory)
The Peak-End Rule, a concept from behavioral psychology, explains that people evaluate experiences primarily based on their peak (the most intense moment) and the end, rather than the overall experience.
For example, if the final product significantly exceeds expectations, it can create a “positive peak” that reshapes the overall evaluation of the experience, even if the initial process involves some frustration. Conversely, if the product disappoints, the initial negative experience combined with the poor outcome reinforces a lasting negative impression.
Supporting Evidence
Another study by Do et al. (2008) examined vacationers’ memories of their trips. They found that peak moments (e.g., an exciting adventure or a frustrating delay) and the end of the trip had a significant impact on how travelers remembered their experience, regardless of the length of the trip or minor events.
A study of customer experiences found that approximately 80% of participants recalled their experiences based on emotional climaxes and the end (Fredrickson & Kahneman, 1993). This underscores the importance of these moments in shaping overall evaluations.
Ultimately, design choices should avoid creating negative climaxes that can ruin the entire experience. Instead, focus on creating positive emotional peaks and satisfying endings. After all, it’s the emotions that stay with users.
A good book to read about the link between design and emotions on a behavioral level is “Homo-Sapiens, 300 000 ans d’expérience client: Ce que les sciences comportementales peuvent apporter aux entreprises” (“Homo-Sapiens, 300,000 years of customer experience: What behavioral sciences can do for companies“), only available in French. An English version could be: “The Power of Moments: Why certain experiences have an extraordinary impact“.
What if real UX is also about manipulation?
From the author’s perspective
Unfortunately, we must conclude that our first definition of user experience is flawed. A great user experience isn’t just about how easy it is to purchase on a website. Or to put it another way, just because there are no bugs, and all the buttons are visible and in the right place, doesn’t mean you’d tell your friend, “I loved my experience on this site“.
A chatbot could respond instantly, but studies show that responding too quickly makes it feel like the chatbot didn’t put enough effort into finding an answer. We are projecting human expectations onto robotic systems. So what can we do?
Lie! Make it seem like the chatbot is “typing,” thinking, or searching for the right information. This illusion builds greater trust in the outcome.
Research on human behavior change shows that simply explaining how a system works isn’t enough to change long-term habits or expectations. For example, if a chatbot provides an immediate answer and displays a message such as “The chatbot searched its entire knowledge base in 0.03 seconds to provide this answer,” it may still feel less reliable to users. Adding something as simple as three dots to simulate “typing” can give the impression of thoughtful effort, fostering greater trust and aligning with human expectations.
Conclusion
The interplay between UX and CRO reveals a delicate balance between user satisfaction and strategic influence. While UX focuses on enhancing the journey to make it seamless and intuitive, CRO often prioritizes achieving tangible results, sometimes through subtle manipulation. Both disciplines, when ethically applied, can complement each other – delivering both an enjoyable experience and measurable results.
Ultimately, the key is to understand the emotional peaks and troughs of user interactions. By fostering trust, aligning design choices with user needs, and avoiding unethical practices, companies can ensure that the means not only justify the ends but also leave users with a positive and lasting impression.
Interested in getting more professional insights like this piece? Good news, our Product Design community shares them monthly in our Product Design Newsletter, to which you can subscribe here.