UX laws and heuristics are valuable tools — they give designers a framework of principles that distil decades of research into actionable guidance, so we don’t have to rediscover the same truths on every project.
The problem is that most of these principles were originally formulated by researchers and academics — people who are comfortable with the caveats and qualifications that academic language carries. By the time these ideas filter down into design practice, the nuance tends to get stripped away. What’s left is a simplified version of the original insight, often applied in contexts the original researchers never intended.
This creates a particular kind of design problem: rules being cited as justification for decisions they were never meant to support. Today we’ll look at seven widely referenced UX design laws that are frequently misapplied — and what they actually say.
Jakob’s Law
Jakob’s Law, named for UX researcher Jakob Nielsen, states that users spend most of their time on other websites — and therefore tend to prefer sites that work the same way as the sites they already know.
In practice, this law is frequently invoked to discourage experimentation and justify adopting familiar design patterns in the name of usability. navigation in the top right. Search in the header. CTAs in blue. Don’t surprise users.
The misunderstanding lies in what “prefer” actually means here. It’s true that users will more quickly understand a familiar interface — but that’s not the same as saying they’ll enjoy it more, remember it better, or convert at a higher rate.
The research is fairly clear that novelty improves both mood and memory retention. If you’re designing an experience that benefits from being memorable — a brand site, a campaign landing page, a portfolio — some degree of novelty is a legitimate design choice, not a violation of Jakob’s Law. The law cautions against confusing users with unconventional patterns; it doesn’t prohibit standing out.
The Goal Gradient Effect
The Goal Gradient Effect suggests that the closer users are to completing a goal, the more motivated they are to finish it. In e-commerce, this is often cited as justification for simplifying the early stages of a checkout flow and deferring complexity — most commonly, hiding shipping costs until the final step.
The problem is that cart abandonment rates tell a different story. In North America, cart abandonment sits at around 74%, and last-minute revelations about shipping costs are one of the most consistently cited reasons. The Goal Gradient Effect assumes you understand what the user’s goal actually is — and on an e-commerce site, users may be using the cart as a wishlist, comparison tool, or price checker rather than as the first step toward purchase.
Showing progress indicators is genuinely useful. But artificially shortening the perceived distance to your preferred goal — by concealing information that might change the user’s decision — tends to produce friction and distrust rather than conversions.
Miller’s Law
If any UX principle has been misapplied more consistently than Miller’s Law, it’s hard to think of one. Miller’s Law states that the average person can hold approximately seven (plus or minus two) items in their working memory at once. This has been used — countless times — to justify limiting navigation menus to no more than five or seven items.
The mistake here is fundamental: Miller’s Law applies to items held in working memory simultaneously, not to items displayed on a screen. When a user looks at a navigation menu, they’re not memorising all the items — they’re scanning for the one they want. Visual scanning and working memory retention are entirely different cognitive processes.
The practical implication is that a navigation with twelve clearly labelled, logically grouped items may be considerably more usable than one with five vague or poorly ordered items. Miller’s Law legitimately applies to things like carousel controls or step indicators — UI elements where users genuinely do need to hold all options in mind at once. It was never meant to cap navigation item counts.
The Aesthetic-Usability Effect
Edmund Burke wrote that “beauty is the promise of happiness.” The Aesthetic-Usability Effect operates on a similar premise: users perceive aesthetically pleasing designs as more usable, even when they aren’t.
This is a real phenomenon, backed by solid research. But designers often use it as cover for decisions that actively reduce usability — low-contrast text, motion-heavy interfaces that obscure content, minimal navigation that leaves users guessing. The reasoning goes: if users think beautiful things are easier to use, make it beautiful and usability follows.
The critical distinction is between perception and reality. Users may initially perceive a visually polished design as more usable — but that perception is tested every time they try to actually use it. When a beautiful interface fails to deliver, the disappointment is often worse than if the design had set lower expectations in the first place. Aesthetic quality buys you goodwill; it doesn’t replace usability.
The Peak-End Rule
The Peak-End Rule, drawn from Daniel Kahneman’s research on memory and experience, states that people judge an experience primarily based on how they felt at its most intense point (the peak) and at its end — not on an average of the entire experience.
Designers commonly apply this by concentrating effort on the most important moments of a user journey — adding an item to a basket, completing a purchase, receiving confirmation — and the final impression the interface leaves.
The misapplication comes when designers try to apply this framework to open-ended experiences like websites, where it’s genuinely unclear what constitutes a beginning, peak, or end. A user browsing a website doesn’t have a defined journey with a clear conclusion — they might arrive, read a single article, and leave. Or they might explore for an hour across dozens of pages.
There’s also a tendency to assume you know which moment is the “peak” for any given user, which is rarely as straightforward as it appears. Designing for peak moments is a useful lens — but it works alongside designing for consistency and exception handling, not instead of it.
Fitts’ Law
In the 1950s, Paul Fitts demonstrated that the time taken to move to and select a target is influenced by both the distance to the target and the size of the target. In plain terms: small buttons are harder to tap, and small buttons far away from where the user’s attention or finger currently is are harder still.
Fitts’ Law is frequently cited when thinking about mobile tap targets — the relatively small viewport means designers need to ensure interactive elements are large enough to tap reliably. This is sound practice.
The misapplication is assuming that distance is as significant a factor on mobile as it is on desktop. On a typical smartphone screen, the distances involved simply aren’t large enough for distance to meaningfully affect tap accuracy — the limiting factor is almost always target size, not target location. On desktop, where screens are large and a mouse can travel significant distances, distance becomes a more relevant consideration.
The practical takeaway for web design is clear: tap targets should be large enough to hit easily, spaced far enough apart to avoid accidental activation, and keyboard-accessible. But don’t overcomplicate your layout decisions by trying to minimise distance between elements in a way that makes no meaningful difference to mobile users.
Occam’s Razor
No roundup of UX principles would be complete without Occam’s Razor — and unfortunately, this one is also routinely misquoted. Occam’s Razor states that, given competing explanations or solutions, the one with the fewest assumptions is preferable. It does not say the simplest solution is always correct, which is how it’s most commonly paraphrased in design contexts.
In an industry where we have extensive tools for testing, measuring, and analysing interfaces, the need to make untested assumptions should be relatively limited. The reason Occam’s Razor is a design trap is precisely this: when designers apply it, they tend to apply it to their own assumptions about what users want — “this simpler interface must be better” — rather than to user behaviour itself.
The correct application of Occam’s Razor in UX is to your users’ mental models, not your design process. Ask which solution requires the fewest assumptions on the user’s part — not which solution feels most elegant to you. Those are often very different answers.
Conclusion
UX laws are most useful when you understand not just what they say, but where their limits are. Each of the principles above contains a genuine insight worth knowing — the problem isn’t the laws themselves, but treating them as absolute rules divorced from context.
The best interface design decisions come from combining established principles with your own data, your users’ actual behaviour, and a clear understanding of what problem you’re trying to solve. Laws are a starting point for thinking — not a substitute for it.
FAQs
What is Jakob’s Law in UX?
Jakob’s Law states that users spend most of their time on sites other than yours and therefore tend to prefer interfaces that work the way they already expect. It’s a caution against confusing users with unconventional patterns — not a prohibition on originality or distinctive design.
Miller’s Law states that people can hold roughly seven items (plus or minus two) in working memory simultaneously. It is frequently misapplied to justify limiting navigation menus to five items — but navigation items are scanned visually, not held in working memory. The law applies to UI elements like step indicators, not to the number of links in a menu.
What is the Aesthetic-Usability Effect?
The Aesthetic-Usability Effect is the finding that users perceive visually pleasing designs as more usable. The important caveat is that this is a perception, not a guarantee — if a beautiful interface fails to actually work well, users’ disappointment tends to be amplified, not reduced.
What does the Peak-End Rule mean for web design?
The Peak-End Rule suggests that people judge experiences based on their peak moment and their ending, rather than an average. It’s useful for thinking about key moments in a defined user journey, but harder to apply to open-ended web browsing where beginnings and endings aren’t clearly defined.
What is Fitts’ Law in UX design?
Fitts’ Law states that the time to reach and select a target depends on both the target’s size and its distance from the user’s current position. For web design, the practical implication is primarily about making tap and click targets large enough and well-spaced — distance is a meaningful factor on large desktop screens but has minimal impact on typical mobile viewports.
What is Occam’s Razor in UX?
Occam’s Razor favours the explanation or solution with the fewest assumptions. In UX, it’s often misapplied as “simpler is always better” — when in fact it should be applied to the user’s cognitive load and mental model, not to the designer’s preference for minimal interfaces.
With over two decades of web design and development expertise, I craft bespoke WordPress solutions at FallingBrick, delivering visually striking, high-performing websites optimised for user experience and SEO.
