Why do users prefer sites that feel familiar? This lesson demystifies Jakob's Law, the UX principle stating that users spend most of their time on other sites. Learn how to leverage existing mental models and conventions to create intuitive, easy-to-use interfaces that reduce cognitive load.
Imagine inviting a friend over to your new apartment. As they walk in, they scan the room, looking for a place to sit. They don't need a map. They don't need an instruction manual. They see a plush, four-legged object with a backrest and cushions, and they know, intuitively, that it’s a sofa. They know its function because they have seen and used countless sofas before. The design language is universal, embedded in their memory through years of experience. Now, imagine if your sofa was a shimmering, amorphous blob suspended from the ceiling by magnetic force. Your friend would hesitate. *Can I sit on that? How do I get into it? Will it hold me?* Their brain, which was ready to relax, is now forced into problem-solving mode. They have to learn a new system from scratch, and the simple act of sitting down becomes a task fraught with uncertainty and effort. This is the essence of Jakob's Law. Coined by Jakob Nielsen, a foundational figure in the field of user experience, the law is built on a simple but profound observation: Users spend most of their time on *other* sites. This means they arrive at your website, your app, or your software with a powerful set of expectations forged in the crucible of a thousand other digital experiences. They expect the shopping cart to be in the top right corner. They expect a logo in the top left to take them back to the homepage. They expect underlined blue text to be a clickable link. These aren't arbitrary rules; they are established conventions that form a shared language of the web. Jakob's Law argues that defying these conventions is like building a sofa that levitates. It might be innovative, even beautiful, but it forces the user to stop, think, and expend mental energy on a task that should be effortless. By leveraging these existing patterns, you aren't being lazy or uncreative. You are speaking a language your users already understand, allowing them to focus not on the mechanics of your interface, but on what they actually came to do.
To truly grasp Jakob's Law, we need to look beyond the screen and into the human brain. Our minds are masterful efficiency machines, constantly building internal roadmaps of how the world works. Psychologists call these roadmaps "mental models." A mental model is a simplified, internalized representation of an external reality. You have a mental model for how a car works (turn key, press pedal, car moves), how a restaurant works (get seated, read menu, order, eat, pay), and how an e-commerce website works (search for item, add to cart, checkout). These models are constructed from every experience we've ever had. They allow us to navigate new situations with surprising speed and accuracy by making educated guesses based on past patterns. When a user lands on a new website, they immediately try to apply an existing mental model. If the site's layout and functionality align with their expectations—if the navigation bar is where they expect, the buttons behave as they predict, the checkout process follows a familiar sequence—their cognitive load is low. Cognitive load is the total amount of mental effort being used in your working memory. When it’s low, the experience feels smooth, intuitive, and even pleasant. The user can dedicate their brainpower to their actual goal, whether it’s buying a book, reading an article, or connecting with a friend. But when a design violates these established conventions, it creates a mismatch with the user's mental model. This is where friction occurs. The user is forced to discard their assumptions and build a *new* mental model just for your site. The cognitive load spikes. This process is tiring, frustrating, and often leads to one simple action: leaving. The cost of learning your unique, "innovative" system is simply too high when a competitor's familiar, predictable site is just a click away. Jakob's Law, then, is a principle of cognitive economics. It reminds us that the user's mental energy is a finite and precious resource, and we should squander it at our peril.
A common fear among designers hearing about Jakob's Law is that it champions conformity over creativity. Does it mean all websites must look the same? Does it spell the end of innovation? Not at all. Jakob's Law isn't a command to copy-paste your competitors' designs. It’s a strategic principle that urges you to be intentional about where you innovate. Think of it as a framework for managing user expectations. By adhering to conventions for the mundane, functional aspects of your design, you earn the user’s trust and free up their cognitive capacity to appreciate what truly makes your product unique. Consider the layout of a car. The steering wheel, accelerator, and brake are in the same place in virtually every vehicle on the road. This isn't a failure of imagination on the part of automotive engineers. It's a critical safety and usability feature. Because these core controls are standardized, you can rent a car in a foreign country and drive it almost immediately, focusing your attention on navigating unfamiliar roads, not on figuring out how to stop. The innovation happens elsewhere—in the engine's efficiency, the comfort of the seats, the intelligence of the navigation system. The same applies to digital design. Use conventional patterns for the foundational elements: navigation, form layouts, button placement, and checkout flows. This is your steering wheel and your brake pedal. Once the user feels comfortable and in control, you can then dazzle them with your unique value proposition—your content, your product selection, your community features, your brand's voice. Innovation shouldn't be about reinventing the door handle. It should be about what lies behind the door. Jakob's Law doesn’t build a cage; it provides the blueprints for a solid foundation, upon which you can build something truly remarkable.
Jakob's Law isn't an isolated principle but part of a larger symphony of user experience laws that govern human-computer interaction. It works in concert with several other key ideas. Hick's Law, for example, states that the time it takes to make a decision increases with the number and complexity of choices. By using familiar layouts, you reduce the number of novel "choices" a user has to process about the interface itself, allowing them to decide more quickly on what matters. Fitts's Law describes the time required to move to a target area (like clicking a button) as a function of the distance to the target and the size of the target. Conventions often place important buttons (like "Add to Cart" or "Submit") in predictable, easily accessible locations, inherently respecting this principle. The Doherty Threshold suggests that productivity soars when a computer and its users interact at a pace that ensures neither has to wait on the other. A familiar interface allows for this rapid interaction because the user doesn't have to pause to decipher the layout. They can move through tasks at the speed of thought. Seen in this context, Jakob's Law is the foundational beat that makes the rest of the symphony work. It sets the rhythm of expectation. By honoring the user's prior knowledge, you create an environment where other usability principles can flourish, leading to an experience that feels not just easy, but seamless—an extension of the user's own intent. It is the quiet, unassuming bedrock upon which truly great design is built, a reminder that the most powerful tool we have is a deep and abiding respect for the user's time, their energy, and their experience.