DePlaybook › Strategies › Jakob's Law
MENTAL MODEL SCHEMA SLOTS IN · FAST CONVENTION FOLLOWED ? CONVENTION BROKEN · NEW SCHEMA REQUIRED MATCH OR PAY THE LEARNING COST
Strategy ⚡ Low

Jakob's Law

Users spend most of their time on other products — so they expect yours to work the same way.

Navigation design Mental models Convention vs innovation Onboarding Information architecture Mobile design

01 — TL;DR

Two sentences.

Jakob's Law — articulated by UX researcher Jakob Nielsen in 2000 — states that users spend most of their time on products other than yours, so they arrive carrying mental models built from accumulated experience across the digital landscape, and your product feels most intuitive when it matches the patterns those models already encode. The corollary: every departure from convention imposes a learning cost on every user, and that cost is only justified when the departure produces a genuinely better experience the conventional approach cannot deliver — not merely a more distinctive one.

The cognitive science behind it

Familiar patterns activate existing schemas — pre-built knowledge structures that let users proceed with minimal deliberate processing. Novel patterns force users either to mis-assimilate (causing errors) or to build a new schema (imposing cognitive load and slowing the task). Jakob's Law is schema theory applied to interaction design: convention leverages prior knowledge; novelty taxes it.

Trigger phrase

When your team is debating whether to depart from a familiar interface convention in favour of a novel design — and the novel design requires users to learn something new without a clear benefit that justifies the learning cost.

02 — When to Use

Apply this when…

→ A design decision involves departing from a widely established convention — hamburger menus, tab bars, breadcrumbs, search placement, form layout — and the team needs a principled framework for evaluating whether the departure is justified
→ Stakeholders are requesting a "unique" or "distinctive" experience that would require users to learn new interaction patterns — Jakob's Law gives you the argument that uniqueness in interface conventions comes at a user cost
→ Competitive analysis reveals a dominant pattern across major products in a category — Jakob's predicts that users entering the category have already learned that pattern and will expect it
→ A new product is being designed in a category where users have substantial prior experience — the design should declare which existing mental models are assets to build on and which patterns it will depart from with sufficient justification
→ An onboarding flow for a product with unconventional patterns needs to bridge the gap between users' familiar mental models and the novel patterns they're about to encounter
→ You need to distinguish platform conventions (do not depart) from category conventions (depart cautiously) from component conventions (depart freely when it serves clarity)

When NOT to apply it

Skip Jakob's Law when the convention being followed actively harms users — dark patterns are sometimes conventions, and the law's foundation is user benefit, not convention perpetuation. Skip it when the product is in a genuinely new category with no established conventions — the law applies to convention adoption, not to original invention. And skip it when convention departure is measurably and substantially better for users — in which case the learning cost is justified and should be supported with appropriate onboarding.

03 — How It Works

The mechanism

Cognitive psychologists Frederic Bartlett and later David Rumelhart established that human comprehension depends on schemas — organised knowledge structures that let new experiences be rapidly categorised through prior knowledge. Familiar interface patterns activate the existing schema and the user proceeds with minimal deliberate processing. Unfamiliar patterns force the user to either mis-assimilate (causing errors) or to build a new schema (imposing cognitive load and slowing the task). Jakob's Law makes this invisible cost operationally useful: before departing from convention, ask whether the departure produces enough genuine benefit to justify the schema-formation cost imposed on every user who encounters it.

01
Identify the operative conventions
Mental models are not universal — they are the accumulated experience of a specific population. Run competitive analysis across the products your target users actually use daily. Note which patterns are dominant, which are split, and which show genuine variation. The conventions to follow are the ones your users have been trained on, not the ones the design team is most familiar with.
02
Distinguish platform, category, and component conventions
Not all conventions carry equal weight. Platform conventions (iOS back gesture, browser back button, desktop window management) — do not depart without extraordinary justification. Category conventions (mobile tab bars, SaaS sidebars, e-commerce search placement) — depart only when the benefit is verified. Component conventions (button appearance, dropdown behaviour, validation format) — depart freely when departure serves clarity.
03
Articulate the user benefit before departing
For any proposed departure, write a one-sentence statement of the user benefit it produces — not the brand benefit, not the visual benefit, but the user-capability benefit. If you cannot complete the sentence "Departing from this convention lets users [accomplish X better than the convention allows]," the departure is not justified by the law.
04
Treat convention-following as a deliberate design choice
The decision to follow a convention is an active choice, not the absence of design. A designer who follows the established tab bar pattern because they verified the category convention, confirmed the user population's mental models, and validated that the IA is well-served by it has made a sophisticated decision. Convention following, done with awareness, is design leadership — not a failure to innovate.
05
Measure learnability, task completion, and first-use error rate
Three signals validate the design. Learnability — how quickly new users complete core tasks without instruction. Task completion vs category competitors — whether the design beats the conventional alternative in the metric the user cares about. First-use error rate — how often users attempt incorrect actions based on imported schemas. High error rates on a specific interaction pinpoint a mismatch between your design and the user's mental model.

Jakob's Law is not anti-innovation

The law is sometimes invoked as a reason to never depart from convention — as if the possibility that users might learn something new is sufficient grounds to reject any change. This is a misreading. Jakob's Law argues that the learning cost of departure must be justified by genuine user benefit, not that learning costs can never be justified. The iPhone forced users to abandon decades of physical button conventions; the departure was justified because the touchscreen metaphor enabled capabilities no button-based interface could match. Jakob's Law would have predicted the learning cost — accurately — and concluded that the benefit justified it. The law is an analytical tool, not a prohibition on innovation.

04 — Real Example

Snapchat's 2018 redesign and the Jakob's Law failure

When Snapchat introduced a major redesign in 2018, one of its primary changes was reorganising the navigation in a way that departed significantly from established conventions. The Stories feed — where friends' and brands' content appeared — was moved from its familiar location to share a space with the Discover feed, mixing friend content with publisher content in ways users found confusing. Discover content, previously confined to one section, now appeared prominently in spaces users associated with friend activity.

The redesign produced one of the most dramatic negative responses to a consumer product redesign in recent history: a petition to revert the changes accumulated over a million signatures, and the company's share price dropped approximately 15% in the weeks following rollout. The core failure was a Jakob's Law violation — users had spent years building strong mental models of Snapchat's navigation and the redesign disrupted those models without providing a benefit they recognised as compensating for the disruption.

Social · Mobile · Snapchat 2018
Convention disruption without perceived benefit produces measurable rejection
The lesson is not that Snapchat should never have changed — their underlying business problem (algorithm-driven content discovery that Instagram had captured) was real. The lesson is that the navigation redesign imposed a Jakob's Law cost that was not repaid by a benefit users could recognise and value. Users who had been efficient and confident navigators became confused and frustrated by a navigation they had to re-learn for no perceived gain. Schema disruption without compensating user benefit is the single most reliable way to convert satisfied users into vocal critics.
1M+ petition · ~15% share drop

05 — In the Wild

Test yourself & see real examples

No examples yet — be the first.

Spotted a product whose navigation conventions are so familiar they're invisible — or one that proudly departs from every convention and makes users work to understand its own logic? Submit a screenshot and annotate what you see. Every approved example gets attributed to you.

✓ Reviewed before publishing ✓ Your name on every example you submit ✓ Violation or fix — both welcome

Seen Jakob's Law respected or violated in a real product? Help grow the evidence base.

06 — Common Mistakes

Where teams go wrong

✗ Treating brand differentiation as sufficient justification for convention departure. "We want our product to feel different from competitors" is a marketing preference, not a user benefit. If you redesign navigation from a conventional tab bar to a novel gesture system because it "feels more premium," you have imposed a schema-formation cost on users and given them a brand benefit in return — a trade Jakob's Law predicts is not worthwhile.
✗ Invoking Jakob's Law to perpetuate conventions that actively harm users. Some conventions persist not because they serve users but because they were established early and now benefit from the same convention-following dynamic the law describes. Confusing cancellation flows, manipulative cookie consent, default opt-ins — these are sometimes conventions. The law's foundation is user benefit, not convention perpetuation; departing from a harmful convention is an application of its principle, not a violation.
✗ Assuming all users share the same mental models. A product for users with limited prior digital experience should follow different conventions than one for developers using many tools daily. A product entering a market with a dominant local competitor should respect that competitor's patterns, not the patterns the design team is most familiar with. Mental models are the accumulated experience of a specific population — identify the population first.
✗ Using Jakob's Law to freeze design at the current convention. Conventions evolve. Hamburger menus that were standard in 2014 are now understood to produce lower discoverability than bottom tab bars. Mobile-first gesture navigation that was unfamiliar in 2010 is now expected by users who grew up on smartphones. Jakob's Law is not an argument to freeze design — it is an argument to understand which convention is currently operative, which requires ongoing competitive analysis.
✗ Invoking Jakob's Law without doing competitive analysis. The law is only as useful as the accuracy of the team's understanding of which conventions the user population has internalised. A team that argues "users expect X" based on the design team's own intuition is making mental-model claims from assumption rather than evidence — which produces the same design failures as not applying the law at all. Empirical grounding is non-negotiable.

07 — Variations & Related Principles

Connected ideas

Jakob's Law is a principle about mental models and the cost of violating them. Its closest relationships are with the cognitive frameworks that explain how those mental models form, and with the design methods that help teams identify which conventions are operative for their specific user population.

Explains the schema-formation cost
Cognitive Load Theory
Convention + count both shape decision speed
Hick's Law
Identifies which conventions are operative
Competitive Analysis
Validates whether departure is justified
Usability Testing
Convention often governs target placement
Fitts' Law
Schemas direct what users notice first
Selective Attention

The most important pairing is Jakob's Law with competitive analysis. Jakob's tells the design team to understand the conventions users bring from other products before making decisions that depart from them; competitive analysis is the method for identifying what those conventions are. A team that invokes Jakob's Law without conducting competitive analysis of the relevant product landscape is making claims about user mental models from assumption rather than evidence — which produces the same design failures as not applying the law at all.

08 — 10-Min Exercise

Run it right now

⏱ 10 minutes · Solo · No prep

The Convention Inventory

Pick the three most important navigational or interaction patterns in your product — the primary navigation structure, the most frequently performed user action, and the most important form or input flow. Write each one down.

1. For each one, open two to three competitor or category-adjacent products and observe how they design the equivalent pattern. Note specifically: how many of these products use the same convention? Is there a clear dominant convention, a split between two approaches, or genuine variation?

2. For each of your patterns, classify your design as one of three: Following the dominant convention, Departing with justification (you can articulate the user benefit), or Departing without clear justification (the reason is aesthetic or historic, not user-benefit-driven).

3. Any pattern in the third category is a Jakob's Law debt. Write a one-sentence articulation of what the user benefit of the departure would need to be to justify it.

4. If you cannot complete that sentence, the pattern is worth reviewing in a usability test to validate whether users actually experience the schema-formation cost the law predicts. The design choice that survives this exercise is the one supported by evidence rather than habit.

10 minutes