The Product Sense Glossary Every Designer Should Know
A door with a flat metal plate where you should push, and a handle where you should pull. You’ve met it. You shoved when you should have tugged, then glanced around to see if anyone noticed. That tiny flash of “what’s wrong with me?” wasn’t your fault. It was the design’s.
Almost every confusing app, form, and checkout flow fails for reasons that already have names. Once you learn the vocabulary, you stop seeing “bad design” as a vague feeling and start seeing the specific, fixable cause. This is your field guide to those words.
Why this matters
You can’t fix what you can’t name. When a teammate says “this screen feels off,” the conversation goes nowhere. When someone says “the signifiers are weak and the cognitive load is too high,” you suddenly know exactly what to change.
A shared vocabulary turns gut feelings into decisions you can debate, test, and improve. It’s also the fastest way to grow your own product sense, because each term is a lens that reveals a problem you used to walk right past.
Skim this now. Come back whenever a term feels fuzzy.
The foundations: seeing through the user’s eyes
These are the big-picture ideas. Everything else is detail underneath them.
Product sense is the skill of judging what to build and why it matters to a real person - before and during the build. It’s taste plus judgment. Not “can we make this?” but “should we, and for whom?”
User empathy is the ability to see and feel a product from the user’s point of view - their goal, their confusion, their fear - instead of your own. You wrote the code, so you know where the button is. They don’t. Empathy is remembering that.
Jobs To Be Done (JTBD) is the idea that people “hire” a product to make progress in their lives. Nobody wants a quarter-inch drill; they want a quarter-inch hole - and really, a shelf on the wall. Design for the goal, not the feature.
Mental model is the picture in a user’s head of how something works. Software feels obvious when it matches that picture and confusing when it fights it. People expect a trash can to hold deleted things until they empty it, so an app that deletes instantly violates the model and scares them.
How things invite action: affordances and signifiers
This pair trips up almost everyone, so let’s make it stick.
An affordance is what an object lets you do. A button affords pressing. A slider affords dragging. A chair affords sitting. It’s the action the thing makes possible.
A signifier is the visible cue that tells you the affordance exists. The underline under text says “this is a link.” The little handle in the corner of a text box says “drag me to resize.” Without signifiers, affordances are hidden, and a feature that exists but can’t be found may as well not exist.
The push-door from the opening is a signifier failure: the flat plate signals “push,” but the design put a pull-handle there instead. The affordance and the signifier disagreed, so you guessed wrong.
The two gulfs: where confusion lives
The cognitive scientist Don Norman described two gaps every user crosses. They’re worth memorizing.
The gulf of execution is the gap between what the user wants to do and figuring out how to do it in the interface. “I want to refund this order - but where is that button?”
The gulf of evaluation is the gap between the system doing something and the user understanding that it happened. “Did my changes actually save, or did I just lose an hour of work?”
Great design narrows both. Clear labels and obvious paths shrink the gulf of execution. Honest, plain-language feedback - “Saved,” not “200 OK” - shrinks the gulf of evaluation.
The mind has limits: cognitive load and the laws
Users arrive with a finite amount of attention. These terms describe how to spend it wisely.
- Cognitive load is the total mental effort a screen demands. The more a user must hold in their head, the heavier and more tiring the product feels.
- Hick’s Law: the more choices you show, the longer a decision takes. Trim the options, or reveal them in stages.
- Miller’s Law: people can hold only about seven items (give or take two) in short-term memory at once. Group and chunk information so it fits.
- Fitts’s Law: the bigger and closer a target, the faster it is to hit. Make important buttons large and easy to reach; make dangerous ones small and far.
- Jakob’s Law: users spend most of their time on other products, so they expect yours to work like the ones they already know. Inventing a brand-new way to do “search” mostly invents new confusion.
- Recognition vs recall: it’s far easier to recognize an option that’s shown than to recall one from memory. This is why menus beat blank command lines for most people - show the choices instead of asking users to remember them.
Tools for taming complexity
Real products are complicated. These ideas keep that complexity from landing on the user.
Progressive disclosure means showing only what’s needed now and revealing advanced options later. Beginners aren’t overwhelmed; experts aren’t blocked. Think of the “More options” link that quietly holds the power-user settings.
Defaults are the pre-set choices a user gets without doing anything. A good default is what 90% of people want, so most never have to configure anything. Defaults are the most powerful design decision you’ll make, because most people never change them.
Constraints are deliberate limits that prevent errors by making the wrong action impossible - like greying out “Submit” until a form is valid. You can’t make the mistake because the design won’t let you.
Friction is anything that slows a user down or makes a task feel harder: extra steps, vague labels, forced decisions, waiting. Usually you want less of it - but a little friction in the right place (a “Are you sure?” before deleting an account) protects people.
Discoverability is how easily a user can find a feature or figure out what’s possible without being told. High discoverability means the product teaches itself.
How feelings get designed
Working isn’t the same as feeling good. These terms cover the emotional layer.
Emotional design is shaping how a product feels - trust, calm, delight - not just whether it functions. Two apps can do the identical task; one feels like a friend, the other like a tax form.
The peak-end rule says people judge an experience mostly by its most intense moment and its ending, not its average. A flight with one great meal and a smooth landing beats a uniformly mediocre one. Design strong peaks and clean endings.
Sins to avoid
Some terms name the traps. Knowing them is how you stop falling in.
Dark patterns are designs that trick or pressure users into acting against their own interest - the hidden unsubscribe link, the sneaky pre-checked box, the “No thanks, I hate saving money” decline button. They work short-term and corrode trust long-term.
The curse of knowledge is the trap behind most of them by accident: once you know how something works, you can’t imagine not knowing. Experts go blind to what confuses beginners. You designed the flow, so it’s obvious to you - which is exactly why you’re the worst judge of it.
How to find these problems before users do
Naming the concepts is step one. Here’s how to actually catch them in your own product.
- Run a heuristic evaluation. Walk through your interface against a short checklist of usability rules of thumb (Jakob Nielsen’s ten heuristics are the classic set). You’ll catch obvious problems in an afternoon without a formal study.
- Go dogfooding. Use your own product the way a real user would - sign up with a fresh account, complete a real task, feel the rough edges firsthand. Pain you experience is pain you’ll fix.
- Interview with The Mom Test. Ask users about their real past behavior, never about your idea. “When did you last do X, and what happened?” gets honest answers, where “Would you use my app?” gets polite lies. The name comes from a simple test: ask questions so grounded in facts that even your mom couldn’t accidentally mislead you.
- Audit one screen at a time. Pick a single screen and ask: What does this afford, and is there a signifier for it? What’s the cognitive load? How many choices (Hick’s Law)? Where are the gulfs?
- Check your defaults. For every setting, ask what most people want - then make that the default and let the rest opt in.
Conclusion
If you remember one thing, make it this: most “user error” is really design error wearing a disguise. Every term here is a way of taking the blame off the person and putting it back where it belongs - on the choices the maker made.
That reframe is the heartbeat of product sense. The maker who internalizes it stops asking “why are users so confused?” and starts asking “what did I assume that they don’t know?”
Which raises the harder question this whole guide circles around: if your own knowledge is the very thing blinding you to your users’ confusion, how do you reliably step outside your own head? That’s where real user research begins - and it’s a skill you can practice on purpose.
Frequently asked questions
What is product sense?
Product sense is the skill of judging what to build and why it matters to a real person - before and during the build. It's about choosing the right thing to make, not just making things well.
What is the difference between an affordance and a signifier?
An affordance is what an object lets you do (a button affords pressing). A signifier is the visible cue that tells you the affordance exists (the button looks raised and clickable). Affordances are possibilities; signifiers are the hints.
What is cognitive load in UX design?
Cognitive load is the total mental effort a screen demands. The more a user must hold in their head at once, the harder and more tiring the product feels. Good design lowers it.
What does Hick's Law say about choices?
Hick's Law states that the more choices you show, the longer a decision takes. The practical takeaway is to trim options or reveal them in stages so users decide faster.
What is a dark pattern?
A dark pattern is a design that tricks or pressures users into actions against their own interest - like a hidden unsubscribe link or a pre-checked box that opts you into something. It's the deliberate misuse of these very principles.