Glossary
Plain-English definitions of the ideas that show up across these deep-dives - from affordances and cognitive load to base rates, habit loops, and the biases that quietly steer your decisions. Every term links to the post that explains it in full.
A
5 terms- Affordance
- What an object lets you do - a button affords pressing, a slider affords dragging. It is the action the thing makes possible.
- Definition Product Sense & Empathy
- Akrasia
- The ancient Greek term for acting against your own better judgment - knowing the right thing to do and doing something else anyway.
- Definition The Knowing-Doing Gap
- Anchoring Bias
- Leaning too hard on the first number you see when estimating something; you adjust away from it but almost never far enough.
- Definition Psychology of Decisions
- Authority Bias
- Deferring to perceived experts or symbols of authority - titles, uniforms, credentials - even when the claim itself deserves scrutiny.
- Definition Psychology of Decisions
- Availability Heuristic
- Judging how likely something is by how easily an example comes to mind, so vivid or recent events feel common even when they are rare.
- Definition Psychology of Decisions
B
2 terms- Balancing Loop
- A feedback loop that resists change and pushes a system back toward a target, like a thermostat clicking the heat on and off.
- Definition Thinking Skills
- Base Rate
- The historical average for similar cases - what Kahneman calls the "outside view" - a powerful antidote to overconfidence in your own specific situation.
- Definition Thinking Skills
C
6 terms- Circle of Competence
- The domain where your understanding is genuinely reliable; knowing where its edge lies matters as much as knowing what is inside it.
- Definition Thinking Skills
- Cognitive Load
- The total mental effort a screen demands; the more a user must hold in their head at once, the heavier and more tiring the product feels.
- Definition Product Sense & Empathy
- Confirmation Bias
- Noticing and remembering only the evidence that fits what you already believe, while quietly discounting everything that disagrees.
- Definition Psychology of Decisions
- Constraints
- Deliberate limits that prevent errors by making the wrong action impossible - like greying out "Submit" until a form is valid.
- Definition Product Sense & Empathy
- Convergent Thinking
- Narrowing a pile of options down to the best one; the necessary partner to divergent thinking, but destructive if used too soon.
- Definition Thinking Skills
- Curse of Knowledge
- Once you know how something works you cannot imagine not knowing, which makes experts blind to what confuses beginners - and the worst judges of their own designs.
- Definition Product Sense & Empathy
D
6 terms- Dark Pattern
- A design that tricks or pressures users into acting against their own interest - the hidden unsubscribe link, the sneaky pre-checked box - working short-term and corroding trust long-term.
- Definition Product Sense & Empathy
- Default
- What happens if you do nothing; the single strongest nudge there is, because doing nothing is always the easiest available action.
- Definition The Knowing-Doing Gap
- Deliberate Practice
- Focused practice at the edge of your ability with clear goals and immediate feedback - what actually builds skill, unlike simply logging comfortable hours.
- Definition The Knowing-Doing Gap
- Discoverability
- How easily a user can find a feature or figure out what is possible without being told; high discoverability means the product teaches itself.
- Definition Product Sense & Empathy
- Divergent Thinking
- Generating many varied ideas without judging them, where quantity and variety are the goal; converge too early and you kill creativity.
- Definition Thinking Skills
- Dopamine
- A brain messenger that fires for surprise and anticipation rather than pleasure, driving wanting rather than liking - the pull behind cravings and habits.
- Definition Psychology of Decisions
E
3 terms- Ego Depletion
- The now-disputed idea that willpower drains like a fuel tank during the day; large replication studies found the effect close to zero.
- Definition The Knowing-Doing Gap
- Emotional Design
- Shaping how a product feels - trust, calm, delight - not just whether it functions; two apps can do the same task while one feels like a friend and the other like a tax form.
- Definition Product Sense & Empathy
- Endowment Effect
- Valuing something more simply because you own it, so you demand more to give it up than you would have paid to get it.
- Definition Psychology of Decisions
F
7 terms- Feynman Technique
- A four-step learning loop: pick a concept, explain it in plain language as if to a child, find where the explanation breaks down, then simplify and repeat.
- Definition Thinking Skills
- First-Principles Thinking
- Breaking a problem down to its most fundamental, verifiable truths and building conclusions up from those alone, ignoring how it has always been done.
- Definition Thinking Skills
- Fitts's Law
- The bigger and closer a target, the faster it is to hit; make important buttons large and reachable, and dangerous ones small and far.
- Definition Product Sense & Empathy
- Fixed Mindset
- The belief that talent is innate and unchangeable, which quietly discourages effort and makes people quit the moment something feels hard.
- Definition Thinking Skills
- Fogg Behavior Model
- B = MAP: a behavior happens only when Motivation, Ability, and a Prompt converge; raising ability by cutting friction is the most reliable lever.
- Definition Thinking Skills
- Framing Effect
- When the wording of a choice changes which option you pick even though the facts are identical - "90% fat-free" and "10% fat" describe the same food.
- Definition Psychology of Decisions
- Friction
- Any small cost or extra step between you and an action; adding or removing even 20 seconds of it changes behavior more than new knowledge does.
- Definition The Knowing-Doing Gap
G
3 terms- Growth Mindset
- Carol Dweck's finding that abilities like creativity can be developed with effort; it consistently produces more output and resilience than a fixed mindset.
- Definition Thinking Skills
- Gulf of Evaluation
- 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?"
- Definition Product Sense & Empathy
- Gulf of Execution
- The gap between what a 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?"
- Definition Product Sense & Empathy
H
5 terms- Habit Loop
- The repeating cycle behind every habit - cue, craving, response, reward - which you reprogram one stage at a time rather than by trying harder.
- Definition The Knowing-Doing Gap
- Habit Stacking
- Anchoring a new habit to an existing one - "After I [current habit], I will [new habit]" - borrowing the neural pathway that is already firing reliably.
- Definition Thinking Skills
- Heuristic
- A mental shortcut that makes judgment fast and usually good enough, but fails in predictable, named ways when the situation doesn't fit the rule of thumb.
- Definition Psychology of Decisions
- Heuristic Evaluation
- Walking through an interface against a short checklist of usability rules of thumb (classically Jakob Nielsen's ten) to catch obvious problems without a formal study.
- Definition Product Sense & Empathy
- Hick's Law
- The more choices you show, the longer a decision takes; the practical fix is to trim options or reveal them in stages so users decide faster.
- Definition Product Sense & Empathy
I
6 terms- Identity-Based Habits
- Tying a habit to who you are ("I am a runner") so each repetition becomes a vote for that identity rather than a chore to endure.
- Definition Thinking Skills
- Implementation Intention
- An "I will [behavior] at [time] in [place]" plan; Peter Gollwitzer's research shows this simple format doubles or triples follow-through.
- Definition Thinking Skills
- Inclined Abstainers
- People who fully intend to act but never do - the group where almost the entire knowing-doing gap actually lives.
- Definition The Knowing-Doing Gap
- Incubation
- The creative stage where you deliberately step away from a problem so your unconscious keeps making associations and hands you the "shower idea."
- Definition Thinking Skills
- Intention-Behavior Gap
- The distance between what you decide to do and what you actually do; across the research, intentions explain only about 28% of behavior.
- Definition The Knowing-Doing Gap
- Inversion
- Working backward from the failure you most want to avoid; as the mathematician Carl Jacobi put it, "invert, always invert."
- Definition Thinking Skills
J
2 terms- Jakob's Law
- Users spend most of their time on other products, so they expect yours to work the same way; inventing a brand-new pattern mostly invents new confusion.
- Definition Product Sense & Empathy
- Jobs To Be Done
- The idea that people "hire" a product to make progress in their lives; nobody wants a drill, they want the hole - so design for the goal, not the feature.
- Definition Product Sense & Empathy
K
1 term- Keystone Habit
- A single habit that drags other good behaviors along with it; exercise is the classic, quietly improving sleep, diet, and focus without you targeting them.
- Definition Thinking Skills
L
3 terms- Latticework of Mental Models
- Charlie Munger's idea of wiring together frameworks from many fields so several lenses hit one decision at once, instead of forcing everything through a single tool.
- Definition Thinking Skills
- Leverage Point
- A place in a system where a small change produces a large, lasting effect; the strongest of all is the paradigm - the shared beliefs the system was built on.
- Definition Thinking Skills
- Loss Aversion
- Losses hurt about twice as much as equivalent gains feel good, so people work harder to avoid losing than to win the same amount.
- Definition Psychology of Decisions
M
2 terms- Mental Model
- 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.
- Definition Product Sense & Empathy
- Miller's Law
- People can hold only about seven items (give or take two) in short-term memory at once, so information should be grouped and chunked to fit.
- Definition Product Sense & Empathy
N
1 term- Never Miss Twice
- The rule that one missed day is an accident but two in a row is the start of a new bad habit, so you always show up the next day.
- Definition Thinking Skills
O
2 terms- Opportunity Cost
- The value of the best alternative you give up; every "yes" is a "no" to everything else you could have done with the same time or money.
- Definition Thinking Skills
- Overconfidence
- Systematically overrating the accuracy of your own judgment, which makes forecasts too narrow and blinds you to how often you are wrong.
- Definition Psychology of Decisions
P
9 terms- Peak-End Rule
- People judge an experience mostly by its most intense moment and its ending, not its average - so design strong peaks and clean endings.
- Definition Product Sense & Empathy
- Plateau of Latent Potential
- The frustrating stretch where effort accumulates invisibly before results break through - like ice doing nothing at 25°F, then melting at 32°F.
- Definition Thinking Skills
- Policy Resistance
- The tendency of a system to neutralize your fix - add highway lanes to cut traffic and you often induce more driving, recreating the jam.
- Definition Thinking Skills
- Pre-Mortem
- Imagining your plan has already failed and working back to what caused it, which surfaces risks that optimism normally hides.
- Definition Thinking Skills
- Present Bias
- The built-in habit of treating right now as far more valuable than any later moment, so anything in the future instantly loses roughly a third of its worth.
- Definition The Knowing-Doing Gap
- Process Goal
- A goal defined by actions fully under your control ("train four times a week") rather than an outcome the world decides - far more effective and less demoralizing.
- Definition The Knowing-Doing Gap
- Product Sense
- The skill of judging what to build and why it matters to a real person - choosing the right thing to make, not just making things well.
- Definition Product Sense & Empathy
- Progressive Disclosure
- Showing only what is needed now and revealing advanced options later, so beginners are not overwhelmed and experts are not blocked.
- Definition Product Sense & Empathy
- Prospect Theory
- Kahneman and Tversky's account of how people actually weigh gains, losses, and risk - from a reference point, with losses looming larger than gains.
- Definition Psychology of Decisions
R
6 terms- Reasoning by Analogy
- Solving a problem by copying what already exists; efficient and good for incremental improvement, but it can never escape the assumptions baked into the template.
- Definition Thinking Skills
- Reciprocity
- The urge to give back when someone gives to us first; it works even with tiny, unwanted gifts, which is why free samples reliably lift spending.
- Definition Psychology of Decisions
- Recognition vs Recall
- It is far easier to recognize an option that is shown than to recall one from memory, which is why menus beat blank command lines for most people.
- Definition Product Sense & Empathy
- Reinforcing Loop
- A feedback loop that amplifies whatever is already happening, producing exponential growth or runaway collapse - the compound interest of systems.
- Definition Thinking Skills
- Resulting
- Judging a decision solely by its single outcome, which teaches the wrong lessons in anything that has luck mixed into the result.
- Definition The Knowing-Doing Gap
- Reward Prediction Error
- The gap between an expected and an actual reward; dopamine fires most when a cue is recognized in anticipation, not just when the reward finally lands.
- Definition Thinking Skills
S
10 terms- Scarcity
- Wanting something more as it becomes rarer or more urgent; "only 2 left" and "ends tonight" work by making a loss feel imminent.
- Definition Psychology of Decisions
- Second-Order Thinking
- Asking "and then what?" beyond the first result of a decision, tracing the chain of later consequences - the antidote to choices that feel good now but cause damage later.
- Definition Thinking Skills
- Self-Handicapping
- Creating an obstacle in advance so a possible failure has a ready excuse - a self-protection strategy that shields self-worth at the cost of results.
- Definition The Knowing-Doing Gap
- Signifier
- The visible cue that tells you an affordance exists - the underline that says "link," the raised edge that says "press me." Without it, a feature is effectively hidden.
- Definition Product Sense & Empathy
- Social Proof
- Looking to what others are doing to decide what is correct, especially under uncertainty - the engine behind reviews, wait-lists, and "bestseller" tags.
- Definition Psychology of Decisions
- Status Quo Bias
- The pull to keep things as they are because change takes effort and doing nothing feels safer, which is what makes default options so powerful.
- Definition Psychology of Decisions
- Sunk Cost Fallacy
- Throwing good resources after a failing path because of what you already spent; spent is spent, and it should never drive the next decision.
- Definition Psychology of Decisions
- System 1 Thinking
- Fast, automatic, effortless thinking that handles most daily decisions using shortcuts; efficient but predictably error-prone.
- Definition Psychology of Decisions
- System 2 Thinking
- Slow, deliberate, effortful analysis that can override System 1's errors but tires quickly - which is why good defaults matter so much.
- Definition Psychology of Decisions
- Systems Thinking
- Seeing a problem as a web of stocks, flows, delays, and feedback loops rather than isolated parts, so you can predict how it will push back over time.
- Definition Thinking Skills
T
2 terms- The Mom Test
- A user-interview method: ask about real past behavior, never about your idea, with questions so grounded in facts that even your mom couldn't accidentally mislead you.
- Definition Product Sense & Empathy
- Two-Minute Rule
- Shrinking any new habit to a two-minute version, because starting is the hard part and a started habit is far easier to continue than to begin.
- Definition Thinking Skills
U
1 term- User Empathy
- 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 expert perspective.
- Definition Product Sense & Empathy
V
1 term- Variable Reward
- A payoff that varies unpredictably, producing the compulsive pull behind slot machines, social feeds, and notification badges.
- Definition Thinking Skills
#
1 term- 5 Whys
- A root-cause technique from Toyota: ask "Why?" five times in a row, each time targeting the previous answer, to move from a surface symptom to the real cause.
- Definition Thinking Skills