Laws of Behaviour
Designer-facing notes on the psychology that shows up in interfaces: Nielsen's usability heuristics alongside biases, effects, patterns, and principles that change how people decide, attend, and feel.
Filters
001Pattern
Aha! Moment
The moment when a new user understands the true value of your product, and why they need it.
- Churn
- Sharing And Referrals
- Complexity & understanding
- +2 more
002Effect
Cognitive Dissonance
The internal discomfort of holding conflicting opinions.
- Churn
- Feature usage
- Habits
- +3 more
003Effect
Cognitive Drift
The experience of losing attention, or your mind 'wandering'.
- Conversion rates
- Attention & interest
- Effort & motivation
- +1 more
004Effect
Cognitive Load
The 'working memory' required to complete a task.
- Churn
- Productivity & efficiency
- Effort & motivation
- +3 more
005Bias
Confirmation Bias
We have a tendency to interpret (or seek out) information that is consistent with our beliefs.
- Attention & interest
- Happiness & enjoyment
006Pattern
Content Blindness
When exposed to similar or identical content, people will subconsciously pay less and less attention to it.
- Attention & interest
- Input quality
007Pattern
Context Craving
In many situations, people will crave context and clarity rather than efficiency.
- Anxiety
- Complexity & understanding
- Input quality
008Pattern
Context Shifting
The process of switching from one 'thing' to another, of which there is a cost.
- Feature usage
- Habits
- Productivity & efficiency
- +1 more
009Pattern
Curiosity Gap
When presented with obviously-incomplete information, people have a tendency to try and fill in the blanks.
- Conversion rates
- Attention & interest
- Effort & motivation
- +1 more
010Effect
Decision Fatigue
People find it harder to make rational decisions, as the total number of decisions that they've made increases.
- Conversion rates
- Habits
- Effort & motivation
- +1 more
011Bias
Default Bias
Making a decision usually requires effort, and it's easier for them to just accept the default option.
- Conversion rates
- Feature usage
- Habits
- +3 more
012Principle
Delegated Decisions
There are downsides to delegating key decisions to your users.
- Churn
- Complexity & understanding
- Feature usage
- +3 more
013Pattern
Doherty Threshold
Slow interfaces bore people.
- Churn
- Attention & interest
- Discomfort & frustration
- +1 more
014Effect
Ego Depletion
After exerting energy on a task, you may be less motivated to start another.
- Conversion rates
- Effort & motivation
- Input quality
015Effect
Endowment Effect
People overvalue things that they own.
- Churn
- Feature usage
- Sharing And Referrals
- +3 more
016Pattern
Experience Creep
Products exponentially grow in complexity.
- Productivity & efficiency
- Complexity & understanding
017Bias
Familiarity Bias
People have a tendency to prefer (i.e., choose) products, services and options that feel familiar to them.
- Conversion rates
- Productivity & efficiency
- Sharing And Referrals
- +2 more
018Principle
Framing
The way in which information is presented, is influential in how it's perceived and understood.
- Conversion rates
- Complexity & understanding
- Perception Of Value
- +1 more
019Effect
Fresh Start Effect
People will often feel more motivated to do something (e.g., learn a new language) if it feels like a fresh start.
- Conversion rates
- Feature usage
- Habits
- +1 more
020Pattern
Fuzzy Context
A little context (but not enough) can create more ambiguity.
- Complexity & understanding
- Discomfort & frustration
- Effort & motivation
021Principle
Gamification
Encouraging engagement with tasks and rewards.
- Churn
- Feature usage
- Habits
- +2 more
022Effect
Goal Gradient Effect
People often become more motivated, the closer they get to their goal (i.e., milestone or achievement).
- Conversion rates
- Feature usage
- Habits
- +1 more
023Effect
Hawthorne Effect
People modify their behaviour under observation.
- Feature usage
- Input quality
024Principle
Hick's Law
It's easier to make decisions with fewer choices.
- Conversion rates
- Complexity & understanding
- Purchases
- +1 more
025Bias
Hyperbolic Discounting
A cognitive bias which explains why people prefer smaller, immediate rewards rather than larger rewards in the future.
- Churn
- Feature usage
- Habits
- +1 more
026Pattern
Intentional Friction
On occasion, it can be beneficial to intentionally add friction into a process.
- Churn
- Attention & interest
- Complexity & understanding
- +1 more
027Pattern
Knowledge Gap
The difference between the information that the user knows, and what they need to know to efficiently use the product or service.
- Attention & interest
- Effort & motivation
- Complexity & understanding
- +1 more
028Principle
Law of Minimal Effort
People subconsciously (think, automatically), will often opt for the path of minimal effort.
- Attention & interest
- Effort & motivation
- Complexity & understanding
- +2 more
029Bias
Loss Aversion
A cognitive bias that describes why the pain of losing is psychologically twice as powerful as the pleasure of gaining.
- Churn
- Conversion rates
- Anxiety
- +2 more
030Effect
Overjustification Effect
If users are being incentivised to complete a task, especially with money or 'rewards', they can be less motivated than they otherwise would be.
- Conversion rates
- Sharing And Referrals
- Effort & motivation
- +1 more
031Principle
Pattern Matching
Your brain is wired to seek shortcuts by trying to match patterns.
- Productivity & efficiency
- Attention & interest
- Effort & motivation
032Effect
Peak-end Rule
People tend to overvalue both the peak of an experience, and the end.
- Sharing And Referrals
- Perception Of Value
- Happiness & enjoyment
033Principle
Progressive Disclosure
The art of progressively exposing complications.
- Feature usage
- Productivity & efficiency
- Attention & interest
- +2 more
034Effect
Pygmalion Effect
A psychological phenomenon whereby broadcasting expectations for someone else, alters their performance.
- Effort & motivation
- Input quality
035Bias
Reactance
Forcing adoption of a behaviour may backfire.
- Churn
- Sharing And Referrals
- Discomfort & frustration
- +1 more
036Pattern
Reactive Onboarding
Reactive onboarding is a method of educating users about your product, by explaining what, and why something happened.
- Feature usage
- Productivity & efficiency
- Attention & interest
- +1 more
037Bias
Recency Bias
A cognitive bias, often called the 'availability heuristic', is where people will favour recent events over historic ones.
- Sharing And Referrals
- Attention & interest
- Complexity & understanding
- +2 more
038Pattern
Reverse Prototype
A method of removing existing functionality, views and steps, to see what the minimal viable product is.
- Churn
- Feature usage
- Productivity & efficiency
- +2 more
039Principle
Selective Attention
Focusing on something specific.
- Attention & interest
- Complexity & understanding
040Effect
Serial Position Effect
When presented with a list of things, people are better at remembering the first and last items, than those in the middle.
- Attention & interest
- Complexity & understanding
- Perception Of Value
- +1 more
041Principle
Social Proof
People adapt their behaviour based on others. Our subconscious shortcut is to use social proof, and look at what others are doing.
- Conversion rates
- Sharing And Referrals
- Perception Of Value
- +1 more
042Pattern
Specificity
Specific actions can be more effective than "general" ones.
- Anxiety
- Attention & interest
- Input quality
043Effect
The Anchor Effect
People are often anchored to an initial piece of information.
- Attention & interest
- Perception Of Value
- Purchases
044Effect
The Decoy Effect
An 'objectively-unsuitable' option will change the value proposition for the others.
- Perception Of Value
- Purchases
045Effect
The FITD Effect
Small actions of compliance can snowball.
- Conversion rates
- Effort & motivation
046Pattern
The Labour Illusion
People have a tendency to perceive products and services more favourably when they're aware of the effort that was put in to create it.
- Conversion rates
- Perception Of Value
- Purchases
047Bias
The Planning Fallacy
People are usually overly-optimistic when estimating the time required to complete a task.
- Effort & motivation
- Discomfort & frustration
- Input quality
- +1 more
048Effect
The Scarcity Effect
A limited supply of something encourages action.
- Conversion rates
- Sharing And Referrals
- Purchases
049Pattern
Tribalism
People enjoy feeling connected in tribes.
- Sharing And Referrals
- Happiness & enjoyment
050Pattern
User Delight
Small moments of delight can have an outsized impact on how users perceive the entire experience.
- Habits
- Sharing And Referrals
- Happiness & enjoyment
051Pattern
User-Initiated Triggers
People are more likely to interact with a trigger (e.g., a push notification, or an alert), if they've set it up themselves.
- Churn
- Feature usage
- Attention & interest
- +1 more
052Pattern
Variable Rewards
Variable rewards (such as spinning a wheel to unlock a prize), often motivate users more than predictable ones.
- Feature usage
- Habits
- Effort & motivation
- +2 more
053Pattern
Visible Lifeboats
The presence of a feature can be reassuring, even if the user doesn't use it.
- Feature usage
- Anxiety
- Discomfort & frustration
054Usability heuristic
Visibility of system status
The design should always keep users informed about what is going on through appropriate feedback within reasonable time.
- Usability
- Task success
- Trust
055Usability heuristic
Match between system and the real world
The design should speak the users’ language, with words, phrases, and concepts familiar to the user, not system-oriented jargon.
- Usability
- Task success
- Trust
056Usability heuristic
User control and freedom
Users often choose system functions by mistake and need a clearly marked emergency exit to leave the unwanted state without having to go through an extended dialogue.
- Usability
- Task success
- Trust
057Usability heuristic
Consistency and standards
Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform and industry conventions.
- Usability
- Task success
- Trust
058Usability heuristic
Error prevention
Even better than good error messages is a careful design that prevents a problem from occurring in the first place.
- Usability
- Task success
- Trust
059Usability heuristic
Recognition rather than recall
Minimize the user’s memory load by making objects, actions, and options visible. Instructions should be retrievable when needed.
- Usability
- Task success
- Trust
060Usability heuristic
Flexibility and efficiency of use
Accelerators—unseen by the novice user—may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users.
- Usability
- Task success
- Trust
061Usability heuristic
Aesthetic and minimalist design
Dialogues should not contain information that is irrelevant or rarely needed. Every extra unit of information competes with relevant units and diminishes their relative visibility.
- Usability
- Task success
- Trust
062Usability heuristic
Help users recognize, diagnose, and recover from errors
Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.
- Usability
- Task success
- Trust
063Usability heuristic
Help and documentation
Even though it is better if the system can be used without documentation, it may be necessary to provide help. Any such information should be easy to search, focused on the user’s task, and list concrete steps to be carried out.
- Usability
- Task success
- Trust