101 Cognitive Biases & Principles That Affect UX


Every time users interact with your product, they:
🙈 Filter the information
🔮 Seek the meaning of it
⏰ Act within a given time
💾 Store bits of the interaction in their memories

So to improve your user experience, you need to understand the biases & heuristics affecting those four decision-cycle steps.

TL,DR

According to the  growth.design  team, 101 cognitive bias and principles that affect UX. Below is the list of the ones that struck us the most.
fmfmerian Over to you, feel free to explore the  full list  and add your favorite ones too!

Hick's Law


Hick's Law predicts that the time and the effort it takes to make a decision, increases with the number of options. The more choices, the more time users take to make their decisions.

Confirmation Bias


People tend to search for, interpret, prefer, and recall information in a way that reinforces their personal beliefs or hypotheses.

Contrast

The user's attention is drawn to higher visual weights.

Color is an inherent part of design. Designers have been known to agonize over choosing a hue or hexcode in the hopes of conveying a specific mood or message in a design. It's important to test colors matching & contrast.

Centre-Stage Effect

People tend to choose the middle option in a set of items.

One explanation for this effect proposed by researchers Valenzuela & Raghubir (2009), is that we tend to think that products are more popular when placed in the middle of an array.

Spark Effect

Users are more likely to take action when the effort is small.

Ask less, get more. Self-destructing invitation, Limited inbox.
fmfmerian Or passwordless auth, like Pitch. Easier signin, simpler FTUX.

Social Proof


When they are unsure or when the situation is ambiguous, they are most likely to look and accept the actions of others as correct. The greater the number of people, the more appropriate the action seems.
fmfmerian As an example, Buffer highlights the testimonial of a though leader to inspire action in its signup page.

Curiosity Gap


The curiosity gap is the space between what users know and what they want or need to know. Gaps cause pain, and to take it away, users need to fill the knowledge gap.

Miller's Law

Users can only keep 7 items in their working memory.

Less information, the better. But you need to choose the best ones.

Authority Bias

Users attribute more importance to the opinion of an authority figure.

Survey Bias

Users tend to skew survey answers toward what's socially acceptable.

Labor Illusion

Loss Aversion


We hate losing or letting go of what we have (even if more could be had). Prospect theory says that a loss hurts more than an equal gain feels good. In other words, losing $1,000 will “hurt” more than the joy of gaining $1,000. 
fmfmerian Example: The Slite "deferred account creation" relies on the fact that you'll want to confirm your account email AFTER you've set up your account because you won't want to lose what you did.

Sunk Cost Effect


People experience the sunk cost effect when they keep doing something as a result of previously invested resources (time, effort, money, etc). That effect becomes a fallacy if it's pushing them to do things that won't make them happier.
fmfmerian Over to you, which  cognitive bias and principles  struck you the most?

How to use this Doc

Below is a list of cognitive biases and design principles for each category.

Browse the full list with the  Table of Contents  from the menu in the top-right hand corner. Looking for examples and tips for a specific principle? Search it in this doc with the keyboard shortcut  Cmd + F .
Let’s dive right in.


101 Psychology Principles That Affect UX

Table of Contents

Table of contents

TL,DR
Hick's Law
Confirmation Bias
Contrast
Centre-Stage Effect
Spark Effect
Social Proof
Curiosity Gap
Miller's Law
Authority Bias
Survey Bias
Labor Illusion
Loss Aversion
Sunk Cost Effect
How to use this Doc
101 Psychology Principles That Affect UX
Table of Contents
Information 🙈
👀 Hick's Law
More
💼 Confirmation Bias
More
👁️ Priming
More
🚛 Cognitive Load
More
⚓ Anchoring Bias
More
👉 Nudge
More
🍰 Progressive Disclosure
More
🎯 Fitt's Law
🐠 Attentional Bias
💔 Empathy Gap
⛵ Visual Anchors
🌶️ Von Restorff Effect
🎖️ Visual Hierarchy
🔭 Selective Attention
✈️ Survivorship Bias
🕶️ Sensory Adaptation
🍒 Juxtaposition
🚦 Signifiers
🎭 Contrast
🚨 External Trigger
🕺 Decoy Effect
More
🎪 Centre-Stage Effect
🖼️ Framing
🍣 Law Of Proximity
🍬 Tesler's Law
🧨 Spark Effect
🥏 Feedback Loop
😻 Expectations Bias
🚆 Aesthetic-Usability Effect
Meaning 🔮
👥 Social Proof
More
🦄 Scarcity
More
💭 Curiosity Gap
More
🖲 Mental Model
More
👨‍👩‍👧‍👦 Familiarity Bias
More
👼 Halo Effect
☎️ Miller's Law
🍱 Unit Bias
🌊 Flow State
🕹️ Skeuomorphism
🎁 Reciprocity
More
👑 Authority Bias
🏺 Pseudo-Set Framing
🎰 Variable Reward
🎊 Group Attractiveness Effect
🚰 Curse Of Knowledge
🎉 Aha! Moment
📮 Self-Initiated Triggers
✏️ Survey Bias
🎭 Cognitive Dissonance
🥅 Goal Gradient Effect
More
💫 Feedforward
💈 Occam's Razor
🎗️ Noble Edge Effect
🏒 Hindsight Bias
🎏 Law Of Similarity
🌗 Law Of Prägnanz
🔦 Spotlight Effect
📆 Fresh Start Effect
Time ⏰
🧗‍♂️ Labor Illusion
More
🚶‍♂️ Default Bias
More
🏦 Investment Loop
More
🕯️ Loss Aversion
More
👞 Commitment and Consistency
More
🏝️ Sunk Cost Effect
More
🌛 Decision Fatigue
🌋 Reactance
More
Observer-Expectancy Effect
🌱 Weber's Law
🔨 Law Of The Instrument
🍭 Temptation Coupling
🎈 Parkinson's Law
🎩 Dunning-Kruger Effect
🌤️ Affect Heuristic
📉 Hyperbolic Discounting
💳 Cashless Effect
🌚 Self-Serving Bias
🥬 Pareto Principle
🔍 Discoverability
🔫 Backfire Effect
🌈 False Consensus Effect
🧙‍♂️ Barnum-Forer Effect
🛋️ IKEA Effect
🧚 Planning Fallacy
Memory 💾
🏕️ Provide Exit Points
More
🎢 Peak-End Rule
More
👅 Sensory Appeal
More
🧩 Zeigarnik Effect
More
🧤 Endowment Effect
More
🦇 The Batman Curse
More
🛍️ Chunking
📸 Picture Superiority Effect
📌 Method Of Loci
🧭 Shaping
💚 Delighters
More
💛 Internal Trigger
💾 Recognition Over Recall
🏰 Storytelling Effect
👹 Negativity Bias
⏰ Availability Heuristic
🌌 Spacing Effect
🏁 Serial Position Effect


Information See-No-Evil Monkey

Eyes Hick's Law

More options lead to harder decisions.

More

Hich's Law Definition
Hick's Law predicts that the time and the effort it takes to make a decision, increases with the number of options. The more choices, the more time users take to make their decisions.
fmfmerian The time it takes to make a decision increases with the number and complexity of choices.

Hick's Law Examples
In a travel booking app like Airbnb, having too many options can lead to a paradox of choice (and churn!):

Trello's 3rd signup step has a dropdown with 15 options. That makes it hard to pick one.

Duolingo's list of lessons can sometimes be overwhelming:

Zapier showed too many navigation links during their upgrade flow which distracts you from crucial checkout steps:

Hich's Law Checklist
Find an area where you have a lot of options or a lot of repetitions.
Try to either reduce the number of options or find ways to hide items. Do they all need to be displayed at once?  🍰Progressive Disclosure 
If you can't minimize the options, try to put them in an easily skimmable order and  make sure the items are familiar;  else, it won't work.

Briefcase Confirmation Bias

People look for evidence that confirms what they think.

More

Confirmation Bias Definition
People tend to search for, interpret, prefer, and recall information in a way that reinforces their personal beliefs or hypotheses.

Confirmation Bias Examples
In times of crisis it's hard not to look for what we want to believe in:

Eye Priming

Previous stimuli influence users' decision.

More

Priming Definition
Subtle visual or verbal suggestions help users recall specific information, influencing how they respond. Priming works by activating an association or representation in users short-term memory just before another stimulus or task is introduced.

Priming Examples
Priming consists of subtle visuals that influence how we respond. The friendly-looking airport landscape lets the users dream about their next trip increasing the chances of a positive experience:

Superhuman's onboarding includes a priming on the fact that you'll receive some helpful onboarding emails from their CEO

Anti-Example: Tinder misses a great opportunity to prime new singles during the onboarding:

Brave cleverly mentioned in the previous onboarding step how they block creepy trackers for a safer browsing experience. This primes you to focus on privacy, making you more likely to choose DuckDuckGo instead of Google search. Brave can hence subtly (but respectfully) reduce the brand awareness of their number one competitor: Google.

Articulated Lorry Cognitive Load

Total amount of mental effort is required to complete a task.

More

Cognitive Load Definition
Cognitive load is the total amount of mental effort that is required to complete a task. You can think of it as the processing power needed by the user to interact with a product. If the information that needs to be processed exceeds the user’s ability to handle it, the cognitive load is too high.

Cognitive Load Examples
A great example of reducing the load is Tinder's profile onboarding:

Hopper's results page has loads of information to parse, making the task of choosing a date harder:

Mario Kart's home page is packed with graphics and gizmos. However, it wasn't random, find out why they designed it that way:


Anchor Anchoring Bias

Users rely heavily on the first piece of information they see.

More

Anchoring Bias Definition
The initial information that users get affects subsequent judgments. Anchoring often works even when the nature of the anchor doesn't have any relation with the decision at hand. It's useful to increase perceived value.

Anchoring Bias Examples
Tinder's pricing table shows the most expensive subscription plan first (the anchor) so that the other plans look inexpensive in comparison:

Brick and mortar shops often display very expensive items in the front with visible price tags so that the item you end up seeking seems cheaper.

Backhand Index Pointing Right Nudge

Subtle hints can affect users' decisions.

More

Nudge Definition
People tend to make decisions unconsciously. Small cues or context changes can encourage users to make a certain decision without forcing them. This is typically done through  priming  default option , salience and perceived variety.

Nudge Examples
While you search for a place to stay, Airbnb nudges you to add a date and number of guests instead of forcing those filter:

The default purchase option on some Amazon products is a "subscription". They incentivize this automatic recurring purchase by offering a discount:

Shortcake Progressive Disclosure

Users are less overwhelmed if they're exposed to complex features later.

More

Progressive Disclosure Definition
An interface is easier to use when complex features are gradually revealed later. During the onboarding, show only the core features of your product, and as users get familiar, unveil new options. It keeps the interface simple for new users and progressively brings power to advanced users.

Progressive Disclosure Examples
One of the best examples of progressive disclosure we've ever seen in an onboarding!

Encouraging users to move from completing simple actions to executing more complex ones lowers the chances that users will feel overwhelmed.

In this case, Hopper offers simple actions to start with: Where from? And where to?

Hopper only shows the bare minimum features when you start searching for a flight:

Less than 16% of Brave daily active users activate Brave Rewards, despite the fact that it's a great system (users get paid to view ads). This is an example of an advanced feature that's best to defer until later through progressive disclosure. Opting for a more gradual approach might not only improve  time-to-value , but also increase the Rewards adoption rate, which generates the majority of Brave's revenues.

Bullseye Fitt's Law

It's easier to aim the bigger the target is.

Tropical Fish Attentional Bias

Users' thoughts filter what they pay attention to

Broken Heart Empathy Gap

People underestimate how much emotions influence user behaviors

Sailboat Visual Anchors

Elements used to guide users' eyes

Hot Pepper Von Restorff Effect

People remember more items that stand out

Military Medal Visual Hierarchy

The order in which people perceive what they see

Telescope Selective Attention

People filter out things from their environment when in focus

Airplane Survivorship Bias

People neglect things that don't make it past a selection process

Sunglasses Sensory Adaptation

Users tune out the stuff they get repeatedly exposed to

Cherries Juxtaposition

Elements that are close and similar are perceived as a single unit

Vertical Traffic Light Signifiers

Elements that communicate what it will do

Performing Arts Contrast

Users' attention is drawn to higher visual weights

Police Car Light External Trigger

When the information on what to do next is within the prompt itself

Man Dancing Decoy Effect

Create a new option that's easy to discard

More

It's a lot easier to make a choice when we compare similar things. Our brain can quickly  evaluate the differences  as opposed to when options are different.

Circus Tent Centre-Stage Effect

People tend to choose the middle option in a set of items

Framed Picture Framing

The way information is presented affects how users make decisions

Sushi Law Of Proximity

Elements close to each other are usually considered related

Candy Tesler's Law

If you simplify too much, you'll transfer some complexity to the users

🧨 Spark Effect

Users are more likely to take action when the effort is small

🥏 Feedback Loop

When users take action, feedback communicates what happened

Smiling Cat with Heart-Eyes Expectations Bias

People tend to be influenced by their own expectations

🚆 Aesthetic-Usability Effect

People perceive designs with great aesthetics as easier to use

Meaning Crystal Ball

Busts in Silhouette Social Proof

Users adapt their behaviors based on what others do

More

Social Proof Definition
Social proof is a convenient shortcut that users take to determine how to behave. When they are unsure or when the situation is ambiguous, they are most likely to look and accept the actions of others as correct. The greater the number of people, the more appropriate the action seems.

Social Proof Examples
Entice users to take action by showing the number of people who did it, like Calm does:

For pricing pages, social proof is often used to represent the most popular package just like in Tinder's "rewind" upsell:

Amazon shows the most common choice of previous buyers like yourself:

Airbnb shows the most popular filters per destination, but that can sometimes back-fire:

Spotify's podcast didn't include social proof, making it hard to know if an episode was worth your time:


Unicorn Scarcity

People value things more when they're in limited supply

More

Scarcity Definition
While scarcity is typically invoked to encourage purchasing behaviors, it can also be used to increase quality by encouraging people to be more judicious with the actions they take. It can come in different forms: Time-limited, Quantity limited, Access-limited. Never fake scarcity if you don't want  reactance !

Scarcity Examples
Uber Eats is one of the rare apps that uses scarcity in a positive way. They offer users to share the costs delivery with other people if they order quickly enough:

Dark Pattern: Mario Kart offers Tours and special items for a limited time to increase conversion rates:

Dark Pattern: Sleepzy uses unjustified scarcity to pressure new users into buying:

Thought Balloon Curiosity Gap

Users have a desire to seek out missing information

More

Curiosity Gap Definition
The curiosity gap is the space between what users know and what they want or need to know. Gaps cause pain, and to take it away, users need to fill the knowledge gap.

Curiosity Gap Examples
Morning Brew uses copywriting open loops and split quiz at the end of their email:

Tinder shows blurry pictures of people who want to "match" with you:

🖲 Mental Model

Users have a preconceived opinion of how things work.

More

Mental Model Definition
A mental model is an explanation of someone's thought process about how something works in the real world. It is a representation of the surrounding world, which might be accurate or not. What users believe they know about your product changes how they use it.

Mental Model Examples
Trello does a mental model migration by gradually persuading new users that their Trello "cards", "boards" and "lists" are better alternatives to traditional "todo lists":


Family: Man, Woman, Girl, Boy Familiarity Bias

People prefer familiar experiences.

More

Familiarity Bias Definition
Users have an innate desire for things they're already familiar with. And the more we experience something, the more likely we are to like it. So, try to use common patterns when creating new experiences.

Familiarity Bias Examples
Superhuman uses familiar keyboard shortcuts to ease the learning curve:

Spotify's podcast play screen is very similar to their song play screen, which eases adoption:

Remember  Snapchat's big redesign?  Well its users remember very well... And they didn't like it! A strong case of familiarity bias.


Baby Angel Halo Effect

People judge things (or people) based on their feelings towars one trait

Telephone Miller's Law

Users can only keep 7 items in their working memory

Bento Box Unit Bias

One unit of something feels like the optimal amount

Water Wave Flow State

Being fully immersed and focused on a task

Joystick Skeuomorphism

Users adapt more easily to things that look like real-world objects

Wrapped Gift Reciprocity

People feel the need to reciprocate when they receive something.

More

Reciprocity Definition
Users are more likely to engage with your product after you provide value. They'll be more likely to trust you and reciprocate.

Reciprocity Examples
That's even more important for big asks, such as changing the default browser you've been using for 10+ years.


Crown Authority Bias

Users attribute more importance to the opinion of an authority figure.

Amphora Pseudo-Set Framing

Tasks that are part of a group are more tempting to complete

Slot Machine Variable Reward

People enjoy rewards, especially unexpected ones

Confetti Ball Group Attractiveness Effect

Individual items seem more attractive when presented in a group

Potable Water Curse Of Knowledge

Not realizing that people don't have the same level of knowledge

Party Popper Aha! Moment

When new users first realize the value of your product

Postbox Self-Initiated Triggers

Users are more likely to interact with prompts they setup for themselves

Pencil Survey Bias

Users tend to skew survey answers towards what's socially acceptable

Performing Arts Cognitive Dissonance

It's painful to hold two opposing ideas in our mind

Goal Net Goal Gradient Effect

Motivation increases as users get closer to their goal

More


A  popular experiment  on this effect showed that a 10-stamp loyalty card pre-stamped twice will be completed faster than an 8-stamp one with 0 pre-stamps.

In the case of this trial timeline, getting users to understand that their journey already has started might increase the trial paywall conversion rate.

Dizzy Feedforward

When users know what to expect before they take action

Barber Pole Occam's Razor

Simple solutions are often better than the more complex ones

Reminder Ribbon Noble Edge Effect

Users tend to prefer socially responsible companies

Ice Hockey Hindsight Bias

People overestimate their ability to predict outcomes after the fact

Carp Streamer Law Of Similarity

Users perceive a relationship between elements that look similar

Last Quarter Moon Law Of Prägnanz

Users interpret ambiguous images in a simpler and more complete form

Flashlight Spotlight Effect

People tend to believe they are being noticed more than they really are

Tear-off Calendar Fresh Start Effect

Users are more likely to take action if there's a feeling of new beginnings

Time Alarm Clock

Man Climbing Labor Illusion

People value things more when they see the work behind them.

More

Labor Illusion Definition
Making users wait for something they requested while showing them how it is being prepared creates the appearance of effort. Customers are usually more likely to appreciate the results of that effort. This is also called the "KAYAK Effect" (based on the travel booking site that used that tactic).

Labor Illusion Examples
The first time you see your potential matches after you complete your profile, Tinder shows the results so quickly that you might doubt of their quality:

KAYAK (travel booking site) once delayed the time search results page to show that it is "crunching data".

TurboTax showed "validation and analysis" screens when you submit your taxes.

Man Walking Default Bias

Users tend not to change an established behavior.

More

Default Bias Definition
Unless the incentive to change is compelling, people are more likely to stick to the default situation presented to them. This is also called the Status Quo Bias. It can be a powerful actor when trying to change behaviors.
FlFlorent This saves your brain mental resources and avoiding stressful decisions.

Some subscription companies exploit this bias unethically by concealing:
…subscription reminders
…incentives to change (e.g., cost)
…shortcuts to cancel (Fitt's Law)

That's why many customers keep their subscriptions active (e.g., gym, Peloton) even if they barely use them. They are considered  Zombie Customers .

Default Bias Examples
Uber Eats' default option is to NOT provide you with disposable items that pollute:

Some Airbnb filters are OFF by default, which can lead to confusion as to what will happen if you switch them ON:

Amazon uses status quo bias to encourage behaviors that aren't necessarily to the user's advantage:

Bank Investment Loop

When users invest themselves, they're more likely to come back.

More

Investment Loops Definition
People invest time, money, information, or effort into a product in anticipation of future benefits. It makes them more likely to return because of the increase in perceived value. When executed properly, user investments load the next trigger to use your product.

Investment Loops Examples
Morning Brew could use personalization to get people to customize the stocks displayed at the top.

Strava encourages you to set personal goals, which will serve as a reminder for you to exercise later on:

Spotify could encourage users to invest time to take podcast notes in-app:

Candle Loss Aversion

People prefer to avoid losses more than earning equivalent gains.

More

Loss Aversion Definition
We hate losing or letting go of what we have (even if more could be had). Prospect theory says that a loss hurts more than an equal gain feels good. In other words, losing $1,000 will "hurt" more than the joy of gaining $1,000. Loss aversion can also lead to  sunk cost fallacy . (Related:  Endowment Effect )

Loss Aversion Examples
Your fear of losing the Duolingo gems you wager encourages you to maintain the practice streak to which you committed:

When you go over the usage limit, Zapier reminds you that you have 30 days to upgrade before you lose your data. It's a powerful incentive to take action now:

Trello's "deferred account creation" relies on the fact that you'll want to confirm your account email AFTER you've created boards, lists and cards because you won't want to lose them.

Mans Shoe Commitment and Consistency

Users tend to be consistent with their previous actions.

More

Commitment & Consistency Definition
When users are asked to do something, their brain instinctually perceive it as a threat. The smaller the initial ask, the smaller the fight or flight response and the more likely they are to agree to gradually bigger requests. Especially since the brain likes to be consistent with its previous actions. It's part of the reason why multi-step forms can perform up to 271% better than a big single-step form.

Commitment & Consistency Examples
Tinder's onboarding splits their signup form in 6 single-question steps to leverage the power of micro-commitment:

Duolingo email notifications cleverly use the fact that you committed to practice a language to ask you if you "still want to learn it":

Depending of the visitors context, some of our  Growth.Design  newsletter opt-in prompts use two steps. We AB tested it against a single step (email field) variante and it generated a lift of +11%.

Desert Island Sunk Cost Effect

Users are reluctant to pull out something they're invested in.

More

Sunk Cost Effect Definition
People experience the sunk cost effect when they keep doing something as a result of previously invested resources (time, effort, money, etc). That effect becomes a fallacy if it's pushing them to do things that won't make them happier.

Sunk Cost Effect Examples
Duolingo encourages you to bet gems if you think you can keep a practice streak for one week:

Netflix: Have you ever watched a boring movie until the end, simply because you started it? That's sunk cost fallacy in action.

World of Warcraft MMORPG: millions of players keep playing (and paying 15$/month) partly because they've already invested so much time and money in the virtual game.

First Quarter Moon Face Decision Fatigue

Making a lot of decisions lowers users' ability to make rational ones.

Volcano Reactance

Users are less likely to adopt a behavior when they feel threatened.

More

When we perceive that our freedom of behavior is being threatened, we develop an intense emotional response resulting from a restriction of our ability to  make decisions .

If people figure out what YouTube is planning, there's a real chance reactance could impact their overall conversions negatively.

When you take away too much of a person's behavioral freedom, it backfires and increases resistance to persuasion. That's why gently nudging a behavior is often better than forcing it.

Observer-Expectancy Effect

When researchers' biases influence the participants of an experiment.

Seedling Weber's Law

Users adapt better to small incremental changes.

Hammer Law Of The Instrument

If all you have is a hammer, everything looks like a nail.

Lollipop Temptation Coupling

Hard tasks are less scary when coupled with something users desire.

Balloon Parkinson's Law

The time required to complete a task will take as much time as allowed.

Top Hat Dunning-Kruger Effect

People tend to overestimate their skills when they don't know much.

Sun Behind Small Cloud Affect Heuristic

People's current emotions cloud and influence their judgment.

Chart Decreasing Hyperbolic Discounting

People tend to prioritize immediate benefits over bigger future gains.

Credit Card Cashless Effect

People spend more when they can't actually see the money.

New Moon Face Self-Serving Bias

People take credits for positive events and blame others if negative.

Leafy Green Pareto Principle

Rougly 80% of the effects come from 20% of the causes.

Magnifying Glass Tilted Left Discoverability

The ease with which users can discover your features.

Pistol Backfire Effect

When people's convictions are challenged, their beliefs get stronger.

Rainbow False Consensus Effect

People overestimate how much other people agree with them.

Man Mage Barnum-Forer Effect

Some people believe in astrology and fortune telling.

Couch and Lamp IKEA Effect

When user partially create something, they value it way more.

Fairy Planning Fallacy

People tend to underestimate how much time a task will take.

Memory Floppy Disk

Camping Provide Exit Points

Invite users to leave your app at the right moment.

More

Provide Exit Points Definition
Exit points are meant to respect people's time. They are opportunities to "put down" the product when users feel they have reached something. They are critical to an overall experience when you want to avoid product fatigue and reactance.

Provide Exit Points Examples
Duolingo's experimental redesign to provide more exit points

Mario Kart Tour missed an opportunity to allow players to gracefully leave their app:

And so did Adobe...

Your brain heavily weighs the peaks and the end of an experience.

That's why it's important to allow users to disengage from your product with a sense of completion.

Customers churn for different reasons, some of which you simply can't control.

So just like any relationship, the key is to:
Remain ethical
Treat people with respect
Give them a good last impression

Roller Coaster Peak-End Rule

People judge an experience by its peak and how it ends.

More


FlFlorent If you want people to change or adopt a new behavior, one of the best ways to achieve this is by making sure the end of their experience is memorable.

Peak-end Rule Definition
Users don't merely evaluate an experience based on the average or a sum of all the micro-experiences. Instead, their brain heavily weighs the peaks (high or low) and the end of the experience. Peaks—when pleasant—often correspond to memorable  delighters  sprinkled into the user journey.

Peak-end Rule Examples
After you pay to upgrade your account, Zapier shows animated confettis as a way to celebrate (and rightfully take your focus away from the hundreds of dollars you just paid!):

Duolingo doesn't provide a clear exit point. This makes the "end" of your in-app experience feel like you're abandoning your learning process (even if you've achieved your goal):

Superhuman shows you its shortcut  Cmd + K  at the end of the onboarding, so you're more likely to remember it:

Tongue Sensory Appeal

Users engage more with things appealing to multiple senses.

More

Sensory Appeal Definition
Why are we tempted to eat sweets when walking by a bakery in the morning? The smell out of the oven is strong enough to make us stop. The sights, sounds, feels, tastes, and smells of products are designed to engage users' senses. And when multiple senses are engaged, people are more likely to create an emotional connection with the brand.

Sensory Appeal Examples
Uber Eats "dry" menu could use sensory appeal to increase desirability:

Superhuman's experimental redesign could use sounds that act as a reward loop to reinforce behaviors:

Puzzle Piece Zeigarnik Effect

People remember incomplete tasks better than completed ones.

More

Zeigarnik Effect Definition
Lewin’s field theory states that a task in progress creates task-specific tension. This tension is relieved when the task is completed, but if the task is interrupted, it stays. That tension makes relevant information more accessible and more easily remembered.

Zeigarnik Effect Examples
Duolingo shows you an incomplete progress bar to encourage you to reach your daily practice goal:

Gloves Endowment Effect

Users value something more if they feel it's theirs.

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Endowment Effect Definition
Users are more likely to want to keep something that they own than acquire that same thing when they don't own it. They tend to overvalue the things they own, regardless of their objective market value. (Related:  Loss Aversion )

Endowment Effect Examples
Trello encourages you to personalize your board through a well-timed nudge so that you perceive it more like "your" workspace:

Bat The Batman Curse

Animal attacks at a young age can sometimes turn people into vigilantes.

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The Batman Curse Definition
Studies have shown that a child's brain can produce unique hormones in reaction to dangerous animal encounters. During puberty, 1 out of 10 children will start seeing the effect of ADN alterations. Their brain becomes wired to look for justice.

The Batman Curse Examples
A recent surge of vigilantes cases in Watopia alerted authorities to investigate the Batman curse. One individual was arrested and revealed that he was  attacked by bats  when he was 6 years old.


Shopping Bags Chunking

People remember grouped information better.

Camera with Flash Picture Superiority Effect

People remember pictures better than words

Pushpin Method Of Loci

People remember things more when they're associated with a location

Compass Shaping

Incrementally reinforcing actions to get closer to a target behavior

Green Heart Delighters

People remember more unexpected and playful pleasures.

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Delighters Definition
We remember and respond favorably to small, unexpected and playful pleasures.

:hear
Superhuman has functions that aren't only useful but just a pure delight.

Yellow Heart Internal Trigger

When users are prompted to take action based on a memory

Floppy Disk Recognition Over Recall

It's easier to recognize things than recall them from memory

Castle Storytelling Effect

People remember stories better than facts alone

Ogre Negativity Bias

Users recall negative events more than positive ones

Alarm Clock Availability Heuristic

Users favor recent and available information over past information

Milky Way Spacing Effect

People learn more effectively when study sessions are spaced out

Chequered Flag Serial Position Effect

It's easier for users to recall the first and last items of a list