Every time users interact with your product, they:
So to improve your user experience, you need to understand the biases & heuristics affecting those four decision-cycle steps.
Below is a list of cognitive biases and design principles (with examples and tips) for each category. Let’s dive right in.
PS: Don’t have time to read the whole list? Get the cheat sheet.
Users filter out a lot of the information that they receive, even when it could be important.
More options leads to harder decisions
People look for evidence that confirms what they think
Previous stimuli influence users' decision
Total amount of mental effort that is required to complete a task
Users rely heavily on the first piece of information they see
Subtle hints can affect users' decisions
Users are less overwhelmed if they're exposed to complex features later
Large and close elements are easier to interact with
Create a new option that's easy to discard
The way information is presented affects how users make decisions
Users' thoughts filter what they pay attention to
People underestimate how much emotions influence user behaviors
Elements used to guide users' eyes
People notice items that stand out more
The order in which people perceive what they see
People filter out things from their environment when in focus
People neglect things that don't make it past a selection process
Elements that are close and similar are perceived as a single unit
Elements that communicate what they will do
Users' attention is drawn to higher visual weights
When the information on what to do next is within the prompt itself
People tend to choose the middle option in a set of items
Elements close to each other are usually considered related
If you simplify too much, you'll transfer some complexity to the users
Users are more likely to take action when the effort is small
When users take action, feedback communicates what happened
People tend to be influenced by their own expectations
People perceive designs with great aesthetics as easier to use
When users try to give sense to information, they make stories and assumptions to fill the gaps.
People value things more when they're in limited supply
Users have a desire to seek out missing information
Users have a preconceived opinion of how things work
People prefer familiar experiences
Users adapt more easily to things that look like real-world objects
People feel the need to reciprocate when they receive something
Users care disproportionately about an individual as compared to a group
People especially enjoy unexpected rewards
When new users first realize the value of your product
Motivation increases as users get closer to their goal
Simple solutions are often better than the more complex ones
Users tend to prefer socially responsible companies
Users change their behavior when they know they are being observed
People judge things (or people) based on their feelings towards one trait
Users can only keep 5±2 items in their working memory
One unit of something feels like the optimal amount
Being fully immersed and focused on a task
Tasks that are part of a group are more tempting to complete
Individual items seem more attractive when presented in a group
Not realizing that people don't have the same level of knowledge
Users are more likely to interact with prompts they setup for themselves
Users tend to skew survey answers towards what's socially acceptable
It's painful to hold to opposing ideas in our mind
When users know what to expect before they take action
People overestimate their ability to predict outcomes after the fact
Users perceive a relationship between elements that look similar
Users interpret ambiguous images in a simpler and more complete form
When trying to censor information ends up increasing awareness of that information
People tend to believe they are being noticed more than they really are
Users are more likely to take action if there's a feeling of new beginnings
Users are busy so they look for shortcuts and jump to conclusions quickly.
People value things more when they see the work behind them
Users tend not to change an established behavior
When users invest themselves, they're more likely to come back
People prefer to avoid losses more than earning equivalent gains
Users tend to be consistent with their previous actions
Users are reluctant to pull out of something they're invested in.
Users are less likely to adopt a behavior when they feel forced
If all you have is a hammer, everything looks like a nail
Hard tasks are less scary when coupled with something users desire
People tend to overestimate their skills when they don't know much
The ease with which users can discover your features
The consequences of the consequences of actions
Making a lot of decisions lowers users' ability to make rational ones
When researchers' biases influence the participants of an experiment
Users adapt better to small incremental changes
The time required to complete a task will take as much time as allowed
People's current emotions cloud and influence their judgment
People tend to prioritize immediate benefits over bigger future gains
People's perception of time is subjective
People spend more when they can't actually see the money
People take credits for positive events and blame others if negative
Roughly 80% of the effects come from 20% of the causes
When people's convictions are challenged, their beliefs get stronger
People overestimate how much other people agree with them
Users tend to adopt beliefs in proportion of others who have already done so
When you believe generic personality descriptions apply specifically to you.
When user partially create something, they value it way more
People tend to underestimate how much time a task will take
Users try to remember what's most important, but their brain prefers some elements over others.
Invite users to leave your app at the right moment
People judge an experience by its peak and how it ends.
Users engage more with things appealing to multiple senses
People remember incomplete tasks better than completed ones
Users value something more if they feel it's theirs
People remember grouped information better
People remember more unexpected and playful pleasures
When users are prompted to take action based on a memory
People remember pictures better than words
People remember things more when they're associated with a location
Incrementally reinforcing actions to get closer to a target behavior
It's easier to recognize things than recall them from memory
People remember stories better than facts alone
Users recall negative events more than positive ones
Users favor recent and available information over past information
People learn more effectively when study sessions are spaced out
It's easier for users to recall the first and last items of a list
If you want to learn more about behavioral psychology and mental models, we recommend these resources:
The four categories of our list come from Buster Benson's work
The big book of mental models and cognitive biases (Gabriel Weinberg)
How to build habit-forming products (Nir Eyal)
The psychology of persuasion (Robert Cialdini)
The hidden forces that shape our decisions (Dan Ariely)
We took the time to summarize each principle in one line.
They are all in a free cheat sheet of cognitive biases principles.
Use it as a user empathy reminder while you build a feature.
“We all have a responsibility to build ethically-designed products and services to improve people’s lives. Growth.Design’s list of cognitive biases and psychological principles is a great reference for any team committed to improving their customers’ user experience. Dan & Louis-Xavier’s comic book case studies show you how.”— Nir Eyal, bestselling author of Hooked and Indistractable
So which principle are you going to try next?
Are there missing elements we should add to the list?
You can reach us at firstname.lastname@example.org, we reply to everyone!