Knowledge
Users filter out much of the information they receive, even when it could be important.
Hick’s Law
More options lead to harder decisions.
Does your site have many diverse products? Maybe too much to choose from?
Confirmation Bias
People look for evidence that confirms what they think.
Does your site reference things the user knows to help guide them to the purpose of the product? What problem is the website solving?
Priming
Previous stimuli influence users’ decisions.
Many new users to your site may be coming from referral sites.
What can you leverage from this previous stimulus to sell your message?
Cognitive Load
The total amount of mental effort that is required to complete a task.
Keep it simple; there is a lot of interaction on your site, and it becomes hard to make a decision.
Anchoring Bias
Users rely heavily on the first piece of information they see.
Should you be more selective and guide them?
Nudge
Subtle hints can affect users’ decisions. This can be, for example, testimonials or a solution to a problem close to the user’s problem.
Progressive Disclosure
Users are less overwhelmed if they’re exposed to complex features later. Start the marathon slow; once invested, they will become more engaged. For example, a payment process should be presented only after the decision to buy has been made to buy.
Fitts’s Law
Large and close elements are easier to interact with.
Banner Blindness
Users tune out the stuff they get repeatedly exposed to. Repeating things does not work in your favor.
The same images repeatedly get zoned out.
Decoy Effect
Create a new option that’s easy to discard. Allow the user to choose and discard; this makes them feel empowered.
Framing
The way information is presented affects how users make decisions.
If a product seems pushy (buy now, buy now!), this will affect their decisions.
Attentional Bias
Users’ thoughts filter what they pay attention to.
Users can selectively ignore features on a website without even knowing it.
Empathy Gap
People underestimate how much emotions influence user behaviors.
How much are you solving the users’ problems, and do they care that you can do it?
Visual Anchors
Elements used to guide users’ eyes.
Von Restorff Effect
People notice items that stand out more. Be careful about what is framed as larger and more colorful, as this will get more attention, and therefore, other things will get less attention.
Visual Hierarchy
The order in which people perceive what they see.
Usually left to right, then top to bottom, often ignoring banners and jumping from large cluster to another.
Selective Attention
People filter out things from their environment when in focus.
If the user is distracted (pop-up, music, flashing banner), they will not focus on your message.
Survivorship Bias
People neglect things that don’t make it past a selection process.
Once ignored, then it takes a lot for them to re-visit.
Juxtaposition
Elements that are close and similar are perceived as a single unit.
Keep things together
Signifiers
Elements that communicate what they will do
Don’t make the user guess what something is or does.
Contrast
Users’ attention is drawn to higher visual weights
Subtle colors changes are often lost on users.
External Trigger
When the information on what to do next is within the prompt itself
A clear call to action on every label and button.
Center-stage Effect
People tend to choose the middle option in a set of items.
Or the second search result in a list.
Law of Proximity
Elements close to each other are usually considered related.
This can work in your favor or actually confuse the user
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
Expectations Bias
People tend to be influenced by their expectations
Aesthetic-Usability Effect
People perceive designs with great aesthetics as easier to use
Assumptions and Bias
When users try to give sense to information, they make stories and assumptions to fill the gaps.
Social Proof
Users adapt their behaviors based on what others do
Scarcity
People value things more when they’re in limited supply
Curiosity Gap
Users have the desire to seek out missing information
Mental Model
Users have a preconceived opinion of how things work
Familiarity Bias
People prefer familiar experiences
Skeuomorphism
Users adapt more easily to things that look like real-world objects
Reciprocity
People feel the need to reciprocate when they receive something
Singularity Effect
Users care disproportionately about an individual as compared to a group
Variable Reward
People especially enjoy unexpected rewards
Aha! moment
When new users first realize the value of your product
Goal Gradient Effect
Motivation increases as users get closer to their goal
Occam’s Razor
Simple solutions are often better than the more complex ones
Noble Edge Effect
Users tend to prefer socially responsible companies
Hawthorne Effect
Users change their behavior when they know they are being observed
Halo Effect
People judge things (or people) based on their feelings toward one trait
Miller’s Law
Users can only keep 5±2 items in their working memory
Unit Bias
One unit of something feels like the optimal amount
Flow State
Being fully immersed and focused on a task
Authority Bias
Users attribute more importance to the opinion of an authority figure
Pseudo-Set Framing
Tasks that are part of a group are more tempting to complete
Group Attractiveness Effect
Individual items seem more attractive when presented in a group
Curse of Knowledge
Not realizing that people don’t have the same level of knowledge
Self-Initiated Triggers
Users are more likely to interact with prompts they set up for themselves
Survey Bias
Users tend to skew survey answers toward what’s socially acceptable
Cognitive Dissonance
It’s painful to hold two opposing ideas in our mind
Feedforward
When users know what to expect before they take action
Hindsight Bias
People overestimate their ability to predict outcomes after the fact
Law of Similarity
Users perceive a relationship between elements that look similar
Law of Prägnanz
Users interpret ambiguous images in a simpler and more complete form
Streisand Effect
When trying to censor information ends up increasing awareness of that information.
Spotlight Effect
People tend to believe they are being noticed more than they are
Fresh Start Effect
Users are more likely to take action if there’s a feeling of new beginnings.
Time
Users are busy, so they look for shortcuts and jump to conclusions quickly.
Labor Illusion
People value things more when they see the work behind them
Default Bias
Users tend not to change an established behavior
Investment Loops
When users invest in themselves, they’re more likely to come back
Loss Aversion
People prefer to avoid losses more than earn equivalent gains
Commitment & Consistency
Users tend to be consistent with their previous actions
Sunk Cost Effect
Users are reluctant to pull out of something they’re invested in.
Reactance
Users are less likely to adopt a behavior when they feel forced.
Law of the Instrument
If all you have is a hammer, everything looks like a nail
Temptation Bundling
Hard tasks are less scary when coupled with something users desire
Dunning-Kruger Effect
People tend to overestimate their skills when they don’t know much
Discoverability
The ease with which users can discover your features
Second-Order Effect
The consequences of the consequences of actions
Decision Fatigue
Making a lot of decisions lowers users’ ability to make rational ones
Observer-Expectancy Effect
When researchers’ biases influence the participants of an experiment
Weber’s Law
Users adapt better to small incremental changes
Parkinson’s Law
The time required to complete a task will take as much time as allowed
Affect Heuristic
People’s current emotions cloud and influence their judgment
Hyperbolic Discounting
People tend to prioritize immediate benefits over bigger future gains
Chronoception
People’s perception of time is subjective
Cashless Effect
People spend more when they can’t actually see the money
Self-serving bias
People take credit for positive events and blame others if negative
Pareto Principle
Roughly 80% of the effects come from 20% of the causes
Backfire Effect
When people’s convictions are challenged, their beliefs get stronger
False Consensus Effect
People overestimate how much other people agree with them
Bandwagon Effect
Users tend to adopt beliefs in proportion to others who have already done so
Barnum-Forer Effect
When you believe generic personality descriptions apply specifically to you.
IKEA Effect
When users partially create something, they value it way more
Planning Fallacy
People tend to underestimate how much time a task will take
Memory
Users try to remember what’s most important, but their brain prefers some elements over others.
Provide Exit Points
Invite users to leave your app at the right moment
Peak-End Rule
People judge an experience by its peak and how it ends.
Sensory Appeal
Users engage more with things appealing to multiple senses
Zeigarnik Effect
People remember incomplete tasks better than completed ones
Endowment Effect
Users value something more if they feel it’s theirs
Chunking
People remember grouped information better
Delighters
People remember more unexpected and playful pleasures
Internal Trigger
When users are prompted to take action based on a memory
Picture Superiority Effect
People remember pictures better than words
Method of Loci
People remember things more when they’re associated with a location
Shaping
Incrementally reinforcing actions to get closer to a target behavior
Recognition Over Recall
It’s easier to recognize things than recall them from memory
Storytelling Effect
People remember stories better than facts alone
Negativity Bias
Users recall negative events more than positive ones
Availability Heuristic
Users favor recent and available information over past information
Spacing Effect
People learn more effectively when study sessions are spaced out
Serial Position Effect
It’s easier for users to recall the first and last items of a list.