# Design rules This is a list of rules generally necessary for good [design](engineering-design.md). Many of them dovetail with our [cognitive biases](mind-bias.md). Least Astonishment Principle - a design should match a user's experience, expectations, and mental models Information filtering - Aesthetic-usability effect - we often perceive [aesthetically pleasing](values-quality.md) design as being more usable - Anchoring bias - we tend to rely heavily on the first piece of information they see - Attentional bias - we filter our thoughts based on what they're paying attention to - Banner blindness - we tune out what they repeatedly see - Centre-Stage Effect - we tend to choose the middle option in a set of items - Cognitive load - we require a certain amount of effort to understand things, which changes based on how the information is presented - Confirmation bias - we tend to look for evidence that confirms what they already think - Contrast - our attention draws to higher visual weights - Empathy gap - designers *severely* underestimate how much emotions influence user behaviors - Expectations bias - we are influenced by their own predetermined expectations - Fitts' law - things are easier for us to interact with when they're large and close - Framing - how information is presented determines how users decide - Hick's Law - more options makes decisions harder - Isolation/von Restorff effect - when showing multiple items, the most different of them will stand out the most - Juxtaposition - elements tend to get grouped when they're similar - Law of proximity - elements tend to get grouped when they're near each other - Mental model - we have a preconceived opinion on how things work - Priming - previous perceptions will influence someone's [decision](people-decisions.md) - Progressive disclosure - we are less overwhelmed from complex features if they're shown later - Selective attention - we filter out things when they're focused on other things - Spark effect - we are more likely to take actions when they're small - Survivorship bias - we neglect things that don't make it past a selection process - Tesler's Law of Conservation of Complexity - everything has a certain amount of complexity you can't remove, and making it simpler only makes it more complicated - Visual hierarchy - there's a natural order of how we see things Information presentation - Decoy effect - create an option that's easy for us to discard - Discoverability - different elements have differing difficulty for us to discover them - External trigger - information on what we should do next is inside the prompt itself - Feedback loop - elements communicate what happens after we take action - Nudge - subtle hints affect our decisions - Occam's razor - All things equal, a simpler thing is better - Provide exit points - invite the user to leave the software at the right moment - Shaping - incrementally reinforce actions to get closer to a target behavior - Signifiers - elements can communicate what they will do - Visual anchors - elements can guide our eyes Finding meaning - Authority bias - we give weight to an authority figure's opinion - Barnum-Forer effect - we believe generic descriptions of a person apply to ourselves - Chunking - we remember grouped information better - Curiosity gap - we want to find missing information - Familiarity bias - we prefer familiar experiences - Goal-Gradient effect - The closer we are to a goal, the faster we approach it - Group Attractiveness effect - individual items feel more attractive when presented in a group - Halo effect - we judge the entirety of something based on one of its traits - Hindsight bias - we overestimate their ability to have predicted an outcome - Law of common region - we perceive elements as groups if they share a clearly defined boundary - Law of Prägnanz - Since it takes the least amount of effort, we distill vague things ibe linked tonto a simpler and more complete form - Law of similarity - we tend to perceive a relationship between similar-looking elements - Law of uniform connectedness - we see visually connected elements as more related than elements with no connection - Noble edge effect - we prefer [organizations](groups-large.md) that appear socially responsible - Parkinson's law - we expand tasks to fill in extra time - Scarcity - we value things more when there's a limited supply of them - Self-initiated triggers - we are more likely to interact with self-made prompts - Singularity - we care disproportionately more about an individual than about a group - Skeuomorphism - we adapt more easily to things that look like real-life objects - Social proof - we adapt our actions from what other people do - Survey bias - we tend to skew survey responses toward socially acceptable answers - Spotlight effect - we believe we're being noticed more than we really are - Streisand effect - censoring information increases awareness of that information - Pseudo-set framing - tasks that are part of a group are more tempting to complete - Temptation bundling - hard tasks are less scary when paired with things we desire - Unit bias - one unit of something feels like the ideal amount - Variable reward - we profoundly enjoy unexpected rewards - Weber's law - we adapt better to small incremental changes Pseudo-conscious states of mind - Affect heuristic - our current feelings cloud and influence our judgment - Aha! moment - when users first realize a product's value - Bandwagon Effect - we tend to believe something proportionally to how much others have believed it - Cashless effect - we spend more when we don't actually see our money - Chronoception - our perception of time is subjective - Cognitive dissonance - we can hold opposing ideas in the mind at the same time - Curse of knowledge - we're often unaware other people don't possess the same knowledge - Dunning-Kruger effect - we tend to overestimate their skills when they don't know much - False consensus effect - we tend to overestimate how much other people agree with them - Feedforward - we know what to expect before acting - Flow state - we can be fully [immersed into a task](success-4_routine.md) - Internal trigger - we can be prompted to act based on a memory - Law of locality - we connect things that are nearby other things - Law of the instrument - the object we use dictates how we perceive everything else - Miller's law - we typically can only keep 3-7 things in our memory at once - Reciprocity - we feel the need to respond when we receive something - Recognition over recall - we recognize things more easily than recalling them from memory Mostly-conscious [decision-making](people-decisions.md) - Availability heuristic - we favor recent and available information over past information - Decision fatigue - making many decisions makes us more irrational toward more decisions - Endowment effect - we value something more if we feel it's ours - Fresh start effect - we're more likely to take action if we feel there's something new to it - Investment loops - when we invest into something, we're more likely to use it later - Jakob's law - when we interact with something, we treat it like other things we're familiar with - Hawthorne effect - we change our behavior when we know we're being observed - Hyperbolic Discounting - we tend to prioritize immediate benefits over larger long-term benefits - Loss aversion - we're more likely to avoid losses than earn the same gains - Sensory appeal - we tend to use things more often that appeal to multiple senses - Status quo bias - we tend to do what we've done before until we have reason to do otherwise - Sunk cost effect - we're slow to pull out of something we've invested into - Reactance - we're less likely to do something when we feel forced Time management - Chipmunk effect - we are more likely to select a video that plays faster than normal playback speed (around 1.2x) - Commitment/consistency - we tend to be consistent with our previous actions - Default bias - we don't tend to change established behaviors - Doherty threshold - we're most productive when we're interacting with their objects with less than 0.4 seconds' delay between events - Labor illusion - we value things more *after* we've done work on it - Labor perception bias - we tend to imagine some things *always* take work - Planning fallacy - we tend to underestimate how much time a task will take - Spacing effect - we [learn more](understanding.md) when [study sessions](mind-memory.md) are spaced out Memory - Delighters - we more easily remember pleasure that's unexpected and playful - Method of loci - we remember things more when it's associated with a location - Negativity bias - we tend to remember negative events more than positive ones - Picture superiority effect - we tend to remember pictures more than words - Serial position effect - we more easily remember the first and last things in a series - Storytelling effect - we remember [stories](stories.md) more than [facts](reality.md) - Zeigarnik effect - we remember uncompleted or interrupted tasks more than completed ones Consequences - Backfire effect - we tend to intensify our convictions when they're challenged - IKEA effect - we value things much more when they partially [create](creations.md) it - Observer-expectancy effect - researchers' biases affect the participants of an experiment - Pareto principle - 80% of the results come from 20% of the causes - Peak-end rule - we judge an experience by its peak and how it ends, *not* not the total sum of our experiences - Postel's law - ideal scenarios come from receiving liberally and sending carefully - Second-order effect - unintended second-level consequences ripple from decisions - Self-serving bias - we tend to take credit for positive events and blame others for negative ones