Patterns, not rules
Psychological effects
A field guide to recurring patterns in judgment, memory, attention, and social life. These are context-sensitive tendencies—not labels for people.
30 articles
Affective forecasting
Predicting how one will feel after a future event, often with errors about intensity or duration.
Anchoring
The influence of an initial value on later numerical estimates, even when the starting point is weakly informative.
Availability heuristic
Estimating likelihood or frequency partly from how easily examples come to mind.
Barnum effect
Rating vague, broadly applicable personality descriptions as uniquely accurate.
Bystander effect
In some emergencies, an individual may be less likely to help when other bystanders are present.
Change blindness
Difficulty noticing substantial changes when they coincide with an interruption or visual disruption.
Confirmation bias
The tendency to seek, interpret, and remember information in ways that fit an existing belief.
Conformity
Changing behavior or expressed judgment toward a group norm.
Dunning–Kruger effect
A debated pattern in which low performers may have difficulty accurately evaluating their own performance.
Framing effect
A shift in preference caused by presenting equivalent information in different ways.
Halo effect
A favorable impression in one area can color judgments of unrelated qualities.
Hedonic adaptation
Emotional responses to changed circumstances often diminish as those circumstances become familiar.
Hindsight bias
After learning an outcome, seeing it as more predictable than it was beforehand.
Illusion of transparency
Overestimating how clearly one’s private thoughts and emotions are visible to others.
In-group favoritism
Giving preferential evaluation or treatment to people categorized as part of one’s own group.
Inattentional blindness
Failing to notice a visible, unexpected object while attention is engaged elsewhere.
Loss aversion
In many choices, a loss relative to a reference point weighs more heavily than an equal-sized gain.
Mere exposure effect
Repeated exposure can increase liking for initially neutral stimuli under some conditions.
Misinformation effect
Post-event information can alter later reports about an experienced event.
Overconfidence
Confidence that is higher than the accuracy or precision of one’s judgments warrants.
Peak–end rule
Retrospective evaluations can be disproportionately influenced by an experience’s most intense point and its ending.
Representativeness heuristic
Judging probability by similarity to a prototype, sometimes underweighting base rates.
Serial-position effects
Items near the beginning and end of a sequence are often remembered better than items in the middle.
Social facilitation
The presence of others can improve performance on well-practiced tasks and impair difficult or unfamiliar ones.
Social loafing
People sometimes exert less individual effort when contributions are pooled and difficult to identify.
Social proof
Using other people’s behavior as information about what is appropriate or likely correct.
Spacing effect
Learning episodes distributed over time generally support longer-term retention better than the same time massed together.
Spotlight effect
Overestimating how much other people notice one’s appearance or behavior.
Stroop effect
Slower or less accurate color naming when a word’s meaning conflicts with its ink color.
Sunk cost effect
Continuing because of resources already spent even when only future costs and benefits should guide the choice.