Encyclopedia of Psychological Effects

Showing all effects

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Effect Name	Category	Explanation
Confirmation Bias	Cognitive	The tendency to search for, interpret, favor, and recall information in a way that confirms one's preexisting beliefs or hypotheses.
Dunning-Kruger Effect	Cognitive	A cognitive bias wherein people of low ability have illusory superiority and overestimate their abilities, while high-ability people may underestimate theirs.
Halo Effect	Cognitive	The tendency for an observer's overall impression of a person, company, brand, or product to influence the observer's feelings and thoughts about that entity's character or properties.
Anchoring Bias	Cognitive	The common human tendency to rely too heavily on the first piece of information offered (the "anchor") when making decisions.
Availability Heuristic	Cognitive	A mental shortcut that relies on immediate examples that come to a given person's mind when evaluating a specific topic, concept, method or decision.
Hindsight Bias	Cognitive	The inclination, after an event has occurred, to see the event as having been predictable, despite there having been little or no objective basis for predicting it.
Sunk Cost Fallacy	Cognitive	The phenomenon where a person is reluctant to abandon a strategy or course of action because they have heavily invested into it, even when it is clear that abandonment would be more beneficial.
Survivorship Bias	Cognitive	The logical error of concentrating on the people or things that made it past some selection process and overlooking those that did not, typically because of their lack of visibility.
Gambler's Fallacy	Cognitive	The mistaken belief that, if something happens more frequently than normal during a given period, it will happen less frequently in the future.
Declinism	Cognitive	The belief that a society or institution is tending towards decline, often nostalgia for a 'golden age' that never existed.
Bystander Effect	Social	A social psychological claim that individuals are less likely to offer help to a victim when other people are present.
Placebo Effect	Social/Physiological	A beneficial effect produced by a placebo drug or treatment, which cannot be attributed to the properties of the placebo itself, and must therefore be due to the patient's belief in that treatment.
Spotlight Effect	Social	The phenomenon in which people tend to believe they are being noticed more than they really are.
Hawthorne Effect	Social/Organizational	The alteration of behavior by the subjects of a study due to their awareness of being observed.
Pygmalion Effect	Social	The phenomenon whereby higher expectations lead to an increase in performance.
Golem Effect	Social	The converse of the Pygmalion effect, where low expectations lead to a decrease in performance.
Groupthink	Social	A psychological phenomenon that occurs within a group of people in which the desire for harmony or conformity in the group results in an irrational or dysfunctional decision-making outcome.
Fundamental Attribution Error	Social	The tendency for people to under-emphasize situational explanations for an individual's observed behavior while over-emphasizing dispositional and personality-based explanations.
Actor-Observer Bias	Social	The tendency to attribute one's own actions to external causes while attributing other people's behaviors to internal causes.
False Consensus Effect	Social	The tendency for people to overestimate the extent to which others agree with them.
Barnum Effect	Social	The tendency for individuals to give high accuracy ratings to descriptions of their personality that supposedly are tailored specifically for them but are, in fact, vague and general enough to apply to a wide range of people.
IKEA Effect	Social	A cognitive bias in which consumers place a disproportionately high value on products they partially created themselves.
Cheerleader Effect	Social	The tendency for people to appear more attractive in a group than in isolation.
Spiral of Silence	Social	A theory that people are less likely to share their opinions if they believe they are in the minority, for fear of social isolation.
Mandela Effect	Memory	A phenomenon in which a large group of people share a false memory of a past event or detail that did not actually occur.
Misinformation Effect	Memory	The tendency for post-event information to interfere with the memory of the original event.
Serial Position Effect	Memory	The tendency of a person to recall the first and last items in a series best, and the middle items worst.
Next-in-line Effect	Memory	When people are unable to recall information presented immediately preceding their turn to speak in a group introduction.
Reminiscence Bump	Memory	The tendency for older adults (over forty) to have increased recollection for events that occurred during their adolescence and early adulthood.
Spacing Effect	Memory	The phenomenon whereby learning is greater when studying is spread out over time, as opposed to studying the same amount of time in a single session.
Testing Effect	Memory	The improved ability to remember information after retrieving it, rather than simply re-reading it.
Zeigarnik Effect	Memory	The tendency to remember incomplete or interrupted tasks better than completed ones.
McGurk Effect	Perceptual	A perceptual phenomenon that demonstrates an interaction between hearing and vision in speech perception.
Werther Effect	Sociological	The increase in suicides that follow a highly publicized suicide, so named after the protagonist in Goethe's novel The Sorrows of Young Werther.
Pareidolia	Perceptual	The psychological phenomenon in which the mind responds to a stimulus by perceiving a familiar pattern where none exists.
Stroop Effect	Attention	The delay in reaction time when the color of the word does not match the name of the color (e.g., the word "red" printed in blue ink).
Mere Exposure Effect	Social	The psychological phenomenon by which people tend to develop a preference for things merely because they are familiar with them.
Self-Fulfilling Prophecy	Social	A prediction that directly or indirectly causes itself to become true, by the very terms of the prophecy itself, due to positive feedback between belief and behavior.
Overjustification Effect	Motivation	The phenomenon where intrinsic motivation to perform a task is diminished by the introduction of external rewards or incentives.
Cocktail Party Effect	Attention	The phenomenon of being able to focus one's auditory attention on a particular stimulus while filtering out a range of other stimuli, as when a partygoer can focus on a single conversation in a noisy room.
Bradbury Effect	Perceptual	A phenomenon where a person perceives a stimulus as being longer or shorter than it actually is, depending on the context.
Boomerang Effect	Social	The unintended consequences of an attempt to persuade resulting in the adoption of an opposing position instead.
Frequency Illusion	Cognitive	The phenomenon in which people who just learn or notice something start seeing it everywhere. Also known as the Baader-Meinhof phenomenon.
Ben Franklin Effect	Social	A proposed psychological phenomenon: a person who has already performed a favor for another person is more likely to do another favor for the other than if they had received a favor from that person.
Romeo and Juliet Effect	Social	The supposed increase in the romantic passion of a couple whose parents oppose their relationship.
Door-in-the-face Technique	Social	A persuasion method where a large, often unreasonable request is made first, to increase the chance that the second, smaller request will be granted.
Foot-in-the-door Technique	Social	A compliance tactic that aims at getting a person to agree to a large request by having them agree to a modest request first.
Von Restorff Effect	Memory	The tendency for an item that "stands out like a sore thumb" (is distinctive) to be more likely to be remembered than other items (the Isolation Effect).
Autokinetic Effect	Perceptual	A visual phenomenon where a stationary, small point of light in an otherwise dark or featureless environment appears to move.