Observer-expectancy effect

Psychology

Outline History Subfields
Basic types
Abnormal Biological Cognitive Comparative Cross-cultural Cultural Differential Developmental Evolutionary Experimental Mathematical Neuropsychology Personality Positive Quantitative Social
Applied psychology
Applied behavior analysis Clinical Community Consumer Counseling Educational Environmental Ergonomics Forensic Health Humanistic Industrial and organizational Interpretive Legal Medical Military Music Occupational health Political Religion School Sport Traffic
Lists
Disciplines Organizations Psychologists Psychotherapies Publications Research methods Theories Timeline Topics
Psychology portal

The observer-expectancy effect (also called the experimenter-expectancy effect, expectancy bias, observer effect, or experimenter effect) is a form of reactivity in which a researcher's cognitive bias causes them to unconsciously influence the participants of an experiment. Confirmation bias can lead to the experimenter interpreting results incorrectly because of the tendency to look for information that conforms to their hypothesis, and overlook information that argues against it.^[1] It is a significant threat to a study's internal validity, and is therefore typically controlled using a double-blind experimental design.

An example of the observer-expectancy effect is demonstrated in music backmasking, in which hidden verbal messages are said to be audible when a recording is played backwards. Some people expect to hear hidden messages when reversing songs, and therefore hear the messages, but to others it sounds like nothing more than random sounds. Often when a song is played backwards, a listener will fail to notice the "hidden" lyrics until they are explicitly pointed out, after which they are obvious. Other prominent examples include facilitated communication and dowsing.

References

↑ Goldstein, Bruce. "Cognitive Psychology". Wadsworth, Cengage Learning, 2011, p. 374

External links

Fallacies of relevance

Ad nauseam (Argument from repetition)
Argumentum ad ignorantiam (Argument from ignorance)
Argumentum ad lapidem / Proof by assertion
Argumentum e silentio (Argument from silence)
Ignoratio elenchi (Irrelevant conclusion)
Invincible ignorance
Moralistic / Naturalistic
Non sequitur
Rationalization
Red herring (Appeal to worse problems
Two wrongs make a right)
Special pleading
Straw man
Thought-terminating cliché (I'm entitled to my opinion)

Appeals to emotion

Genetic fallacies

Ad hominem	Abusive Association (Reductio ad Hitlerum) Circumstantial (Appeal to motive Bulverism) Poisoning the well Tu quoque

Authority (Accomplishment Ipse dixit Poverty / Wealth) Nature Tradition / Novelty (Chronological snobbery)

Etymological fallacy

Appeals to consequences

Argumentum ad baculum (Appeal to force)
Wishful thinking

Other appeals

Argumentum ad temperantiam (Argument to moderation)
Popularity

List of fallacies
Other types of fallacy
Philosophy portal

Formal fallacies

Masked man fallacy

In propositional logic	Affirming a disjunct Affirming the consequent Denying the antecedent Argument from fallacy False dilemma

In quantificational logic	Existential fallacy Illicit conversion Proof by example Quantifier shift

Syllogistic fallacy	Affirmative conclusion from a negative premise Exclusive premises Existential Necessity Four-term fallacy Illicit major Illicit minor Negative conclusion from affirmative premises Undistributed middle

Other types of formal fallacy List of fallacies

Informal fallacies

Correlative-based fallacies	False dilemma (Perfect solution fallacy) Denying the correlative Suppressed correlative

Fallacies of illicit transference	Composition Division

Deductive fallacies	Accident Converse accident

Inductive fallacies	Sampling bias (Cherry picking McNamara fallacy) Base rate fallacy / Conjunction fallacy False analogy Hasty generalization / Slothful induction Misleading vividness Overwhelming exception

Questionable cause	Animistic (Furtive) Correlation proves causation (Cum hoc ergo propter hoc) Gambler's (inverse) Post hoc Regression Single cause Slippery slope Texas sharpshooter Third-cause Wrong direction

Vagueness / ambiguity	Accent Amphibology Continuum fallacy / Sorites paradox False precision Slippery slope

Equivocation	Equivocation False attribution Quoting out of context Loki's Wager No true Scotsman Reification

Question-begging fallacies	Circular reasoning / Begging the question Loaded language (Leading question) Compound question / Loaded question No true Scotsman

List of fallacies Other types of fallacy Philosophy portal

Biases

Biases in judgment and decision-making	Acquiescence bias Anchoring bias Attentional bias Attribution bias Belief bias Choice-supportive bias Cognitive bias Confirmation bias Congruence bias Correspondence bias Halo effect Hindsight bias Hostile attribution bias Memory bias Outcome bias Response bias Self-serving bias Status quo bias Survivorship bias

Statistical biases	Bias of an estimator Information bias Lead time bias Omitted-variable bias Sampling bias Selection bias Self-selection bias Social desirability bias Spectrum bias Systematic error Systemic bias

Other	Academic bias FUTON bias Media bias No abstract available bias Publication bias Reporting bias

Hidden messages

Main	Hidden messages Subliminal message

Audio	Backmasking Reverse speech

Numeric	Numerology Theomatics Bible code Cryptology

Visual	Fnord Paranoiac-critical method Pareidolia Sacred geometry Steganography Visual cryptography

Other	Anagram Apophenia Asemic writing Easter egg Clustering illusion Observer-expectancy effect Pattern recognition Palindrome Unconscious mind

Observer-expectancy effect

See also

References

External links