Observer-expectancy effect: Information from Answers.com

The observer-expectancy effect (also called the experimenter-expectancy effect, 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. 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, dowsing, and applied kinesiology.

References

External links

Skeptic's Dictionary on the Experimenter Effect
The rat study
An article that speaks of Expectancy effects in paranormal investigation
Another article by Rupert Sheldrake
Songs of Praise (With subtitles) An example of observer-expectancy effect involving subtitles which alter the observer's interpretation of audio.

v • d • e Fallacies of relevance

General	Absurdity • Accident • Ad nauseam • Argument from ignorance • Argument from silence • Argumentum ad populum • Base rate • Compound question • Loaded question • Argument to moderation • Moralistic • Naturalistic • Proof by assertion • Irrelevant conclusion • Special pleading • Straw man • Style over substance • Two wrongs make a right

Appeals to emotion	Fear • Flattery • Nature • Novelty • Pity • Ridicule • Repugnance • Spite

Genetic fallacies	Ad hominem (Ad hominem tu quoque) • Appeal to authority • Appeal to motive • Appeal to tradition • Appeal to wealth • Appeal to poverty • Association • Bulverism • Chronological snobbery • Ipse-dixitism • Poisoning the well • Appeal to etymology • Reductio ad Hitlerum • Appeals to intellectual and mental stability or capability

Appeals to consequences	Appeal to force • Wishful thinking

v • d • e Formal fallacies

Masked man fallacy • Appeal to probability • Bare assertion fallacy

Fallacy of propositional logic:	Affirming a disjunct • Affirming the consequent • Argument from fallacy • False dilemma • Denying the antecedent

Fallacy of quantificational logic:	Existential fallacy • Illicit Conversion • Proof by example • Quantifier shift

Syllogistic fallacy:	Affirmative conclusion from a negative premise • Exclusive premises • Necessity • Four-term Fallacy • Illicit major • Illicit minor • Undistributed middle

List of fallacies (formal and informal) • Other types of formal fallacy

v • d • e Informal fallacies

Begging the question · Fallacy of distribution (Composition · Division) · Gambler's fallacy and its inverse · Many questions · Red herring fallacy · Special pleading

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

Deductive fallacies	Accident · Converse accident

Inductive fallacies	Biased sample · Conjunction fallacy · False analogy · Hasty generalization · Misleading vividness · Overwhelming exception

Vagueness and ambiguity	Continuum fallacy · False precision · Slippery slope

Equivocation	Equivocation · False attribution · Fallacy of quoting out of context · Loki's Wager · No true Scotsman · Reification

Questionable cause	Circular cause and consequence · Correlation does not imply causation (Cum hoc) · Post hoc · Regression fallacy · Single cause · Texas sharpshooter · Wrong direction

List of fallacies · Other types of fallacy

v • d • e Biases

Cognitive bias	Confirmation bias · Correspondence bias · Hindsight bias · Memory bias · Outcome bias

Statistical bias	Systematic bias · Systemic bias · Bias of an estimator · Omitted-variable bias · Lead time bias · Selection bias · Biased sample · Recall bias · Information bias · Observer bias

Other/ungrouped	FUTON bias/No abstract available bias

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Observer-expectancy effect

See also

References

External links