Sometimes the results of these experiments were so surprising they challengedconventional wisdomabout the human mind and actions.

In other cases, these experiments were also quite controversial.

Some of the most famous examples include Milgram’s obedience experiment and Zimbardo’s prison experiment.

Rhesus monkey clings to surrogate mother.

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Explore some of these classic psychology experiments to learn more about some of the best-known research in psychology history.

While the wire mother provided food, the cloth mother provided only softness and comfort.

Pavlov’s experiments with dogs established classical conditioning.

Pavlov’s Dog

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During the 1950s, psychologist Solomon Asch conducteda series of experimentsdesigned to demonstrate the powers of conformity in groups.

When asked alone, the students were highly accurate in their assessments.

In other trials, confederate participants intentionally picked the incorrect line.

Three men sitting on bench, view of shows

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A rat would learn that pressing a level delivered a food pellet.

Or the rat would learn to press the lever so you can halt electric shocks.

In reality, the learner was actually a confederate in the experiment who pretended to be shocked.

Pigeons in Operant Conditioning Test

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Why This Experiment Is Notable

Milgram’s experiment is one of the most controversial in psychology history.

Zimbardo’s famous studywas referred to after the abuses in Abu Ghraib came to light.

It is worth noting criticisms of Zimbardo’s experiment, however.

Voltage box used to give shocks to experiment participants

Isabelle Adam/Flicker/CC BY-NC-ND 2.0

doi:10.1177/0957154X19898997

Gantt WH.Ivan Pavlov.Encyclopaedia Brittanica.

B.F. Skinner Foundation.A brief survey of operant behavior.

doi:10.1371/journal.pone.0209704

Zimbardo PG.Philip G. Zimbardo on his career and the Stanford Prison Experiment’s 40th anniversary.

'The Stanford Prison Experiment' New York Premiere

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2013;2(2):79-92.

Specter M.Drool: How Everyone Gets Pavlov Wrong.The New Yorker.2014; November 24.