7 Famous Psychology and Science Experiments

Tap an experiment to see the full explanation.

Pavlov's Dog

1890s — By repeatedly pairing a bell sound with food, Ivan Pavlov trained dogs to salivate at the sound of the bell alone, establishing the concept of "classical conditioning."

The Milgram Obedience Experiment

1961 — Showed that ordinary people would administer what they believed were dangerous electric shocks to another person simply because an authority figure instructed them to, revealing the unsettling psychology of obedience.

The Stanford Prison Experiment

1971 — Ordinary college students were randomly assigned roles as guards or prisoners and, within a short time, became deeply immersed in their roles with dramatic behavioral shifts — the experiment became a landmark case in research-ethics debates.

The Double-Slit Experiment

1801 (Thomas Young) — Demonstrated that light behaves as both a particle and a wave simultaneously, and later became a foundational pillar of quantum mechanics.

The Little Albert Experiment

ateApril 1920 — By repeatedly exposing an infant to a white rat alongside a loud, frightening noise, researchers conditioned a fear response, showing that fear itself can be learned in humans through conditioning.

The Marshmallow Test

1970s — Children were offered an extra marshmallow if they could resist eating the one in front of them, examining the relationship between a child's ability to delay gratification and later life outcomes.

The Asch Conformity Experiment

1950s — A social psychology experiment showing that people will often go along with an obviously wrong answer if everyone else around them confidently states the same wrong answer.

Why These Experiments Are Still Talked About Today

These experiments offered fundamental insight into human psychology and the physical world, and went on to shape academic research and research-ethics standards. Some could never be conducted the same way today due to ethical concerns, but their findings remain important lessons.

Frequently Asked Questions

Could these experiments be conducted again today?

Experiments like Milgram's or the Stanford Prison Experiment, which caused real psychological distress to participants, could not be replicated in their original form under modern research-ethics standards.

Does the marshmallow test result still hold up?

Later research revisited the original conclusions and found they may not have adequately accounted for other variables, like a child's home environment — today the results are interpreted more cautiously.