The basic setup: shocking a stranger on a stranger's instruction

Milgram recruited ordinary adult men (and, in later variations, women) from New Haven through newspaper ads, telling them they'd participate in a study of learning and punishment. Each volunteer, in the role of "teacher," was instructed by an experimenter in a lab coat to administer electric shocks of increasing voltage to a "learner" in another room every time the learner gave a wrong answer, with a shock generator clearly labeled up to a lethal-sounding 450 volts.

The learner was a confederate actor, and the shocks were never actually delivered, but the teacher believed they were real, hearing pre-recorded protests, cries of pain, and eventually ominous silence from the other room as the voltage climbed. The experimenter's only tool for keeping teachers going was a small set of scripted verbal prods — "please continue," "the experiment requires that you continue" — with no threats or coercion involved.

The study measured a single number: how far up the shock scale each participant was willing to go before refusing to continue.

Takeaway: the entire apparatus of "authority" in the study was just a calm voice and a lab coat — no force, no threats, just permission repeated.