C1 Lesson: The Experiment That Went Too Far

Level: C1 (Advanced)

Content Objective: Students examine the 1971 Stanford Prison Experiment, its famous narrative of situational evil, and the recent research that has challenged how much of that story can be trusted.

Language Objective: Students learn to use reported speech and hedging language (reportedly, is alleged to have, according to, seems to) to relay contested claims without asserting them as settled fact.

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1. Reading Section

In August 1971, a psychology experiment at Stanford University became one of the most famous, and most frequently retold, studies in the history of the discipline. Conducted by Philip Zimbardo, it appeared to show how quickly ordinary people could descend into cruelty once given power over others, a lesson later invoked to explain everything from prison violence to the abuse of detainees at Abu Ghraib.

Zimbardo recruited twenty-four male college students, randomly assigning half to play prisoners and half to play guards in a mock jail built in the basement of a university building. The guards were given uniforms, batons, and mirrored sunglasses; the prisoners were arrested at their homes by real Palo Alto police, fingerprinted, and given numbers instead of names. The study was designed to run for two weeks.

According to the story that made Zimbardo famous, the situation spiraled out of control almost immediately. Within the first two days, prisoners had staged a rebellion, and guards responded by using fire extinguishers, stripping prisoners of their clothing, and confining the instigators to solitary confinement. One prisoner reportedly suffered a breakdown so severe that he had to be released after only thirty-six hours, though in a 2017 interview he claimed the breakdown had been faked so that he could return to studying for an exam. When a visiting researcher, Christina Maslach, objected that the guards were forcing prisoners to wear bags over their heads, Zimbardo later admitted that he had so thoroughly internalized his role as superintendent that he needed someone else to point out what was happening. He ended the study on the sixth day, more than a week earlier than planned.

For nearly five decades, this account was treated as more or less definitive. Zimbardo has repeatedly said that the experiment demonstrated the overwhelming power of situations to shape behavior, regardless of an individual’s personality, and the study became a fixture of introductory psychology courses worldwide.

In 2018, however, the French researcher Thibault Le Texier published a book challenging this narrative, later expanded into a 2019 peer-reviewed article. According to Le Texier, archival recordings show that the guards were not simply reacting spontaneously to the situation; they are alleged to have been actively coached by the research team on how to behave, in order to produce results that would confirm conclusions Zimbardo had largely reached in advance.

The evidence Le Texier cites includes a recording in which the undergraduate playing the role of warden can be heard encouraging one guard to be “tough” for the benefit of the study. One participant guard, David Eshelman, has since acknowledged that he deliberately invented new ways to humiliate prisoners, drawing inspiration from a film character he identified with, and admitted that on one shift he instructed prisoners to simulate degrading acts.

Zimbardo and his colleague Craig Haney issued a rebuttal, arguing that Le Texier’s critique was largely an ad hominem attack that ignored contradicting evidence. Still, a 2024 National Geographic documentary tracked down several of the original participants. Many of them are reported to have confirmed much of what Le Texier had described, including one man, Kent Cotter, who said he had quit the experiment before it even began because he was troubled by what his fellow guards seemed eager to do.

So was the Stanford Prison Experiment a demonstration of situational evil, or a demonstration of how convincingly a determined researcher can shape the outcome he expects? Zimbardo still maintains that his original interpretation holds. What does seem clear, however, is that the experiment’s most lasting legacy may not be its findings at all, but the ethical review boards it inspired, created specifically to prevent researchers from steering their subjects toward a predetermined conclusion.

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2. Vocabulary Section

Word / Phrase	Meaning	Example
descend (into)	to move gradually into a worse or more negative state	It appeared to show how quickly ordinary people could descend into cruelty.
internalize	to make an attitude, belief, or role part of your own way of thinking or behaving	Zimbardo admitted that he had so thoroughly internalized his role as superintendent.
fixture	something so firmly established that it seems a permanent part of a place or system	The study became a fixture of introductory psychology courses worldwide.
spontaneous	happening naturally, without being planned, coached, or caused by outside influence	The guards were not simply reacting spontaneously to the situation.
coach (verb)	to instruct or train someone privately, especially in what to say or do	They are alleged to have been actively coached by the research team on how to behave.
rebuttal	a formal response that argues against a previous claim or criticism	Zimbardo and his colleague Craig Haney issued a rebuttal.
ad hominem	an argument that attacks a person’s character rather than addressing their actual argument	Le Texier’s critique was largely an ad hominem attack that ignored contradicting evidence.
predetermined	decided or fixed in advance, before the relevant process or event has taken place	Researchers steering their subjects toward a predetermined conclusion.

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3. Example Sentences (Target Grammar in Use)

• Zimbardo later admitted that he had so thoroughly internalized his role as superintendent that he needed someone else to point out what was happening.
• One prisoner reportedly suffered a breakdown so severe that he had to be released after only thirty-six hours, though in a 2017 interview he claimed the breakdown had been faked.
• According to Le Texier, archival recordings show that the guards were not simply reacting spontaneously to the situation; they are alleged to have been actively coached by the research team.
• One participant guard, David Eshelman, has since acknowledged that he deliberately invented new ways to humiliate prisoners.
• Zimbardo and his colleague Craig Haney issued a rebuttal, arguing that Le Texier’s critique was largely an ad hominem attack.
• Many of them are reported to have confirmed much of what Le Texier had described, including one man, Kent Cotter, who said he had quit the experiment before it even began.

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4. Grammar Section

Reported Speech and Hedging Language

When relaying a claim that is disputed or unverified, careful writers distinguish between what is directly reported by a source and what is merely alleged or believed. Reported speech (using verbs like said, admitted, claimed, argued, acknowledged, with an appropriate tense shift) attributes a statement to its source. Hedging language (reportedly, is alleged to have, is reported to have, according to, seems to) signals that a claim has not been independently confirmed by the writer, without dismissing it outright.

Form	Function	Example
reporting verb + that-clause (with backshift)	attributes a specific statement to a named source	Zimbardo later admitted that he had so thoroughly internalized his role as superintendent that he needed someone else to point out what was happening.
reportedly / allegedly	signals a claim the writer has not personally verified	One prisoner reportedly suffered a breakdown so severe that he had to be released after only thirty-six hours.
is/are alleged to have + past participle	a formal hedge for a contested claim about the past	They are alleged to have been actively coached by the research team on how to behave.
is/are reported to have + past participle	a formal hedge indicating secondhand confirmation, short of full certainty	Many of them are reported to have confirmed much of what Le Texier had described.
according to X	attributes a claim to a specific source without the writer endorsing it	According to Le Texier, archival recordings show that the guards were not simply reacting spontaneously.

Quick Tip: Reported speech and hedging serve different jobs: reported speech (X said that…) tells the reader exactly who is responsible for a claim, while hedges (reportedly, is alleged to have) tell the reader how confident to be in it. A rigorous writer often combines both: “Zimbardo claims that participants suffered no lasting harm” attributes the claim to Zimbardo while leaving its truth an open question, which “Participants suffered no lasting harm” does not.

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5. Comprehension Questions

A. True or False

1. The Stanford Prison Experiment was originally designed to run for two weeks.
2. Zimbardo ended the study exactly on the day it was originally scheduled to end.
3. Thibault Le Texier’s research concluded that the guards’ behavior was entirely spontaneous.
4. According to the passage, participants interviewed for the 2024 documentary entirely contradicted Le Texier’s account.

B. Short Answer

5. What did Christina Maslach object to, and how did Zimbardo later describe his own state of mind at that point in the study?
6. According to Le Texier, what specific piece of evidence contradicts the claim that the guards’ cruelty was spontaneous?
7. How did Zimbardo and Craig Haney respond to Le Texier’s critique, and what happened when participants were later interviewed for a documentary?
8. According to the final paragraph, what might be the experiment’s most lasting legacy, regardless of which interpretation is correct?

C. Fill in the Blank / Transform — Rewrite each sentence using the reported speech or hedging form indicated in brackets.

9. Direct: “I quit before the experiment began because I was troubled by what my fellow guards seemed eager to do,” Kent Cotter said. (Rewrite as reported speech.)
10. It is claimed, without full confirmation, that the guards were coached by the research team. (Rewrite using “alleged to have”.)
11. People say that participants in the 2024 documentary confirmed Le Texier’s account, but this has not been independently verified by the writer. (Rewrite using “reported to have”.)
12. Direct: “The experiment demonstrated the overwhelming power of situations to shape behavior,” Zimbardo has said. (Rewrite as reported speech.)

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Next lesson: C1 — “The Lie That Became a National Scandal”