Modern Milgram Experiments: plumbing the horror of only following orders

Nature reveals a new generation of Milgram experiments – the 50-year-old psychological tests that had subjects electrocute (or believe they were electrocuting) other people on command – and have found that people are fine with causing real pain… as long as someone else tells them to:

“If others can replicate this, then it is giving us a big message,” says neuroethicist Walter Sinnot-Armstrong of Duke University in Durham, North Carolina, who was not involved in the work. “It may be the beginning of an insight into why people can harm others if coerced: they don’t see it as their own action.”

The study may feed into a long-running legal debate about the balance of personal responsibility between someone acting under instruction and their instructor, says Patrick Haggard, a cognitive neuroscientist at University College London, who led the work, published on 18 February in Current Biology.

…Milgram did not assess his participants’ subjective feelings as they were coerced into doing something unpleasant. And his experiments have been criticized for the deception that they involved — not just because participants may have been traumatized, but also because some may have guessed that the pain wasn’t real.

Modern teams have conducted partial and less ethically complicated replications of Milgram’s work. But Haggard and his colleagues wanted to find out what participants were feeling. They designed a study in which volunteers knowingly inflicted real pain on each other, and were completely aware of the experiment’s aims.

In his experiments, the volunteers (all were female, as were the experimenters, to avoid gender effects) were given £20 (US$29). In pairs, they sat facing each other across a table, with a keyboard between them. A participant designated the ‘agent’ could press one of two keys; one did nothing. But for some pairs, the other key would transfer 5p to the agent from the other participant, designated the ‘victim’; for others, the key would also deliver a painful but bearable electric shock to the victim’s arm. (Because people have different tolerances to pain, the level of the electric shock was determined for each individual before the experiment began.) In one experiment, an experimenter stood next to the agent and told her which key to press. In another, the experimenter looked away and gave the agent a free choice about which key to press.

To examine the participants’ ‘sense of agency’ — the unconscious feeling that they were in control of their own actions — Haggard and his colleagues designed the experiment so that pressing either key caused a tone to sound after a few hundred milliseconds, and both volunteers were asked to judge the length of this interval. Psychologists have established that people perceive the interval between an action and its outcome as shorter when they carry out an intentional action of their own free will, such as moving their arm, than when the action is passive, such as having their arm moved by someone else.

When they were ordered to press a key, the participants seemed to judge their action as more passive than when they had free choice — they perceived the time to the tone as longer.

EEG recordings also showed that those giving the shocks didn’t have emotional reactions to the act of giving the shock as much as to the act of being ordered to give the shock.