In the early 1960s, Yale University psychologist Stanley Milgram shocked America when he demonstrated that ordinary people will commit acts of violence that conflict with their personal conscience and moral convictions if instructed to do so by an authority figure.

Now, a replication of that famous experiment is uncovering some of the same findings and controversy.

In the original experiment, Milgram asked ordinary people to administer painful -- and in some cases, even fatal -- shocks to other people posing as research subjects. The maximum voltage they could administer was 450 volts -- enough to cause permanent damage or even death to the study subject.

In reality, the "research subjects" were not receiving any shock. But the act of inflicting harm on another individual was still very much real to the people administering the voltage.

Although many of the participants that were asked to administer shocks expressed hesitation or even gently refused to continue going on with the experiment, Milgram found that about two-thirds of all the participants completed the study and administered the full 450 volts of shock.

Jerry Burger, lead investigator of the new study and a professor of psychology at Santa Clara University, said that his modified version of the study came to a similar conclusion: About 70 percent of the participants continued administering shock until they reached the highest voltage point.

But because the participants administering the voltage were deceived into believing that they were really shocking the study subjects, some ethics experts say the research goes too far.

"I feel quite strongly that this research study does not meet ethical research standards," said Dr. Michael Grodin, professor of bioethics, human rights, philosophy and psychiatry at the Boston University School of Public Health. "This is still deception research where the subject is not told that deception will be used."

Conforming to New Ethical Standards

Still, few would argue that the researchers in the most recent study paid far more attention to the ethical pitfalls of this research, compared to the one conducted more than 40 years ago.

Milgram's experiment took place before many of the formal guidelines for professional conduct and institutional review boards, or IRBs, had been established. In fact, many say the concern over the emotional state of the participants in this study was a significant factor behind the development of ethical standards for human experimentation.

In light of this, Burger was initially unsure whether he would even be able to conduct a similar experiment. His team took a number of steps to ensure that the replication of Milgram's experiment conformed to current ethical standards.

"The most important difference [from Milgram's experiment] was that we stopped the procedure much earlier, only asking participants to go up to the 150-volt point," Burger said. Additionally, he said they "screened participants for ethical concerns because we didn't want them to have a very negative response to this."

Dr. Jeffrey Spike, associate professor of medical humanities and social sciences at the Florida State University College of Medicine, said he believed these steps were "an acceptable compromise" in solving the ethical problem of causing the study participants emotional duress.

Still, a healthy ethical debate rages on over whether it is acceptable to use such forms of deception, possibly causing psychological distress, to reach a scientific conclusion. But Spike noted that considering what was learned from both Milgram and Burger's experiments about the human tendency to obey figures of authority -- even at some rather extreme costs -- the use of deception is justified.

"Stanley Milgram's experiments are among the most important in the history of experimental psychology, if not the most important," Spike said. "They are true classics, and help to explain phenomenon we read with shock and disbelief in the paper every day."