The BBC's follow-up to the notorious Stanford prison experiment ended early with fraternisation between guards and inmates rather than the disturbing violence of the original research.
There had been fears that staging a similar experiment might produce the same problems that led to psychologist Philip Zimbardo's research being curtailed early in 1971.
Then, relations between the Stanford University students playing guards and inmates in a simulated prison degenerated into physical and mental abuse and prompted Dr Zimbardo to remark: "These guys were all peaceniks. They became like Nazis."
Concern that The Experiment , filmed inside a prison built within a studio at Elstree, Hertfordshire, would have the same result were met with a range of safeguards, thorough screening of the 15 male participants and scrutiny from the British Psychological Society's ethics committee.
Far from prompting an explosion of aggression, some of those involved felt peacenik tendencies dominated proceedings during the nine days of filming in December.
While the stress of the Stanford experiment prompted one inmate to go on hunger strike, prisoners in the BBC version are believed to have staged a break-out and returned with food.
The two psychologists who guided the science behind the experiment were overjoyed with the results, which they feel will prove scientifically important.
Alex Haslam, professor of social psychology at Exeter University, said there had been no attempt to replicate the Stanford prison experiment.
"It would have been a trivial issue to put people together and for them to get on badly. We wanted to extend Zimbardo's work and look at what drives positive group behaviour," he said.
Professor Haslam said the research progressed so smoothly that it ended a day early and had produced a wealth of data that would take months to process.
"There were some moments of profound, positive forms of social behaviour that you could not script," he said, though he added that there were also darker sides to the study.
Stephen Reicher, a psychologist at St Andrews University and joint editor of the British Journal of Social Psychology , said collaboration with the BBC allowed the scientists to study human behaviour on a level far beyond what was possible with their usual limited resources.
The Experiment is pencilled into the BBC's schedule for this April.