The 1977 power blackout in metropolitan New York triggered rampant arson and looting that cost millions of dollars, while public behavior during this year's sweeping power shutdown has proved far more peaceful.
Experts in sociology and psychology say the difference reflects large cultural changes, not the least of which is the shock to the national psyche of the Sept. 11 terrorist attacks.
"When you've lived through hell, purgatory is a breeze," said Robert R. Butterworth, a Los Angeles-based clinical psychologist. "I think people breathed a collective sigh of relief, and said, 'We can do this.' I think people said, 'We better help each other because we're all in this together.'"
Had the current crisis struck before Sept. 11, 2001, at least one expert believes, the outcome could have been very different.
"As bad as September 11th was, it was good for New York" on Thursday, said Steven J. Danish, a professor of psychology and director of the Life Skills Center of the Virginia Commonwealth University. "It was preparation for what to do when things go bad."
In explaining the relative calm, analysts also factor in a lower crime rate, less police tension and an improved financial situation in New York City over that of 1977. Even the time of day of the latest blackout played into the results.
By far, the current blackout more closely parallels the events of Nov. 9, 1965, when a cascading system failure plunged 30 million people in the Northeast into darkness within 15 minutes, yet the collective mood remained calm and orderly.
That tone changed a dozen years later, on a hot night in mid-July 1977, when lightning struck two high-voltage power lines just north of New York City. Eight million people lost power, and looting erupted in what Time magazine called "the night of terror."
But there might be less to learn from those earlier blackouts than from the recent terrorism attacks, Danish contends.
"People forgot all the good and bad of '65 and '77," he said. "What they do remember is [two] years ago."
And what they did Thursday, for the most part, was take a breath and do what they needed to do. A positive crowd mentality developed. Some directed traffic. Others helped people struggling to walk. Still others calmed people who were frightened.
"People have had experience with this now," Danish said. "They know what to do. When you have that experience, and you're dealing with something positively, then you start to have more confidence in your ability to deal with it that way."
The 1977 blackout occurred at a time of strife in New York City when there was a higher crime rate, tension with police and financial crisis.
It was just minutes after the 1977 blackout began, "when men in trucks equipped with chains and hooks were being paid by crowds to rip off the iron gates and fences that protected neighborhood stores," according to one study of the blackout.
"Within fifteen minutes, stolen goods were being offered to neighborhood residents who were on the streets or stranded in apartment buildings without elevator service," the study said.
"The 1977 one is the oddity because of the looting and the breakdown of law and order," said Norman M. Bradburn, assistant director for social, behavioral and economic science at the National Science Foundation in Arlington, Va. "My hypothesis would be that a lot of people viewed it as not a product of external enemies or an act of God, but as caused by the system."
Tempers tend to flare more when people believe that a problem is caused by a breakdown in an economic or governmental system, he said.
Like the current problems, that blackout also struck in the heat of the summer, but at night - two factors that would have fueled tensions, said Bradburn, who studied the 1965 blackout while at NORC, a national organization for research at the University of Chicago.
"A lot of people would have been out on the streets anyway and edgy and maybe looking for trouble," he said. "People might have thought it's a temporary blackout in our neighborhood, we'll take advantage of it quickly. Once mob action gets started, it's hard to stop it."
Peter H. Rossi, a retired professor of sociology at the University of Massachusetts, Amherst, explains the 1977 violence by the stark difference in the crime rate then. Rossi was director of NORC at the time the organization studied the 1965 blackout.
"The amount of law and order in New York City is considerably higher today than it was in 1977," he said.
That this blackout started during daylight gave the public and authorities several hours to mobilize, said Neil J. Smelser, a professor emeritus of sociology at the University of California, Berkeley.
Additional security consciousness and emergency preparedness after the terrorism attacks also probably contributed to the public calm, said Smelser, who wrote a book called Theory of Collective Behavior and has served on advisory panels of the national academies on the nature of terrorism and America's vulnerability to it.
"We're a little better able to experience and handle surprises than we were before September 11th," he said. "We have learned to live with a chronic level of uncertainty. If you're living in a comfortable era, surprises are a lot harder to deal with."
Butterworth, the clinical psychologist, pointed to reports of sporadic looting in Ottawa in the current blackout.
"They didn't have that scare like we did in New York," he said. "When people are kind of watching out for each other, the criminals back off."