By Ellen Wulfhorst
NEW YORK (Reuters) - Some days New Yorkers look up and remark wistfully that the sky is the same blue as on September 11, 2001. Other days they look up at the sound of an airplane, momentarily worried that it may be flying too low.
New Yorkers, often characterized by outsiders as rude, if not hard-hearted, were dramatically changed by the hijacked plane attacks that felled the World Trade Center towers a decade ago.
Many are anxious, some are angry and most are saddened, yet New Yorkers seem to feel more caring and compassion toward one another, say experts who studied responses to the attacks.
Most vivid is a reflexive fear response to anything that sounds or looks remotely like an attack, they say.
Just two months after September 11, an American Airlines jet crashed into a seaside neighborhood in Queens, killing 265 people and scaring many residents into thinking another assault was underway. Now thunderstorms, the recent earthquake and even unexpected fireworks displays trigger frightened concern.
"One clear-cut reaction when the earthquake hit was 'Oh my God, it's terrorism,'" said Judith Richman, an epidemiologist at the University of Illinois at Chicago who studied the impact of September 11 on mental health.
"It's in the back of people's minds. They fear it's another attack."
Fearfulness shows too in the intolerance that has grown since September 11, observers said, pointing to opposition to the proposed construction of an Islamic center and mosque near Ground Zero and to anti-Muslim discrimination.
Last year, a New York City cab driver was attacked by a man who asked if he was Muslim and celebrated Ramadan, then slashed his neck, face and shoulders.
Yet people in New York can show more care toward each other than they once did. A blackout in 2003 was largely a good-natured affair, with city residents directing traffic and helping one another navigate darkened streets. It was a far cry from the looting and mayhem of the city's infamous 1977 blackout.
More recently, neighbors rushed to one another's aid ahead of the feared onslaught of Hurricane Irene, said Richman.
"People have learned to reach out to help people in danger," she said.
Much more quiet a response to September 11 is what New York clinical psychologist Yael Danieli, who specializes in massive trauma, calls an "unspoken sadness."
"A very deep sea of sadness is in the soul of people. It's in the soul of survivors, and I believe forever in the soul of New York," she said.
But playwright Christopher Shinn, whose play "Where Do We Live" looked at life around September 11, said he believes New York has scarcely begun to feel the true effects of the attacks.
"Once things went back to normal, there was never a second stage where we said ...'Now we have some perspective. We can begin thinking about it,'" he said. "I'm still waiting for that. If anything, we're in denial."
(Editing by Jackie Frank)