That was the issue facing thousands of workers in New York, Washington and Newark on a Monday morning in early August, after their offices had been pinpointed as possible terrorist targets. Most shrugged off the warnings and trudged off to wait in line to be searched and scanned.

Let’s look at four factors that diminished the sense of risk for these office workers — and how the same factors shape perceptions of risk in your workplace.

1) Get used to it

Psychologists call this dulling effect habituation. You can see it in your own workers after they’ve gotten into a routine. Clean out a septic tank or operate a punch press for the first time and you’re on high alert. Later, your sense of an elevated threat wanes.

Being desensitized to risk is healthy to a degree. Otherwise, we might not get out of bed in the morning. Thousands of office workers might have pulled the covers up on that Monday morning. But as a safety pro, you need to know when habituation turns dangerous, when your people are running on automatic pilot.

2) Peer pressure

This is typical peer pressure rearing its head. Risk communications expert Peter Sandman has a list of 16 reasons why employees sometimes ignore safety precautions; reason number 13: “My friends would laugh at me.”

Again, you need to monitor when peer pressure crosses the line from motivating to dangerous. More than a few shortcuts have been taken in the name of “social conformity.”

Some quotes in the papers from employees at targeted sites carried a macho tone (or maybe it was New Yorkers just being themselves) that belied another side of peer pressure — that desire to look cool under fire. “I’m not going to let some guy with a bomb-making degree from Kandahar University” change my day, one broker cracked.

Probably the most pronounced form of peer pressure was an almost unspoken sense that it was a matter of patriotic duty to show up for work Monday morning. What’s called “top down” pressure was also evident.

“The terrorists want to scare us,” said New York Senator Charles Schumer. “It’s almost a moral imperative for everybody to go about their jobs.”

“Make no mistake, New York City is not going to be cowed by the terrorists,” declared Mayor Michael Bloomberg.

“You can’t scare me” is reason number five on Sandman’s list for resisting precautions. Reason number 16: “Screw ’em all.”

Like the other factors we’re discussing, defiance is a double-edged sword. Directing it at an enemy is one thing, at the safety department is another. And you can take resistance too far and become foolhardy.

3) Motivated inattention

“I didn’t sleep last night because I was thinking about coming in here,” said a woman entering the Citigroup Center in New York.

Two different reasons for ignoring a risk: “I’m terrified” (number six on Sandman’s list) and “I know I should but it’s a pain” (number eight).

Sandman calls both of these forms of “motivated inattention.” In an article he wrote in the July 2004 issue of The Synergist, he explains: “Sometimes when people aren’t paying attention to risk it’s not because they’re busy or daydreaming or worried about a different risk. It’s because they don’t want to pay attention to that particular risk.”

For the sleep-deprived woman, the risk is too painful to think about. For the stock trader, it’s an inconvenience.

In many cases, employees are motivated to ignore risks because they sense a double message being sent about safety. Yes, there’s a safety mission statement in the lobby. But “my boss doesn’t mean it about safety” (Sandman’s reason number 14.)

Productivity is what really counts. Also known as: “Management is sending a double message” (number 15).

Employee perception surveys, small group “sensing sessions,” or just walking around and having conversations are ways of unlocking hidden reasons for taking risks that workers might be too embarrassed or intimidated to talk about openly.

4) Knowledge is power

“If anything, this place is over-protected,” said a computer analyst waiting to get into the New York Stock Exchange.

“Everyone is going to do their job the best they can to protect us,” said a financial advisor.

These are comments of fully-informed employees who are knowledgeable about the risks they face. Risk communication experts applauded the specific details given by homeland security czar Tom Ridge during that August scare.

Studies show people are far more anxious when they are given sketchy or no information about what to pay attention to. Alerts that are rich in specifics give people hazard cues to focus on. They feel empowered, more in control.

“I definitely came walking down here with my eyes wide open,” said an accountant at the World Bank building in Washington.

That’s what you want — mindful employees on alert. But you must be discerning when educating and training employees about safety and health risks. Are workers over-confident about protections? Are they confused or frightened by too much information (just study your average MSDS, for example)?

Public safety officials and executives at the organizations under terrorist surveillance won high marks for their open and honest communication with employees. But the employee perceptions of risk on display at the potential terrorist targets were also lowered for reasons enumerated by Peter Sandman in a list of outrage factors posted on his Web site www.psandman.com: