It makes sense, she said, that a photographer's natural reaction would be to flash his camera.
"I'd attribute it more to a lack of experience than of desire or will," she said.
Psychologists Bibb Latane and John Darley defined the "Bystander Effect" in their 1970 book, The Unresponsive Bystander: Why Doesn't He Help? based on a series of lab experiments. They found that when there are plenty of people witnessing the scene, people are less likely to offer help for two main reasons.
First, because we get our cues from others, if several people are not reacting, we may follow suit. Second, the responsibility gets watered down: If you're the only one present, the responsibility clearly lies with you. But if there's a crowd of 10, you may feel your responsibility is only 10 percent.
"We need to educate people that that's an inclination, and that you have to step out of that mindset," Narvaez said. "And if you're a victim, looking people in the eye can help. So if you're in a car accident, look someone in the eye and say, ‘I need your help.'"
(An article in Slate outlines what to do if you find yourself stranded on subway tracks.)
In general, our brains reward altruistic behavior. Neuroscientist Jordan Grafman coauthored a study that showed that donating money activates a system in the brain concerned with reward and reinforcement more than receiving a gift.
"But many people are willing to give money and may not be willing to jump down in front of a train," said Grafman, the Director of Brain Injury Research at the Rehabilitation Institute of Chicago. "Under conditions like danger, the pattern of activation in the brain is very different."
Professional photographers sympathize with Abbasi.
"I must assume that the photographer believed that taking the photo would alert the train driver enough to stop," Ohio University professor Stan Alost told Gawker. "I doubt any working photojournalist would knowingly choose to photograph a scene anticipating death or injury of a subject unless they felt that there was nothing they could do to help."
The bottom line? "I would give him a break," Narvaez said.