Beyond Comprehension: We know that genocide and famine are greater tragedies than a lost dog. At least, we think we do.

But the paradox does not end there. Even if 10 deaths do not make us feel 10 times as sad as a single death, shouldn't we feel at least twice as sad? There is disturbing evidence that shows we may actually care less. I suspect that if the Insiko had been carrying 100 dogs, many people would have cared less about their fate than they did about Hokget. One hundred dogs do not have a single face, a single name, a single life story around which we can wrap our imaginations and our compassion.

The evidence for what I am going to call the telescope effect comes from a series of experiments. Psychologist Paul Slovic of the University of Oregon asked two groups of volunteers shortly after the Rwandan genocide to imagine they were officials in charge of a humanitarian rescue effort. Both groups were told their money could save 4,500 lives at a refugee camp, but one group was told the refugee camp had 11,000 people, whereas the other group was told the refugee camp had 250,000 people. Slovic found that people were much more reluctant to spend the money on the large camp than they were to spend the money on the small camp.

Intrigued, Slovic pressed further. He asked different groups of volunteers to imagine they were running a philanthropic foundation. Would they rather spend $10 million to save 10,000 lives from a disease that caused 15,000 deaths a year, or save 20,000 lives from a disease that killed 290,000 people a year? Overwhelmingly, volunteers preferred to spend money saving the 10,000 lives rather than the 20,000 lives. Rather than tailor their investments to saving the largest number of lives, people sought to save the largest proportion of lives among the different groups of victims.

We respond to mass suffering in much the same way that we respond to most things in our lives. We fall back on rules of thumb, on feelings, on intuitions. People who choose to spend money saving 10,000 lives rather than 20,000 lives are not bad people. Rather, like those who spend thousands of dollars to find a single dog rather than directing the same amount of money to save a dozen dogs, they are merely allowing their hidden brain to guide them.

Our empathic telescopes are activated when we hear a single cry for help -- the child drowning in the pond, the dog abandoned on an ocean. When we think of human suffering on a mass scale, our telescope does not work, because it has not been designed to work in such situations. Humans are the only species that is even aware of large-scale suffering taking place in distant lands; the moral telescope in our brain has not had a chance to evolve and catch up with our technological advances. Our conscious minds can tell us that it is absurd to spend a boatload of money to save one life when the same money could be used to save 10. But in moral decision-making, as in many other domains of life where we are unaware of how unconscious biases influence us, it is the hidden brain that usually carries the day.

Slovic once told volunteers about a 7-year-old girl in Mali who was starving and in need of help. They were given a certain amount of money and asked how much they were willing to spend to help her. On average, people gave half their money to help the girl. Slovic asked another group of volunteers the same question, except instead of the girl, volunteers were told about the problem of famine in Africa, and that there were millions of people in dire need of help. The volunteers gave half as much money as the volunteers in the first group.

Slovic took the experiment that showcased the little girl in Africa a step further. He told another group of volunteers about a little boy in Mali. One group of volunteers was asked whether they would give money to the little girl; another was asked whether they would donate money to the little boy. A third group of volunteers was told about both the boy and the girl and asked how much they were willing to give. People gave the same amount of money when told about either the boy or the girl. But when the children were presented together, the volunteers gave less.

Journalists sometimes talk about compassion fatigue, the inability of people to respond to suffering when the scale or length of the suffering exceeds some astronomical number. But Slovic's work suggests that compassion fatigue starts when the number of victims rises from one to two.

"The feelings of sadness dropped," Slovic said of the volunteers who were told about the two children in need of help. He added, "You can't lock onto two people in need of help as closely as you can lock onto one person. You can't make an emotional connection as strongly to two as to one. If empathy is putting yourself in someone else's shoes, think of putting yourself in two people's shoes. It does not work. It falls apart."

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After would-be rescuers from two fishing vessels frightened Hokget below decks, the effort to save the dog continued, but hope was fading. There was talk of dispatching the U.S. Navy to sink the Insiko as a way of ensuring that any release of hazardous materials would occur hundreds of miles from shore. This, of course, would kill the dog -- assuming it was still alive. Facing intense public pressure to save Hokget, government officials concluded that asking the Navy to sink the tanker -- 750 miles from Hawaii, nearly 2,500 miles from the U.S. mainland, and drifting away from the United States -- posed unacceptable environmental risks. The Coast Guard finally agreed to access $250,000 in U.S. taxpayer funds to recover the Insiko. It wasn't officially called an animal rescue effort. Instead it was authorized under the Oil Spill Liability Trust Fund, based on the argument that if the aimless Insiko managed to drift westward for 250 straight miles, it might run aground on Johnston Atoll and harm marine life. (The environmental concern was a lovely touch, given that the United States used Johnston Atoll for decades as a nuclear weapons test site and a dumping ground for chemical weapons from various wars.)

The American Quest was called up again -- this time funded by taxpayers -- to rescue Hokget. On April 26, nearly a month and a half after the dog's ordeal began, the tugboat's crew found the Insiko and boarded the tanker. The 40-pound female was still alive, and hiding in a pile of tires. It was a hot day, so Brian Murray, the American Quest's salvage supervisor, went in and simply grabbed the terrier by the scruff of her neck. The dog was terrified and shook for two hours. Her rescuers fed her, bathed her and applied lotion to her nose, which was sunburned.

Hokget arrived in Honolulu on May 2 (with the Insiko hauled in tow so its diesel could be salvaged) and was greeted by crowds of spectators, a news conference, banners welcoming her to America and a red Hawaiian lei. After a period in quarantine, Hokget was adopted by the family of Michael Kuo, a friend of the Insiko's captain, who lives outside Honolulu. She put on weight and was signed up for dog classes.

Shankar Vedantam is a Washington Post staff writer and can be reached at vedantams@washpost.com. This article was adapted from hisbook, "The Hidden Brain: How Our Unconscious Minds Elect Presidents, Control Markets, Wage Wars and Save Our Lives," to be published this week by Spiegel & Grau, an imprint of Random House.For more information, visit www.hiddenbrain.org.