Decision-thinking is not unlike poker—it often matters not only what you think, but also what others think you think and what you think they think you think. The mental process is similar. Naturally, this card game has often been of considerable interest to people who are, by any standards, good thinkers.

    The great mathematician John von Neumann was one of the founders of game theory. In particular , he showed that all games fall into two classes : there are what he called games of “ perfect information ”,games like chess where the players can't hide anything or play tricks : they don't win by chance , but by means of logic and skills . Then there are games of “imperfect information”, like poker, in which it is impossible to know in advance that one course of action is better than another.

    One mistaken idea about business is that it can be treated as a game of “perfect information”. Quite the reverse, business, polities, life itself are games which we must normally play with very imperfect information. Business decisions are often made with many unknown and unknowable factors, which would even puzzle the best poker players. But few business people find it comfortable to admit that they are taking a chance, and many still prefer to believe that they are playing chess, not poker.

    You're rushing to work and a man ahead of you collapses (跌倒) on the sidewalk. Do you stop to help? In a study of by-standers, it was found that some people avert their gaze and keep on walking rather than stop and get involved. “There is a tendency to decide that no action is needed.” says a psychologist. “The first thoughts that pop into (进入) your mind often keep you from offering help. In order to take action, you have to work against them.” Here are some common thoughts that might prevent you from helping.

    Why should I be the one? I'm probably not the most competent (有能力的) person in this crowd. You might think someone older or with more medical knowledge should offer assistance (帮助).

    What if he doesn't really need my help? The fear of embarrassment is powerful; no one wants to risk looking foolish in front of others.

    No one else looks concerned-this must not be a problem. We can follow the people around us, but most  people tend to hold back their emotions in public.

     “If you spot (发现) trouble and find yourself explaining inaction, force yourself to stop and evaluate the situation instead of walking on,” says the psychologist. “Then retry to involve other people; you don't have to take on the entire responsibility of being helpful. Sometimes it's just a matter of turning to the person next to you and saying, “It looks like we should do something.” Or asking someone if an ambulance has been called and, if not, to call for one. Once you take action, most people will follow you.”

    I sit on the stoop (门廊) in front of my friend's house at the top of a steep hill. And now my friend is late, and I'm stuck here waiting.

    I see a man approaching.

    "Por favor. Call 911," the man says. "Finger. Cut." With his left hand, he is pressing the handkerchief around his right little finger.

    "No. Have. Phone," I say, as if English is also my second language.

    "Have phone," he says, and dips his chin toward his front pants pocket. There, I find a phone, and call 911.

    The operator answers, and I say "I'm with this guy, and he cut his finger."

    "Did he cut it off?"

    "Did you cut it off?"

    "Sí." He sighs.

    "Yes. He cut it off."

    "Where is it?" the operator asks.

    "Where is it?"

    "Upstairs," he says, pointing with his elbow to the house next door.

    "Go get it," she instructs me.

    I follow the man toward the house. Inside, I see a table saw(锯), and the blood spreading across the ceiling, but I don't see the finger. I lift up each foot and look underneath to be sure I've not stepped on it. I'm getting that jumpy, tight-shouldered feeling like when you've lost sight of a spider that was on your ceiling a moment ago.

    "Do you see it?" I ask him.

    He points at his own finger beside the table saw. I grab a paper towel, pinching it carefully, the way you might pick up a harmless but frightening insect.

    "We have secured the finger," I tell the operator.

    "Hang tight. The ambulance is on its way."

    We sit on the stoop waiting for the ambulance.

    "You're going to be OK," I say, putting my free hand on his sawdust-covered back.

    "Gracias," he says.

    "De nada. Esta no problemo," I reply in broken Spanish.

    It feels good to be able to comfort someone, anyone. For months now, the second my hands would go idle(闲散的), a familiar depression would climb on my back. I have been trying to put on a good face for my kid, but I feel as if I've been failing. Could I save myself? I wouldn't know how. But I am determined to save this man.

    Finally the ambulance arrives, picks him up, and they're off.

    Throughout the evening, I can't stop worrying about the man. I decide to call the hospital.

    "Hi! I helped a guy who cut off his finger, and I don't even know his name, but I'm wondering whether he came to your hospital."

    The nurse says, "His name is Jose Ramos, and he's waiting for surgery. Would you like to leave a message?"

    "No. I don't want to bother him. I just wanted to be sure he was OK."

    The next morning, I call the hospital again. This time, I'm put through to Jose's room. "How was the surgery?"

    "No surgery," he says. "No enough blood."

    "Oh, I'm sorry," I say.

    Later that day, I remember that old proverb about how if you save someone's life, you are responsible for them for the rest of their life, which never made sense to me before. Shouldn't the person who got saved owe a debt, and not the other way around? But today, I get it. It's a great honor to help someone in need.

    I start keeping a lookout for other people in need of assistance. I help push a stalled car out of the road. I aid a disoriented cyclist when her bike gets clipped by a car. I adopt a dog. Then one day, a month or two after the finger incident, I realize I have completely forgotten to be depressed. I've been so busy playing the role of local hero that I have ignored to drag my feet and stare into space and imagine the world without me.

    Now, more than a decade has passed since Jose's accident. Occasionally I search for "Jose" plus "Ramos" plus "finger." I wish I could see him again, to see how he's getting on. But more important, to thank him, because when he lost his finger, he saved my life.

    Gregory Talley used to sleep in a park or under a bridge. The 50-year-old has been homeless for more than 10 years.

    “It is hard. It's hard to live homeless. You filled every day trying to find cut where you are going to get something to eat. If I hadn't found wonderful Fairfax County Kennedy Shelter, I wouldn't know where I would be by now. I might be dead,” Talley said.

    The Kennedy Shelter is one of the facilities New Hope Housing provides for homeless people.

    Pam Micheli has devoted her life to making the lives of this vulnerable（易受伤的）population better as executive director of the non-profit organization.

    “I went to Africa in 1985. And I saw a huge amount of poverty, but I saw so much hope. And I decided that I should try to do something that would bring hope to people,” Michell said.

    When Michell began working with New Hope Housing 25 years ago, its three shelters had about 80 beds. Now, it has 350 beds and serves about 1,500 homeless people every year. She has expanded the program beyond just providing beds for the night.

    “We do outreach（拓展）, we do prevention, we do permanent housing. We do transitional housing. We have an education program with all sorts of different things to move people to end their homelessness,” she said, “Our Out of Poverty program is not just about money. It's about you could be spiritually poor, you could be relationship poor ... you could be educationally poor. So it is focusing on how you get out of this poverty that has brought you to being homeless. The program tries to teach the shelter residents self-reliance（自立）and work values, and includes courses on planning and personal responsibility.

    “I learned I still have opportunities to change it and I can change it,” said shelter resident Lewis Webster. “It is just about going forth in doing necessary work to do it. I mean if you really want better, you would do better and that's the frame of mind of me now.”

    Nancy Ballard, 60, went for a routine checkup that turned into something extraordinary. She had just completed her master's in botanical illustration. In fact, she was canting a painting of a plant she'd done when she arrived at her doctor's San Francisco office. “It would be great if we had artwork like that for our chemotherapy(化疗)rooms, ”the nurse said. Ballard asked to see one.

    She was shocked by what she found. The walls were bare, and the paint was chipping(剥落).She could tell where old artwork had hung because of the naked nails. It was a depressing room for a depressing routine—patients had chemo drips for perhaps several hours, often with nothing to look at other than those sad walls. She couldn't imagine how anyone could even think about getting healthy in a room like that. As it happened, Ballard's physician, Stephen Hufford was ill with cancer himself, so finding time to decorate the rooms was low on his to-do list. So Ballard made it her mission to brighten up the place.

    She wrote to 20 local interior designers and asked whether they would donate their time and money to transform just one of Dr. Hufford's rooms each. Six of them wrote back almost immediately. Each of them ultimately chose a theme: The dragonfly room, for example, now features bright artwork and dragonfly wall ornaments. Most rooms got new paint, light fixtures, artwork, and furniture. Each room cost about $5, 000.

    Dr. Hufford was delighted.“ All the patients feel soothed by it.” he noted. He even said that his own tone of voice was different in the rooms and that he was better able to connect with his patients.

    Ballard was so encouraged that she created a nonprofit to raise money and decorate more spaces. Since then, she has worked on 20 projects, including one in Pennsylvania. She once went to Philadelphia for a ribbon cutting, and a woman there was on her third battle with cancer. When she saw what Ballard had done, she said, “I'm gonna beat it this time.I thought I wasn't going to, but now I know I'm gonna beat it.”