It all began with a stop at a red light.

    Kevin Salwen was driving his 14-year-old daughter,Hannah,back from a sleepover in 2006.While waiting at a traffic light,they saw a black Mercedes Coupe on one side and a homeless man begging for food on the other.

    "Dad,if that man had a less nice car,that man there could have a meal," Hannah protested.The light changed and they drove on,but Hannah was too young to be reasonable.She pestered（纠缠）her parents about inequity,insisting that she wanted to do something.

    "What do you want to do?" her mom responded. "Sell our house?"

    Warning!Never suggest a grand gesture to an idealistic teenager.Hannah seized upon the idea of selling the luxurious family home and donating half the proceeds（收入）to charity,while using the other half to buy a more modest replacement home.

    Eventually,that's what the family did.The project—crazy,impetuous（鲁莽的）and absolutely inspiring—is written down in detail in a book by father and daughter scheduled to be published next month: The Power of Half.It's a book that,frankly,I'd be nervous about leaving around where my own teenage kids might find it.An impressionable child reads this,and the next thing you know your whole family is out on the street.

    At a time of enormous needs in Haiti and elsewhere,when so many Americans are trying to help Haitians by sending everything from text messages to shoes,the Salwens offer an example of a family that came together to make a difference—for themselves as much as the people they were trying to help.In a column a week ago,it described neurological（神经生物学的）evidence from brain scans that unselfishness lights up parts of the brain normally associated with more primary satisfaction.The Salwens' experience confirms the selfish pleasures of selflessness.

    Mr.Salwen and his wife,Joan,had always assumed that their kids would be better bigger house.But after they downsized,there was much less space to retreat to,so the family members spent more time around each other.A smaller house unexpectedly turned out to be a more family-friendly house.

    Unlike most other holidays, the history of April Fools' Day. Sometimes called All Fools' Day, is not as the totally clear. The only point in time that can be agreed on as the beginning of this tradition was 1582,in France. Before that year, the New Year was celebrated for eight days, beginning  on March 25.The reform of the calendar celetxration reached the highest point on April l_With the riform of the calendar under Charles 1X,the Gregorian calendar (公历, 阳历）was introduced, and New Year's Day was moved to January 1.

    However, because in those days communications were not as developed as they are today, many people did not receive the news for several years. Some people refused to accept the new calendar and continued to celebrate the New Year on April, These backward people were considered “foots” by other peopk. They were often sent on “fools” errands (徒劳无益的工作)or were made the taragets of jokes.

    This developed, over time, into a tradition of playing a trick on someone on the first day of April. The tradition eventully spread to England and Scotland in the eightreenth century. It was later introduced to the American colonies of both the Britain and Francc.April Fools' Day thus developed into an  international fun feast,so to speak,with different nationalities specializing in their own kind of humor at the expense of their friends and families.

    It's generally believed that people act the way they do because of their personalities and attitudes.They recycle their garbage because they care about the environment.They pay $5 for a caramel brulee latte because they like expensive coffee drinks.

    It's undeniable that behavior comes from our inner dispositions（性情）,but in many instances we also draw inferences about who we are,as suggested by the social psychologist Daryl Bern,by observing our own behavior.We can be strangers to ourselves.If we knew our own minds,why would we need to guess what our preferences are from our behavior?If our minds were an open book,we would know exactly how much we care about the environment or like lattes.Actually,we often need to look to our behavior to figure out who we are.

    Moreover,we don't just use our behavior to learn about our particular types of character—we infer characters that weren't there before.Our behavior is often shaped by little pressures around us,which we fail to recognize.Maybe we recycle because our wives and neighbors would disapprove if we didn't.Maybe we buy lattes in order to impress the people around us.We should not mistakenly believe that we always behave as a result of some inner disposition.

    Whatever pressures there can be or inferences one can make,people become what they do,though it may not be in compliance（符合）with their true desires.Therefore,we should all bear in mind Kurt Vonnegut's advice:"We are what we pretend to be,so we must be careful about what we pretend to be."

    That cold January night, I was growing sick of my life in San Francisco. There I was, walking home at one in the morning after a tiring practice at the theater. With opening night only a week away, I was still learning my lines. I was having trouble dealing with my part-time job at the bank and my acting at night at the same time. As I walked, I thought seriously about giving up both acting and San Francisco. City life had become too much for me.

    As I walked down empty streets under tall buildings, I felt very small and cold. I began running, both to keep warm and to keep away any possible robbers. Very few people were still out except a few sad-looking homeless people under blankets.

    About a block from my apartment, I heard a sound behind me. I turned quickly, half expecting to see someone with a knife or a gun. The street was empty. All I saw was a shining streetlight. Still, the noise had made me nervous, so I started to run faster. Not until I reached my apartment building and unlocked the door did I realize what the noise had been. It had been my wallet falling to the sidewalk.

    Suddenly I wasn't cold or tired anymore. I ran out of the door and back to where I'd heard the noise. Although I searched the sidewalk anxiously for fifteen minutes, my wallet was nowhere to be found.

    Just as I was about to give up the search, I heard the garbage truck pull up to the sidewalk next to me. When a voice called from the inside, "Alisa Camacho?" I thought I was dreaming. How could this man know my name? The door opened, and out jumped a small red-haired man with an amused look in his eyes. "Is this what you're looking for?" he asked, holding up a small square shape.

    It was nearly 3 a. m. by the time I got into bed. I wouldn't get much sleep that night, but I had got my wallet back. I also had got back some enjoyment of city life. I realized that the city couldn't be a bad place as long as people were willing to help each other.

    Living next to the Spellmans, our new neighbors, almost drove my mother crazy. If shewasn't shaming them for not attending church, or complaining to her sister Jackie about theway the Spellman girls dressed, then she was shoeing the Spellman's dogs out of our yard or filing noise complaints with the police, My mother had never been so busy.All she ever spoke of any more were the Spellmans and their wrongdoings.

    One Sunday afternoon after church service, my mother was driving old Ms Parker home to her house on the hill when we got a flat tire. As far as changing the tire, let's just say that we were at the mercy of the good Lord. Since old Ms. Parker lived so far up that hill, not a lot of traffic drove by us. It had been about fifteen minutes since the last car passed when we heard the rattling and puttering of an old pickup truck as it pulled over to assist us.

    The Spellman boys ran up on our car like a NASCAR pit crew. Before my mother could even protest, they had taken the tire off. "Her spare is flat," said the middle one to the big one. " Give her ours” replied the big one, barely acknowledging the sacrifice. My mother was stunned. "I don, t know what to say, "she stammered. The big one said, "Well, the Lord said love your neighbor, and we are neighbors, right?

    The next day when the Spellman's dogs went through my mother's flower garden, she put out a bowl of water for them. When she saw the Spellman girls walking out with nothing but a halter on, she lectured them about being upright ladies and offered them sweaters. And when she heard the Spellman's music through our walls, she tried to dance a little bit. She even invited the Spellmans to be part of the good neighbors committee. Now the neighborhood was a better place.