Soaping up your hands may do more than just get rid of germs. It may wash away the inner confusion you feel right after being forced to make a choice between two appealing choices, according to a new study. The study builds on the past research into a phenomenon known as “the Macbeth effect” (麦克白效应）.

    It turns out that Shakespeare was really onto something when he imagined Lady Macbeth trying to clean her conscience by rubbing invisible bloodstains from her hands.

    A few years ago, scientists asked people to describe a past wrong act. If people were then given a chance to clean their hands, they later expressed less guilt than people who hadn't cleaned.

    This finding interested W. S. Lee, a researcher. “Anything from the past, any kind of negative emotional experiences, might be washed away,” says Lee.

    He decided to test hand washing's effect on one kind of bad feeling：the tension we feel after being forced to choose between two attractive choices, because picking one choice makes us feel that we've lost the other. People usually try to calm this inner conflict by later exaggerating (夸大）the positive aspects of their choice.

    He had students rank 10 different music CDs. Then he offered students two of the CDs and told them to select one as a gift. Some students then used liquid soap. Others only looked at the soap or sniffed (闻)it. “Actually, you do not need water and soap,” says Lee.

    Later, the students again had to rank all the music CDs. People who didn't wash their hands had the normal response — they scored their take-home CD higher, suggesting that they now saw it as an even more attractive one than before. But this wasn't true for the hand washers. They ranked the music about the same. “They feel no need at all to justify (证明…正确）the choice,” says Lee.

    But the effects of it just aren't clear. Schwarz says it's too soon to know whether people should head for a sink after making a tough choice. He says washing may help decision-makers by cleaning away mental disorder. But perhaps if they don't go through the usual post-decision process of justifying their choice, they might feel more sorrow in the long run.

    I am building a tiny house. Not a dollhouse, but a livable space with bed, kitchen, storage-everything you'd need to live.

Why did I decide to build a house? I hoped it would give me skills that really matter in life, such as using tools for construction. And in building the house, I would understand how much labor goes into a home and truly appreciate what I am living in.

    But this past year, life gave me a heavy hit: My father, one of my best friends and my tiny house construction partner, died in a traffic accident.

    This is where my enthusiasm conics from now: the desire to finish my house for my father. Because of this decision, I now have some life experiences that some adults don't have. I can relate not only to people who want to build a house, but also to people who have lost a parent. And to all of them, I can say that giving up is not a choice.

    Still, without the help of my friends and family. I would probably stop my project. My friend Luke came to help the week after my father died; he knew I needed to get my walls up. The guidance from fellow tiny house builders and their families has been helpful. Putting windows in is no easy. And installing(安装) electricity is not something you do in your dreams. Ten hours of stabbing (戳) your fingers with metal string and getting shocked a couple times is not ideal.

    Sometimes when people get a hard knock, they stay down. I didn't. I didn't only want to show that anyone can build their own house; I also wanted to show that when I was handed lemons. I not only made lemonade. I made a delicious lemon cake.

    The oddness of life in space never quite goes away. Here are some examples.

    First consider something as simple as sleep. Its position presents its own challenges. The main question is whether you want your arms inside or outside the sleeping bag. If you leave your arms out, they float free in zero gravity, often giving a sleeping astronaut the look of a funny balled （芭蕾）dancer. “I'm an inside guy,” Mike Hopkins says, who returned from a six-month tour on the International Space Station. “I like to be wrapped up.”

    On the station, the ordinary becomes strange. The exercise bike for the American astronauts has no handlebars. It also has no seat. With no gravity, it's just as easy to pedal violently. You can watch a movie while you pedal by floating a microcomputer anywhere you want. But station residents have to be careful about staying in one place too long. Without gravity to help circulate air, the carbon dioxide you exhale (呼气) has a tendency to form an invisible （隐形的）cloud around you head. You can end up with what astronauts call a carbon-dioxide headache.

    Leroy Chiao, 54, an American retired astronaut after four flights, describes what happens even before you float out of your seat,”Your inner ear thinks your're falling . Meanwhile your eyes are telling you you're standing straight. That can be annoying—that's why some people feel sick.” Within a couple days —truly terrible days for some —astronauts' brains learn to ignore the panicky signals from the inner ear, and space sickness disappears.

    Space travel can be so delightful but at the same time invisibly dangerous. For instance, astronauts lose bone mass. That's why exercise is considered so vital that National Aeronautics and Space Administration (NASA) puts it right on the workday schedule. The focus on fitness is as much about science and the future as it is about keeping any individual astronauts return home, and, more importantly, how to maintain strength and fitness for the two and a half years or more that it would take to make a round-trip to Mars.

    One evening at a busy crossroads, I noticed a sister struggling to keep her little kid under control while she talked on the pay phone. She wanted him to stay still next to her, but he wanted to run and play by the road, close to rushing buses and taxis. One could sense the woman's frustration, that she was pulled in too many directions: She was angry at the person on the telephone and shouting at the younger that she would “snap（折断）his leg” if he moved again. As I waited for the traffic light to change, the child began to complain and struggle to free himself from the woman's grasp. She dropped the phone, seized（抓住）the neck of his tiny. T-shirt and gave him a back-hand blow across the face that I know made his little head spin.

    The light changed, and passers-by continued on their way. But I stood there, fixed to the pavement. I knew this extremely upset woman would carry through on her threat of violence to the child. Before, I had wanted to get close to her and offer to watch the youngster while she dealt with the troubling situation on the phone. Now I wanted to comfort the little boy. I also wanted to speak to the sister to calm her and to caution（告诫）her, as I wish someone had cautioned me when I was passing my pain on to my daughter and causing her emotional suffering. But I was chicken. I thought, she may think I'm out of line, or I may be her next target.

    Often I've thought about that child and the many others abused（虐待）by adults. I wonder how they will internalize（使……藏在心底）their pain, and if it will crush their spirits. Will this little boy grow up to be an abusive man? Will he be gloomy（阴郁的，沮丧的）and withdrawn（孤僻，内向的）? Will he find it hard to communicate with women, with other men? Or will he survive and be sensitive, caring and determined not to continue the cycle?

    There is too much cruelty（残忍）in the world, too much cruelty between people. I tremble at the increasing verbal（言语的）bitterness and violence among Black girls, and among young mothers trying to discipline their children. This behavior isn't class-or age-related: I hear sharp words from Black women from all walks of life who are overworked and stressed out and have grown impatient. At times I, too, become impolite to others, or, like the sister on the phone, strike out at（抨击）those closest to me.

    Often we're tired because we've made the wrong choices. Young girls who still need mothering are loaded with children. We sisters easily get hurt and annoyed when we don't compromise with our own sense of self. Our personal fulfillment requires knowing what is best for us, setting our boundaries（界限）and keeping them undamaged. We will always be asked to do more than we are comfortable doing. When we know our boundaries, we can decline comfortably. People—and we ourselves—will act in ways we don't like. But they, like us, are still worthy of love.

    Whatever irritates（激怒）us about a person should be examined. Is the person reflecting behavior in us that needs to be changed? Often, when I find people irritating, I find they mirror something about me that I need to correct.

    What's needed in our personal relationships is a return to gentleness and tolerance（容忍）. We must allow one another our learning experiences. Just as violence results to violence, verbal violence—the hard words and sharp tones we use to release inner stress—adds to the distance between us.

    What we people of African root must do to become, and continue to be strong begins with love, sensitivity and our ability to work together. We Black women have these spiritual resources in abundance（丰富）. Now we must encourage them to create a peaceful place—for ourselves, our children, our men.

    High school biology teacher Kelly Chavis knew smartphones were a problem in her class. But not even the students realized how much of a problem the devices were until Chavis did an in-class experiment.

    For one class period, students used a whiteboard to count every Snapchat, Instagram, text, call that appeared on their phones. Chavis is among a growing number of teachers, parents and health experts who believe that smartphones are now partly to blame for increasing the levels of student anxiety. "One girl, just during the one hour, got close to 150 Snapchat notifications. 150!" she said.

    Jean Twenge, a psychology professor at San Diego State University in California, said it is not a coincidence that youth mental health issues have risen with the number of phones. "This use of phones has led to a loss of sleep and face-to-face interactions necessary for their growth," she said.

    Researchers are still not sure whether phones cause student depression or depression causes phone use. But nearly 60 percent of parents said they worry about the influence of social media on their child's physical and mental health.

    Both schools and parents are starting to take steps to deal with the problem. Many public schools pay outside companies to watch students' social media activity for signs of anxiety. Other schools invite in yoga teachers and comfort dogs to help calm students.

A new study reveals that pigeons (鸽子) can tackle some problems just like artificial intelligence, enabling them to solve difficult tasks that might challenge humans. Previous research has theorized that pigeons employ a problem-solving strategy, involving a trial-and- error approach, which is similar to the approach used in AI models but differs from humans' reliance on selective attention and rule use. To examine it, Brandon Turner, a psychology professor at the Ohio State University, and his colleagues conducted the new study. 

In the study, the pigeons were presented with various visual images, including lines of different widths and angles, and different types of rings. The pigeons had to peck (啄) a button on the right or left to indicate the category to which the image belonged. If they got it correct, they received food; if they were wrong, they received nothing. Results showed that, through trial and error, the pigeons improved their accuracy in categorization tasks, increasing their correct choices from about 55% to 95%. 

Researchers believed pigeons used associative learning, which is linking two phenomena with each other. For example, it is easy to understand the link. between "water" and "wet". "Associative learning is frequently assumed to be far too primitive to. explain complex visual categorization like what we saw the pigeons do," Turner said. But that's exactly what the researchers found. 

The researchers' AI model tackled the same tasks using just the two simple mechanisms that pigeons were assumed to use: associative learning and error correction. And, like the pigeons, the AI model learned to make the right predictions to significantly increase the number of correct answers. For humans, the challenge when given tasks like those given to pigeons is that they would try to come up with rules that could make the task easier. But in this case, there were no rules, which upsets humans. 

What's interesting, though, is that pigeons use this method of learning that is very similar to AI designed by humans, Turner said. "We celebrate how smart we are that we designed artificial intelligence: at the same time, we regard pigeons as not clever animals," he said.