Before I studied psychology, I used to think that people would laugh when funny things occurred. While I was right about that, I discovered there are lots of other psychological factors that make people laugh other than the funny part of a joke. When someone laughs at a joke, there will usually bemore than one reason that makes him laugh—and the more reasons there are, the more powerful the joke will be.

    I was attending a stand-up comedy show in Egypt, and when the man started to make fun of pedestrians crossing streets, everyone laughed their hearts out. The main reason those people strongly laughed was that almost allof them felt angry towards pedestrians who crossed streets carelessly. The joke wasn't only funny, it also made the audience feel that they were right about being angry at those pedestrians. That is, people were laughing both because ofthe funny joke and because of the happiness experienced as a result of the psychological support they got.

    The better a joke makes a person feel, and the more it includes other psychological factors, the more the person will like it. For example, if you envy one of your friends, and someone tells a joke that is funny and, at the same time, makes your friend seem stupid, then you will probably laugh atit louder than if you weren't jealous of him.

    In short, we don't laugh only when we hear something funny; we also laugh when we experience some kind of happiness that results from the other psychological factors involved in the joke. I strongly discourage making fun of anyone or belittling someone to make someone else laugh. All Iwant to explain is that if your joke supports a person's emotions, he will certainly like it a lot.

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    Have you ever wondered why the roots of the plants always know which way to grow—into the soil but not above it? Some British scientists have recently solved this mystery.    

      It turns out that roots have special hairs that tie them into the soil and help them grow their way past obstacles, a team at the John Inners Center in Norwich reports in the February 29 issue of Journal Science.

    "The key is in the fuzzy(有绒毛的) coat of hairs on the roots of plants," says professor Liam Dolan. "We have found a growth control system that enables these hairs to find their way and to become longer when their path is clear."

    Root hairs explore the soil in much the same way a person would feel their way in the dark. If they come across an obstacle, they make their way around until they can continue growing in an opening. I the meantime, the plant is held in place as the hairs grip the soil.

    The hairs are guided by a clever chemical trick. A protein(蛋白质) at the tip of the root hairs called RHD2 helps them to take calcium(钙) from the soil. Calcium makes the hairs grow, and produce more RHD2, and take more calcium.

    But when an obstacle blocks the hair's path, or the hair reaches the surface of the soil, the cycle is broken and growth starts in another direction.

    This system gives plants the flexibility to explore a complex environment and to live in even the most unpromising soils, says Dolan.

    In poor soils such as in parts of Australia and Africa, native plants have adapted by producing enormous numbers of root hairs. A better understanding of this adaptation will allow scientists to develop hairy rooted crops that can grow in unfriendly environments.

    According to Dolan, "Research in the John Inners Center is taking a breeding approach(育种方法) to increase hair length in wheat but it will be some time before new cultivars(栽培变种) are developed."

    We could say that any animal that knows how to find food, avoid being eaten, and raise babies is pretty smart. But can animals learn and remember or can they solve problems?

Many animals have good memories for where food is — a useful skim Scrub jays (灌丛鸦) may be the champions. In one experiment, scientists put them in pre-made holes. After the jays had hidden some food, they were taken out. Scientists mapped where the food was hidd6n and then remove ii, which meant the jays couldn't find the holes by smell. But when the jays came back again, they went right to the hiding they had used. In the wild, they remember where thousands of holes arc. Could you do that?

    Another important smart skill is being able to spot shapes and generalize. This kind of test work best with animals that see well and are interested in pictures. Call in the pigeons(鸽子)! In this test, pigeons had to learn to pick out photos with trees in them, and to ignore photos that didn't include any trees. Once they had learned the rules, they were very adept at it.

    Scientists have to be careful when they test animals for smarts, and the person giving the test has to know the animal really well, in one experiment, a few bananas were hung out of reach over a p on the ground. Monkeys figured out right away how to get the bananas: pick up a stick and knocked down. But clever elephants kept failing this test. Finally scientists figure out why. An elephant's trunk work as both its hand and its nose. When it got the stick, it couldn't smell the bananas. When the elephants were given a couple of boxes instead, they quickly use them to make a step and got the bananas.

    As we're learning, the world is full of smart animals, each thinking in its own special way.

    The United States Postal Service(LISPS)is offering a way to people who are interested in seeing tomorrow's mail today. The postal service will send consumers images(图像)of their letters, magazines and other mail before they arrive. The new service is called Informed Delivery. It is an attempt to remain competitive in an ever—changing world.

    Postal service officials say the increased use of email, digital messaging services and social media has made it difficult to stay relevant. David Rupert is a media relations specialist who spoke about the competition the agency now faces. Whether you turn on a television or your computer, or people come to your door with different products and services, all of those are competing for consumers' time and energy, he said.

    Interested users are first required to sign up for Informed Delivery. Once registered, the consumer receives a daily email with virtual(虚拟)images of letters or other things to be delivered. The US Postal Service says it can especially help those who have a mailbox at their local post office, so they know when to get their mail：

    Another postal offering is a service that seeks to make advertising-related mail-often called junk mail—more fun. The service uses virtual and augmented reality(虚拟现实和增强现实)to let consumers interact with their junk mail. Many companies put special coding on their advertising, which can give users an interactive experience. Some companies even put virtual reality eyeglasses in the mail to make their ads come to life. Consumers have mixed reactions to virtual and augmented reality advertising. “You can find some good things within junk mail. It is a good idea. We'll see how it works, ”Postal service user Victor Teah said. But Jocelyn Coatney doesn't think it would change her mind about junk mail. “For some, that might be fun. But for me, it would be useless, ”she said.

    Are you familiar with the greeting, "Can I add you on WeChat?" It seems like every time we meet new friends or colleagues nowadays, the first thing that springs to mind is adding each other on the app. Nevertheless, more than 80 percent of WeChat users report feeling stressed or anxious when they receive a large number of messages, according to a study done recently by the app's developer Tencent(腾讯). In other words, WeChat can overwhelm(使应接不暇) us, while also breaking down the boundaries between our work and private lives.

    Just think how easy it is now for bosses to hand out assignments during the holiday, so long as they have your WeChat contact. When you're at the cinema enjoying a romantic movie or having a barbecue in the backyard, you can never cut yourself off from the outside world unless you switch off your phone. Not to post something in WeChat Moments before replying to your boss first!

    Apart from interrupting your leisure time, WeChat can also reduce your productivity at work. For many office workers, logging in to WeChat on their computers at the start of the day has become routine. But what if browsing the Moments distracts us from doing the work? The app steals our time without us even noticing it, making us have the false belief that we are busy all the time.

    And as if that weren't bad enough, there're the "one-off" friends who take up space on our WeChat friend list. A handy way to check how many one-off friends you have is to take a look at your chat history with them. Sometimes, you only sent the initial friend requests so you could invite them to a WeChat group or inform them of something for your boss. Yet still, as your friend count(好友数量) ever goes up, it can make you feel the need to post selfies(自拍) and share details of your life in your Moments, just so you can stay up to date.

    With WeChat, all our spare time is swallowed up by the constant torrent of messages and our attention keeps getting diverted by Moments and pop-up ads. So it's time that we should do something to nip this problem in the bud.