There are two main types of non­verbal communication. Body language is the first. Body language is body movements that depend on a person's attitude or feelings. Body language includes the way people walk，how they stand，and their facial features. In other words，any kind of meaning is shown by a person's attitude or body movements. For example，when a boy is sad he may drop his head and walk slowly. Or，if a girl is happy，she might run and jump or stand up straight and put her hands in the air. People don't have to say anything to show how they feel about things. The colour of people's skin may even show how they feel. For example，if people with light coloured skin get embarrassed，their skin may turn red，or if they are worried，they might get pale. Body language can be voluntary(主动的) or involuntary(无意识的)．An interesting fact is that blind children will smile when happy even though they have never seen a smile.

    The next main type of non­verbal communication is gestures. Gestures are communications like facial expressions，hand signals，eye gazing，and body postures. Examples include smiles，handshakes，waving，and raising certain fingers to say something. For instance，if you saw a friend at a noisy carnival，you might smile and wave at your friend. You might also point at the Ferris wheel if you wanted to meet your friend there. You could do all of these things without saying a word. Another great example is in baseball when the catcher signals to the pitcher the kind of pitch to use for the batter that is up.

    Suppose you become a leader in an organization. It's very likely that you'll want to have volunteers to help with the organization's activities. To do so, it should help to understand why people undertake volunteer work and what keeps their interest in the work.

    S Let's begin with the question of why people volunteer. Researchers have identified several factors that motivate people to get involved. For example, people volunteer to express personal values related to unselfishness, to expand their range of experiences, and to strengthen social relationships. If volunteer positions do not meet these needs, people may not wish to participate. To select volunteers, you may need to understand the motivations of the people you wish to attract.

    S People also volunteer because they are required to do so. To increase levels of community service, some schools have launched compulsory volunteer programs. Unfortunately, these programs can shift people's wish of participation from an internal factor (e.g. “I volunteer because it's important to me”) to an external factor (e.g. “I volunteer because I'm required to do so”). When that happens, people become less likely to volunteer in the future. People must be sensitive to this possibility when they make volunteer activities a must.

    S Once people begin to volunteer, what leads them to remain in their positions over time? To answer this question, researchers have conducted follow-up studies in which they track volunteers over time. For instance, one study followed 238 volunteers in Florida over a year. One of the most important factors that influenced their satisfaction as volunteers was the amount of suffering they experienced in their volunteer positions. Although this result may not surprise you, it leads to important practical advice. The researchers note that attention should be given to “training methods that would prepare volunteers for troublesome situations or provide them with strategies for coping with the problem they do experience”.

    S Another study of 302 volunteers at hospitals in Chicago focused on individual differences in the degree to which people view “volunteer” as an important social role. It was assumed that those people for whom the role of volunteer was most part of their personal identity would also be most likely to continue volunteer work. Participants indicated the degree to which the social role mattered by responding to statements such as “Volunteering in Hospital is an important part of who I am.” Consistent with the researchers' expectations, they found a positive correlation(正相关) between the strength of role identity and the length of time people continued to volunteer. These results, once again, lead to concrete advice: “Once an individual begins volunteering, continued efforts might focus on developing a volunteer role identity....Items like T-shirts that allow volunteers to be recognized publicly for their contributions can help strengthen role identity”.

    Why Do People Blink Their Eyes?

    People blink(眨眼) their eyes tens of thousands of times every day. Scientists have long believed blinking was an involuntary movement and served mainly to keep the eyeballs wet. But a new study suggests it has a more important purpose.

    An international team of scientists from the University of California at Berkeley studied the blinking of human eyelids. The journal Current Biology published their findings. The team said they found that blinking “repositions our eyeballs so we can stay focused” on what we are seeing. They said that when we blink our eyelids, the eyes roll back into their sockets--the bony area that surrounds and protects the eyes. However, the researchers found the eyes don't always return to the same position. They said this causes the brain to tell the eye muscles to reorganize our eyesight.

    Gerrit Maus is the lead writer of the report. He serves as an assistant professor of psychology at Nanyang Technological University in Singapore. Maus says: “Our eye muscles are quite sluggish(迟缓的) and imprecise, so the brain needs to constantly adapt its motor signals to make sure our eyes are pointing where they're supposed to. Our findings suggested that the brain measures the difference in what we see before and after a blink, and commands the eye muscles to make the needed corrections.” The researchers said that without such corrections our surroundings would appear unclear and even jumpy. They said the movement acts “like a Steadicam(摄影稳定器) of the mind.”

    The researchers said they asked volunteers to sit in a dark room while staring at a small dot on a flat surface. They used special cameras to follow the volunteer's blinks and eye movements. After each blink, the dot was moved one centimeter to the right. The volunteers did not notice this, but the brain did. It followed the movement and directed the eye muscles to refocus on the dot. After the dot was moved in this way 30 times, the volunteers' eyes changed their focus to the place where they predicted it would be.

    Professor Maus says “Even though participants did not consciously register that the dot had moved, their brains did, and adjusted with the corrective eye movement. These findings add to our understanding of how the brain constantly adapts to changes, commanding our eye muscles to correct for errors in our bodies' own hardware.”

    If you're a fan of smart technology, you may have had some sleepless nights lately.

    That's because Alexa, the artificial intelligence (AI) behind US company Amazon's Echo smart speakers, has been "letting out an automatic, creepy (令人毛骨悚然的) cackle," for no apparent reason, according to BBC News.

    Many social media users shared their stories of Alexa scaring them with the seemingly unprompted laugh.

    "Every time Alexa laughs, an angel dies," Tesla and SpaceX founder Elon Musk joked on social media.

    On March 7, Amazon released an update that fixed the problem, saying that the laugh was triggered (引发) by Echo devices mistakenly thinking that users had said the command "Alexa, laugh".

    However, what should have been a funny story raised the ongoing topic of man versus machine.

    With the rise of artificial and robotic technology, "Digital machines have started to demonstrate (展示) broad abilities in pattern recognition, complex communication, and other fields that used to only belong to human," wrote Erik Brynjolfsson and Andrew McAfee in their book The Second Machine Age: Work, Progress, and Prosperity in a Time of Brilliant Technologies. They believe that AI will "do more and more, and our lives will get better".

    However, ever since the earliest days of AI, there have been concerns that some day, software will take over the world, leaving the fate of humans unknown.

    "With artificial intelligence we are summoning (召唤) the demon ," Musk told students during a meeting at MIT in 2014. "If I had to guess at what our biggest existential threat is, it's probably that. So we need to be very careful."

    Many scientists have shared the same concern. The late British physicist Stephen Hawking said at a technology conference in Portugal in November that "computers can, in theory, imitate human intelligence, and exceed it… AI could be the worst event in the history of our civilization." If creators are to safely control AI, however, Hawking suggested that they "employ best practice and effective management".

    "I am an optimist and I believe that we can create AI for the good of the world," he said at the conference. "We simply need to be aware of the dangers, identify them, employ the best possible practice and management, and prepare for its consequences well in advance."

    Washing habits have changed over the years. In the 16th century, most people had a bath once a month…if they were lucky. Up until the 1950s, it was once a week. Only just recently has the concept of daily showering become popular. But now, according to the New York Times, things are changing again.

    The latest trend is known as "soap-dodging". It basically consists of washing less, having fewer showers and using less soap. "I just wash my hair once a month now," said Brett Dawson, a 32-year-old management consultant. "I have just one bath a week," said Miriam Bayliss, a 28-year-old accountant.

    And it appears to be growing in popularity. A poll last year for tissue manufacturer SCA found that 41% of British men and 33% of women don't shower every day. And 12% of people have a proper wash just once or twice a week. Further research by Mintel found that more than half of British teenagers don't wash every day-with many opting for a quick spray of deodorant (除臭剂) to mask any smell. But why?

    There are a variety of reasons. Some claim that daily hair-washing is unnecessary. Commentator Matthew admitted that he hadn't shampooed his hair for a decade. Others say they just don't have the time. In 2008, the chemist Boots reported a 45% rise in sales of dry shampoo - a product that can be sprayed on hair between showers.

    And some people want to help the environment. "I limit my showers to about twice a week," said Nigel Hamerstone, a 42-year-old architect. "The rest of the time I have a sink wash." he adds. "I believe that I'm as clean as everyone else, and it's helped get my water consumption down to around 20 litres a day - well below the 100 to 150 average in the UK."

    So, will you be joining the new "washing revolution"?

    I recently came in contact with celebrity magazines. My family isn't one to give money for pictures of skinny, drunk celebrities with paragraphs about their relationships and shopping cart times. Thus, I was excited to finally get a chance to read about other people's attractive yet troubled lives.

    Right away I noticed how each magazine seemed to be a copy of the other. They had headlines and pictures that were almost the same. Still, the pictures of perfectly constructed faces with cute designers outfits going on with their daily lives made me read on.

Wait, celebrities taking their dogs for walk? Spending an afternoon at a park? All of these things seemed so ordinary—things my own family and I do together often. I suddenly realized how unextraordinary the people in these magazines were. They are simply normal people who happen to have a cool job and much money. For some reason, pictures of them doing things like buying milk at the store appeal to millions of readers. Then, when these regular people mess up, their mistakes is painted onto hundreds of newspapers and internet sites.

    What if every time we made a mistake, it was made public? Have you ever failed a test? Imagine seeing pictures of you on the front of a newspaper with headlines like, "Regular Schooling Isn't Enough". You'd be embarrassed. Now, I'm not necessarily taking the celebrity's side. I'm more realizing the fact that these people we were crazy about are just ordinary human beings with many photographs following them around. Role models? I'd think not. Personally, I'd rather look up to people in any community who have accomplished a lot instead of an ordinary person walking his dog in Berverly Hills.