5 . If you have some free time to socialize, do you prefer to spend it with your best friend or partner, or with a larger group of people?

A new study investigated what group size people actually look for and encounter in everyday life. The scientists asked more than 4, 000 people from the U. S. and the Netherlands to report the size of their social groups for a wide variety of activities. For eight different activities (going to a bar, chatting at work, chatting off work, having dinner, going on a holiday, going to a movie theatre, working on a project, playing sports), people reported a group size of two more often than they reported larger group sizes. Interestingly, for about half of these activities, women reported a group size of two significantly more often than men did, suggesting that women prefer a social group size of two even more than men do.

The researchers also used a research technique called real—time experience—sampling in the second part of the study. 274 volunteers were asked seven times a day to report the last social situation they had experienced. The results were clear. Two was the most common group size with 52. 6 percent. Thus, this part of the study also suggested that two is the most common group size in social interactions.

So why do people prefer spending their time with one other person compared to spending their time with larger groups? Researchers explained that in general, social interactions with just one other person allow for more control of the situation, especially when it comes to reciprocity ( 互助). When we interact with just one other person, one's choices directly affect the other person and only that person. Thus, it is easy to distinguish whether there is mutual cooperation (for example, both people take turns paying for dinner) or whether someone acts selfishly (for example, one person never pays the bill). In larger groups, the situation gets much more complicated.

7 . Even with wonderful friends, family and a partner, I don't always want to be surrounded by people. “Table for one? Or will someone else be joining you?” A dinner reservation for one person never fails to raise a few eyebrows. I actively choose to spend time alone when possible. But not everyone has the luxury of choosing to be alone, of course, many are forced into one-on-one time because they have no one.

But for those of us who spend our days surrounded by colleagues in the workplace, our evenings and weekends with family, friends and partners, all the while being constantly bombarded by WhatsApp,social media and email, time to ourselves can be a rare treat. Time to yourself not only gives you the chance to do practical things you don't normally get round to but also the activities your pals don't want to do. In a less real way, spending time alone also allows-or perhaps forces- you to sit with your own thoughts, to think about things that might normally be drowned out by conversation and the noise of companionship. When you're alone you get time to think without purpose.

It is worth noting that I'm a real introvert(性格内向者）,so perhaps sitting alone with my thoughts-refilling my energy reserves-might just be indulging personality traits that others don't have. But I believe more people could benefit from it.

Given this constant social conditioning since childhood that we should be surrounded by people , it's no wonder many hesitate to press forward at the idea of spending time alone-a sign we've failed at climbing that social ladder. And if you're an extrovert who gets their energy from other people, this must be even harder. But as someone who has come to love spending time alone, even when there are many wonderful souls in my life I can spend time with, I wish more people would give solo a go.

Reservation for one, please.

8 . Imagine that you found a wallet in the street containing a stranger 's contact details but no cash. Would you go out of your way to return it to its owner? Now imagine that the same wallet contained a few banknotes. Would that change your response? Alain Cohn of the University of Michigan and his colleagues have taken such behavioral economics around the world.

In different countries Dr. Cohn's research assistants entered public buildings like banks, museums and police stations. They handed in a fake wallet to an employee in the reception area, saying they had found it on the street outside, before making a hurried exit. Each wallet was a see-through plastic card case containing three identical business cards with a unique email address and a fake native's name, a shopping list and a key. Most importantly, some wallets also included $13.45, while some had no cash. Then, the team simply waited to see who would email the “owner” about returning the wallet.

In 38 of the 40 countries, the wallets with money in them were returned more often than those without: 51% compared with 40% for the cashless. While rates of honesty varied greatly between different countries, the difference within individual countries between the two return rates was quite stable around 11 percentage points. In addition, wallets containing a larger sum of money ($94.15) were even more likely (by about another ten percentage points) to be returned than those with less, although the “big money” experiment was done in only three countries.

With greater temptation (诱惑), then, comes greater honesty - at least when it comes to lost wallets and small cash. Interestingly, though, when Dr. Cohn and his team surveyed a sample of 299 volunteers, most of them predicted that the more money there was in a wallet, the more likely it was that it would be kept.

A certain doubt about the motivation of others is probably good for survival, so the response of the general population may be understandable. But is the warm inner satisfaction coming from “doing the right thing” also a powerful reason? As this study shows, such thought is real and universal

9 . The most universal facial expression is the smile --its function is to show happiness and put people at ease. A smile says, " I like you. You make me happy

That's why dogs make such a hit. They are so glad to see us that they almost jump out of their skins.     1    

A baby’s. smile has the same effect. Have you ever been in a doctor's, waiting room and looked around at all the sad faces waiting impatiently. to be seen? There were six or seven patients waiting when a young woman came in with a nine-month-old baby. She sat down next to a gentleman who was more than a little impatient about the long wait for service. The baby just looked up at him with that great big smile that is so characteristic of babies,    2    . Soon he struck up a conversation with the woman about her baby and his grand-children and then the entire reception room joined in, and the boredom and tension were changed into a pleasant and enjoyable experience     3    . Telephone companies throughout the US have a program called “phone power” which is offered to employees who use the telephone for selling their services or products. In this program they suggest that you smile when talking on the phone. Your “smile” comes through in your voice.

You don’t feel like smiling?     4    . If you are alone, force yourself to whistle or hum a tune or sing. Act as if you were already happy, and that will tend to make you happy.

Your smile is a messenger of your goodwill.    5    .To someone who has seen a dozen people frown or turn their faces away, your smile is like the sun breaking through the clouds Especially when someone is under pressure from his bosses, his customers, his teachers or parents or children, a smile can help him realize that all is not hopeless that there is joy in the world.