Are we getting more stupid? According to Gerald Crabtree, a scientist at Stanford University in the US, we are.  You may not want to hear this, but Crabtree believes that human intelligence reached its peak more than 2,000 years ago and ever since then has been going downhill. “If an average Greek from 1,000 BC were transported to modern times, he or she would be one of the brightest among us,” Crabtree told The Guardian.

    At the heart of Crabtree's thinking is a simple idea. In the past, intelligence was critical for survival when our ancestors had to avoid dangerous animals and hunt for food. The difference of being smart or stupid is often life or death. However, after the spread of agriculture, when our ancestors began to live in dense ( 稠密的）farming communities, the need to keep their intelligence in peak condition gradually reduced. This is not hard to understand. Most of the time,pressure is what keeps us going – you need the pressure from your teachers to finish your homework; the pressure of looking pretty prompts(促使) you to lose weight when summer comes. And the same is also true of our intelligence – if we think less, we become less smart.

    These mutations(变) are harmful to our intelligence and they were all developed in the past 3,000 years. The other evidence that Crabtree holds is in our genes. He found that among the 2,000 to 5,000 genes that we have that determine human intelligence , there are two or more mutations in each of us. However, Crabtree's theory has been criticized by some who say that early humans may have better hunting and surviving abilities, but people today have developed a more diverse intelligence. For example, spearing a tiger doesn't necessarily require more brainpower than playing chess or writing a poem. Moreover, the power of modern education means a lot more people have the opportunity to learn nowadays. “You wouldn't get Stephen Hawking 2,000 years ago. He just wouldn't exist,” Thomas Hills of the University of Warwick, UK, told Live Science. “But now we have people of his intellectual capacity doing things and making insights(洞察力) that we would never have achieved in our environment of evolutionary adaptation.”

    Mrs. Blake teaches English in a large school in the inner area of a big city on the west of coast. Even since she was a young girl, she has wanted to become a teacher. She has taught eight years now and hasn't changed her mind. After she graduated from high school， she went on to college. Four years later，she received her bachelor's degree （B A） in English and her teaching certificate（证书）. Then she went to teach in the secondary schools of her state. In the summers，Mrs. Blake takes more classes； she hopes to get a master's degree （M A）. With an MA，she will receive a higher salary and if possible， she hopes to get a doctor's degree as well. The school day at Mrs. Blake's high school，like that in many high schools in the United States，is divided into one hour each. Mrs. Blake must teach five of these periods. During her free period，which for her is from 2 to 3 P.M. ，Mrs. Blake must meet with parents，make out examinations，check assignments at all，Mrs. Blake works continuously from the time she arrives at school in the morning till the time she leaves for home late in the afternoon.

    We were on tour a few summers ago, driving through Chicago， when right outside of the city, we got pulled over(被迫停车). A middle-aged policeman came up to the car and was really being troublesome at first. He said,“ You were speeding. Where are you going in such a hurry?” Our guitarist, Tim, told him that we were on our way to Wisconsin to play a show. Then his way towards us totally changed. He asked, “Oh, so you boys are in a band(乐队)?” We told him that we were. He then asked all the usual band questions about the type of music we played and how long we had been at it.

    Suddenly, he stopped and said, “Tim, you want to get out of this ticket, don't you?” Tim said, “Yes.” So the officer asked him to step out of the car. The rest of us, inside the car, didn't know what to think as we watched the policeman talk to Tim. Then the policeman put Tim in the back of the police car and threw the car into reverse(倒车), stopping a few feet in back of our car.

    Now we suddenly felt frightened. We didn't know if we were all going to prison. Suddenly, the policeman's voice came over in a loudspeaker. He said, “Ladies and gentlemen, for the first time ever, we have Tim here singing on Route 90.” Later we knew, the policeman had told Tim that if he sang one of our songs over the loudspeaker in the police car, we would get out of the ticket. Seconds later, Tim started screaming into the receiver. The policeman enjoyed the performance, and sent us on our way without a ticket.

    The islands of Malta and Gozo are brilliant for a family holiday, packed with fun places to visit whatever your children's ages. The islands' small size means everywhere is within easy reach.

    Sandy beaches and swimming spots

    One of Malta's best beaches for families is soft-sanded, sheltered Golden Bay. Older children can try activities such as stand-up paddle boarding, sailing or windsurfing, while the gentle slope of the beach makes it easy for younger kids to safely paddle in the sea.

    Eating out

    Children are welcome at most restaurants, though more upmarket places often only accept older kids. There are often kids' menus that tend to offer pizza, but you can always ask for a half portion of a starter dish (portions are huge in Maltese restaurants). With a wide range of cuisines on offer, children are bound to find something they'll like, Maltese food is strongly influenced by Italian cuisine, so there's pizza and pasta galore, and some kids will love the national dish-fried rabbit

    Accommodation

    Try to schedule at least a few days on Gozo as there are lots of self-catering farmhouses with pools to rent and it's even easier to get around than Malta. Smaller hotels in Valletta usually only accept older children.

    Transport and other tips

    The easiest way to get around Malta and Gozo is to drive, but the local bus service is reliable, easy to use, and fairly inexpensive. Buses are frequent between major towns, but only roughly hourly to and from smaller places. Ferries run between Malta and Gozo, and you can take tourist boats over to Comino.

All animals play. Runing, rolling and wrestling with each other is a way for them to have fun, of course. But it also seems to be how they communicate and strengthen bonds with each other.

When a dog comes up to another dog, front legs bowed and his tail high, his buddy knows he wants to play. But new research shows that this play behavior is surprisingly similar when horses and dogs play.

To study interspecies communication, Elisabetta Palagi and her colleagues from the University of Pisa found 20 YouTube videos of dogs and horses playing where their interactions lasted at least 30 seconds. They analyzed the videos, looking for specific pattern of play.

They found that while playing, both dogs and horses often had relaxed, open mouths-which is common playful facial expression in mammals. Some also copied each other's movements, like pretending to bite, playing with an object, or rolling on their backs on the ground. A 2,000-pound horse can play with a relatively tiny dog because the two are able to communicate their intentions.

"It's an important study because it shows how two animals who look and behave so differently can nevertheless manage to negotiate how to play in a way that's comfortable for both," Barbara Smuts, a behavioral ecologist at the University of Michigan, told National Geographic.

It's even more noteworthy given the large size difference between horses and dogs. The dog is vulnerable (易受伤的) to injury by the horse, and the horse has a deeply rooted tendency to fear animals that look like wolves."

Next up, the researchers write, is exploring the development and shaping of interspecies communication that “can be at the basis of a universal language of play".

Here are four books recommended by one of the most respected editors from Reader's Digest. If you have time to dip yourselves into the books, they can surely offer much food for thought.

Face It

Debbie Harry

HARPERCOLLINS

Picture this: it's the late 1970s and the punk music scene is starting to take hold. The band releases the album ParallelLines, which becomes the greatest hit. Everyone wants to attend her concert and some teenage girls even dream to be her. Now 75, Harry bares all about herself in Face It, starting from her childhood. Part shocking, this book is as humorous, moving and vigorous as its subject.

Scatterbrain

Henning Beck

NEWSOUTHBOOKS

If there is no obvious connection among what we see, the brain will substitute in the rest of the information without you even noticing, Beck says in the chapter Memory. In this "user's guide for your brain", he argues that mistakes are the keys to success. He combines science with brain-boosting advice and real-life stories to take the reader on a fascinating adventure through human memory.

You're Not Listening

Kate Murphy

PENGUINERANDOM HOUSE

When was the last time you listened to someone? Really listened without thinking about what you wanted to say next? And when was the last time someone really listened to you? Compared with talking, listening isn't considered so important, argues journalist Kate Murphy, but she insists it is actually the more powerful position in communication. Her insights could transform your conversations, your relationships and your life.

The Right-Brain Work Out

Russel Howcroft with Alex Wadelton

PENGUIN

In 1968,1600 five-year-olds were given a creativity test. They were retested at ages 10 and 15 and their scores were compared against adults. While 98 per cent of five-year-olds were assessed in the "highly creative" range (genius level), only two per cent of adults could be considered "highly creative". In The Right-Brain Work Out, the authors promise to re-train your brain to be more creative, using 70 questions to challenge you.