Self-driving vehicles have been proposed as a solution for the rapidly increasing number of fatal traffic accidents, which now cause 1.3 million deaths each year.

    While we have made great progress in advancing self-driving technology, we have yet to explore how autonomous vehicles will be programmed to deal with situations that endanger human life, according to a new study published in Frontiers in Behavioral Neuroscience.

    To understand how self-driving cars might make these judgments, the researchers looked at how humans deal with similar driving dilemmas.

    When faced with driving dilemmas, people show a high willingness to sacrifice themselves for others, make decisions based on the victim's age and turn onto sidewalks to minimize the number of lives lost. Ethical（伦理的）guidelines tend to disagree with human instincts（本能） in this case, saying that no life should be valued above another.

    “The technological advancement and adoption of autonomous vehicles are moving quickly but the social and ethical discussions about their behavior are lagging behind,” says lead author Lasse T. Bergmann from University of Osnabrück, Germany.

    Automated vehicles will eventually outperform their human counterparts, but there will still be circumstances where the cars must make an ethical decision to save or possibly risk losing a human life.

    The study is especially relevant considering earlier this year a self-driving Uber car struck and killed a passenger in Arizona, in an incident widely regarded as the first death resulting from an autonomous vehicle.

    An ethics commission launched by the German Ministry for Transportation has created a set of guidelines, representing its members' best judgement on a variety of issues concerning self-driving cars. These expert judgments may, however, not reflect human instinct.

    Bergmann and colleagues developed a virtual reality experiment to examine human instinct in a variety of possible driving situations. It was based on the well-known ethical thought experiment—the trolley problem.

    In this experiment, there is a trolley running down the railway tracks. Ahead, on the tracks, there are five people tied up, unable to move, and the trolley is headed straight for them. A person is standing some distance off in the train yard, next to a lever（操作杆）.If he pulls this lever, the trolley will turn to a different set of tracks. However, there is one person tied up on the side track. Does the person choose to pull the lever and kill one person, or do nothing and let five people die?

    Bergmann recognized that the majority of people would not approve of the proposal made by the ethics commission that a passenger in the vehicle should not be sacrificed to save more people. “We find people chose to save more lives, even if this involves turning onto the sidewalk, endangering people uninvolved in the traffic incident,” said Bergmann, “Furthermore, subjects considered the factor of age, for example, choosing to save children over the elderly.” He also realized further discussion and research were needed. “Driving requires a complex weighing of risks versus rewards, for example, speed versus the danger of a critical situation,” Bergmann explained.

    People with bigger brains tend to score higher on standardized tests of intelligence, according to new study findings.

    However, the study author Dr. Michael A.McDaniel of the Virginia Commonwealth University in Richmond emphasized that these findings represent a general trend, and people with small heads should not automatically believe they are less intelligent. For instance, Albert Einstein's brain was "not particularly large", McDaniel noted." There's some relationship between brain size and intelligence on the average, but there's plenty of room for exceptions," he said.

    Interest in the relationship between brain size and intelligence grew in the1830s, when German anatomist(解剖学家) Frederich Tiedmann wrote that he believed there was "an unquestionable connection between the size of the brain and the mental energy displayed by the individual man". Since that statement, scientists have conducted numerous studies to determine if Tiedmann's assertion was correct. Most studies have looked into the link between head size and intelligence. More recently, however, researchers have published additional studies on brain size and intelligence, measured using MRI scan(核磁共振成像扫描).

    For his study, McDaniel analyzed more than 20 studies that looked into the relationship between brain size and intelligence in a total of 1,530 people. The studies showed that on the average, people with larger brain volume tended to be more intelligent. The relationship between brain volume and intelligence was stronger in women than men, and in adults than in children. McDaniel notes in the journal Intelligence.

    McDaniel is not sure why the relationship was stronger for adults and women. "Other research has shown that women, on the average, tend to have smaller brains than men, but score just as well—if not higher—in tests of intelligence," he said.

    McDaniel insisted that the relationship between brain size and intelligence is not a "perfect" one. "One can certainly find lots of examples of smaller-sized people who are highly intelligent," he said, "But, on the average, the relationship holds."

    When my sister Mertie told me she had put out tomato plants last summer, I was quite impressed.

    Since she was a garden-beginner, Mertie researched exactly how far apart to space her tomato plants; what kind of fertilizer to use; how to keep away the bugs（害虫）, etc. Once they were planted, she took care of them daily, anxiously awaiting the juicy tomatoes to appear. But, day after day, her plants were tomato-less while all of her neighbors who had also put out tomato plants were already enjoying the fruit of their labor.

    Frustrated (upset), Mertie gave in and went to the market to search fresh tomatoes. While paying, Mertie told the farmer her troubles. The farmer paused to think for a moment and then asked, "Well, what kind of tomatoes did you plant?"

    "I think they were called Big Boy," Mertie remembered.

    "Well there's your problem," the farmer explained. "Big Boy and Better Boy tomatoes have a 95-day growing period whereas regular tomato plants produce fruit in as few as 70 days…you just have to wait a little longer for the Big Boys."

    With that new knowledge, Mertie went home with excitement, knowing they would be worth the wait.

    Thinking about my sister's gardening experience, I had to smile. She just didn't know that Big Boy tomatoes took longer--neither did I--but once she discovered that information, she was no longer discouraged and upset about the lack of tomatoes on her plants. Instead, she was encouraged and excited to see them a few weeks later.

    It makes me wonder how many of us have "Big Boy" dreams in our hearts, yet we just don't realize that they are of the "Big Boy" variety so we are discouraged and worn out with the waiting process. Instead of waiting with excitement, we give up on our dreams and figure we must have done something wrong to stop them from coming to pass. Frustrated, we see other people's dreams coming true, and we wonder why ours haven't yet been achieved.

    Let us begin by saying what causes our dreams. Our dreams do not come from another world. They are not messages from some outside source. They are not a look into the future, either.

    All our dreams have something to do with our feelings, fears, longings, wishes, needs and memories. If a person is hungry, or tired, or cold, his dreams may include a feeling of this kind. If the covers on your body, such as a quilt or a blanket, have slipped off your bed, you may dream that you are sleeping on ice or in snow. The material for the dream you will have tonight is likely to come from the experience you have today.

    So the subject of your dream usually comes from something that has effect on you while you are sleeping（feeling of cold, a noise, a discomfort, etc. ）and it may also use your past experiences and the wishes and the interests you have now. This is why children are likely to dream of fairies, older children of school examinations, hungry people of food, homesick soldiers of their families and prisoners of freedom.

    To show you how this is happening while you are asleep and how your needs and wishes can all be joined together in a dream, here is the story of the experiment. A man was asleep and the back of his hand was rubbed with a piece of absorbed cotton. He would dream he was in hospital and his charming girlfriend was visiting him, sitting on the bed and feeling his hand gently!

    There are some scientists who have made a special study of why we dream, what we dream and what those dreams mean. Their explanation of dreams, though a bit reasonable, is not accepted by everyone but it offers an interesting approach to the problem. They believe that dreams are mostly expressions of wishes that did not come true. In other words dreaming is a way of having your wishes carried out.

    There is some unwelcome news for students preparing for exams and officers putting in long hours—you don't need that "refreshment (提神) break" as much as you may think.

    Scientists believed it was not easy for people to continue their work if they felt the need to have a snack or a rest to make them feel better. They argued that the only way to regain willpower is by supplying more energy to our bodies with rest, food or entertainment.

    But psychologists have challenged this theory, saying weak willpower is in your head. They found that a person's mindset (理念) and belief about willpower determine how long and how well they'll be able to work on a tough mental exercise. "If you think of willpower as something that's limited, you're more likely to be tired when you perform a difficult task," said Professor Veronika Job. "But if you think of willpower as something that is not easily depleted, you can go on and on."

    The researchers led by Mr. Job designed an experiment to test the students' beliefs about willpower. After a tiring task those who believed or were led to believe that willpower was a limited resource performed worse on standard concentration tests than those who thought of willpower as something they had more control over.

    Mr. Job said, "Students who may already have trouble studying are being told that their powers of concentration are limited, and they need to take frequent breaks. But a belief in willpower as a non-limited resource makes people stronger in their ability to work through challenges."

    The findings could help people who are battling with temptation (诱惑): people following strict diets and doing exercise regularly to lose weight, people trying to overcome addictions, employees facing a tight deadline. Willpower isn't driven by a biologically based process as much as we used to think.

    When you visit America, you will see the word Motel on signs and notice boards. It is made up of "motor" and "hotel" and it is really a hotel for people who arrive by car (however, you don't need a car to stay at one). You have to pay when you arrive for your room, which usually has a bath. Meals are not provided, but there will certainly be a cafeteria (自助餐馆). Americans eat a lot of salads and sandwiches. Along the main roads there are a lot of motels. Each tries to offer more than next. Some provide television in every bedroom; others have swimming pools; and so on. Motels are especially useful when you are in the country, far from a town or city. You will also find them in the big National Parks.

    In these great National Parks, you may meet guests you don't expect to see. An American friend told me a little story. In the middle of a moonless night she heard strange noises outside her motel window in the Yellowstone National Park in Wyoming. Thinking it might be a thief, she jumped out of bed, opened the door and crept towards a dark shadow. As she got close, she saw the thief. She was dreadfully frightened: it wasn't a human thief ­ it was a big black bear. The bear was turning over some empty tins with its paw, looking for tasty bits of food. My friend decided to leave that particular thief alone!

    There are also, of course, places called "rooming houses", where they receive lodgers (房客). You will see such signs as Tourists or Rooms Rent, and you could try one of these. A word of warning ­ looking for a room in New York during the tourist season is like looking for gold on the moon!