The term “crop circle” or “circles” was created by a researcher, Colin Andrews, to describe the strange circles and complex geometries(复杂的几何图形). He has researched what has shown up in fields of wheat, barley, rye, corn, soy beans and other crops for years.

There are numerous theories(理论)that have been given to explain crop circles of unknown origin(起源). It is notable for most people that when crop circles have been made by human hands, the plants themselves are damaged. But the plants in the stricken area continue to grow and ripen, and none of the stalks are broken nor the seed heads crushed.

Another strange thing about these particular types of crop circles is that the genetic(基因的)structure of the plants themselves has been changed. This does not happen to the crop circles that have proven to be the work of pranksters (玩恶作剧的人).

In 1966, in the small town of Tully Queensland, Australia, one of the most famous accounts of a UFO, as well as the possible link to crop circles, was given. A farmer was working on his farm and said that he saw a saucer-shaped craft (飞行器)fly 30 or 40 feet above a swamp (沼泽地)and then fly away at extremely high speed. The farmer decided to look into the area where he thought the craft had been hovering (盘旋)and he found the plants there intricately woven (杂乱地编织) in a clockwise pattern.

The crop circle phenomenon (现象)became a very hot topic during the late 1980s. No less than 12,000 genuine crop circles have been discovered all cross the world. In countries like the former Soviet Union, the UK, Japan, the U. S. and Canada, this strange phenomenon continues to appear and baffle anyone who observes it because no rational explanation exists. In a wheat field in Monroe County, Tennessee, a pattern ranging about 150 feet in diameter(直径)was discovered on May14, 2007. Captain Bryan Graves of the local sheriff’s department discovered it while flying.

The crop circle phenomenon has never stopped appearing across the world since it was discovered. Could it be that extraterrestrial (来自天外的)beings are trying to communicate with humans? If so, what is the message they are trying to send? The mystery continues.

It is universally accepted as one of life’s bleak but unavoidable facts: as we get older, our brains get slower. But now a study, based on data from more than 1 million people, suggests that mental processing speed remains almost constant until the age of 60.

The analysis puts perceived (感知的) reductions in speed down to people becoming more careful as they get older. This could account for the large body of research that has concluded that mental processing speed peaks at about the age of 20 and undergoes a steady decline from that point onwards.

“Our finding is encouraging, as our results show that average levels in mental speed in contexts demanding fast and forced decisions do not decline until rather late in the lifespan,” said Dr Mischa Von Krause, of Heidelberg University.

The study, published in the journal Nature Human Behaviour, used data from 1, 185, 882 participants, aged 10 to 80 years, in Harvard’s Project Implicit, an online tool that has been used to collect data. Participants are required to answer some questions.

The analysis suggested that 20-year-olds were quickest because they were the most willing to trade accuracy for speed. The researchers concluded that the purely mechanical part of the response (how fast a person sees the question and taps the keyboard) was quickest in those aged 14-16. Mental processing state appeared to peak at about age 30, and declined only very slightly between 30 and 60. Participants also made fewer mistakes as they became older, at least until the age of about 60.

Von Krause said the work raised the suggestion that people may excel (擅长) at different tasks depending on their age. “Obviously, there are real-life tasks where it is crucial to avoid mistakes, such as in a medical diagnosis, while in other tasks, such as avoiding an obstacle on the road, speed is more important,” he said. However, he added that, within certain limits, people were likely to be able to adapt their decision-making style to the demands of a situation.

Paul Ekman(2003), a leading researcher on the study of human emotions and expression, posits that there are six basic human emotions found throughout the world, across gender, age and culture. These include: anger, disgust, fear, joy, sadness, and surprise. Another theorist, Izzard, argues that we have ten basic emotions including: anger, contempt, distress, fear, guilt, interest, joy, shame and surprise. 【小题1】However, these are the most robust.

So for those of us who can, and do, feel emotions on a regular basis, what impact do they have on our life, our thinking, behaviours and overall well-being and why do we have them in the first place? Well, the evolutionary benefits of negative emotions are clear: they narrow our thought-action repertoires (储备)(or, simply speaking, what we think about and the range of actions we are engaged in)to those that best promoted our ancestors’ survival in life-threatening situations. 【小题2】Thus, fear makes us want to run, and anger makes us want to thrash out (打击) at the aggressor.

The human brain’s ability to hone in one real or potential danger is a left-over by-product of evolutionary and adaptive tendencies. 【小题3】Thousands of years ago, people survived if they were able to selectively attend to danger or dangerous situations that could lead to extinction of their genetic line. Although once useful, this selectivity can lead us to narrow in consciously on what is wrong, rather than what is right with ourselves and the world around us. However, recent studies have shown that people who score high on self-reported experiences of positive emotions have an attention bias toward positive information(Strauss and Allen, 2006).

But what use are positive emotions and do they have any action repertoires? 【小题4】Fredrickson started work on her groundbreaking and widely accepted theory of the broaden-and-build functions of positive emotions in the early 1990s. Her research, in several laboratory-controlled experiments, has demonstrated that positive emotions broaden our thought-action repertoires, undo negative emotions and build resilience.