【推荐2】Are you the kind of person who always keeps a bar of chocolate nearby? Perhaps you feel weak or sleepy without your sweets. If so, you may have a problem that millions of others have: sugar addiction.

Addiction means using a substance or doing an activity over and over again, in spite of its bad effects. Playing computer games, drinking, and eating arc examples of activities that can develop into addictions.

There are four stages of behavior that happen during a sugar addiction. Stage one begins with a strong wish for something sweet. This happens because sugar causes the body to produce dopamine (多巴胺). It is a chemical that creates feelings of happiness. In stage two, even after sugar has been eaten, the desire remains and grows. This is because the body becomes less sensitive to the effect of sugar over time. So, it is necessary to eat more sugar to produce the positive emotions. In stage three, when a sugar need is not satisfied, the person feels bad. Sugar addicts experience bad emotional symptoms. They also feel physical symptoms, such as headaches, sleepiness, and lack of energy. Over time, a sugar addiction will reach stage four. This is when the worst health effects of sugar addiction can be seen. Unhealthy body weight and depression are examples.

Breaking a sugar addiction can be challenging, but it is important for your health. There are a few things to keep in mind. It’s simple advice you probably have heard before. Eat three meals a day, get enough sleep, and exercise often. Choose healthy sweets, like fruit, and avoid salty snacks. These usually cause people to want to eat sweets. Don’t push yourself too hard. Remember that lifestyle changes happen slowly.

【推荐3】Being able to tell human faces apart is a skill that almost every person has, although some are far better at it than others. But a new study from the journal Scientific Reports says that this is not just a skill that humans possess. Even fish can do it.

Following up on research studying different species’ abilities to recognize human faces (sheep, dogs, cows, horses, and birds have all been tried), the researchers from the University of Oxford and the University of Queensland decided to pick an animal that does not have an evolved neocortex (大脑新皮层), the part of the brain that processes sight and sounds, and does not have a close relationship with humans. That way, there would be no reason why these test subjects would have a past history of identifying human faces. So they picked the archerfish, a reef fish variety that shoots water into the air to knock its prey(猎物) out of the sky. They used this adaptation to have the fish spray water at a face on a monitor hanging over their tanks for a reward. Most of the fish were able to pick out their learned face, even when colours were taken away or methods were used to make the face shapes unclear.

This study gives more backing to the hypothesis (假设) that differentiating between faces is not just a skill that big-brained organisms are born with. It is possible that a good portion of recognizing faces is learned over time. The development of the neocortex may contribute only to quickly process a large number of faces in varying situations. But more work needs to be conducted to find a deeper link to this possible learned behaviour. The subject(实验对象) of this study was very small—only eight fish were used altogether. Also, the faces displayed on the monitor were only white, female faces from a German database, shown in a frontal view, with no expressions. Other animal trials have shown that some species, like pigeons, respond more to differing angles and varied expressions.