5 . Migration (迁移) has become a flashpoint for debate in many countries. But research from the McKinsey Global Institute (MGI) finds that it generates significant economic benefits and more effective integration (融合) of immigrants (移民) could increase those benefits.

Moving more labor to higher-productivity settings boosts global GDP. Immigrants of all skill levels contribute to this effect, whether through entrepreneurship (创业) or through freeing up natives for higher-value work. In fact, immigrants make up just 3. 4 percent of the world’s population, but MGI’ research finds that they contribute nearly 10 percent of global GDP. They contributed roughly $6.7 trillion to global GDP in 2015 — some $3 trillion more than they would have produced in their origin countries. Developed nations realize more than 90 percent of this effect.

Employment rates are slightly lower for immigrants than for native workers in top destinations, but this varies by skill level and by region of origin. Wide-ranging academic evidence shows that immigration does not harm native employment or wages, although there can be short-term negative effects if there is a large inflow of immigrants to a small region, if immigrants are close substitutes (代替者) for native workers, or if the destination economy is experiencing a downturn.

Realizing the benefits of immigration depends on how well new arrivals are integrated into their destination country’s labor market and into society. Today immigrants tend to earn 20 to 30 percent less than native-born workers. But if countries narrow that wage gap to just 5 to 10 percent by integrating immigrants more effectively across various aspects of education, housing, health, and community engagement, they could generate an additional boost of $800 billion to $1 trillion to worldwide economic output annually. This is a relatively conservative goal, but it can produce broader positive effects, including lower poverty rates and higher overall productivity in destination economies.

The stakes are high. The success or failure of integration can last many years, influencing whether second-generation immigrants become fully participating citizens who reach their full potential or remain in a poverty trap.

6 . People may typically think of memory as the recollection of the past. Memory enables people to learn from past experiences and apply that knowledge in present circumstances. It is a vital part of our identity. So is culture, the way of life specific to a group of people.

Cultural memory is the constructed understanding of the past that is passed from one generation to the next through text, oral traditions, monuments and other symbols. Cultural memory is often amassed in objects, such as museums or historical monuments. To understand culture, humans access a mass of cultural symbols, such as books. Artifacts (历史文物) of the past provide insights into where we came from. Libraries and the Internet keep a seemingly boundless amount of data on what it means to be part of a culture. Cultural memory is the longest-lasting form of memory.

Like all forms of memory, cultural memory has important functions. For example, it makes the experiences a nation owns clear. It provides us with an understanding of the past and the values of the group to which we belong. Besides, it creates a form of shared identity and a means for communicating this identity to new members. The most powerful forms of cultural memory may involve memories of past disastrous experiences undergone by groups of victims. For example, in Russia, their role in World War Ⅱ — in which tens of millions of Russians were killed — is still an important part of modern Russian identity. Because all groups have cultural memory, it can bring about a spirit of resistance or survival among threatened groups.

The main function of cultural memory is not to recall the past, whether it is good or bad. Rather, it is to use knowledge of past experiences to avoid making the same mistakes again and again. Aleida Assmann, a professor who has worked on memory theory since the 1960s, calls this “remembering forward”. Cultural memory enables people to adapt to their culture; it enables cultures to adapt to new circumstances by keeping traces (痕迹) of what worked in the past.

7 . Three young American men were on a crowded train when they came across a dangerous robber. Ignoring their personal safety, they rushed the robber and controlled him. Only some people seem capable of this sudden form of heroism (英雄主义). Why some men rise to the occasion — and others don’t — has been a bit difficult to explain. Psychologists have explored this question through biological and personality psychology.

Of course, heroism and courage can appear in many forms, and men and women risk their reputation (名声), health, and social recognition to do what they think is right. When it comes to physically risky bravery, people assume that men will take the lead. There are sound biological reasons for this fixed image. One of the most common fears in men is that they will be viewed as a coward (懦夫), and a man who fails to display physical courage will suffer damage to his reputation in a way that a woman will not. Throughout history, gaining a higher position among peers (同龄人) has been the ticket that needs to get punched for a man to attract future wife and father children.

People tend to have an idea of what heroes are like. When rating (打分) the personalities of movie heroes, participants expected them to be more hard-working, open to experience, approachable, and emotionally stable than the average person. But some studies suggest that people who show heroic behavior usually have the personalities of madmen: risk-taking, coolness under stress, and an eagerness to take over in social situations.

The study of the relationship between personality and heroism is at an early stage. Psychologists are still at a loss to predict in advance who will heroically step up when needed. Often, the hero is an otherwise ordinary person who finds himself on an extraordinary occasion. Meanwhile, some individuals trained to behave heroically might hesitate in a dangerous situation. Various factors like identities, occasions and specific training will influence the final heroism. Hopefully, the right mix of occasion and personalities enable courage to carry the day.

10 . That artificial food dyes (染料) are unhealthy is not news. Some are known to cause hyperactivity (多动症) in some children, affecting their ability to learn. But regulatory agencies (监管机构) around the world don’t necessarily agree on which food dyes are a problem, or why. That may soon change. A 2021 peer-reviewed report by California’s Office of Environmental Health Hazard Assessment concluded that artificial food dyes “cause or worsen neurobehavioral (神经行为的) problems in some children” and that the current levels that are regarded safe for consumption by the federal government are too high.

California is now considering requiring warning labels on food products and dietary supplements containing the seven most commonly used artificial dyes. The warning label requirement would put California on par with the European Union, which since 2010 has required food products containing certain artificial food dyes to carry warning labels about their negative effect on activity and attention in children.

Artificial dyes are used in foods for one reason: to make products look prettier. Bright colors make candies appealing, especially to kids. But dyes are also in chocolate cake mixes, salad dressings and other products that don’t seem to cry out for a color boost.

In Europe, it was the 2010 label lawmaking that triggered (引发) companies’ decisions to reformulate. “If you’re a company, you do not want to put a warning label on your product.” says Lefferts, an environmental health consultant. Warning labels are why European Starburst Fruit Chews are now colored with natural products, not the artificial dyes that brighten their North American counterparts (同类商品).

Given that artificial food dyes are used far more than needed, we need to be more cautious. After all, we don’t dye fresh fruits and vegetables, but we do dye candy and sprinkles, points out Joe Schwarcz, a chemistry professor at McGill University in Montreal. “The foods in which you find food dyes are foods that are poor in nutrition,” he says. “If you limit foods that contain food dyes, you automatically make your diet better.”