2 . This question has fascinated behavioural scientists for decades: why do we give money to charity?

The explanations for charitable giving fall into three broad categories, from the purely altruisic (利他的)— I donate because I value the social good done by the charity. The “impurely” altruistic— I donate because I extract value from knowing I contribute to the social good for the charity. And the not-at-all altruistic— I donate because I want to show off to potential mates how rich I am.

But are these motives strong enough to enable people to donate as much as they would want to? Most people support charities in one way or another, but often we struggle to make donations as often as we think we should. Although many people would like to leave a gift to charity in their will, they forget about it when the time comes.

Many people are also aware that they should donate to the causes that have the highest impact, but facts and figures are less attractive than narratives. In a series of experiments, it was found that people are much more responsive to charitable pleas that feature a single, identifiable beneficiary(受益者), than they are to statistical information about the scale of the problem being faced. When it comes to charitable giving, we are often ruled by our hearts and not our heads.

The good news is that charitable giving is contagious—seeing others give makes an individual more likely to give and gentle encouragement from an important person in your life can also make a big difference to your donation decisions— more than quadrupling them in our recent study. Habit also plays a part— in three recent experiments those who volunteered before were more likely to do donate their time than those who had not volunteered before.

In summary, behavioural science identifies a range of factors that influence our donations, and can help us to keep giving in the longer term. This is great news not just for charities, but also for donors.

3 . The rate of childhood obesity in the U. S. has tripled over the past 50 years. The American Academy of Pediatrics (AAP) made waves this year by recommending that doctors put obese kids as young as two years old on intensive, family-oriented lifestyle and behavior plans. It also suggested prescribing weight-loss drugs to children l2 and older and surgery to teens 13 and older. This advice reflects the organization’s adoption of a more active position on childhood obesity.

Yet the lifestyle programs the AAP recommends are expensive, inaccessible to most children and hard to maintain. Few weight-loss drugs have been approved for children. And surgery has potential risks and few long-term safety data. Furthermore, it’s not clear whether interventions in youngsters help to improve health or merely add to the psychological burden overweight kids face from the society.

Rather than paying close attention to numbers on a scale, the U. S. and countries with similar trends should focus on an underlying truth: we need to invest in more and safer places for children to play where they can move and run around, climb and jump, ride and skate.

Why is it so hard to get kids moving? Experts blame the problem on the privatization of sports — as public investment in school-based athletics dwindles, expensive private leagues have grown, leaving many kids out. In addition to fewer opportunities at school, researchers cite increased screen time and a lack of safe places for them to play outside the home. New York City, for example, had 2,067 public playgrounds as of 2019 — a very small amount for its large population. In Los Angeles in 2015, only 33 percent of youths lived within walking distance of a park.

Kids everywhere need more places to play. Public funding to build and keep up these areas is crucial, but other options such as shared-use agreements can make unused spaces available to the public. These opportunities aren’t primarily about changing children’s waistlines — they’re how we keep childhood healthy and fun.

6 . California has been using recycled wastewater for many years. A team has used it to make ice surfaces for the game of hockey(冰球运动). It has been used to make snow for the sport of skiing. And farmers use it to water their crops. But it has not been used directly for drinking water.

Recently, California officials approved new rules to let water agencies recycle wastewater and put it right back into the pipes that carry drinking water to homes, schools, and businesses. It is a big step for California.

California’s new rules would let—but not require—water agencies to take wastewater, treat it, and then put it right back into the drinking water system. That means proving to people that recycled water is not only safe to drink but also not dirty. California would be just the second US state to permit this, following Colorado. It has taken officials more than 10 years to develop these rules, a process that included several studies by independent groups of scientists.

A project in San Diego is aiming to produce nearly half of the city’s water through recycling wastewater by 2035. And the Metropolitan Water District of Southern California aims to produce up to nearly 570 million liters(升)a day for its 19 million people. Adel Hagekhalil is with Metropolitan Water. He said the new rules will permit new projects that have not yet been considered.

California’s new rules require the wastewater be treated for all bacteria and viruses, even if they are not present in the wastewater. In fact, the treatment is so intense that it removes all of the minerals that make fresh drinking water taste good. That means the minerals need to be added back at the end of the process. Polhemus is a director of the drinking water group for the California Water Resources Control Board. “It’s at the same drinking water quality, and probably better in many instances,” he said, adding that it takes time and money to build these treatment centers. So, they will only be available for bigger cities at first.

7 . Pet owners love their dogs more than their cats. Although previous studies have already suggested this finding, scientists from the University of Copenhagen wanted to research more deeply into whether cultural factors affected the results. Their findings are published in the journal Frontiers in Veterinary Science.

In the survey across Denmark, Austria and the United Kingdom, 844 dog owners, 872 cat owners and 401 people who owned both dogs and cats were asked questions about their pets. Overall, the participants had higher attachment scores for dogs than for cats. Owners were more likely to insure (给……投保) their dogs and paid more to dogs’ treatment. However, the results differed dramatically across countries. For example, the United Kingdom’s results were in favor of dogs, although only slightly. Australia had a very clear preference for dogs. Emotional attachment to dogs was highest in Denmark. The Danes were also less likely to buy insurance for their cats, compared with their dogs.

“While people care more about their dogs than their cats in these countries, the degree of difference varied between countries,” Professor Peter Sandoe of the University of Copenhagen, the study’s first author, said in a press release. “It doesn’t therefore seem to be a universal phenomenon (现象) that people care much less about their cats than their dogs.”

The difference between countries may be due to cultural differences and attitudes toward pets, the study suggested. This may be the result of the country’s history with rural animals and how often they interacted with people. These factors may have influenced societal attitudes toward pets in modern times.

“Our study only looks at three countries in Europe,” professor Clare Palmer of Texas A&M University, a co-author of the paper, said in the press release. “It raises interesting questions regarding what comparative studies of other countries might find,” she went on. “Perhaps there are countries where the level of care for and attachment to cats is, in fact, higher than dogs?”

8 . One strategy for reducing food waste’s environmental impact seems contrary to common sense: Open more grocery stores. That’s according to new research from Elena Belavina, an expert in operations management and supply chains.

The food we throw out because it goes bad when cleaning out the fridge makes a surprisingly large contribution to global warming. One-third of all food produced is wasted, a problem responsible for carbon emissions (排放物) equivalent to all road transportation, said Belavina.

When consumers can purchase food nearby, they shop more often but buy less each time, ultimately wasting less. “The more stores you have, the lower food waste is going to be,” said Belavina. “Very small increases in store density (密度) can have a very high impact.”

Belavina found that in Chicago, which she said is typical of many American cities, adding just three or four markets within a 10-square-kilometer area would reduce food waste by 6% to 9%. That would achieve an emissions reduction comparable to converting (改装) more than 20,000 cars from petrol to electric power.

Most big cities are well below the ideal density of grocery stores that would minimize food waste, the research determined. In Chicago, that would be about 200 markets within a 10-square-kilometer area — compared to 15 currently — but most of the benefit from reduced emissions would be achieved by about 50 markets. New York City, with its abundance of produce stands and neighborhood markets, comes closest to its ideal density.

Urban planners, city governments and activists should pursue policies encouraging an ideal density of grocery stores based on each city’s population, she said. Chain stores’ sustainability plans should analyze how their store networks and supply chains contribute to food waste and emissions overall.

“We actually see some moves toward going a little bit back in time and those small corner stores and mom-and-pop stores are making a comeback,” she said.

9 . Everywhere I look, there are new buildings under construction. The neighborhoods that I knew as a boy, filled with beautiful old buildings, have mostly disappeared, and in their place, modern, high-rise buildings have appeared. There is good reason for this. Residents want all the conveniences of modern living. However, how can our children understand and maintain their cultural identity if we erase so much of the physical evidence of it?

The arguments for preserving historic buildings are not simply about an emotional attachment to the past. There are also good economic arguments in favour of preservation. The renovation (修缮) and preservation of historic districts can become an economic engine, drawing tourists and small businesses to the area. For example, in Dubai, the historic Al Bastikiya district draws thousands of tourists every year from all over the world. It also attracts local residents, eager to learn about their city's past.

Some have argued that historic preservation is too expensive, but many recent projects have demonstrated that this is not necessarily the case. In fact, renovation of an existing structure for adaptive reuse can cost about £40 per square metre less than even the most basic new construction, while preserving the beauty of the original building. And, although it is often claimed that old buildings have a more significant environmental footprint than new construction because they aren’t very energy efficient, architects and environmental experts maintain that the greenest building is the one that is already built. New construction almost always has a more serious environmental impact (影响) because it requires the use of all-new materials that must be transported, often over long distances, instead of recycled materials that are already on site. We recycle so many other things. We can and should recycle buildings, too.

Historic preservation is an option that opens many possibilities; demolition (拆毁), in contrast, is irreversible. Once these treasures are lost, they are lost forever, an important link in our heritage that can never be recovered.

10 . ByteDance’s Douyin has been trialing a food delivery service since December as it looks to expand its business beyond advertising. It potentially competes itself against major e-commerce companies like Alibaba and Meituan. And the company is now considering extending the service beyond the trial.

A Douyin spokesperson says that the company has been “testing a feature in Beijing, Shanghai and Chengdu that enables merchants (商人) to promote and sell ‘group-buying’ packages to Douyin users in these select cities and have them delivered”. Restaurant owners often livestream on Douyin to market their business. While doing this, they can offer discounts and coupons (优惠券) for their food to users watching the videos. Multiple users can then purchase that offer mainly and choose a time within two days for the food to arrive. The model is very different from Meituan and Alibaba’s Ele.me which are both on-demand food delivery services.

The digital giant has approached restaurant owners and food enterprises in the three cities to promote their dishes on the app. Douyin states that the success of the trial run will determine whether the in-app meal delivery service will be expanded to other cities. “We would consider expanding the feature to more cities in the future depending on the testing results. There is no detailed timeline yet,” a Douyin spokesperson says.

China’s food delivery industry is dominated by Meituan and Ele.me. Douyin has fewer food buying options than Meituan and Ele.me. But ByteDance’s tentative (暂定的) steps into the market suggest it wants a slice of the market. Major e-commerce platforms are getting into the food delivery business.

One Weibo post reads, “More platforms could be advantageous for both food business owners and regular consumers.” Users think the competition will help registered vendors (销售商) and users because customers will have more options and food business owners can use the platform that charges the lowest service fee.