In nature, you may see many insects and animals of different colors. Have you ever wondered why locusts are super delicious food for birds, but it is not always an easy job for birds to catch them. It is neither because locusts are good jumpers or runners nor because they are smarter than their enemies. The reason is that the colors of locusts change with the colors of crops. When crops are young, locusts look green. But when autumn comes, locusts change to the yellow and brown color as crops do.

Brown bears, tigers and other animals move quietly through forests. They can’t be seen easily by their enemies. This is because they have colors similar to the trees. For the same reason, polar bears that live on a land of snow and ice are white. Butterflies and bees living among the flowers are colorful like flowers. Soil insects are mostly dark-colored and they live under the soil in a dark and wet environment. However, insects with colors different from plants can easily be found and eaten by others. So in order to survive, they have to hide themselves in the daytime and appear only at night.

Have you ever noticed some even stranger acts? The ink fish in the sea can send out some very black ink when it faces danger. As the ink spreads over, its enemies will find themselves suddenly in a dark world. At the same time the ink fish immediately swims away. That is how it keeps itself safe though it is not strong at all.

Since the beginning of social-comparison theory in the early 1950s, psychologists and sociologists have piled up evidence that human beings form opinions of themselves — their looks, gifts, intelligence, and achievement — based in large part on the qualities they see in the people with whom they identify and associate. When those comparisons lead to inaccurate self-representations or evaluations, this distortion is sometimes referred to as the "frog-pond effect."

The phrase stems from a 1966 paper that found college students at elite universities who had low GPAs tended to view their own academic abilities less favorably than students at lower-tier colleges who had good GPAs. “It is better to be a big frog in a small pond than a small frog in a big pond," the author of that paper wrote.

The "frog-pond effect" continues to show up in research today.

“We use the term 'frog-pond effect' as shorthand for this tendency of people with a high rank in a low-rank group to evaluate themselves more favorably than people with a low rank in a high-rank group,” says Ethan Zell, PhD, author of the PLOS One study and an associate professor of psychology at the University of North Carolina, Greensboro.

“These effects are magnified when we're comparing ourselves to people we view as peers.”

In other words, we look at other people as a frame of reference when we are evaluating ourselves. While "upward" social comparisons can make us feel less attractive, less capable, or otherwise inferior, "downward" social comparisons tend to have just the opposite effect. "These effects are magnified when we're comparing ourselves to people we view as peers, or those in a similar situation to ourselves," Zell explains.

Research has found that all of us engage in social comparisons — consciously or unconsciously — dozens and perhaps hundreds of times each day. To one extent or another, these comparisons influence every aspect of our well-being and behavior, from our confidence and self-regard, to our willingness to take risks, to the likelihood that we'll develop anxiety or depression.

Upward social comparison is not inherently harmful."It can inspire us to take better care of ourselves, or to be ambitious in positive ways," Zell says. But like anything else, too much of it can cause problems.

"Social media and technology have really expanded the reach of comparisons," Zell says. Many of us can't help but feel inferior when we're exposed to image after image or post after post of people who seem cooler, more interesting, funnier, prettier, or more stylish than we are.

Before social media, most of our comparisons were based on face-to-face interactions with friends, schoolmates, co-workers, and those who occupied our real-world social spheres. We saw the good and the bad — the features and the flaws — in something closer to equal measure. And this helped properly calibrate our self-assessments.

All of this suggests that limiting your exposure to online sources of upward social comparison may pay all sorts of dividends. In the infinitely large pond that is the internet, almost all of us are going to end up feeling like small frogs.

In late summer, Death Valley National Park earns its name. The heat in this region of California and Nevada is unbearable. Despite the heat, there was a slow but steady drop of water into the collection bottle of Omar Yaghi’s device, a group of components resembling a telescope. By the end of the day, this system had collected only a few millilitres of water — barely enough for a refreshing sip. But these results, published in July, represent a landmark in the field of Atmospheric Water Harvesting (AWH).

The key ingredient in this device — a water-absorbing chemical called MOF-303 — has the potential to deliver life-sustaining volumes of clean water to regions that currently struggle to access it. “The vision there is to have something like a village-scale device,” says Yaghi, a chemist at the University of California. “If you’ve got a tonne of MOF-303, you could deliver about 500 litres of water a day.”

By current estimates, roughly two billion people lack access to clean drinking water. Desalinated seawater can meet some of this need, but the technology required remains costly and is limited to coastal regions. This accounts for the growing enthusiasm for alternative solutions that extract clean water from the air.

“It is estimated that Earth’s atmosphere contains nearly 13,000 cubic kilometres of water — over six times the volume of the world’s rivers. We cannot exhaust it — it’s always refilled in the process of natural water cycle,” says Tian Li, a materials scientist at Purdue University. And although many of the most promising AWH technologies are still at the stage of lab demonstrations, the field is quickly developing towards real-world systems that produce plentiful amounts of water at low cost.