Ariel Novoplansky, an ecologist in Israel, set up an experiment among pea plants to study how they communicate with each other.

In the experiments Ariel put the pea plants in rows of containers. The center plant in the row was the target. The pea plants had been grown with two main roots. On one side, each pea plant had one root in its own pot and the other reaching into a neighbor’s pot. The central plant connected to its closest neighbor, which connected to another neighbor, and so on down the line. On the other side, all the plants kept their roots in their own pots, unconnected to their neighbors.

With everything ready, the ecologist created a dryness for the central target plant, which had quickly closed up its leaf pores (气孔) to save water. Amazingly, the connected plants on one side gradually closed up their leaf pores, even though only one of them had experienced real dryness. On the other side, with unconnected roots pea chain, all their pores stayed open. This means the warning signal didn’t travel from the stressed plants leaves through the air, but only from its roots through the soil.

It’s possible that plants are just eavesdropping (偷听) even if the damaged plant didn’t mean to send signals to them. Maybe the damaged plant leaks certain chemicals and nearby roots could sense those signals. But the plants with connected roots that weren’t dried out passed on the drought signals to their neighbors too, which means simple eavesdropping probably isn’t the answer. They seem to be having a real conversation, picking up information on one side and sharing it with a neighbor on the other.

The benefit to a plant that receives this information is pretty clear. But what’s the benefit to sending a danger signal to your neighbor? Remember, your neighbor may actually be you.

Most adults firmly believe that as kids reach their teens, they start to take crazy risks that get them in trouble. Do teenagers simply love taking all risks much more than adults? A recent study suggests otherwise.

Scientists designed a simple experiment involving 33 teenagers and three other age groups. In the experiment, the researchers tried to distinguish between two very different kinds of risk-taking. The first they called a tendency to take known risks (when the probability of winning is clear) and the second they called a tendency to take unknown risks (when the possibility of success is uncertain).

The study offered participants the opportunity to play two kinds of games. They had the chance to win money, with one game offering a known risk and the other offering an unknown risk. On each round of the game, each participant had to choose between taking a sure $5 and known or unknown risks of winning a lot more. If on one particular round they had picked the $5 for sure choice, then they got $ 5. But if on that round they had chosen to take a risk, the rules of the game will determine whether or not they had won. If they did win, they went home with between $8 and $125. And, of course, if they lost, they went home with nothing.

What the scientists found was really quite surprising. It turned out that the average teenager was very irresolute when risks were known---more careful than college students or parent-aged adults, and as careful as grandparent-aged adults. This means that when the risks were known, teenagers were not risky in their behavior at all. Only when the risks were unclear did teenagers choose them more often than other groups.

So, what does all of this mean? The research suggests that adults should probably focus more energy on trying to educate teenagers about risks than limiting them. Teenagers who understand the risks associated with a decision are more likely to be careful in their behavior.

Handwriting notes in class might seem out of date as smartphones and other digital technology include every aspect of learning across schools. But a steady stream of research suggests that taking notes in the traditional way — with pen and paper or even tablet — is still the best way to learn, especially for young children, And now scientists are focusing on why.

The new research, by Audrey van der Meer and Ruud van der Weel at the Norwegian University of Science and Technology (NTNU), is based on a 2014 study. That work suggested that people taking notes by computer were typing without thinking, says van der Meer, a professor at NTNU. “It’s very attractive to type down everything that the lecturer is saying, she says. “It kind of goes in through your ears and comes out through your fingertips, but you don ‘t process the information.”

But when taking notes by hand, it’s often impossible to write everything down; student have to actively pay attention to the information and process it. This conscious (有意识地) action can make it easier to stay engaged and grasp new concepts.

Sophia Vinci-Booher, an assistant professor at Vanderbilt University who was not involved in the new study, says its findings are exciting and consistent with past research. “You can see that in tasks that really combine the motor and sensory systems together, such as in handwriting, there’s clear tie between this motor action being accomplished and the visual and conceptual recognition being created,” she says. “As you’re drawing a letter or writing a word, you’re taking this cognitive understanding of something and using your motor system to create it.”

That creation is then fed back into the visual system, where it’s processed again — strengthening the connection between an action and the images or words associated with it. It’s similar to imagining something and then creating it: when you materialize something from your imagination (by writing it, drawing it or building it), this reinforces the imagined concept and helps it stick in your memory.