Like the rest of us, scientists have long suspected the healing capacity of a good hug. Unlike the rest of us, they' ve gone about trying to prove it. 

" Laboratory studies suggest that things like hugs help us feel safer. They can also make us less sensitive to physical pain and less reactive when we' re faced with threatening experiences, "  says Michael Murphy. He is a research professor in the Department of Psychological Sciences at Texas Tec h University. " This lab work has shown that hugs and other touch behaviors are related to stress. The more stress we have, the more our heart rates and blood pressure go up. At this time, hugs and other forms of personal touch may give off all sorts of feel-good chemicals, so that stress can be reduced. " 

" There' s a lot that we still need to learn, and there' s a lot we don' t know, "  Murphy says. " However, what seems to be rising up is that hugs, as well as other forms of loving and gentle touch, are really powerful. They remind people that they' re cared about and that they have someone in their corner. " 

" We expect touch. When we were born, we were placed in our mothers' arms almost immediately. In that first year of our life, we spend a lot of time being held by other people. And as we grow up, we seek out hugs and touch as a way of connection. I think what we have lost in the past few years are these really easy opportunities to be reminded of connection. " 

While he was at Carnegie Mellon, Murphy was the lead author of a hug-centered 2018 article in the scientific journal PLOS One. In a series of interviews with 404 adults over a two-week period, the researchers found that receiving a hug is associated with the attenuation of negative emotions that occur on days with interpersonal conflicts. That is to say, generally, hugs help to reduce the negative impacts that personal conflicts may cause in our daily lives. 

It's an attractive idea: By playing online problem-solving, matching and other games for a few minutes a day, people can improve such mental abilities as reasoning, verbal skills and memory. But whether these brain training games deliver on those promises is up for debate.

A research team gathered more than eight thousand volunteers globally after collecting their submission of an online questionnaire about their training habits and which, if any, programs they used. Some one thousand participants reported using brain training programs for about eight months, on average, though durations ranged from two weeks to more than five years. Next, the volunteers completed 12 cognitive (认知) tests assessing their mental abilities. They faced specially designed memory exercises, such as mentally rotating objects, pattern-finding puzzles and strategy challenges.

When looking at the results, researchers saw that brain trainers on average had no mental edge. Even among the most dedicated, who had used training programs for at least 18 months, brain training didn't boost thinking abilities above the level of people who didn't use the programs. Participants who had trained for less than a month, also performed on par with people who didn't train at all.

"No matter how we sliced the data, we were unable to find any evidence that brain training games were connected with cognitive abilities," says leader of the team. That held true whether the team analyzed participants by age, program used, education or socioeconomic status – all were cognitively similar to the group who didn't use the programs, suggesting that brain training games don't live up to its name. Accordingly, the study advocates no more time sitting at a computer and doing little tasks.

If you were bringing friends home to visit, you could show them the way. You know the landmarks—a big red house or a bus-stop sign. But what if you were swimming in the middle of the Atlantic Ocean? Could you still find your way home? A loggerhead turtle（海 龟）could. 

According to Dr. Ken Lohmann, loggerheads have a magnetic（磁力的）sense based on Earth's magnetic field. It helps them locate the best spots for finding food and their home beaches. Scientists already know that several other animals, such as whales and honeybees, can detect（探测到）magnetic fields. The difference between them and loggerheads, however, is the way they learn to use their magnetic sense. Young whales and honeybees can learn from adults. Loggerheads are abandoned as eggs.

As newborn loggerheads have no adults to learn from, what helps them figure out how to use their magnetic sense? Lohmann thinks one of the cues was light on the sea. 

Baby loggerheads hatch only at night. However, a small amount of light reflects off the ocean. The light makes that region brighter. Heading toward the light helps them get quickly out to sea, where they can find food. Lohmann tested whether newborn loggerheads use this light source to set their magnetic "compasses"（罗盘）. He and his team put some newborns in a water tank and recorded which way they swam. Around the tank, the scientists created a magnetic field that matched the Earth's. They set a weak light to the east of the magnetic field. Then they let the newborns go.

At first, the newborns swam toward the light. After the scientists turned off the light, the turtles that had seen the light in the east always swam toward east. When the researchers reversed（颠倒）the magnetic field, these turtles turned around and swam toward the new "east".

This and the follow-up experiments all showed that loggerheads use light from the outside world to set their magnetic "compasses" and then remember the "correct" direction. If a turtle hatches on a brightly-lit beach, that would damage its magnetic sense forever and make survival hard for the turtle.

Lohmann's work has led others to protect the habitat of this endangered species. Yet many questions about these creatures remain unanswered, and researchers have a lot to study.