【推荐2】Do dogs understand us?

Be careful what you say around your dog. It might understand more than you think.

A border collie named Rico recognizes the names of about 200 objects, say researchers in Germany. The dog also appears to be able to learn new words as easily as a 3-year-old child. Its word-learning skills are as good as those of a parrot or chimp.

In one experiment, the researchers took all 200 items that Rico is supposed to know and divided them into 20 groups of 10 objects. Then the owner told the dog to go and fetch one of the items and bring it back. In four tests, Rico got 37 out of 40 commands right. As the dog couldn't see anyone to get clues, the scientists believe Rico must understand the meanings of certain words.

In another experiment, the scientists took one toy that Rico had never seen before and put it in a room with seven toys whose names the dog already knew. The owner then told Rico to fetch the object, using a word the dog had never heard before.

The correct object was chosen in seven out of l0 tests, suggesting that the dog had worked out the answer by process of elimination (排除法). A month later, Rico remembered half of the new names, which is even more impressive.

Rico is thought to be smarter than the average dog. For one thing, Rico is a border collie, a breed (品种) known for its mental abilities. In addition, the 9-year-old dog has been trained to fetch toys by their names since the age of nine months.

It's hard to know if all dogs understand at least some of the words we say. Even if they do, they can't talk back. Still, it wouldn't hurt to sweet-talk your dog every now and then. You might just get a big, wet kiss in return!

【推荐3】Taking an afternoon nap could keep your brain sharp, a new study has found. Adults ages 60 and older who took afternoon naps showed signs of better mental mind compared to those who didn't nap, according to a study published in General Psychiatry earlier this week.

Researchers analyzed napping habits in 2, 214 Chinese people aged 60 and older and measured their cognitive abilities using several cognitive tests. Participants took the Mini-Mental State Examination and the Beijing version of the Montreal Cognitive Assessment, both of which test for memory, language and other cognitive abilities. In every category listed in the study, nappers scored statistically higher on average compared to those non-napping people. Researchers did not gather data from people under 60, so a correlation cannot be drawn between napping and younger generations.

Sleeping behaviors can be affected by a variety of factors, said Dr. David Neubauer, associate professor at Johns Hopkins University. Daily routines, medication use and sleep disorders can all play a role in how frequently someone takes a nap, he said.

Neubauer recommended taking a shorter “power nap" of up to 20 minutes to decrease the chances of transitioning into slow-wave sleep, which makes people feel dizzy when they wake up. Napping can be a healthy part of an older adult's day, Neubauer acknowledged, but make sure sleepiness isn't due to a treatable nighttime sleep disorder. "Older individuals who want to do all they can to preserve their cognitive functioning should put nighttime sleep in the first place."