Most dog owners are convinced that their four-legged friends know exactly what they mean when they use certain words like “sit”, “stay”, or “treat”. However, scientists have always wondered whether dogs really understand human speech or if they rely on other clues to arrive at the meaning.

To find the answer, scientists at Atlanta’s Emory University did a study. They began by asking the owners of twelve dogs of various breeds to train their pets to identify two toys-a stuffed animal and a ball. Once the dogs had mastered the task, they took turns inside a functional magnetic resonance imaging(fMRI)scanner(功能性磁共振成像扫描仪). The owners then tested their dogs’ language skills by first calling out the names of the toys they had been trained to recognize and then saying meaningless words such as “bobbu” and “bodmick” while holding up random objects the dogs hadn’t seen before.

The fMRI scans revealed that the regions of the dogs’ brains responsible for auditory(听觉的)processing showed different brain patterns when they heard words they were familiar with, compared with the ones they had never heard before. While not enough to prove that the dogs were picturing their toys when they heard the word, it did indicate some sort of recognition. The scientists believe this is an important step forward in understanding how dogs process language.

An even more interesting thing was that the dogs’ brains showed a higher level of neural activity at the sound of unknown words. This is the exact opposite of what happens in human brains. The scientists guess the dogs may become excited at the new words to try to understand them in the hope of delighting their owners.

However, though your pet may understand human speech, the scientists recommend using visual and scent cues(视觉和气味的提示)for training. “When people want to teach their dogs a trick, they often use a verbal command because that’s what we humans prefer,” Prichard, a Ph.D.at Emory’s Department of Psychology and the study’s first author, says. “From the dog’s perspective, however, a visual command might be more effective, helping the dog learn the trick faster.”

How to Move an Aquarium(鱼缸)

What happens to the aquarium when it’s time to move it? Careful planning is important to success in giving your fish the best chance of arriving safely in their new environment.

Stop feeding a few days before your move. 【小题1】 Because sopping feeding will prevent the fish from over polluting their water during the move. Many fish will create extra waste when stressed. Waste products in the water rob(掠夺) the water of oxygen.

【小题2】 Each bag will need to be sealed(密封). Place the fish in the bags, with each school in its own bag. Each bag should have enough water. If traveling a long distance , you will need to add oxygen into the bags. The quickest way is to open the bags and fill new air in the bags before resealing them.

Prepare a clean styrofoam(泡沫) cooler of a proper size. You will be placing bags of water and fish into the cooler, so make sure that there is enough space for all of your fish. 【小题3】 So try to find a cooler with a big enough floor.

Set up your aquarium as soon as possible after arrival. Fill it with new conditioned water and place the bags in the aquarium for about ten minutes to allow the water temperatures to equalize. Then, open the bags, and fill each bag with one cup of water from the aquarium. 【小题4】

Watch the fish carefully in the bags with the combination of old and new water. If they appear to be healthy , net them and place them in the aquarium. 【小题5】 Then follow the process above again.

Across the globe only 10 percent of the population are left-handed—and it has been that way for thousands of years. But when you look into the sports world, lefties exist in large numbers. Why? The answer lies in the relative balance between cooperation and competition in human society, says a new study published in Britain’s The Journal of the Royal Society Interface.

The study by professor Daniel Abrams and Mark Panaggio of applied science points out that for society to function efficiently—hand in hand—cooperation is key. And cooperation favors same-handedness—so we can share tools, for example, and more easily teach each other skills.

On the other hand, competition favors the element of surprise. And this is why “left-handers have the advantage in any sport where there’s direct physical contest,” Abrams said. “They have the surprise advantage in that they practice more against the right-handers, but the right-handers don’t practice much against them. “It’s also the reason lefties haven’t been wiped out,” evolutionarily speaking. “Left-handed people have always had this built-in advantage for this kind of competition,” Abrams said. Thus, so long as there’s competition in society, lefties will survive.

Adams and Panaggio created a computer model that correctly predicted the percentage of left-handed athletes in several sports. About half of major league baseball players and pro boxers are left-handers, while among PGa golfers the number of lefties is a mere 4 percent.

“Golf is one of our go-to examples for the cooperative effect,” Abram said. “Left-handers seem to be selected against in golf, and the reason for that is that golf has a cooperative aspect to it. Especially when people first begin playing golf they tend to borrow or rent clubs, and left-handed clubs are harder to find and they’re more expensive. So there’s a cooperative advantage in that people can share clubs when they’re all of the same handedness.”

But it’s not just golf that can be challenging. Living as a left-handed minority in a world designed for the right-handed majority can be really dangerous. “Evidence from outside the sports world is that left-handers are more likely to be involved in accidents in various ways,” Abrams said.

So when picking players for the office softball team, you want to choose as many lefties as you can to maximize your chance of winning—but don’t be surprised when they show up to the game injured.