Scientists in Israel have taught goldfish an unusual way to reach a target — by driving a small robotic car on dry land.

Six goldfish, regardless of their weight and size, took part in the experiment and were taught to drive in 30-minute sessions, conducted three times a week, every two days. The experiment was led by researchers at the Ben-Gurion University of the Negev. They wanted to see if goldfish's ability to navigate (导航) depends on their natural environment, or if they could navigate even under very unusual conditions.

To test the goldfish, the researchers created a special robotic car that could drive forward, backward, and from side to side. The scientists called the car a Fish Operated Vehicle (FOV).

Goldfish was placed inside a water tank on the FOV. Using a special system, the car tracked where the goldfish was and what direction it was swimming in. The FOV would then automatically move in the same direction. To prevent the goldfish from getting stuck in barriers such as walls, researchers equipped the car with lidar (激光雷达). The researchers tested them by placing the car in a small room with a pink target on one side — that was where the fish were supposed to arrive. The fish were rewarded with food when achieving the task.

The fish did indeed learn to drive the FOV, becoming more skillful in its operation over time both in terms of achieving tasks and in the time taken to complete that task. The researchers wanted to check that the fish weren't just memorizing a set of movements to earn a reward, so they repeated some tests with a new starting position or added other targets that were a different color. They found the goldfish were able to deal with those changes.

Though the experiment showed that the fish were able to navigate to a target, it's not likely that the fish knew they were controlling a car. The researchers say that in the future it may be possible to change the FOV to test these ideas.

The 7,400 or so languages in use today speak to the fact that our species is born to communicate. But while it is tempting to view language as merely a consequence of our extraordinary cognitive（认知的）powers, Caleb Everett thinks there may be more going on. 

In A Myriad of Tongues: How languages reveal differences in how we think, he argues that language itself may shape our understanding of the world and our experience of time and space. To put it another way, the language we speak may influence the way we think. 

Such a provocative（挑衅的）idea might have been controversial（有争议的）a few decades ago, says Everett, because language experts restricted themselves to analyzing languages of industrialized, higher-income countries. But we now know they fall short of representing the variety of languages spoken today-and the more we learn about understudied tongues, the more evidence we find for the complicated interplay between language and thinking. 

Take Berinmo, a language of Papua New Guinea, as an example. Unlike English speakers, explains Everett, Berinmo speakers struggle to remember whether an object they were shown earlier was blue or green-perhaps because that language doesn't distinguish between these colours. But it does make a formal distinction between yellowish-greens and other greens, and Berinmo speakers typically find it easy to remember which of these colours an object they saw earlier was painted, while English speakers struggle to do this. 

Language also influences how we think about objects. Yucatec Maya, spoken in Mexico, encourages its speakers to classify objects according to their material properties rather than their function. Where an English speaker might group a plastic comb and a wooden comb together and exclude a wooden stick, a Yucatec Maya speaker would usually group the wooden objects together. English-speaking people get the information they need by sight alone. 

We live through a language extinction event predicted to see the loss of about 30 per cent of today's tongues by 

2100. His book makes it clear this is more than just a tragedy（悲剧）for local communities. Given the insights that languages offer into the human mind, their disappearance is a loss for us all. 

Guided Tour of Harry Potter London Locations

If you are a fan of Harry Potter, the Wizards London Walk is a perfect way to spend a couple of hours in London. You will get to see more than 10 filming locations from the Harry Potter movies. 

The tour features Harry Potter London film locations Meanwhile, you also have a chance to explore famous London landmarks and attractions like St Paul's Cathedral and Millennium Bridge and Big Ben. Along the way you'll have plenty of chances to take lots of pictures and see the filming locations up close. 

Come and explore Harry Potter London filming locations on our magical tour

Please also note:

This tour is not accessible for wheelchair users or for parents with prams 

Anyone who is 17 years old or younger must be accompanied by adults on all tours.