Once upon a time, researchers dreamed of building a robot storyteller. It would not only entertain (娱乐) young children, but also help them learn well. This dream has come true. The robot is called Tega. It is cute and appears to be useful in increasing young children’s language skills. Developed by a team at the Massachusetts Institute of Technology (MIT), Tega sounds like a child, makes its body and face full of life while storytelling and explains the tales on a screen with pictures.

In an eight-week experiment, Tega read picture books to 67 children aged from 4 to 6 in weekly meetings lasting an hour. During the meetings, Tega asked questions to have knowledge of the listeners’ language skills, tested them on a word’s meaning or asked them to describe a character. For example, Tega asked, “What do you think will happen to the boy?” Tega also recorded the facial expressions and body positions of the children to see how interested they were. For example, keeping the body forward was considered a good sign. After the book was finished, the children retold the story to Tega in their own words.

One group of kids played with a personalized version (版本) of the robot, which improved each time it interacted with the kids, learning about their language skills from the conversations they had. For this group, Tega chose which book to read based on what it thought would be most suitable for the children’s language level. Every second time, Tega would replace (替换) several words in the story for these children with more difficult words with similar meanings, such as “clamour” in place of “noise”.

A second group interacted with a non-personalized Tega that remembered the children each week, but chose stories to read at random (随机的) from its library of 81 picture books. For this group, the story difficulty increased every two weeks. A third group of kids didn’t interact with Tega at all.

Several weeks after the last meeting, the team found that all the children who played with Tega had increased their vocabularies (词汇), but the personalized group learned the most words. Their error rate on a vocabulary test dropped by 23 percent, almost double that of the non-personalized group. The stories that the children told back to the personalized robot were also longer and more wonderful, says team member Hae Won Park.