In an attempt to replicate the early experiences of infants, researchers in England have created a robot that can learn simple words in minutes just by having a conversation with a human. The work, published in the journal PLoS One, offers insight into how babies transition from babbling to speaking their first words.
The 3-foot-tall robot, named DeeChee, was built to produce any syllable in the English language. But it knew no words at the outset, speaking only babble phrases like "een rain rain mahdl kross."
During the experiment, a human volunteer tried to teach the robot simple words for shapes and colors by using them repeatedly in regular speech. At first, all DeeChee could comprehend was an unsegmented stream of sounds. But DeeChee had been programmed to break up that stream into individual syllables and to store them in its memory. Once there, the words were ranked according to how often they came up in conversation; words like "red" and "green" were prized.
DeeChee was designed to recognize words of encouragement, like "good" and "well done." That feedback helped transform the robot's babble into coherent words -- sometimes in as little as two minutes.
If repetition of sounds helps infants learn a language, then it's not surprising that our first words are often mainstays like "mama" and "dada." But why don't we start using common and simple words like "and" or "the" at the same time?
The answer, said study leader Caroline Lyon, a computer scientist at the University of Hertfordshire, is that the words that form the connective tissue of our language -- words such as "at," "with" and "of" -- are spoken in hundreds of different ways, making them difficult for newbies to recognize. On the other hand, more concrete words like "house" or "blue" tend to be spoken in the same way nearly every time.
Because the study relied on the volunteers speaking naturally, Lyon said it was crucial that the robot resemble a person. DeeChee was programmed to smile when it was ready to pay attention and to stop smiling and blink when it needed a break. (Though DeeChee was designed to have a gender-neutral appearance, humans tended to treat it as a boy, according to the study.)
"When we asked people to talk to the robot as a small child, it seemed to come quite naturally to them," she said. "When they talk to a bit of disembodied software, you don't get the same response."