2007年VOA标准英语-Scientists Develop New Theory on How Toddlers L

By Jessica Berman
Washington
03 August 2007

There's a period in the development of toddlers when they seem to learn a new word every day.  There are different theories about why young children undergo what experts call a word spurt¹. But one psychologist believes it may have to do with how young children learn difficult words.   VOA's Jessica Berman reports.

At around one year of age, most babies utter their first word.  A short time later, a second word is spoken. 

Bob McMurray is a professor of psychology² at the University of Iowa.

"And it would be very tempting³ to say, 'Wow, look at the rate of acquisition has sped up,' right?  'It took them a year to learn mommy but only a month to learn daddy.' But in actuality that child was probably working on that word daddy all along.  They really spend a year and a month to learning the word daddy," he explained.

McMurray says once toddlers begin speaking their first few words, it is only a matter of time before they seem to learn words at a faster rate.  According to the psychologist, the first word spurt usually occurs around 18 months of age.

A toddler learns the word for 'sheep'

When the burst of language occurs, McMurray says, the conventional theory among psychologists is that toddlers are rapidly developing specialized⁴ learning tools, such as the ability to recognize that objects have names. 

But according to a computer model McMurray created, toddlers have "word spurts⁵" after they have gathered enough easy, similar sounding words - like mama, dada, dog and cat.  Once they have mastered these words, by repeating them over and over again, they then tackle more difficult words.  McMurray says the exposure to more difficult words is a key factor in the word spurt.

"The critical factor is actually how many words are hard and how many words are easy.  So, as long as you have, and this is what we were able to prove mathematically, more difficult words than easy words, you're always going to get some kind of acceleration⁶ in word learning," he added.

McMurray believes his model demonstrates that the word spurt of toddlers is the result of their understanding of more complex words.

"Kids are keeping track of lots and lots of words at the same time," he explained.  "They may not be using all of the words they've learned, but as they are hearing words, they are soaking [them] up.  They are not waiting until they are done learning one word before moving on to the next."

The study on toddlers' word development is in the journal Science.

1 spurt   

v.喷出；突然进发；突然兴隆

参考例句：

• He put in a spurt at the beginning of the eighth lap.他进入第八圈时便开始冲刺。
• After a silence, Molly let her anger spurt out.沉默了一会儿，莫莉的怒气便迸发了出来。

2 psychology   

n.心理，心理学，心理状态

参考例句：

• She has a background in child psychology.她受过儿童心理学的教育。
• He studied philosophy and psychology at Cambridge.他在剑桥大学学习哲学和心理学。

3 tempting   

a.诱人的, 吸引人的

参考例句：

• It is tempting to idealize the past. 人都爱把过去的日子说得那么美好。
• It was a tempting offer. 这是个诱人的提议。

4 specialized   

adj.专门的，专业化的

参考例句：

• There are many specialized agencies in the United Nations.联合国有许多专门机构。
• These tools are very specialized.这些是专用工具。

5 spurts   

短暂而突然的活动或努力( spurt的名词复数 )； 突然奋起

参考例句：

• Great spurts of gas shoot out of the sun. 太阳气体射出形成大爆发。
• Spurts of warm rain blew fitfully against their faces. 阵阵温热的雨点拍打在他们脸上。

6 acceleration   

n.加速，加速度

参考例句：

• All spacemen must be able to bear acceleration.所有太空人都应能承受加速度。
• He has also called for an acceleration of political reforms.他同时呼吁加快政治改革的步伐。