近日,宾夕法尼亚大学心理学家Elika Bergelson和Daniel Swingley 开展一项针对6到9个月大的婴儿的研究,并指出:通过日常的语音活动,婴儿学习有关食物和躯体的词语意义。这项研究发表在这周的《国家科学院》(PNAS)期刊上。研究指出,当处于仅能发出“ba-ba”和“da-da”语音的年龄时,婴儿能理解一些常见事物的词语。
这项研究推翻了之前人们对婴儿学习所持有的认识:6到9岁的婴儿虽然能感知和理解语音,但不能掌握语音传达的意义。大多数心理学家认为,直到快接近1岁生日,婴儿的语言理解能力才会出现。
据Bergelson称,婴儿经常被看作是“语音前体”,但是很少研究验证婴儿何时开始理解语音的特定意义。考虑到婴儿在10或11个月前经常不说词语,甚至连有意义的姿势都没有,人们很容易认为在第一年的大多数时间内婴儿不能理解语音。
为了验证这一想法,Bergelson 和 Swingley 招募护理人员,让她们把各自的孩子带到实验室去完成2个不同的实验。第1组,婴儿坐在护理人员的大腿上,目视着能够显示食品和躯干图像的屏幕。护理人员带着头戴式耳机,听到诸如“看苹果”或“苹果在哪里?”的语音,然后向婴儿重述,她们还带着头盔以避免看到视屏。视觉捕捉装置能辨别婴儿注视的方向和时间,并能跟踪他们的视线;另1组实验具有相同的步骤,不同之处是屏幕上呈现着自然环境中的物体(如食物放在桌上或人体形象)而非食品和躯体。当听到关于屏幕上事物的词语时,婴儿如果把目光长久停留在该事物上,就表明他们能听懂。
Bergelson 和Swingley 共检测了33个6到9个月大的婴儿,此外,研究人员还用10到20个大的婴儿完成相同的测试,用以比较这2个年龄段在语音辨别的能力。
作为分析的一部分,Bergelson 和Swingley纠正了与言语无关的视觉运动;不管父母怎么说,对婴儿而言,一些事物总是比另一些事物有趣。例如,在无趣的和色彩绚丽的杯之间婴儿会更多地看后者。
研究人员发现,6到9个月大的婴儿把目光更多地锁定在有名称的图像上,这表明他们能理解与特定事物相关的词语。该研究首次证实这个年龄段的婴儿能理解这类词语。
Swingley称:“之前的研究是对于mommy 和 daddy等词语的理解,而对类、属性词语的较多使用是我们研究的不同之处。”
Bergelson 和 Swingley希望发现6到9个月大的婴儿存在学习模式,但是,对6个月、7个月和8个月、9个月的婴儿进行比较,研究人员没有发现任何提高。Swingley称:“这是一个惊奇的结果,我们不知道在这一段时间内为什么保持同一水平的理解能力。”(生物谷Bioon.com)
doi:10.1073/pnas.1113380109
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TAt 6–9 months, human infants know the meanings of many common nouns
Elika Bergelson and Daniel Swingleya
It is widely accepted that infants begin learning their native language not by learning words, but by discovering features of the speech signal: consonants, vowels, and combinations of these sounds. Learning to understand words, as opposed to just perceiving their sounds, is said to come later, between 9 and 15 mo of age, when infants develop a capacity for interpreting others’ goals and intentions. Here, we demonstrate that this consensus about the developmental sequence of human language learning is flawed: in fact, infants already know the meanings of several common words from the age of 6 mo onward. We presented 6- to 9-mo-old infants with sets of pictures to view while their parent named a picture in each set. Over this entire age range, infants directed their gaze to the named pictures, indicating their understanding of spoken words. Because the words were not trained in the laboratory, the results show that even young infants learn ordinary words through daily experience with language. This surprising accomplishment indicates that, contrary to prevailing beliefs, either infants can already grasp the referential intentions of adults at 6 mo or infants can learn words before this ability emerges. The precocious discovery of word meanings suggests a perspective in which learning vocabulary and learning the sound structure of spoken language go hand in hand as language acquisition begins.