Perszyk Danielle R, Waxman Sandra R
Psychology Department, Northwestern University;
Psychology Department, Northwestern University.
J Vis Exp. 2017 Apr 19(122):55435. doi: 10.3791/55435.
At birth, infants not only prefer listening to human vocalizations, but also have begun to link these vocalizations to cognition: For infants as young as three months of age, listening to human language supports object categorization, a core cognitive capacity. This precocious link is initially broad: At 3 and 4 months, vocalizations of both humans and nonhuman primates support categorization. But by 6 months, infants have narrowed the link: Only human vocalizations support object categorization. Here we ask what guides infants as they tune their initially broad link to a more precise one, engaged only by the vocalizations of our species. Across three studies, we use a novel exposure paradigm to examine the effects of experience. We document that merely exposing infants to nonhuman primate vocalizations enables infants to preserve the early-established link between this signal and categorization. In contrast, exposing infants to backward speech - a signal that fails to support categorization at any age - offers no such advantage. Our findings reveal the power of early experience as infants specify which signals, from an initially broad set, they will continue to link to cognition.
出生时，婴儿不仅更喜欢听人类的发声，而且已经开始将这些发声与认知联系起来：对于三个月大的婴儿来说，听人类语言有助于物体分类，这是一种核心认知能力。这种早熟的联系最初是广泛的：在3个月和4个月时，人类和非人类灵长类动物的发声都有助于分类。但到6个月时，婴儿缩小了这种联系：只有人类发声有助于物体分类。在这里，我们要问的是，当婴儿将最初广泛的联系调整为更精确的联系（仅由我们人类的发声引发）时，是什么在引导着他们。在三项研究中，我们使用了一种新颖的接触范式来检验经验的影响。我们记录到，仅仅让婴儿接触非人类灵长类动物的发声就能使婴儿保持这种信号与分类之间早期建立的联系。相比之下，让婴儿接触倒叙语音——一种在任何年龄都无法支持分类的信号——则没有这样的优势。我们的研究结果揭示了早期经验的力量，因为婴儿会从最初广泛的信号集中确定哪些信号将继续与认知联系起来。
