A new study from Northwestern University shows what many mothers already know: their babies are a lot smarter than others may realize. （Credit: iStockphoto/Jason Lugo）

ScienceDaily （May 7, 2009） - A new study from Northwestern University shows what many mothers already know: their babies are a lot smarter than others may realize.

Though only five months old, the study's cuties indicated through their curious stares that they could differentiate water in a glass from solid blue material that looked very much like water in a similar glass.

The finding that infants can distinguish between solids and liquids at such an early age builds upon a growing body of research that strongly suggests that babies are not blank slates who primarily depend on others for acquiring knowledge. That's a common assumption of researchers in the not too distant past.

"Rather, our research shows that babies are amazing little experimenters with innate knowledge," Susan Hespos said. "They're collecting data all the time."

Hespos, an assistant professor of psychology at Northwestern, is lead author of the study, which will appear in the May 2009 issue of Psychological Science.

In a test with one group of infants in the study, a researcher tilted a glass filled with blue water back and forth to emphasize the physical characteristics of the substance inside. Another group of babies looked at a glass filled with a blue solid resembling water, which also was moved back and forth to demonstrate its physical properties.

Next all the infants were presented with test trials that alternated between the liquid or solid being transferred between two glasses.

According to the well-established looking-time test, babies, like adults, look significantly longer at something that is new, unexpected or unpredictable.

The infants who in their first trials observed the blue water in the glass looked significantly longer at the blue solid, compared to the liquid test trials. The longer stares indicated the babies were having an "Aha!" moment, noticing the solid substance's difference from the liquid. The infants who in their first trials observed the blue solid in the glass showed the opposite pattern. They looked longer at the liquid, compared to the solid test trials.

"As capricious as it may sound, how long a baby looks at something is a strong indicator of what they know," Hespos said. "They are looking longer because they detect a change and want to know what is going on."

The five-month-old infants were able to discriminate a solid from a similar-looking liquid based on movement cues, or on how the substances poured or tumbled out of upended glasses.

In a second experiment, the babies also first saw either liquid or a similar-looking solid in a glass that was tipped back and forth. This time, both groups of infants next witnessed test trials in which a cylindrical pipe was lowered into either the liquid-filled glass or the solid-containing glass.

The outcomes were similar to those of the previous experiment. Infants who first observed the glass with the liquid looked longer in the subsequent test when the pipe was lowered onto the solid. Likewise, the infants who looked at the solid in their first trials stared longer when later the pipe was lowered into the liquid.

The motion cues led to distinct expectations about whether an object would pass through or remain on top of the liquid or solid, the Northwestern researchers noted.

"Together these experiments provide the earliest evidence that infants have expectations about the physical properties of liquids," the researchers concluded in the Psychological Science study.

Hespos primarily is interested in how the brain works, and, to that end, her research on babies' brand new, relatively uncomplicated brains provides invaluable insights. She also is doing optical imaging of babies' brains, in which the biological measures confirm behavioral findings.

"Our research on babies strongly suggests that right from the beginning babies are active learners," Hespos said. "It shows that we perceive the world in pretty much the same way from infancy throughout life, making fine adjustments along the way."

In addition to Hespos, the co-investigators of the Psychological Science study are Alissa Ferry, a graduate student, and Lance Rips, professor of psychology, at Northwestern.

来自西北大学的一项新的研究显示，虽然很多准妈妈们都知道自己的宝宝非常聪明，但事实上他们的聪明程度超出了很多人的想象。（编辑：iStockphoto/Jason Lugo）

科学日报（2009年5月7日）--来自西北大学的一项新的研究显示，虽然很多准妈妈们都知道自己的宝宝非常聪明，但事实上他们的聪明程度超出了很多人的想象。

从这项研究中许多准妈妈们好奇的眼光中我们可以看到，虽然宝宝只有五个多月大，但是他们就能够区分出两个很相似的杯子中的物体，一杯是水，另一杯是很像水的蓝色固体物质。

研究显示，婴儿在这么早的阶段就能够区分液体和固体。在此基础上，越来越多的研究深刻表明，宝宝们的大脑在最初发育的时候并不是处于空白状态，并不需要依靠外界力量来获取一定的知识。

"相反，我们的研究显示，宝宝们在一些小实验中表现出来的先天性知识令人非常惊奇，"Susan Hespos说道。"他们时时刻刻都在接受外界的信息。"

Hespos是西北大学的一位心理学助理教授，他率先发起了这项研究，并将于2009年5月出现在《心理科学》这份期刊上。

在这项研究的测试中，研究人员将婴儿分为两组，对于其中一组婴儿，他们将一杯矿泉水来回摇晃以强调这杯水的物理特性；而对于另外一组婴儿，他们则选择了一杯类似于水的蓝色固体物质，同样来回摇晃来显示出它的物理属性。

接下来，呈现在所有婴儿面前的是，研究人员将这两杯不同的液体和固态水进行轮流转换。

根据最近一项公认的研究显示，婴儿就像大人一样，对于一些新颖的、意外的或者是无法预测的事物尤其关注。

对于第一组婴儿来说，相对于液态水的测试，他们观察固态水的时间要明显比观察液态水的时间长。当婴儿们看到不同于液态水的固态物质时，他们则发出一声"哇哦"来表示对该事物更加感兴趣。所以，在第一组测试中的婴儿观察液态水时表现出了相反的形态。对于固态水的测试，婴儿们观察液态水的时间则相对长一些。

"同样变幻莫测的是，婴儿观察事物的时间长短强烈印证了他们了解事物的程度，"Hespos说道。"他们长时间的观察一件事物，是因为他们察觉到了事物的变化，并想知道这个事物将如何变化下去。"

基于"运动暗示"理论，以及杯子里的物体是怎样倒出来或者流出来这一线索，五个月大的婴儿就能够把固态物体和类似的液态物体区分开来。

对于第二组实验测试的婴儿来说，宝宝们第一眼看到的其中一杯来回摇晃的固态物体，或者另一杯液态物体。接下来，两组试验中的婴儿同时见证了一个事实，那就是这两杯固态和液态物体分别被倒入一个圆柱形的容器中。

事实证明，前面两组实验的结果是完全一致的。在接下来的测试中，当圆柱形容器中被倒入固态物体的时候，第一组试验中的婴儿则观察液态物体的时间更长些。同样地，当圆柱形容器中被倒入液态物体的时候，第一组试验中的婴儿观察固态物体的时间更长些。

西北大学的一位研究人员指出，这种"运动暗示"理论导致了两种截然不同的猜想，那就是是否存在一种物质在液态或固态物体的顶部之间传递或逗留。

这两组实验同时得出了一个结论，那就是婴儿在早期阶段就能够估计出液态物质的物理属性。"研究心理科学的一位专家推论了这一结果。

Hespos最感兴趣的是婴儿的大脑是如何运作的，因此最后，她对于婴儿大脑全新的、相对而言比较简单的研究给人们提供了一个非常宝贵的见解。她还对婴儿的大脑进行光学成象研究，并通过生物学上的方法证实了这一"运动暗示"理论。

"我们这项基于婴儿的研究强烈表明，婴儿从生下来开始就具有主动学习的能力。"Hespos说道，"这同时表明，我们几乎用同样的一种方式来观察这个世界，从婴儿早期的阶段一直延伸到我们整个的生命历程，并在成长的道路上不断进行自我调整和改变。"

在西北大学，除了Hespos,还有很多人在研究这项理论，比如，心理科学研究院的合作研究员Alissa Ferry、研究生、以及心理学教授Lance Rips等。