一直好奇：婴儿出生前到底能看见什么？
在大多数人的印象中，胎儿就只会在母亲子宫里静静成长，别的啥都不会做。但研究却发现，孕晚期胎儿的视力比我们想象中要发达得多。他们甚至能够选择自己想看什么。
Researchers from Lancaster University in the United Kingdom were keen on expanding the understanding of fetal sight capabilities. "We have been able to explore the use of all the fetal senses except vision up until now," explains lead researcher and professor of psychology Vincent Reid in an email interview. "There is a lot that we know about newborn babies and their vision, but almost nothing with fetuses just before they are born. The newborn is very good at processing faces and prefers to look at faces over any other shape so it was logical to explore the development of this preference before birth."
英国兰卡斯特大学的研究者就希望进一步了解胎儿的视力。主要研究者Vincent Reid称，“关于胎儿的其它感官，我们已经有了很多了解。我们也知道了有关新生儿视力的很多事情，但胎儿出生前的视力如何，我们却几乎完全不知道。新生儿很擅长辨别人脸，比起其它形状的事物，他们也更喜欢观察人脸。所以我们可以假定，他们在出生前就发展出了这一偏好。”
A total of 39 fetus were examined (there would have been more, but some of the babies were in deep sleep because they missed the memo about participating in a research study, while others experienced poor image quality). They ranged in gestational age from 231 to 252 days, and were all single births.
接受检查的总共有39个胎儿(本来有更多的，但有的孕妇忘记过来检查，也有的是因为拍出来的图像质量太差)。胎儿的胎龄都在231-252天之间，并且都是单独一胎。
Obviously, since the fetal participants were still cooking in their moms' wombs, so the researchers resorted to noninvasive attempts to assess their visual capabilities. To do so, the scientists shone a light through the maternal tissue. "The light consisted of three dots," Reid explains. "When these are arranged to represent two for the eyes and one for the mouth, newborn babies prefer to look at them more than anything else. So we didn't show fetuses a 'face' but an image that was 'face-like.'"
由于胎儿还在子宫内发育成长，研究者需要借助非侵入性手段了解他们的视力。科学家使用光线在母亲体外进行照射。Reid称，“这些光线包含三个点，模仿人脸的两只眼睛和一个嘴巴。新生儿很喜欢看人脸，所以我们虽然不能直接给胎儿展示一张脸，但可以使用类似人脸的形状。”
The researchers used 4D ultrasound to measure if and how much the fetuses turned their heads in response to the stimuli. They also showed the same three-dot pattern, but inverted (so it didn't resemble a face in structure) to the fetuses. As it turns out, non-face-like dots were none too appealing. "Turning it upside down means that newborns do not find it interesting," Reid notes.
研究者使用4D超声波观察胎儿是否会转动头部来回应这些光点。他们还将这三个点倒转了过来(这样就不像人脸了)，结果胎儿就没那么感兴趣了。
Although subtle, attraction to the face-like configuration of three dots makes a big difference in what we understand about developing sight. "It means that we have this preference even before we are born," Reid says. "[It] is either due to being innate or due to experiences prior to birth."
胎儿对模拟人脸的三个光点很感兴趣。Reid说道，“这意味着我们早在出生前就发展出了这个偏好，这可能是天生的，也可能跟在子宫内的经历有关。”
Another major finding of this research is that it moves up the human visual timeline. "We now know that the fetus actively engages with visual information in the [prenatal] environment," Reid says. "The head movement was a deliberate movement to track the stimuli that we presented. This means that we can now look at many other aspects of fetal vision."
该研究的另一重大成果是将人类的视觉时间轴往前推了一截。研究者称，“我们现在知道了，胎儿会主动观看事物。在观察中我们发现，当光点出现时，他们会主动做出头部运动。这样的话，我们以后就可以进一步研究胎儿的视力了。”
Indeed, the study has laid the groundwork for future delving into fetal vision, because as it stands right now, little is known about how much fetuses can see. "Nobody has looked at this before," Reid says. "A week-old infant has very poor focal vision. It is all blurred. The same will be true for a fetus a few weeks before birth. We know that premature infants can see shapes, lights, and details. But thatis once they are born, and it could be that the prenatal environment is different. We need to find out."
有了这个研究作为基础，科学家就能进行更多调查了。几周大的婴儿焦点视觉很差，他们看到的东西都是模糊的，而出生前几周的胎儿应该也是。Reid的团队也将研究胎儿是否能够辨别数量和观察运动，因为新生儿就能这么做。假如他们可以，这将刷新我们对人类视觉发育的认识。
