Modern human babies are essentially learning machines. After birth, their brains grow in ___1___, allowing infants to ___2___ for future social and cognitive achievement. But it wasn’t that way for Neandertals. At least in terms of the shape of their brains, Neandertal newborns pretty much coasted into adulthood.
Scientists have shown that Neandertal brains are about the same size as ours. Yet our Paleolithic brethren are not known for having been great scholars. To ___3___ this cognitive conundrum, researchers took CT scans of 11 Neandertal brains, including one newborn. And they compared these images to those of modern humans.
They found that baby braincases are similar in size and shape, regardless of their parentage. All are elongated, most likely to smooth passage through the birth canal. But modern human baby brains grow more globular in the first year of life, changes that reflect a massive wave of neural development.That phase change is ___4___ in Neandertals, whose brains retain that extended newborn shape throughout their lives. The results appear in the journal Current Biology. [Philipp Gunz et al., "Brain development after birth differs between Neanderthals and modern humans"]
It’s not clear whether our well-rounded brains made us the pointy-headed intellectuals we are today. But they do make us ___5___ in a cap and gown.
【视听版科学小组荣誉出品】
leaps and bounds lay the groundwork probe absent look smart
现在的婴儿都是纯天然学习机。出生以后，他们的大脑就会迅速发育，为将来获得社会经验、提高认识打下基础。但生活在远古的尼安德特人的大脑却并非如此，至少在大脑的形状上，尼安德特新生儿与成人之间并无差异。 尼安德特人的大脑和现代人的大脑在大小上相差无几，但生活在旧石器时代的人类祖先之中并未出现贤能之人。为了破解这一谜题，研究人员对包括一名新生儿在内的11名尼安德特人的大脑进行了CT扫描，并将影像图与现代人类的进行了对比。 结果发现，不论父母是尼安德特人还是现代人，其新生儿颅骨的形状大小都极其相似，都是拉长形的，这很可能是为能够顺利从产道出生而形成的。而现代人类大脑的这段发育时期是尼安德特人所没有的，他们的大脑结构终生都停滞在婴孩时期。该研究报考刊登在《当代生物学》上。 是不是因为大脑发育得太完全而让我们变成了尖头知识分子，这还不得而知，不过让我们体面了不少倒是真的~