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.
【視聽(tīng)版科學(xué)小組榮譽(yù)出品】
leaps and bounds lay the groundwork probe absent look smart
現(xiàn)在的嬰兒都是純天然學(xué)習(xí)機(jī)。出生以后，他們的大腦就會(huì)迅速發(fā)育，為將來(lái)獲得社會(huì)經(jīng)驗(yàn)、提高認(rèn)識(shí)打下基礎(chǔ)。但生活在遠(yuǎn)古的尼安德特人的大腦卻并非如此，至少在大腦的形狀上，尼安德特新生兒與成人之間并無(wú)差異。 尼安德特人的大腦和現(xiàn)代人的大腦在大小上相差無(wú)幾，但生活在舊石器時(shí)代的人類(lèi)祖先之中并未出現(xiàn)賢能之人。為了破解這一謎題，研究人員對(duì)包括一名新生兒在內(nèi)的11名尼安德特人的大腦進(jìn)行了CT掃描，并將影像圖與現(xiàn)代人類(lèi)的進(jìn)行了對(duì)比。 結(jié)果發(fā)現(xiàn)，不論父母是尼安德特人還是現(xiàn)代人，其新生兒顱骨的形狀大小都極其相似，都是拉長(zhǎng)形的，這很可能是為能夠順利從產(chǎn)道出生而形成的。而現(xiàn)代人類(lèi)大腦的這段發(fā)育時(shí)期是尼安德特人所沒(méi)有的，他們的大腦結(jié)構(gòu)終生都停滯在嬰孩時(shí)期。該研究報(bào)考刊登在《當(dāng)代生物學(xué)》上。 是不是因?yàn)榇竽X發(fā)育得太完全而讓我們變成了尖頭知識(shí)分子，這還不得而知，不過(guò)讓我們體面了不少倒是真的~