Hey, guys! Welcome to [Listening]!
Before today’s listening, let’s check the answers to the last episode.
- making you drowsy;
According to one study, the skulls of some Americans have actually grown over the past 120 or so years. But what is the reason for that? How about people from other countries? Wanna know the answers? Do the listening and you’ll get them!
Click the button at the bottom of the screen to play the audio. Please fill in the blanks and leave your answers in the comment. The answers will be revealed in the next episode.
Let’s get started!
The story of human ______(1 Word Missing) goes something like this: Millions of years ago, homo sapiens began to evolve from the prehistoric ancestor we share with our monkey cousins. First, we evolved the ability to walk upright. Then we began fabricating more elaborate tools. Finally, around 50,000 years ago, we emerged as more or less fully modern humans with large, fully human brains. And since then, our craniums and the brains they harbor have stayed pretty much the same.
Except that, according to one study, the skulls of some Americans have actually grown over the past 120 or so years. Specifically, skulls have become larger by about eight millimetres, or a third of an inch. Which may not sound like much, but the growth theoretically allows for additional brain matter roughly equivalent to the size of a tennis ball.
Now, before we go any further, we need to deal with a tricky detail of the study, namely, that the researchers looked almost ______(1 Word Missing) at skeletons of white Americans. Why? Because, historically, mainly white Americans had donated skeletons to the collections the researchers studied. So while it may be the case that the skulls of Americans of many ethnicities have grown, the study provides evidence only for one group.
In any case, it’s not at all clear that larger skulls have translated to larger brains or to greater intellect. It’s also not clear why the skulls the researchers looked at got bigger. American life has changed so much over the past century and a half that it will take years of research to begin to identify possible causes.
But, ______(1 Word Missing), the observation is interesting as another detail in the complex story of human evolution.
That’s all for [Listening] today!
Please leave your answers in the comments below! 😘
See you next time!