Language
Origins of Us - Brains
Stone hand axes, and the more complex culture that follows them, tell us about the behaviour of our ancestors. But they also do more than that, they tell us about their minds. Because, in order to be able to make a complex stone tool, it certainly helps to be able to understand what other people are thinking. But you also have to have a mental image, an abstract idea in your mind of what that tool is going to look like. And it's been suggested that this mental ability to make stone tools is related to something else - language.
We are unique in our ability to speak. But the moment when human language first evolved is shrouded in mystery. Language is such an important human characteristic, but there's no direct evidence of when it evolved.
We can't even look at the vocal tracts of our ancestors - they're made of soft tissue, cartilage, muscle, ligaments, membranes. They don't fossilise like bones do.
The only certainty is that language is central to one human species which emerged in Africa around 200,000 years ago, and that's us, Homo sapiens. We use language in every aspect of our lives, from idle gossip to sharing our deepest thoughts. Forming this range of sounds involves many parts of our anatomy.
The parts of the anatomy used to create speech range from the lips at the front, to the teeth, hard palate and the soft palate and the large muscle that is the tongue, important for moulding the sound, and deep within the larynx are the vocal cords themselves.
Air from my lungs is forced between my vocal cords, causing them to vibrate. The sound passes upwards and is moulded by my tongue and my lips, emerging as speech.
Our ability to vocalise our inner thoughts gave our species the power to teach and learn at a level of complexity no other animal on Earth can match. Human language is so much more than just a series of sounds. It draws on something else which seems uniquely human, and that is symbolic thought.
When we name something, we create an abstract representation of it, and crucially, we can take that idea and share it with someone else. With language, ideas are not just their own, they become common property.
Using language to share ideas, we could build on the knowledge and culture on those who had gone before us. Over time, our brains evolved to be much larger than those of all our ancestors.
