The Homo genus faced a a big problem with the difficulties between men and women over procreation and food. One important contributor to the solution was the development of language. Now, there are as many theories explaining the rise of language as there are explanations for the fall of Rome, so we shouldn’t be too dogmatic here. We know that language started developing several million years ago, but it’s difficult to assign a single cause. Perhaps it was toolmaking, or coordination of the hunt, or any of a hundred other factors. The most compelling hypothesis I have read is that language developed out of “shared attention”. It starts with Gronk and Thunk together, when Gronk sees a big dangerous predator that Thunk doesn’t see. Gronk points frantically at the predator and makes a variety of loud noises. Here’s the key trick: Thunk follows the direction of Gronk’s pointing finger to locate the big mean predator. Now Thunk sees the predator and they both know that they should run like hell. 

The ability to direct another person’s attention by pointing was an easy first step, and it was crucial to the development of language. Indeed, following another person’s attention was so valuable that Homo species evolved to show more eye white than iris; this makes it easy to see exactly where somebody is looking. You can’t do that with most species, and not even dogs can readily follow your pointing. So once people were able to direct others’ attention, it was a short step to assign auditory labels to the things they were pointing at: names. I point at the big mean predator and say ‘lion’. I point at the fruit and say ‘apple’. After enough pointing and speaking, we end up with a pretty big vocabulary.

Again, I emphasize that the details of all this are controversial and complicated. For example, it may be that people originally relied more heavily on miming than on language. Instead of telling you how to make a flint tool, I just did it and you watched. Maybe I’d point to key factors while working. Whatever the precise order of events and the relative importance of difference causal factors, Homo species eventually developed language. We do know that our own species, Homo Sapiens Sapiens, arose just 200,000 years ago and those people were anatomically indistinguishable from us today, so the physical capability to speak full-fledged language has been with us for at least 200,000 years.

Language permitted people to ask questions like, “Will you still love me in the morning?” or “Is it really my child?” One of the biggest leaps was making explicit the notion of tense that had already been developed as part of the social relationships mental module. Humans had already developed the concepts of past and future as part of their social relationships. Concepts already in use, like reciprocity and obligation, were built on top of the concepts of past and future. (“Because I shared my food with you yesterday, tomorrow, you must share your food with me .”) Language made those concepts explicit. In so doing, the basic deal between the sexes became more accountable in two ways. First, the deal could be made in front of witnesses who would presumably help enforce the deal in the future. This is how the institution of marriage arose. By exchanging vows in front of both families, the man and woman made cheating on the deal harder to get away with.

Second, the application of language to the battle of the sexes allowed each party to apply lie detection techniques to the other party’s statements. We tend to think of lying as a simple activity: one merely speaks false words, and the listener will be fooled. In practice, the mental mechanisms behind language creation aren’t so easily subverted. The words we speak are not simply stamped out on some mindless production line -- they are wrung out of the brain like water from a sponge. To deliberately speak an untruth requires a controlled distortion of the entire cognitive process. It requires great effort and concentration, and can never be done perfectly. No matter how hard we try, a lie never emerges from our minds as smoothly and cleanly as the truth does. A skilled observer can often detect the effort of lying. The cues are subtle, and some people are better at it than others. Over the millennia, men and women have been locked in an arms race, each side improving its lie-telling skills even as it honed its lie-detecting talents.

There’s always a catch, and in this case the catch was that language skills require huge amounts of brain matter. So once again, brains ballooned, skulls swelled, and childbirth became even more difficult. This was starting to look like a vicious circle. It is entirely conceivable that the human line could have been snuffed out by a failure to keep up with the ever-growing demands of that monster brain perched on top of that scrawny spinal cord. But luckily, the benefits of larger brains were always one step ahead of the costs, and the human brain expanded like a tick who’s struck an artery.

But lurking inside those developing linguistic skills lay
something else that was to have profound significance for humankind.

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