There are actually different classes of force at work on culture, in the two examples I gave, in the previous lecture. In this lecture I want to look at just one of them. I will called this class, inertial forces. It is relevant to the story about the roast and the roasting pan. If we ask ourselves the question, why do the daughter and granddaughter cut off the end of the roast? The answer is, that the granddaughter learned how to prepare the roast from her mother. The mother had in turn, learned it from her mother. Let's diagram the situation this way, much the way we diagram the crossing of cultural boundaries, way back in unit two. Here, the cultural element is cutting the end off the roast before putting it in the pan. The arrows indicate the direction of the motion over time from the grandmother, to the mother, to the daughter. But why did the daughter learn the technique from her mother? The answer is, because it was there to be learned. This is a form of inertia, using an analogy from physics. And more specifically, we could say that this is a kind of existential inertia. In other words, someone learns some element of culture because it is there to be learned. It already exists, and its existence precedes the learner. A great deal of culture passed on in the family, is passed on because of existential inertia. Take for example the first language someone learns. It's often called, in English, the person's mother tongue. Why they learn that language, and not some other? The answer is, because it was there to be learned. People were around the child, when the child was in the phase of learning to speak a language, and that's the language they were speaking. Similarly, I learned to brush my teeth after breakfast when I was a child. That way of doing things was there for me to acquire, not some other way. Karen learned proper Vietnamese table manners, in the family in which she grew up. In her case, she had to learn to invite guess to the table to eat. She did not learn to ask permission to eat. These are patterns acquired through existential inertia. There is, however, another subtype of inertia force, that I'll call habitual inertia. Habitual inertia results from doing the same thing over, and over, and over, again. The result is often embodied cultural patterns, part of what we were calling earlier, the bodily habitus. In the case of, part of what we were calling earlier the bodily habitors. In the case of language, habitual inertia gives rise to the phenomenon of accent and speaking. When someone tries to learn a second language later in life, they speak it with an accent they acquired because of their first language, their mother tongue. So, for example, a native speaker of American English can usually pick out someone who is a native speaker of, say, Mandarin Chinese, but who learned English, say, during college. Similarly, when I speak Portuguese in Brazil, I can be identified as someone speaking with an American accent. Okay, yeah I know, we never think of ourselves as speaking with an accent. An accent is what other people have. But in truth, everyone, everywhere has an accent. It's just that the accent becomes noticeable, only when they are immersed in speakers who have a different accent. Or, more precisely, our culture and our neurology. A child is born with the ability to speak any language on the planet. And unless they have a problem, they will be able to speak that language like any other native speaker. So, when Chinese migrants come to the US and have children, their children are able to speak with a flawless American accent. Well, actually, they may possibly retain some very slight patterns from the English of their parents, but most people would not notice this. The children will sound just like any other American. But, the neural pathways for producing speech sounds that are characteristic of a given language, get reinforced by speaking that language. And other neural pathways deteriorate. So the accent literally becomes part of our bodies. People find it difficult, and even impossible, to acquire a flawless accent in another language once they reach adulthood. And so here, you should remember that old Roman saying, habit is second nature. It really does transform our biology, and here we should add that, habitual inertia also resists change. We'll talk more about inertia and change in the very next lecture.