I began to realize that romantic love is not an emotion. In fact, I had always thought it was a series of emotions, from very high to very low. But actually, it's a drive. It comes from the motor of the mind, the wanting part of the mind, the craving part of the mind. The kind of mind -- part of the mind -- when you're reaching for that piece of chocolate, when you want to win that promotion at work. The motor of the brain. It's a drive.
And in fact, I think it's more powerful than the sex drive. You know, if you ask somebody to go to bed with you, and they say, "No, thank you," you certainly don't kill yourself or slip into a clinical depression. But certainly, around the world, people who are rejected in love will kill for it. People live for love. They kill for love. They die for love. They have songs, poems, novels, sculptures, paintings, myths, legends. In over 175 societies, people have left their evidence of this powerful brain system. I have come to think it's one of the most powerful brain systems on earth for both great joy and great sorrow.
And I've also come to think that it's one of three basically different brain systems that evolved from mating and reproduction. One is the sex drive: the craving for sexual gratification. W.H. Auden called it an "intolerable neural itch," and indeed, that's what it is. It keeps bothering you a little bit, like being hungry. The second of these three brain systems is romantic love: that elation, obsession of early love. And the third brain system is attachment: that sense of calm and security you can feel for a long-term partner.
And I think that the sex drive evolved to get you out there, looking for a whole range of partners. You know, you can feel it when you're just driving along in your car. It can be focused on nobody.
I think romantic love evolved to enable you to focus your mating energy on just one individual at a time, thereby conserving mating time and energy. And I think that attachment, the third brain system, evolved to enable you to tolerate this human being -- (Laughter) -- at least long enough to raise a child together as a team.
So with that preamble, I want to go into discussing the two most profound social trends. One of the last 10,000 years and the other, certainly of the last 25 years, that are going to have an impact on these three different brain systems: lust, romantic love and deep attachment to a partner.
The first is women working, moving into the workforce. I've looked at 130 societies through the demographic yearbooks of the United Nations. And everywhere in the world, 129 out of 130 of them, women are not only moving into the job market -- sometimes very, very slowly, but they are moving into the job market -- and they are very slowly closing that gap between men and women in terms of economic power, health and education. It's very slow.
For every trend on this planet, there's a counter-trend. We all know of them, but nevertheless -- the Arabs say, "The dogs may bark, but the caravan moves on." And, indeed, that caravan is moving on. Women are moving back into the job market. And I say back into the job market, because this is not new. For millions of years, on the grasslands of Africa, women commuted to work to gather their vegetables. They came home with 60 to 80 percent of the evening meal. The double income family was the standard. And women were regarded as just as economically, socially and sexually powerful as men. In short, we're really moving forward to the past.
Then, women's worst invention was the plow. With the beginning of plow agriculture, men's roles became extremely powerful. Women lost their ancient jobs as collectors, but then with the industrial revolution and the post-industrial revolution they're moving back into the job market. In short, they are acquiring the status that they had a million years ago, 10,000 years ago, 100,000 years ago. We are seeing now one of the most remarkable traditions in the history of the human animal. And it's going to have an impact.
I generally give a whole lecture on the impact of women on the business community. I'll only just say a couple of things, and then go on to sex and love. There's a lot of gender differences; anybody who thinks men and women are alike simply never had a boy and a girl child. I don't know why it is that they want to think that men and women are alike.
There's much we have in common, but there's a whole lot that we do not have in common. We are -- in the words of Ted Hughes, "I think that we were built to be -- we're like two feet. We need each other to get ahead." But we did not evolve to have the same brain.
And we're finding more and more and more gender differences in the brain. I'll only just use a couple and then move on to sex and love. One of them is women's verbal ability. Women can talk.