The Great Depression of the 1930s saw more American unmarried women working from nine to five, mostly in repetitive, boring, subordinate, dead-end jobs. But the number of working women doubled between 1870 and 1940. During World War II it doubled once again.

Women have a better sense of smell than men do, and it's even sharper in the middle of their menstrual cycle, when estrogen levels peak and women are more likely to be deciding whether a man's attractive.

People have been looking for love potions since hunter-gatherer societies.

There were real reasons that you were attracted to somebody originally. The brain doesn't pick willy-nilly. Unless you part ways hating each other for some reason, that mechanism could get triggered again. You can literally fall in love again.

Falling in love was not really a choice; it just struck me.

We evolved in a tropical climate where the smells of plants and flowers were all around us. We spent a lot of time in the trees with a lot of sunlight and no clothes.

There's magic to love... Millions of years ago we evolved three basic drives: the sex love, romantic love, and attachment to a long-term partner. These circuits are deeply embedded in the human brian. They're going to survive as long as our species survive on what Shakespeare called, this "mortal coil."