As a motivator of human behavior, social status is nearly as fundamental as sex and death. But unlike your ability to procreate or to stay alive, your social status can be given to you only by others. You’re only truly at the top of the social hierarchy if everyone else wants to be where you are. High status is what’s called a “positional good,’’ meaning its value is determined, at least in part, by how badly other people want it.

Jewels of all kinds are also positional goods — valuable only because we all agree that they are — which is why they’re so useful as signifiers of social status. This messy mix of human desire, perception, and value is key to understanding the outsized role jewels have played in history, argues Aja Raden in her new book, “Stoned: Jewelry, Obsession, and How Desire Shapes the World.’’

Raden, a professional jeweler and amateur historian, focuses on historical specifics, like how the company De Beers built a near monopoly on diamond mining in South Africa by the early 20th century or how the Spanish Empire rose to world dominance around the turn of the 16th century due to a huge influx of plunder from the Americas. But she also shows how jewels are a bridge between world history and everyday human psychology.

Raden spoke with Ideas by phone from Santa Barbara, Calif. Below is an edited excerpt.

IDEAS: Where do we get our jewelry obsession?

RADEN: Beauty has a very powerful effect on the human brain. And scarcity has an even more powerful effect, no matter what the item is that’s perceived to be scarce. When you think other people are getting something and you might not, your brain really freaks out. So the jewelry industry was poised to exist from the day human beings stood up and started acting like human beings.

IDEAS: What about the connection between jewels and royalty?

RADEN: They have always been used as a signifier of power and wealth in different times and places. There’s an emerald crown that has been found — Neolithic. A caveman crown. It’s made out of resin and bone and wood. It’s as caveman-like as you would expect, except it’s got emeralds in it. Because people have always felt the way they feel about jewels.

IDEAS: Just before the French Revolution, Marie Antoinette was tainted by a scandalous story involving one of the most expensive pieces of jewelry ever made. But Elizabeth I of England’s intimate connection to pearls helped her hold onto power for decades. Why the difference?

RADEN: Those stories go very much hand-in-hand. Marie Antoinette did it all wrong. Jewels are nothing if not symbols. They’re symbols, they’re signifiers, they’re ways we gauge each other’s worth. She let people associate her with the nasty side of it, whereas Elizabeth very consciously and deliberately chose jewels that were associated with purity and virginity and royalty. As politicians say today, she was “on message.’’ And it got to a point so intense it became iconography. In every painting of her there were rules. She had to have the white face, she had to have this many pearls, and she created almost a pseudo-religious political cult. And she did it very subtly.

IDEAS: In the years after Christopher Columbus’s voyage, Spain began colonizing South America and took control of very productive emerald mines there. Then what happened?

RADEN: They started mining half a million carats at a time and shipping them back to Spain. And for a minute, Spain was rolling in it. The problem was they spent the money faster than it could show up, physically. At that point everyone in Europe knew Spain had stepped in it. Yet they were willing to grant them credit on this international scale. They issued the first interest-bearing government treasury bonds that basically promised a return on loaned money with the backing of these treasure ships from the Americas. And everyone had faith that they would just keep coming. And that was the beginning of our modern economy.

But it never occurred to them that the money itself would become worthless. And it did, because the money was jewels and they oversaturated the market. And when money itself becomes worthless, it causes crippling inflation. It causes massive depressions, and Spain’s economy imploded.

IDEAS: Japan also found itself drowning in jewels in the early 20th century when Kokichi Mikimoto finally figured out how to grow, or culture, pearls on a mass scale.

RADEN: That was a massive, historic scientific achievement in and of itself, but it also gave Japan its first and only domestically grown product for export. They were the sole exporter of millions of perfect pearls. Suddenly they had a seat at the table, they had money, they had respectability. Although, it didn’t go over well with pearl dealers in the West. The problem with his pearls is, if there’s an unending supply, are they still valuable? And the pearl dealers of the rest of the world were afraid he would flood the market with millions of pearls and just gut the economy of that particular precious good, by making it not scarce.

IDEAS: But pearls are still valuable. How did Mikimoto avoid flooding his own market?

RADEN: He engaged in a lot of publicity stunts to promote his pearls. My favorite was when he took tons of them and burned them in a bonfire in front of the Ministry of Commerce. He said they weren’t good enough — that perfection was attainable, but not if you cut corners, and these were flawed. And he just shoveled them into a barrel and burned them while people stood there gasping.

And then the other half of his publicity stunt was the Taisho-Ren. It took many, many years to assemble. And it was, at the time, the biggest, most perfect, most perfectly well-matched pearl necklace in the world. And it made those priceless wild pearls look a little bit shabby by comparison. And he sort of realigned people’s sense of perfection. It’s not a pearl that’s valuable, it’s a pearl that looks like this.

He also marketed them at a huge range. So pearls were no longer the purview of aristocracy and the extremely wealthy. Everyone could have them, they just could only have a certain size or they could only have a certain color, depending on what they could pay. If you go into a Mikimoto store now, they still have boards with strands of pearls showing you the gradient of perfection. And it’s a really interesting way to market it. It works incredibly well.

IDEAS: Talk about the rise of the engagement ring, because that seems to encapsulate a lot of these themes.

RADEN: We assume diamond engagement rings are this timeless tradition, but they’re not. Your grandparents may or may not have even had a diamond ring. And it started because about a hundred years before that, the diamond rush in South Africa began when a little boy tripped over a rock in a river and that rock was a huge diamond. At the same time, Cecil Rhodes, an intense imperialist, leveraged control over all of the plain in South Africa. In the end, he gained control of 90 percent of the diamond supply.

The diamond rush never stopped rushing. It keeps going to this day. And it occurred to the people at De Beers, the company founded by Rhodes, that they had spent decades gaining control over something that was no longer precious. Because what makes a gem precious tends to be its scarcity relative to the people who want it.

By the time World War II was over, there was no aristocracy. The whole landed gentry classes of Europe were missing or poor, and there was nobody to sell these diamonds to even if they pretended they were scarce. The only people who had disposable income in the ’40s and ’50s were this new emerging class of people, primarily in America, called the middle class. And they had as much money as the aristocracy of Europe, they just had it spread out over millions of people. So everybody could afford a diamond but only very tiny ones.

And so De Beers went to an advertising company and they said, “Help us sell these diamonds to the middle class.’’ Ernest Oppenheimer, the man who was in charge at that point of De Beers, asked if “propaganda in various forms’’ could be useful in selling their products. And it was. Together, they invented modern advertising. They invented market research. They invented consumer psychological testing. And in that way, over the course of the last 50 or 60 years, they’ve so thoroughly indoctrinated the populous with the notion that diamonds are the most valuable thing on the planet — diamonds mean love, diamonds mean forever, and most of all diamonds mean marriage — that people are hesitant to get engaged without one and they’ve even managed to spread it around the globe.

IDEAS: Could that kind of advertising work for everything or only because jewels are a positional good?

RADEN: A lot of things are sold that way and it’s not even intentional, but indoctrinating. We’re compelled to obtain that which we’re taught to value. And what De Beers did so brilliantly is they taught us to value these things which aren’t really worth much, and then we become socially compelled in this arms race to obtain them. We have to at least have one — just to show we’re in the right class. And then if our friends all have one, maybe two. We need a bigger one because that’s human nature.

Kelly O’Brien can be reached at kelly.obrien@globe.com.