This episode was brought to  you by Music for Scientists, now available wherever you stream music. [♩INTRO].

When most people think of archaeology, they imagine Indiana Jones-type digging in holes, looking for objects made by ancient communities. And that’s partly true.

But there’s another field where the archaeologists are the ones making the objects. It’s called experimental archaeology. Experimental archaeologists make  hypotheses about how people in the past crafted various artifacts or  performed incredible feats.

Then, researchers test those hypotheses  by attempting to recreate the methods. This can involve anything from  reconstructing Polynesian boats to brewing the beer Egyptian pharaohs drank. And by replicating these processes, researchers gain an understanding  of how advanced ancient people were.

They can actually feel what it  was like to live in the past. And they can even learn how  to improve our lives today by resurrecting long-forgotten technologies. Some of the most common things  experimental archaeologists recreate are stone tools.

And surprisingly, replicating these objects  doesn’t just reveal things about our ancestors’ handiwork, but also tells  us about their cognition and language. In 2010, experimental archaeologist Lyn Wadley explored ancient people’s cognition  by replicating hafted spears. Hafted weapons are made by attaching a stone blade to a wooden shaft using a sticky substance.

And they seem pretty simple,  until you make them from scratch. Wadley performed chemical analyses  to determine the exact materials people in Africa used to craft hafted  weapons around 70,000 years ago. Then, she had a go at it herself  and published the results in the journal Current Anthropology.

After collecting the materials, she used  a rock to carve other rocks into blades. This is called flint-knapping, or just knapping. And yes, using a stone to chip a rough  rock into a tool as sharp as a scalpel is exactly as hard as it sounds.

In her test, Wadley used one of the  blades to whittle a stick into a shaft. Next, she crushed rocks to make ochre,  which is a pigment made from rocks rich in iron oxide, the same compound  that makes rust, rust-colored. Then, she mixed the ochre with  beeswax and sap from an acacia tree and cooked it in a fire to make glue.

By the time she finished crafting the spears,. Wadley concluded that humans  from that time were capable of complex cognition, which involves  mental flexibility, abstract thinking, planning abilities, and more. Specifically, she proposed that people  had to engage in abstract thinking to imagine how to invent a  multi-ingredient adhesive.

They also needed to be mentally  flexible, because each batch of glue has to be prepared differently depending on, like, the stickiness of the  sap that particular day. And people were using planning  because they needed to wait up to six days for the glue to set. Plus, they must have developed advanced language to teach each other the skills.

And she isn’t the only  researcher who’s proposed this. In fact, many scientists suspect language  showed up in the first place because our ancestors needed to school each  other in the art of stone toolmaking. But it’s difficult to prove that because  talking, you know, doesn’t fossilize.

So, in 2017, experimental archaeologists  taught stone-knapping to newbies to determine how much communication  was necessary to learn the craft. They chose a type of knapping that was  invented around two million years ago. One group of newbies tried to learn  by observing expert flint-knappers and imitating them, with no language involved.

And the results... were kind of terrible. Another group of beginners  was taught with gestures. And they did pretty well.

But a third group was taught  with spoken communication. At first, they did as well as the gestural group. But in the second phase of the  experiment, only the speech group was able to remember the method  and perform it on their own.

This suggests that this kind communication  is the best way to help people retain the information they’ve learned. And while the researchers didn’t look at  this specifically, that’s likely true of signed languages as well, since they  convey the same amount of information. Either way, the researchers concluded  that language may well have emerged to teach people to skillfully bang rocks together.

Now, stone tools were some of the first things experimental archaeologists  recreated, starting in the 1800s. But experimental archaeology didn’t really  come into its own until the mid-1900s. And one of the things that launched it was a boat.

In 1947, a Norwegian  anthropologist named Thor Heyerdahl set out to prove a controversial hypothesis. He proposed that the Polynesian  Islands in the South Pacific were settled by South Americans  who drifted some 8000 kilometers across the ocean in wooden rafts. And to prove this was totally possible,  he and five other people went to Peru and built the Kon-Tiki, a  13-meter-long balsa wood raft based on explorers’ records of  ancient South American boats.

Then they set off, and 101 days later, successfully crashed into a reef on  the Tuamotu Islands in Polynesia. Except… it turned out  Heyerdahl’s hypothesis was wrong. In 2003, scientists used DNA  studies to show that South Americans didn’t actually settle Polynesia.

But the Kon-Tiki was still hugely significant,  in that it helped scientists reimagine what was possible to study  with experimental archaeology. And it paved the way for a  more successful experiment: the 1976 voyage of the Hōkūleʻa,  a replicated Polynesian canoe. This time, it wasn’t just a boat being recreated:.

It was a nearly forgotten navigation technique. At the time, the scientific community  was debating how people settled the Polynesian Triangle starting around 800 BCE. The Polynesian Triangle comprises more  than 1000 islands sprinkled around 25 million square kilometers of  ocean between Hawai’i, New Zealand, and Rapa Nui, or Easter Island.

Many scientists argued that  Polynesians accidentally found the various islands  by drifting with the wind. Others gave the Polynesians more  credit and believed they deliberately discovered islands using  finely-tuned navigation techniques. To settle the issue,  archaeologists, anthropologists, and historians designed a  Polynesian voyaging canoe.

They based it on canoe drawings from the 1700s and their best guess about what  earlier canoes looked like. Next, they found a master navigator  from Micronesia named Mau Piailug one of the few people left in  the world who was well-versed in ancient Polynesian wayfinding. Piailug and crew set off  from Hawai’i in the canoe, navigating by the sun, the stars, the clouds; the flight patterns of land-based birds; and the feel of the ocean  swells, which change direction as they bounce off distant  lands and blow with the winds.

After 34 days, they arrived  in Tahiti just as planned a journey of more than 4000 kilometers. And by succeeding, they demonstrated  that ancient Polynesians did have the sophisticated skills required to explore  and populate thousands of islands. And that’s one of the things  about experimental archaeology:.

It inspires a lot of respect for our  ancestors’ knowledge and expertise. That’s certainly the case when it comes to  historic people’s culinary talents, too. Because yes, experimental  archaeologists also bake bread, brew beer, and cook medieval meals.

Recreating long-forgotten food and drink  allows researchers to experience the same tastes, smells, and other sensations  that ancient people experienced. It can tell researchers  about ancient people’s diet, health, culture, and  knowledge of culinary science. Plus, it’s tasty.

Like, in 2019, an archaeologist, a physicist, and a microbiologist resurrected  4000-year-old Egyptian yeast. And they’re using it to bake bread and brew beer the way it was done in the time of the pharaohs. Which is incredible for so many reasons.

First: Yes, yeast can survive in a  hibernation-like state for thousands of years. And if you feed it the kind of grain  that it ate thousands of years ago, in this case, emmer wheat,  it will wake up and be like, “Hey, let’s make some bread.” Knowing this, the scientists got access  to Egyptian artifacts in a museum. Then, they took a specially-designed  syringe and suctioned up yeast from beer vessels, bread pots, and  a bread loaf that had been buried under a pharaoh’s tomb. Next, they began a series of experiments.

They brewed one beer using  yeast from a beer vessel, and another beer using yeast from the bread, because one question they’re  trying to answer is how much ancient Egyptians knew about the science of yeast. If the bread yeast and the beer  yeast are the same species of fungi, it might mean the Egyptians  were scraping the frothy yeast off of their beer and  kneading it into their dough. And that would suggest they knew  that the same mysterious something was making their bread rise  and their beer ferment.

Which doesn’t sound like a big deal  to us now, but would have been huge. Our current understanding of history  is that scientists didn’t know exactly what yeast was and what it did for  beer and alcohol until the mid-1800s. At the time we’re filming in 2021, it looks like the Egyptians actually  didn’t know that, because the two beers tasted very different.

But the upcoming DNA tests will tell us for sure. In the meantime, these scientists  are trying to fill in the gaps of the archaeological record,  because inconveniently, ancient Egyptians didn’t leave behind recipes. So the scientists are studying  chemical analyses of baked goods, plus drawings of bakers on a tomb wall.

And they’re conducting baking experiments  to figure out how ancient Egyptians nurtured their sourdough and  baked it in clay pots buried underground with a bunch of coals. Besides just being a good time, this  is also important to learn because bread and beer were central  to ancient Egyptian culture. In fact, the people who built the  pyramids were paid in bread and beer.

So, baking and tasting  4000-year-old bread gives us a feel for what it was like to be a pyramid  builder — without all the heavy lifting. Now as you’ve probably noticed, experimental archaeology can  be an immersive experience! And some experiences are  more immersive than others.

Like, when you build a Neolithic  farm and start living on it. A lot of experimental archaeology  takes place at archaeological museums, or open-air museums. These are places that have  replicated farms, houses, forts, or other structures from the past.

And the public can visit to learn  about life in various time periods. But these museums can also be  sites for scientific research, like at Lejre Historical-Archaeological  Experimental Center in Denmark. This place is famous for an extreme experiment.

Around the world, there are archaeological  sites where houses or villages have burnt down, maybe because of a cooking  accident or pyromaniac marauders. And these sites can be difficult to analyze. So in 1967, archaeologists at Lejre  filled a replica Iron Age long-house with pottery and other objects.

And then they set it on fire. 25 years later, other  archaeologists excavated the site. Crucially, they were not told what the  original house looked like or what was in it. The researchers then compared their  analysis of the charred remains to the original house to help archaeologists  better interpret scorched sites.

Overall, the researchers were really accurate. But they were shocked that  the 25-year-old burned house had deteriorated so much it  resembled a legit Iron Age house from more than 2000 years ago. They concluded that some  other archaeological sites might actually be burned dwellings  that have decayed beyond recognition!

In other experiments, archaeologists  are trying to replicate super-strong. Roman concrete and Bronze Age  insulation to learn how modern people can build more sustainable structures. Construction contractors  from Austria are even looking at archaeological experiments  to improve building materials.

Because really, experimental archaeology  is part science, part adventure, and part exploration, but  it’s not just about the past. It can also help us understand some  great skills and ideas from years gone by that might help us live better lives today. And it’s efforts like these that are  celebrated in the album Music for Scientists, a tribute to science and the  people who make it happen.

It was inspired by the beauty of science and of making our world,  and our past, more knowable. The album is also an homage  to the people of science. If you think you’d enjoy  listening to Music for Scientists, check out the link in the  description to get started. [♩OUTRO].