Origins of Behaviorally Modern Humans
Since 2010, our understanding of the origins of Anatomically Modern Humans (AMH) has gotten much clearer. But anatomically modern humans were not necessarily behaviorally modern. Contemporary people use symbolism and art in their daily lives. But most evidence of art (cave paintings, figurines, carved tools, etc.) dates to no more than 40,000 years ago. Most (although not all) of this modern behavior is associated with Anatomically Modern Humans. But the dates make it clear that Anatomically Modern Humans were around for 160,000 years, at least, before they commonly created art and symbolism. Additionally, other groups of Middle Pleistocene Humans, such as Neandertals, created art and symbolism, but only occasionally. Why?
What do anthropologists mean by "modern behavior" anyway?
Symbolism is a critical part of your life. You're using symbolism right now, because the written language requires visual symbols to represent sounds. But symbolism is so much deeper and broader than that. Think about walking into a party where you don't know anyone. How do you decide who to talk to? How do others decide whether to approach you? The clothes we wear, the way we do our hair, our make-up or tattoos, our body language, our accent, all of these are part of our performance of identity. We tell people about ourselves - and we learn about others - through these symbols. We may not realize these are symbolic actions or items, but if we spend time in a different culture, we may be surprised to find that we can't "read" the identity performance of others, or that we misinterpret the symbols. This can include everything from an "a-ok" hand signal (considered a rude sexual gesture in some cultures), to not recognizing typical gendered clothing, to misreading a common phrase (for example, when someone from the South says "Bless your heart", they're really saying "Aren't you an idiot?").
As I sit typing this, some of the symbols I am using include: earrings, skirt, long hair, and colors that are part of my gender performance; a wedding ring to signal that I'm married; a deliberate choice of clothes for both comfort and for my particular job/status. I can't come to class in pajamas, for example, but not because they wouldn't cover my body or keep me warm, but rather because they don't use our cultural symbolism of "professor", "teacher", or "authority figure". Similarly, I can't come to class in spandex tiger-striped leggings, a halter top, and bleach-blonde teased-up hair (sorry for the visual), not because, again, these clothes wouldn't cover my body or keep me warm, but because these clothes don't use our cultural symbols related to "intelligence" or "expert/scholar". Would I be any less a professor, or any less intelligent, if I came to work in those clothes? Of course not, but my performance of identity would be interpreted very differently by people who didn't know me.
This brings up the main question about symbolism and art: It's not why do we engage in symbolism, but rather whom do we engage in symbolism for?(1) The short answer is: people we don't know. I would have no reason to send signals about my gender, my marital status, my religion, my education, or my ethnicity to someone who already knows me well. All of my friends and family members know I'm female, married, Catholic, a PhD, and Euro-American. When I signal these aspects of my identity, I do so to those who don't know. This allows us a simple, cognitive short-cut for categorizing people, and helps us to frame our interactions without having to grill them on their personal identity.
Where do we first see modern behavior, and who engaged in it?
As I mentioned above, the vast majority of symbolic and artistic behavior occurs from 40,000 years ago up to the present day. Since most of the humans alive during that time frame were Anatomically Modern Humans, anthropologists used to assume that only Anatomically Modern Humans were capable of modern behavior. We now know, however, that modern behaviors occurred sporadically before 40,000 years ago, and that those modern behaviors can be associated with any population of Middle Pleistocene Humans, not just those with chins.
Examples of early (pre-40kya) modern behavior:
Pinnacle Point, 165,000 years ago, South Africa: This site has the earliest evidence for the use of pigment (drawing on skin or clothing). Archaeologists also found a large number of fish and shellfish remains at the site. This site is associated with Anatomically Modern Humans.
Katanda, 80,000 years ago, Democratic Republic of the Congo: The "art" from this site is in the form of beautifully carved bone harpoons for fishing. Archaeologists found numerous fish bones at the site. This site is associated with Anatomically Modern Humans.
Blombos Cave, 77,000 years ago, South Africa: This cave includes one of the earliest pieces of art (OK, it's not much to write home about, but still...). The site was also full of fish bones and shellfish, including indications that the people there had eaten deep water fish. This site is associated with Anatomically Modern Humans.
La Chapelle-aux-Saints, 50,000 years ago, France: This cave site is one of the earliest confirmed burials of the dead. At least one individual was deliberately laid in a grave that had been specially prepared for the body. We cannot know the exact religious beliefs of Middle Pleistocene Humans, but this burial shows a symbolic honoring of the dead, and potentially a belief in the afterlife. This burial was of (and by) a Neandertal.
Saint Césaire, 45,000 years ago, France: During the period of contact between Anatomically Modern Humans and Neandertals, the Neandertals produced a unique set of cultural artifacts, including advanced stone tools and jewelry of bone. This set of items is called the Châtelperronian, and the site of Saint Césaire is one of the places where it has been well studied. This site is associated with Neandertals.
Gorham's Cave, 30,000 years ago, Gibraltar: A carving at the back of the cave is about as "artistic" as the one in Blombos, but nonetheless signifies symbolic behavior. The site is also full of fish, bird, and shellfish remains. This site is associated with Neandertals.
Why there? Why then?
All the Middle Pleistocene Human populations were capable of symbolic behaviors, not just Anatomically Modern Humans. However, before 40,000 years ago, they very seldom engaged in symbolic behaviors, even Anatomically Modern Humans. So why did modern behavior become common 40,000 years ago, and when we do find it earlier, why?
The answer is related to the question I asked above: For whom do we symbolize?(4) For most of human evolution, our ancestors lived in small groups, with probably only 30-50 people. Neighboring groups would occasionally come into contact, and people would move between groups, but generally any one individual only met a couple hundred people in their lifetime. Such small numbers made it easy to know everyone. Symbolism and identity performance weren't necessary under those circumstances.
But after 40,000 years ago, populations grew larger. And even before 40,000 years ago, there were certain places where, for whatever reason, local populations were larger. With higher population densities came symbolism, ways of signaling identity and group membership, to help oneself and others navigate an increasingly complex social context. So it appears that the capacity for "modern" behavior was there all along (or at least in all Middle Pleistocene Humans), but it came out only when needed, in the context of high population densities.
You may have noticed a patterns in the list of sites above, the tendency for early examples of symbolic behavior to be associated with fishing, shellfishing, and the hunting of other small or non-terrestrial animals (like birds). This supports the idea that modern behavior is a response to high population density. We originally adapted to be large game hunters. Remember that Erectines developed the ability to efficiently run long distances in hot weather, exhausting their prey. This is why the majority of Middle Pleistocene sites are full of the bones of large, terrestrial animals. But our fundamental running adaptation is useless if we're hunting fish. (Don't try to outrun a fish, it wastes your time and annoys the fish.) So why would a few Middle Pleistocene people go after these resources? Because they didn't have enough large, terrestrial game to feed everyone.
We can see, both in modern hunters and gatherers, and in ancient ones, that most communities focus on large, terrestrial game, if it's available. But if the community is too large, or if the number of large animals is too small, then they will turn to prey that is more difficult to catch, that requires specialized tools (like harpoons or nets), or specialized techniques. The association of symbolic behavior with fishing suggests that those communities were too large to live off of big terrestrial animals alone.
Nobody who has been to a city would doubt that our human ability to live in large groups is an important part of our adaptation. We can live in much larger communities than any other ape. In many ways, this is the true "modern" behavior.
Footnotes:
(1) Another quick note about symbolism: Technically, it's incorrect to end a sentence in a proposition. But why? Does doing so make it harder for you to understand the sentence? No. Avoiding a proposition ending ("For whom do we engage in symbolism?") has nothing to do with comprehension, and everything to do with signaling to your audience that you're so highly educated that you can follow a bunch of esoteric and unnecessary rules largely derived from Latin and inappropriately applied to a Germanic language in the 17th and 18th centuries. Ignoring that rule (as I did above) signals that I am even more highly educated, so I know when to break the rule to better preserve the sense of the sentence. See, ain't symbolism fun?(2)
(2) Notice the use of "ain't" in that sentence, which itself is a no-no according to grammatical rules. What do you think the use of "ain't" symbolizes?(3)
(3) I could keep doing this all day...
(4) See what I did there?