Abbreviated Science Round-up: An inherent bias against bias is still a bias
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I’m starting out this week by admitting one of my own biases … against bias. And how that can lead to bias. if that sounds confusing, it’s because it’s a difficult issue. Here’s the article that spawned it: Hominins arrived in China over two millAbbreviated Science Round-up: An inherent bias against bias is still a bias
I’m starting out this week by admitting one of my own biases … against bias. And how that can lead to bias. if that sounds confusing, it’s because it’s a difficult issue. Here’s the article that spawned it: Hominins arrived in China over two million years ago. A paper by a team from the Chinese Academy of Sciences reports the discovery of stone tools from a site called Shangchen in eastern China, dating back 2.1 million years. That’s an extraordinary number, as the oldest previously known human-line remains outside of Africa are a couple of teeth that date to around 1.8 million years. Pushing back the exodus of human relatives from Africa by 300,000 years doesn’t “upend” or “rewrite” human evolution by any means—no matter how many media reports this week implied that it does. However, it could call for a reordering of the sequence of events when it comes to the dispersal of various human ancestors, and touch on again the idea that some groups of humans have ancestors who developed parallel to modern humans outside of Africa. The findings in this case are a set of stone tools — flaked flint, flint cores, and simple scrapers — that show evidence of being “worked.” There are also animal bones in the location that may indicate butchering activity. There are no human bones. And here’s my issue with this. I’m very reluctant to believe this article because of two things. Let’s call them “rocks” and “geography.” Rocks: In theory, worked stone tools should be a very handy indicator of human presence. Departing a little bit (but only a little bit) from the topic, the reason there are so many fossils of trilobites in ancient rocks isn’t just because trilobites were so abundant (though they were), but because they, like arthropods today, molted their hard outer shell multiple times as they grew. So a single trilobite could potentially leave behind many fossils. Humans, inconveniently for paleoanthropologists, don’t do that. We have just one skeleton to leave behind. So when human populations are small, there may not be many bones to go around. Which is why several human occupation sites in Asia and elsewhere are marked by only a bone here, a tooth there. On the other hand, one human could make a lot of stone tools. So tools should be easier to find than bones. Stone tools are the cast off trilobite shells of human fossils! Only … it’s not that easy. Because while it’s easy to identify an exquisitely made fluted arrowhead, or grooved ax, or a distinct Clovis spearpoint, that’s not what we are talking about here. These are rocks whose “working” amounts to not much more than being smacked around a bit. It is very easy to mistake a naturally broken rock for something man, or near-man, made. That’s especially true when it’s being examined by folks who really, really want to find something. And it’s why the history of anthropology and archaeology is replete with “artifacts” that, on close examination … aren’t. So the fact that Shangchen has rocks, but no human bones, no definite proof of deliberate fires, and no clear evidence of butchering … makes me a doubter. Geography: And now we come to the one where my own bias-bias gets in the way. Whenever anthropologists start suggesting something that might, even with a few twists and turns, lead to the idea that some groups of humans evolved, or at least partially evolved, in Asia, it fires off my auto-dander-up response. That’s because, at least as far back as Darwin suggesting that most apes today are found in Africa and it was very likely that humans also evolved in Africa, people have been suggesting that some groups didn’t originate in that “dark continent.” Instead, they’ve searched for ways to suggest that some groups evolved in Asia. Perhaps groups that eventually became part of a proto-Indian-Iranian migrant group also known as Aryans. In short, I look at every article indicating greater early human presence in Asia as a possible foot-in-the-door to an argument that some groups of humans evolved separately from others. Because “separately from” is a short hop to “better than.” And that’s where my own prejudice gets tangled in this thing. Because … maybe these guys are right. Maybe early hominins were prowling around China, hacking up the local pig population, hundreds of thousands of years earlier than expected. Maybe my own prejudices against prejudice is making me prejudice. Honestly, I hate to think that my own feelings about a matter of science are being swayed because there’s an outcome I want to see. After all, isn’t that exactly what I’m accusing the always-hunting-Aryan group of doing? However, I promise that I will eagerly dive into the possible consequences of this dating. But first … they’re going to need better rocks. Or a single tooth. That’s not a lot to ask. Read more