Hank Green: There are a lot of things that I don't understand about the species Homo sapiens, what makes us us? What makes us move the way we do, think the way we do, and kill the way we do? I'm Hank Green, and this week on SciShow News, I give you a little bit of insight into human nature. [SciShow Intro plays] Now, there are other species that also kill each other, but new research suggests that one kind of violence that may seem uniquely human--war--is not a fundamental part of our nature. Anthropologists in Finland reached this conclusion in the journal Science, published on Thursday. The most basic form of human society, they say, is a group of mobile foragers, mostly egalitarian bands of people that subsist on wild plants and animals. They live nomadically and flexibly, making new rules and rejecting centralized power in leadership. Sounds like some kind of anarchist's daydream, but that's the way that we humans organized ourselves through the vast majority of our existence, and some forager bands still flourish in parts of the world today. So the anthropologists used those groups to examine the motivations behind human violence. They randomly chose 135 descriptions of lethal aggression from ethnographic studies of such bands, examining and categorizing the motives behind the deadly acts. The found that about 2/3 of the killings were motivated by specific personal conflicts, having nothing to do with the dynamics of larger groups, and 85% of the violence was between people of the same ethnicity, within and not between ethnic groups. So the researchers conclude that while war and ethnic violence between groups is obviously prevalent today, in humanity's most basic form, it appears to be quite rare. Now, of course, they're not saying that racism and group conflict doesn't exist, just that they're not necessarily human nature, and this is exactly in line with most mammalian behavior. In many mammal species, aggression has been observed between individuals, for individual reasons, and the anthropologists claim no other mammal engages in warfare, except, of course, for Ewoks. Also proving that we're not alone in what makes us who we are, biologists at Aarhus University in Denmark showed that chimps and orangutans have long term memory. The study, published in the journal 'Current Biology' on Thursday shows how ten apes were able to remember the location of tools they saw being hidden three years earlier. The apes observed the tools being hidden in different spots, and then had a chance to retrieve and use them a few times. Three years later, facing the same tasks, all of the apes quickly found the tools again, while a control group of ten apes that had never seen the tools weren't able to. In a similar experiment, 9/10 apes were able to remember the location of tools they'd seen only once two weeks earlier, but none of the ten control apes were able to find them. This suggests not only that humans aren't alone in having long-term memory, but also, that it appeared early in our evolutionary history, much earlier than we thought. Finally, while some scientists have been trying to figure out what makes us think like humans, other scientists are trying to figure out what makes us move like humans. If you haven't had your mind blown by this yet, allow me to introduce you to Atlas, a humanoid robot brought to you by the U.S. Department of Defense. A company called Boston Dynamics just unveiled this prototype. It was commissioned by the Pentagon's Defense and Research Projects Agency, or DARPA. And I know what you're all thinking, SkyNet is finally here, it's happening, we will be killed by the machines, well thus far at least, Atlas was not made to ice Sarah Connor, it is intended to be used for disaster response, equipped with sensors and joints and limbs that imitate human function, it's designed to work just like a human, drive vehicles, use tools, walk through terrain to test unstable environments before we do. And it also does a lot of stuff we can't, like smash through walls and enter radioactive zones. Of course, Atlas will not be capable of going rogue. When it's put to use in a few years, it'll be controlled by human operators, which I guess means it can only be as imperfect as we are. Thank you for watching SciShow News, if you have an idea for a topic you'd like us to cover or a question or a comment, leave it in the comments below and don't forget to follow us on Facebook and Twitter, and of course, if you want to keep up to date on all the latest breaking science news, you can go to YouTube.com/SciShow and subscribe. [SciShow endscreen plays]