It's Friday, and here's the latest video from Science Friday:
Science Friday
Courtesy Science Friday
In perhaps the cutest study published in the Proceedings of the National Academy of Sciences, psychologist Marcel Zentner and Tuomas Eerola found that babies will spontaneously boogie when they hear music and other rhythmic sounds. The findings suggest babies are not great dancers, but they smile more when they do hit the beat.
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For the woman in the middle, the other two are numbers 151 and 152: Even on Facebook.
Courtesy Brother O'MaraOooh, Facebook. You’re like a little invisible community of invisible robot people. You let us know what our worst enemies are up to these days, what our cousins look like when drunk, and who really identifies with Rihanna’s “Umbrella.” (No, like, really. When the sun shines, we’ll shine together, you know?)
And, of course, you’re turning out to be a fun sociological laboratory.
Remember a year and a half ago when you found out that you were a narcissist for having so many Facebook friends? And you were all, “Whatever. That guy I high-fived in the hotel lobby and I are besties, and he’s a vital friend, and so adding him to my friends list doesn’t mean that I’m just trying to accumulate meaningless social capital by presenting to the world how many people are interested in me in some way.”
And I was all, “Yeah, ok, you’re right.” Because your feelings, even if you are a narcissist, are very important to me, and I didn’t want you to be a sad narcissist.
But you know what else is important to me? Being right. And also science. So check this out: All but 150 of your Facebook friendships are… meaningless!
Say what?! My friendship with the Argentinean with a very similar name to mine is meaningless?
Yes, I’m afraid so. If you’re being honest with yourself, you and Juan Gordon aren’t actually that close.
Guess who's under the limit: Me. But it's only because I'm not friendly. Ever.
Courtesy JGordon
See, evolutionary anthropologists have found out that humans can keep track of about 150 relationships. And that number is nothing to sneeze at; 150 is a lot of relationships, perhaps the most of any animal.
As the new PBS series, The Human Spark, points out, brain size (at least in primates) seems to relate to the number of individuals an animal can keep track of. Chimps, with fairly large brains, can keep track of about 50 individuals. Humans have brains about three times the size of a chimp’s brain, and we can keep track of about three times that number of individuals. It’s part of why we can live in huge cities, and all that. (Read more about it and see clips from The Human Spark at Science Buzz’s Human Spark page.)
And that seems to be the rule: we can have meaningful relationships with only about 150 people. (I don’t mean meaningful in the “we tell each other secrets under the blankets” way, but rather in the “something that can be called a ‘relationship’ in anything by the most inclusive sense of the word” way.)
So what about those other 527 Facebook friends you have? Are they just chopped liver? Yeah, pretty much. Evolutionary anthropologists at Oxford University wanted to see if the 150 relationships rule remained true in online communities, where people seem to have much, much larger networks of “friends,” so they compared the actions of Facebook users with thousands of friends to those with hundreds of friends (or less.) The anthropologists found that there was no difference between the groups’ number of interactions on Facebook. That is, people with thousands of friends didn’t interact with or follow the actions of any more users than people with a couple hundred friends did. Just like in real life, you can have meaningful relationships with only so many people, and the rest are just there to (maybe) make you look cooler.
What do you think? Did you and your giant friend list just get sonned by anthropology, or do you think you and your 2000 friends are proving that online communities and relationships don’t follow the limits of biological evolution? (Because, of course, when the sun shines we—all 2000 of us—shine together.)
How does food matter to human evolution? We could ask this guy?
Courtesy Lord JimWhat makes human beings so special? How did we evolve into an agriculture-developing, city-building, history-making, world-changing species that can live on every continent and even in outer space?
Scientists have been asking questions about our evolutionary trajectory and human "uniqueness" for as long as there's been science - and guess what? We still don't know the answer! Some of our best theories are explored by anthropologists in the PBS television series The Human Spark, airing throughout the month and also online at the PBS website. If you're curious, you might want to watch, but don't do it on an empty stomach! Many of the theories that anthropologists have developed to explain how we became human involve food.
That food and evolution would go hand in hand is not really surprising, since food is necessary to survival and an important and dynamic part of our environment. Did a search for nutritious plants and animals lead our ancestors to new environments, causing our species to adapt and change? Did hunting and eating meat mean the evolution of new physical characteristics? How has agriculture changed our environment and species over time? How will present and future foods change what it means to be human in the future?
Some evolutionary theories involving food look not just at what we ate, but how we ate it - namely the invention of fire and the use of heat to cook food. Think about it: our Hominid ancestors needed calories in order to develop into the big-brained humans we all know and love. How did they do it? And what did this mean for human evolution?
Sure, eating meat was an important dietary step, but cooking root vegetables can transform hard-to-chew or even poisonous plant parts into nutritious food that can be consumed out of season. With cooking, environments that would otherwise provide few nutritious options suddenly become bountiful. This change in diet may also have led to changes in body size and shape - even social structures! Large teeth and jaws were less desirable once food could be more easily chewed, and delaying the gratification of food until it could be cooked may also have meant that our species had to develop new social skills.
Those social skills - the same ones that mean you and I can now share a burger or beer without fighting each other for scraps - may be one of many "sparks" that makes us human.
If you live in the Twin Cities, you can meet an anthropologist and here how he thinks food impacted human evolution by attending tonight's Cafe Scientifique program in Minneapolis.
After some three and a half billion years of life’s evolution on this planet – and after almost two million years since people recognizable as human first walked its surface – a new human burst upon the scene, apparently unannounced.
It was us.
Until then our ancestors had shared the planet with other human species. But soon there was only us, possessors of something that gave us unprecedented power over our environment and everything else alive. That something was – is – the Human Spark.
What is the nature of human uniqueness? Where did the Human Spark ignite, and when? And perhaps most tantalizingly, why?
In a three-part series to be broadcast on PBS in 2010, Alan Alda takes these questions personally, visiting with dozens of scientists on three continents, and participating directly in many experiments – including the detailed examination of his own brain.
"The Human Spark"
Twin Cities area show dates and times:
- Wednesday, January 6, 7:00 pm, on 2
- Thursday, January 7, 1:00 am, on 2
- Thursday, January 7, 3:00 pm, on LIFE
- Wednesday, January 13, 7:00 pm, on 2
- Thursday, January 14, 1:00 am, on 2
- Thursday, January 14, 3:00 pm, on LIFE
- Wednesday, January 20, 7:00 pm, on 2
- Thursday, January 21, 1:00 am, on 2
- Thursday, January 21, 3:00 pm, on LIFE
- Sunday, January 24, 1:00 pm, on 2
- Sunday, January 24, 2:00 pm, on 2
- Sunday, January 24, 3:00 pm, on 2
"Our Origins: Exploring the Human Spark"
Twin Cities area show dates and times:
- Sunday, January 24, 4:00 pm, on 2
- Sunday, January 24, 8:00 pm, on MN
- Sunday, January 31, 12:00 pm, on LIFE
Help this little boy find his parents: Sorry. I couldn't find any pictures from Encino Man.
Courtesy coteIt’s a weird suggestion, I know, because you probably give a lot of thought to whom the various cavemen had sex with anyway, regardless of the weather. But give it a little extra thought today. Because it’s nice out, and the dark corners of your brain could use the sunlight.
So, you guys all know that we aren’t the only human species ever to exist, right? The human family tree had other branches before it got to us (take a look at our Human Spark feature for more on that), and there were times when more than one species lived in the same area, and—in all probability—had interactions with each other. Neanderthals, for instance, lived alongside modern humans for many thousands of years in ice age Europe. Keep in mind, “Neanderthal” isn’t just a synonym for “cave-man.” Neanderthals were a distinct species—they had heavier, longer skulls, and thick, strong bodies. The modern humans of ice age Europe would have looked, more or less, like us. And because the two species were living in the same area for so long, it seems pretty likely that they interacted. But did those interactions include, you know, dinner, dancing, and romantic music?
Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Germany says yes, for sure they were having sex.
On one hand, these are sort of fightin’ words. People have suggested that Neanderthals faded into extinction as they interbred with modern humans, but when human DNA was compared with a sequence of Neanderthal DNA, it didn’t look like there was any overlap. That is, if there was any interbreeding, the Neanderthal contributions to our genes have been so diluted with human genes that it doesn’t appear that we have any Neanderthals in our family at all.
On the other hand… Well… I mean… People do all sorts of stuff… We all just want someone to love, right? Or, you know, just think of what a puppy will do to a piece of furniture. And humans and Neanderthals are a lot more similar to each other than puppies and ottomans. Too much? I don’t think so. Look at ligers. Or tigons. Or mules. Similar animals interbreed all the time, but very often they have infertile offspring. And that would explain why we don’t see any Neanderthal genes around today—everybody could have been doing it like it was 2012, but if the offspring couldn’t reproduce it wouldn’t matter to future generations.
Another factor that could explain the lack of genetic overlap (despite Paabo’s certainty of caveman/Neanderthal sexiness) is that our Neanderthal DNA sample just isn’t good enough. Mitochondrial DNA from Neanderthals doesn’t show up in modern humans, and while that’s an incredibly valuable genetic marker, it only makes up a tiny fraction of an organism’s total DNA. The Neanderthal genome hasn’t been completely sequenced yet, and that’s what Paabo means to do. Once we can fully compare the genomes, we can see if the two species became at all mixed.
Because they were definitely doing it.
What makes humans unique? Do we have characteristics that make us different from other animals? PBS will be broadcasting a three-part series on the topic this fall. In advance of the series premiere, the producers want you to tell them why humans are special. You can submit a photo, a video, or text. Some entries will appear on screen, so make a grab for your 15 seconds of fame, and send in your ideas.
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