Tag Archives: evolution of intelligence

Where is everybody? Maybe we’re (some of) the first.

A followup to yesterday’s post on the Fermi Paradox, some reasons the Universe could have been less suitable for the evolution of complex life until recently, making us one of the first intelligent species to evolve.

1) Metallicity. Chemical elements heavier than helium are formed inside stars, after the Big Bang. Elements heavier than iron are formed in exploding supernovas. These elements have been building up over time. Maybe they had to reach a threshold abundance to make complex life possible.

On its own, it’s not clear this would have prevented intelligent life from arising long ago. The Sun has a high “metallicity” (concentration of heavy elements), but there are stars in the Milky Way older than the Sun with higher metallicities. But metallicity could combine with GRBs (below): toward the center of the galaxy there are more heavy elements but also more GRBs.

2) Gamma Ray Bursts (GRBs). GRBs are bursts of gamma rays (high frequency radiation) lasting from milliseconds to minutes, like GRB 080319B. (Check out tweets for January 11.) They are probably supernovas or even larger explosions with one pole of the exploding star pointed at the Earth. A major GRB could irradiate one side of the planet, and also affect the other side by destroying the ozone layer, causing mass extinctions. GRBs may have swept the Milky Way frequently in the past. The good news is they’re probably getting less frequent. This could be the first time in the history of the Milky Way that enough time has passed without a major GRB for intelligent life to evolve. If true, we should think about how to protect ourselves from the next one – lots of sunblock recommended.

If GRBs are such a threat, we might expect to find evidence that they have caused mass extinctions in the past (not wiping out all life obviously). For more on this, check out upcoming blog posts and tweets for the end-Ordovician, March 3.

3) Panspermia (life from elsewhere). Pretty much as soon as Earth could support life, we see evidence of single-celled organisms. Then life evolves slowly for a long time. The usual story about this is that the origin of life is easy, and it happens as soon as possible. But there is another possibility (illustrated below). It may be that the transition from simple replicating chemical systems to bacteria with genomes of tens of thousands of DNA base pairs is a slow process that happened over many billions of years somewhere off Earth. Then newly forming planets in the nebula that gave rise to Earth were “infected” by this source, by meteorites carrying early cells. (It would have been easier for meteorites to carry life from star system to star system when the Earth was first formed than it would be today.) Back when our hypothetical “Urth” was forming, a billion years before Earth, there might not have been any planets with cellular life on them as potential sources of life-bearing meteorites.

Untitled

Where is everybody?

Today, January 16, covers the period 5.62 to 5.31 billion years ago in Logarithmic History, beginning a billion years before the origin of our solar system. Back then, stars were forming at a fast clip in the Milky Way and other spiral galaxies. So let’s suppose… Suppose one of those older stars resembled the Sun, and had a planet like Earth orbiting around it – call it Urth. And suppose life originated on Urth more or less as on Earth and followed more or less the same evolutionary path. With this head start, intelligent life could have evolved a billion years ago, and today there could be intelligent Urthians (or their robot descendants) a billion years ahead of us.

There’s an urban legend that says that Einstein called compound interest the strongest force in the universe. Einstein didn’t actually quite say this, but it’s not a crazy thing to say. For example, consider how compound interest works, backward, on our Logarithmic History calendar. December 30 covers a period 5.46% longer than December 31, December 29 is 11.1% longer (because 1.0546 * 1.0546 = 1.112), and so on. At this rate of compounding we wind up with January 1 covering 754 million years. The same math implies that if we invested 1 dollar at 5.46% interest, compounded annually, then after 364 years we’d have 754 million dollars.

With even the slightest compound rate of increase, a billion year old Elder Race would have plenty of time to fill up a galaxy, and undertake huge projects like dismantling planets to capture more of their suns’ energy. Which raises the question, posed by Enrico Fermi in 1950: “Where is everybody?” There are more than 100 billion stars in our galaxies, more than 100 billion galaxies in the visible universe (actually, according to recent estimates, the number may be more than  1 trillion). If there are huge numbers of billion year old Elder Races around, why hasn’t at least one of them taken the exponential road and made themselves conspicuous?

There’s a large literature on the Fermi paradox. Here I consider just one sort of explanation. Maybe we’re one of the first intelligent species to evolve because the universe was somehow less suitable for the evolution of complex life before now. (To be continued).

Learn This One Weird Trick (Part Two)

… that humans use, and now you can too! (Continued from the previous post.)

recursion 3) Recursion. What if you have one mirror facing a second mirror, so the first mirror shows what’s in the second mirror, which shows what’s in the first mirror …? What if you take a chameleon, which tries to take on the color of its surroundings, and put it on a mirror? What if you point a video camera at the very screen that’s showing what the video camera is pointing at? What if (getting mathematical) you use a function in defining that same function? What if you use the cleaning attachment from your vacuum cleaner to suck dust off the vacuum cleaner itself? (Okay, the last one is a bit lame.) The basic idea in each of these cases is called recursion, which is a major concept in mathematics and computer science. Douglas Hofstadter’s Gödel, Escher, Bach is all about recursion. Some people think recursion – nesting ideas about ideas inside one another in a potentially infinite hierarchy, or (for syntax) phrases inside phrases — is central to human uniqueness. Noam Chomsky has lately been pushing a hard-core version of this argument. Here he is with Robert Berwick defending his view.

Related to the idea of recursion is the idea of “meta-representation”: not just having ideas about the world but having ideas about ideas, being able to put a box around a proposition, and then attaching a tag to it that says the equivalent of “This is true” or “This is false” or “This will be true later” or “Suppose this were true,” and then manipulating it accordingly. A nice little essay in “imagination,” elaborating this idea, is here from Simon Baron-Cohen, best known as an authority on autism.

4) Shared intentionality. Suppose you and I are friends with a couple, Fred and Wendy Smith. I tell you “I saw Wendy Smith kissing a man in the park yesterday.” Logically speaking, there’s nothing to say the man wasn’t Fred. But you’ll probably assume that I meant she was kissing someone other than Fred. Why? Well if the man had been Fred I could just as easily have said “I saw Wendy Smith kissing Fred in the park yesterday.” Since I didn’t say that, you assume I mean to convey the man wasn’t Fred. Note this only works if both of us try to pack as much relevant information into our sentences as possible and know the other person is doing the same. (If you think this sounds like recursion, you’re right.) Back in the 1950s, Paul Grice, a philosopher, worked out a lot of how we pack non-literal meanings into sentences. But the same principles are at work even when people are communicating non-linguistically. This leads to another theory of human uniqueness: human beings are uniquely good at developing shared intentions with one another: each party knows the other party is trying to communicate something, so they converge on the correct answer. People may have been doing this even before language evolved. Following up on this can quickly get you into game theory, where a central concept is “common knowledge”: not just “I know X” and “You know X,” but “I know X,” and “I know X is common knowledge,” and similarly for you. Here’s a philosophical treatment.

sclera But you can skip the philosophy if you want and move on to a telling little piece of anatomy that’s relevant here. In most mammals, including chimpanzees, the sclera (white of the eyes) is not visible. It’s hard to tell where a chimpanzee is looking, easy for a human. Human eyes make it easy to cooperate in sharing attention, a first step in developing shared intentions. If you know your card games, chimpanzees are playing poker, humans are playing bridge.

Our discussion of human uniqueness on Logarithmic History has been frustratingly short on specific dates. But human sclera are probably a fairly simple trait genetically, and we may soon enough discover the genes involved and even tell how long ago they mutated.

Learn This One Weird Trick … (Part One)

… that humans use, and now you can too!

There are people who think that human beings are nothing special. Sure (the argument goes) people have uniquely large brains. But all sorts of creatures have unique features. Elephants are the only animals with trunks. Tamarins and marmosets are the only primates that give birth to twins. Platypuses are the only venomous mammals. Spotted hyenas are the only mammals whose females sport pseudo-penises (through which they give birth!). And so on. If we could ask members of these species they’d claim that they’re the special ones.

But of course we can’t ask them, and in any case, this isn’t a very convincing argument. Human beings have an absolutely outsize impact on the Earth, and the advent of human beings looks like one of the major evolutionary transitions, comparable in importance to the origin of the eukaryotic cell or multicellular life. But even if we buy this, it still leaves open the question of whether there’s a key adaptation – a One Weird Trick – that accounts for the exceptional course of human evolution. Here are some candidates that being are being batted around these days:

1) The cognitive niche. The basic idea is at least as old as Aristotle, that human brings are defined by their capacity for Reason. A modern version of this is advocated by evolutionary psychologist John Tooby and cognitive scientist Steven Pinker. Pinker in particular has elaborated the argument that humans are uniquely adapted to acquire and share knowledge, by virtue of a suite of cognitive, social, and linguistic adaptations. We’ve already touched on several aspects of this: Human beings seem to have taken the capacity for thinking about physical space and retooled it for thinking about the abstract cognitive space of possession – a social relationship. (Other abstract cognitive spaces include kinship, time, and change-of-state.) And humans seem to harness the machinery for processing the sounds of interacting solid objects in creating major categories of phonemes. For a more complete exposition, here’s an academic article by Pinker, and a talk on youtube.

2) Culture. Rob Boyd and Pete Richerson, who’ve done a lot of mathematical modeling of cultural evolution, are skeptical about the “cognitive niche” argument. Too much culture, they argue, is things that have been learned by trial-and-error, and are passed on from one generation to the next without people understanding why they work. They appeal, as anthropologists have for generations, to the importance of culture. We mentioned earlier their argument that the frequency of climate change in the Ice Age was nicely calibrated to favor social learning rather than individual learning or instinct. Joseph Henrich provides a recent defense of the importance of culture. Contra Pinker, he thinks humans often don’t have a good cause-and-effect understanding of the things they do, but depend heavily on imitation and the accumulated wisdom of the elders.

Coming up: Part Two. Recursion and Shared Intentionality

Where is everybody? Maybe we’re (some of) the first.

A followup to yesterday’s post on the Fermi Paradox, some reasons the Universe could have been less suitable for the evolution of complex life until recently, making us one of the first intelligent species to evolve.

1) Metallicity. Chemical elements heavier than helium are formed inside stars, after the Big Bang. Elements heavier than iron are formed in exploding supernovas. These elements have been building up over time. Maybe they had to reach a threshold abundance to make complex life possible.

On its own, it’s not clear this would have prevented intelligent life from arising long ago. The Sun has a high “metallicity” (concentration of heavy elements), but there are stars in the Milky Way older than the Sun with higher metallicities. But metallicity could combine with GRBs (below): toward the center of the galaxy there are more heavy elements but also more GRBs.

2) Gamma Ray Bursts (GRBs). GRBs are bursts of gamma rays (high frequency radiation) lasting from milliseconds to minutes, like GRB 080319B. (Check out tweets for January 11.) They are probably supernovas or even larger explosions with one pole of the exploding star pointed at the Earth. A major GRB could irradiate one side of the planet, and also affect the other side by destroying the ozone layer, causing mass extinctions. GRBs may have swept the Milky Way frequently in the past. The good news is they’re probably getting less frequent. This could be the first time in the history of the Milky Way that enough time has passed without a major GRB for intelligent life to evolve. If true, we should think about how to protect ourselves from the next one – lots of sunblock recommended.

If GRBs are such a threat, we might expect to find evidence that they have caused mass extinctions in the past (not wiping out all life obviously). For more on this, check out upcoming blog posts and tweets for the end-Ordovician, March 2.

3) Panspermia (life from elsewhere). Pretty much as soon as Earth could support life, we see evidence of single-celled organisms. Then life evolves slowly for a long time. The usual story about this is that the origin of life is easy, and it happens as soon as possible. But there is another possibility (illustrated below). It may be that the transition from simple replicating chemical systems to bacteria with genomes of tens of thousands of DNA base pairs is a slow process that happened over many billions of years somewhere off Earth. Then newly forming planets in the nebula that gave rise to Earth were “infected” by this source, by meteorites carrying early cells. (It would have been easier for meteorites to carry life from star system to star system when the Earth was first formed than it would be today.) Back when our hypothetical “Urth” was forming, a billion years before Earth, there might not have been any planets with cellular life on them as potential sources of life-bearing meteorites.

Untitled

Where is everybody?

Today, January 16, covers the period 5.96 to 5.63 billion years ago in Logarithmic History, just over a billion years before the origin of our solar system. Back then, stars were forming at a fast clip in the Milky Way and other spiral galaxies. So let’s suppose… Suppose one of those older stars resembled the Sun, and had a planet like Earth orbiting around it – call it Urth. And suppose life originated on Urth more or less as on Earth and followed more or less the same evolutionary path. With this head start, intelligent life could have evolved a billion years ago, and today there could be intelligent Urthians (or their robot descendants) a billion years ahead of us.

There’s an urban legend that says that Einstein called compound interest the strongest force in the universe. Einstein didn’t actually quite say this, but it’s not a crazy thing to say. For example, consider how compound interest works, backward, on our Logarithmic History calendar. December 30 covers a period 5.44% longer than December 31, December 29 is 11.1% longer (because 1.0544 * 1.0544 = 1.111), and so on. At this rate of compounding we wind up with January 1 covering 751 million years. The same math implies that if we invested 1 dollar at 5.44% interest, compounded annually, then after 365 years we’d have 751 million dollars.

With even the slightest compound rate of increase, a billion year old Elder Race would have plenty of time to fill up a galaxy, and undertake huge projects like dismantling planets to capture more of their suns’ energy. Which raises the question, asked by Enrico Fermi in 1950: “Where is everybody?” There are more than 100 billion stars in our galaxies, more than 100 billion galaxies in the visible universe. If there are huge numbers of billion year old Elder Races around, why hasn’t at least one of them taken the exponential road and made themselves conspicuous?

There’s a large literature on the Fermi paradox. Here I consider just one sort of explanation. Maybe we’re one of the first intelligent species to evolve because the universe was somehow less suitable for the evolution of complex life before now. (To be continued).

Learn This One Weird Trick (Part Two)

… that humans use, and now you can too! (Continued from the previous post.)

recursion 3) Recursion. What if you have one mirror facing a second mirror, so the first mirror shows what’s in the second mirror, which shows what’s in the first mirror …? What if you take a chameleon, which tries to take on the color of its surroundings, and put it on a mirror? What if you point a video camera at the very screen that’s showing what the video camera is pointing at? What if (getting mathematical) you use a function in defining that same function? What if you use the cleaning attachment from your vacuum cleaner to suck dust off the vacuum cleaner itself? (Okay, the last one is a bit lame.) The basic idea in each of these cases is called recursion, which is a major concept in mathematics and computer science. Douglas Hofstadter’s Gödel, Escher, Bach is all about recursion. Some people think recursion – nesting ideas about ideas inside one another in a potentially infinite hierarchy, or (for syntax) phrases inside phrases — is central to human uniqueness. Noam Chomsky has lately been pushing a hard-core version of this argument. He’s enough of a big wheel in language and cognition to get people talking about it, but I think it’s fair to say he hasn’t convinced too many people.

4) Shared intentionality. Suppose you and I are friends with a couple, Fred and Wendy Smith. I tell you “I saw Wendy Smith kissing a man in the park yesterday.” Logically speaking, there’s nothing to say the man wasn’t Fred. But you’ll probably assume that I meant she was kissing someone other than Fred. Why? Well if the man had been Fred I could just as easily have said “I saw Wendy Smith kissing Fred in the park yesterday.” Since I didn’t say that, you assume I mean to convey the man wasn’t Fred. Note this only works if both of us try to pack as much relevant information into our sentences as possible and know the other person is doing the same. (If you think this sounds like recursion, you’re right.) Back in the 1950s, Paul Grice, a philosopher, worked out a lot of how we pack non-literal meanings into sentences. But the same principles are at work even when people are communicating non-linguistically. This leads to another theory of human uniqueness: human beings are uniquely good at developing shared intentions with one another: each party knows the other party is trying to communicate something, so they converge on the correct answer. People may have been doing this even before language evolved.

sclera There’s a telling little piece of anatomy that’s relevant here. In most mammals, including chimpanzees, the sclera (white of the eyes) is not visible. It’s hard to tell where a chimpanzee is looking, easy for a human. Human eyes make it easy to cooperate in sharing attention, a first step in developing shared intentions. If you know your card games, chimpanzees are playing poker, humans are playing bridge.

Our discussion of human uniqueness on Logarithmic History has been frustratingly short on specific dates. But human sclera are probably a fairly simple trait genetically, and we may soon enough discover the genes involved and even tell how long ago they mutated.