Human Uniqueness - Breaking the Philosophical Mold

09/2514, M. Anthony Mills, the Slate

In an address to the Pontifical Academy of Sciences, Saint John Paul II famously described the theory of evolution as “more than a hypothesis.” Nevertheless, he maintained, the philosophical supposition of reductive materialism, which many assume to be a consequence of the biological theory, “is incompatible with the truth of man.”

Reductive materialism views man’s spirit -- esprit in the original french, signifying spirit, mind, or intellect -- as an “epiphenomenon” of material forces. This supposition fails, the pontiff argued, not because the theory of natural selection is deficient, but because “with man, we find […] a difference of an ontological order, an ontological leap.” Evolution may be the best theory of how the human animal came onto the scene; but this should not obscure the fact that the human person is ontologically – i.e., metaphysically – unique.

Many classical, medieval, and early modern thinkers accepted humankind’s ontological uniqueness. For Immanuel Kant, freedom and moral duty were uniquely human, while Descartes argued that humans alone possessed a spiritual substance, distinct from matter, which grounds the characteristics that we take to be most fundamentally human, the things we value most, including our capacity to reason, to experience beauty, even to love. Long before, Aristotle argued that although man is an animal, he is unique in the desire and capacity to pursue knowledge for its own sake. St. Thomas Aquinas wedded this latter conception to the Imago Dei, according to which man alone is created in the image and likeness of God.

But once Darwin proposed that man evolved from primitive organic life, all differences between animal and man appeared to be of “degree,” rather than of “kind.” For if our intellectual and moral faculties resulted from natural selection, then these capacities would seem to differ little from those of other “higher mammals.” Some embraced the idea: the vaunted pursuit of knowledge for its own sake was a trait like any other, somehow aiding our survival. Others redoubled efforts to differentiate man from beast.

Recent philosophers have taken up the cause. Some, such as analytic philosopher John Fischer, follow Kant in vigorously defending the importance of free will to make sense of our distinctively human obligations. Others, like William Hasker, take a more metaphysical approach.

Hasker thinks Descartes was right to distinguish mind from matter, but wrong to oppose them. There is a duality between the two; but Cartesian dualism fails to explain how they interact. Reductive materialism, by contrast, rightly abjures the idea of a mind radically distinct from matter; but it fails to account for the reality of mind. The solution, says Hasker, is to see the mind as compatible with, even growing out of, material forces, though not reducible to them. “Mind” is a real, but “emergent,” entity.

According to philosopher Tim Crane, talk of “degrees” and “kinds” is unhelpful when considering the question of human uniqueness. If the differences between humans and animals are “of degree,” then these degrees, he says paraphrasing Daniel Dennett, differ enormously in kind. But we needn’t understand such differences in a mysterious way. In fact, Crane argues, “evidence from psychology,” rather than metaphysics, suggests that Aristotle’s criterion for human uniqueness may be correct after all. The “pursuit of knowledge for its own sake” may be a distinctive “psychological trait of humans,” compatible with “an evolutionary account.”

Crane’s approach is estimable for rejecting what he calls the “ideological misconception of science,” namely, that there is nothing “distinctively human” in the natural world, but without invoking anything supernatural. In the end, however, if the differences between humans and animals remain no more significant than those between, say, tool-using apes and single-celled amoebas, the question remains: does science leave room for the kind of “ontological difference” to which John Paul II refers?

Crane’s writing on consciousness suggests another line of argument. The philosophical tradition called phenomenology holds that conscious experience has an inherently first-person character. This is what philosophers call “intentionality,” meaning that consciousness is always consciousness of the surrounding world, including oneself and others. Crane has argued that intentionality may be the “mark of the mental,” while others suggest it may be the mark of the human.

If consciousness does have this distinctively intentional character, then many aspects of human experience may simply be beyond the scope of physics and biology, if not incompatible with them. Biology and physics are adequate for those aspects of the human animal explicable in terms of impersonal material causes, but one’s own awareness of this or that – or indeed of oneself -- is neither impersonal nor material. Intentionality cannot be made sense of in purely third-person terms. If the phenomenologists are right, then, the data of consciousness are not reducible to material causes.

But how should we understand phenomenological description itself? Is it a “science” of consciousness? If not, what is it? Is it continuous with the natural sciences, as Crane suggests, or more “fundamental,” as Husserl, the founder of phenomenology, thought? In any case, all attempts to describe conscious experience in a rigorous manner have met with difficulties – to say nothing of the concept of intentionality, which many philosophers find suspicious.

The problem lies, perhaps, in the philosopher’s prejudice that there must be a systematic and objective procedure for analyzing what is by definition neither systematic nor objective: our first-person experiences. This is a bit like analyzing what makes good jokes funny: interesting perhaps, but jokes either make people laugh, or they don’t.

That the rich texture of human experience greatly exceeds the findings of natural science – which are themselves part of that texture – is the kind of truth that needs no philosophical justification. The difference between a Rembrandt and a hack has a basis in physics and chemistry – paint is material after all. But the essential difference is aesthetic. Similarly, a morally upright choice may have a basis in biological or psychological nature; but the category of moral uprightness is neither biological nor psychological.

Before phenomenology, the French philosopher Henri Bergson argued that such relatively unusual human experiences – aesthetic judgments, exemplary moral acts – are exceptions that prove the rule. Even mundane experiences, which, unlike aesthetic and moral ones, may not have a normative dimension, do have a quality partly understandable in scientific terms, but ultimately not reducible to them.

Consider the experience of waiting for a lump of sugar to dissolve in a cup of tea. There is a chemical explanation for this process and an objective, publicly agreed upon, way to measure its duration. But, Bergson observed, the experience of waiting is neither a public nor an objective affair; one’s subjective state of mind – impatient, tired, etc. – determines how one experiences the objective fact. That is, the first-person experience of time is something over and above the third-person description of it.

From the scientific point of view, making tea is more or less identical on each occasion: the same chemical processes are at work and the amount of time, if it varies at all, varies by some objective measure (seconds or minutes). But the experience of making tea is patently not the same on each occasion. There is a profound difference between, say, making tea for the first time, and having made tea with one’s grandmother every Sunday afternoon, doing so for the first time after her death. Such qualitative differences are more readily captured by art and literature – think, for example, of Proust’s novel In Search of Lost Time – than by chemistry. But, Bergson argues, such considerations are precisely what we need to make sense of our experiences, mundane and profound alike.

The sober-eyed scientist will respond: so much the worse for your experience; the truth lies with the objective fact. But such first-person experiences are, in fact, what matters most to us. Not that the chemical explanation is wrong. Bergson’s point is that we don’t go about our daily lives as chemists. To dismiss our everyday dealings – in which we have aspirations, mourn the loss of loved ones, and make moral choices, aesthetic judgments, and cups of tea – as irrelevant reports of objective processes is to dismiss just about everything. There is no need to appeal to anything mysterious; even something as mundane as the experience of making tea reminds us just how much of reality exceeds what the physical, chemical, or biological facts reveal.

It may be that this richness does not admit of scientific investigation. And it is hard to see how one could prove that it is distinctively human, a mark of ontological difference. But we may have an answer to the question, “Does science leave any room for such a difference?” If even banal human experiences possess a metaphysical coloring that cannot be explained away by natural science, then surely Bergson is right that this is true also of our most profound experiences. As John Paul II wrote:

“The experience of metaphysical knowledge, of self-consciousness and its reflexivity, of moral conscience, liberty, or of aesthetic and religious experience—these must be analyzed through philosophical reflection, while theology draws out the ultimate meaning according the Creator's designs.”

Science may suggest that we are neither physically nor biologically unique. But here is a reminder that not all differences are graspable in scientific terms; the “ontological difference” between man and nature is surely one such difference. 

M. Anthony Mills is a PhD candidate in philosophy at the University of Notre Dame.

http://www.slate.com/bigideas/are-we-alone/essays-and-opinions/anthony-mills-opinion

Are We Alone?                

Marcelo Gleiser, the Slate

Introduction

Imagine for a moment that you live in Ancient Greece and one night you decide to go out and look at the stars. What would you see? In a way, the night sky would look exactly the way it looks to someone camping at Yosemite in 2014; and yet, the sight would be radically different. An Ancient Greek looking at the night sky perceived the universe rotating around the Earth, which was thought to be located in the center of a perfectly spherical universe that contained all celestial bodies and everything else that existed.

This is how Western civilization perceived the universe for more than twenty centuries: a set of nested spheres, as it was depicted by the Ptolemaic system. Fixed stars constituted the outer spheres that circled around the planets’ orbits. Closer to the center, the moon’s trajectory formed the inner sphere. The world inside the moon’s orbit was thought to be different from everything above it. The Earth was not just the center of the universe, but an entirely unique place. This view concurred with the Biblical doctrine that God created life solely on Earth, where he reserved a special place for man, whom he created in his image and likeness. From Ancient Greece until Early Modernity we conceived ourselves, under this paradigm, as unique beings that inhabited the pivotal place around which everything else revolved.

Then along came Copernicus, who started noticing some discrepancies between his observations of planetary movements and the predictions of the Ptolemaic system. He proposed a new vision of the cosmos, one in which the Earth no longer served as the pivot around which the heavens revolved. Over the next 600 years, we came to terms with the idea that not only are we not at the center for the universe, but that we find ourselves living in just one among many universe-like things existing in space. These realizations have had a deep impact in our sense of uniqueness. A XXI century camper at Yosemite no longer pictures himself at the center of the universe, but rather as one among millions of living creatures inhabiting one among innumerable planets.

Basic mathematics suggests that it is highly unlikely that we are alone. Without going very far: the Milky Way is just one among hundreds of billions of galaxies in the observable universe, and it contains about two hundred billion stars, fifteen percent of which are expected to have earth-sized planets in their “Goldilocks Zone” (the zone where it is possible to contain water in liquid form). Considering that the Earth is made out of the same building blocks as the rest of the cosmos, the probability that this is the only planet where life exists becomes increasingly remote.

Nevertheless, we still lack evidence of extraterrestrial life. Besides probabilistic calculations, and perhaps the wishful thoughts of science fiction fans, do we have any reason to think that there is life outside of Earth? The “Rare Earth Hypothesis”, which is endorsed by some prominent skeptics in the field of astrobiology, claims that we don’t. In fact, it affirms that the life-friendly conditions given on Earth are hardly repeatable anywhere else in the universe. Yet exoplanet researchers are finding ever-more potential candidates, including the recent observation of an Earth-sized world orbiting a Sun-like star. Today, David Charbonneau and David Latham of Harvard University are devising sophisticated methods by which we could search the atmospheres of these exoplanets for biomarkers of life. Even if the physical conditions of those planets do not match exactly those of the Earth, this doesn’t rule out the existence of other forms of life that differ widely from our own.

A totally different question is whether we have reasons to think there is intelligent or civilized life outside planet Earth. Facing this question arises an apparent contradiction between the high probability of there being extraterrestrial civilizations and our complete lack of evidence of their existence. This is known as the “Fermi Paradox,” after the Italian physicist Enrico Fermi. The SETI Research Center at Berkeley currently searches for traces of radio emissions emanating from other planets; none have been found so far. Skeptics take the absence of evidence as a sufficient base to rule out the existence of such a form of life. Other researchers, like Daniel Werthimer, hold that “absence of evidence is not evidence of absence,” and they attribute the lack of evidence to a wide range of factors, from how recently we have begun the search to how differently we may perceive time and space.

What would happen to our sense of uniqueness if we were to find intelligent life outside planet Earth? How similar to us must our neighbors be in order for us to count them as fellow living creatures? How different must they be if they’re not to destroy our self-image as exceptional creatures? Research on extraterrestrial life forms may open up questions regarding the very boundaries of what constitutes life. Is our definition of life too restrictive to accommodate extraterrestrial forms of life? Furthermore, is it sufficiently ample to accommodate all the diversity of life in our home planet?

Research performed by Nathan Wolfe and his team at Stanford University suggests that there may be different forms of life, that are still unaccounted for and do not fit in any of the three identified realms of life. They have coined the term “dark biological matter” to refer to this unidentified kind of genetic material. Dark biological matter constitutes 20% of the genetic information in samples of human nasal swaps. These discoveries are controversial, and many people believe that it is premature to talk about a fourth domain of life -- but if these researchers are correct, it appears as though there is an entirely unexplored form of life, that has been, not just under our noses, but inside of them, this whole time.

Can this newly acquired knowledge of the diversity of life on Earth inform us of possible forms of life elsewhere in the universe? How does it impact the way we perceive the human species? Given what we know about life on Earth, can we consider ourselves exceptional among the known species? How does our species compare to its fellows?

The differentiation of Homo Sapiens from other primates throughout evolutionary history was led by a positive feedback loop involving traits like bipedality, decrease in canine size, increase in brain size, and some behavioral adaptations, such as cooperative breeding, changes in diet, and use of tools. The fossil record reveals a continuous change that took place over 2.5 million years involving diverse lineages. The exact point at which to draw a line in the speciation of humans is uncertain, but even though the details of the process are still subjects of controversy, that humans share a common ancestor with other primates seems to be a matter of fact. In purely physiological terms, the human species does not stand out among its fellows.

In a speech delivered at Oxford in 1864, former British Prime Minister Benjamin Disraeli claimed that Darwinian evolutionary theory opens an important question: “The question is this: Is man an ape or an angel? My Lord, I am on the side of the angels.” Certainly it seems as though there must be something else that makes us humans exceptional. Is there any characteristically human feature that justifies the belief that we, and only we, are made in God’s image and likeness? How do we make sense of the idea that, even though every species is unique, the human species is somehow “uniquiest,” as Theodosius Dobzhansky put it?

In the Buddhist tradition, humans are distinguished for being the only creatures capable of attaining a state of enlightenment. This state consists of an infinite expansion of empathy that is achieved when an individual is capable of identifying with everything around him. In this tradition, our capacity for empathy places us in a unique position. Nevertheless, it has been recently observed that other primates are also capable of empathy, as they demonstrate altruistic and moral behaviors. Several studies have found that chimpanzees respond to unfair treatments of innocent individuals by grooming them. They also respond to the distress of others by sharing food, thereby revealing a capacity for primitive moral reasoning and empathy.

The idea that empathy is an exclusively human trait is also challenged by the discovery of spindle cells in the brains of cetaceans. These cells are considered to be responsible for triggering emotional reactions to the perception of pain in others. It is not only the case that whales and dolphins manifest empathetic behaviors. We also know that they possess the same neural hardware that is responsible for these behaviors in humans. For a long time, the presence of spindle cells in the anterior cingulate was thought to be an exclusive trait of humans and other higher primates. Studies conducted at the Mount Sinai School of Medicine in New York and the New York Consortium in Evolutionary Primatology have found that cetacean brains have had these cells for twice as long as human brains, and possess three times as many spindle cells as our brains do.

Indeed, many of the behavioral patterns that were once considered to be uniquely human have been discovered to be manifest, albeit more modestly, in the behavior of some other species. Distinctively human characteristics, such as language, culture, intelligence, and politics, can arguably be discerned in the behavior of other primates, though to a much lesser extent, and with a lesser degree of complexity and sophistication. Furthermore, likeness to human intelligence has been displayed not only by other animal species but also by a new kind of being: computer software. In 1997, IBM chess computer Deep Blue beat the world champion, Garry Kasparov. More recently, after almost one hundred years of research on artificial intelligence, Eugene Goostman, a computer program designed by a Russian team, succeeded in the Turing test by convincing thirty percent of the judges that it was a 13-year-old Ukranian boy.

In what capacity does it seem humans are unique? Consider the human mind. While the human brain may in some respects resemble those of other higher-order primates, the human mind possesses qualities that appear utterly unique. We have the ability to operate with symbols and to think abstractly. In virtue of these, our language has characteristics that are not even approximated by the more primitive languages of other creatures. Its compositional structure enables us to produce infinitely many sentences out of a finite number of words. Whereas animals merely use language for literal communication, we are capable of going beyond literality, and using language for a wide variety of ends: lying, sarcasm, humor, figurative speech and poetry. Moreover, with language we are able to perform actions that are unheard of in the rest of the animal kingdom: marrying, voting, and asking questions about purpose, meaning, and design. Our ability to operate with symbols also seems to underwrite many other behaviors and capacities that some consider to be exclusively human, such as the production of diverse forms of art, and complex moral codes.

Empirical findings in primatology, evolutionary biology, linguistics and neuroscience underscore the continuity of human beings with other animal species. It remains striking that, despite that continuity, we still appear to be the “uniquiest” species on our home planet. Are we similarly distinctive throughout the universe? The answer depends heavily on the findings of further empirical research, the ways in which we understand the concept of uniqueness, and the way we measure what sets us apart from others, whether it be measured in the nanometers of our DNA or the light-years in our galaxy.

Marcelo Gleiser is the Appleton Professor of Natural Philosophy at Dartmouth College and author of "The Island of Knowledge."

http://www.slate.com/bigideas/are-we-alone/essays-and-opinions/introduction

The evolution of beauty: Face the facts         

What makes for a beautiful visage, and why, may have been discovered accidentally on a Russian fur farm

The Economist, 11/16/13

BEAUTY, the saying has it, is only skin deep. Not true. Skin is important (the cosmetics industry proves that). But so is what lies under it. In particular, the shape of people’s faces, determined by their bone structure, contributes enormously to how beautiful they are. And, since the ultimate point of beauty is to signal who is a good prospect as a mate, what makes a face beautiful is not only an aesthetic matter but also a biological one. How those bone structures arise, and how they communicate desirable traits, are big evolutionary questions.

Until now, experiments to try to determine the biological basis of beauty have been of the please-look-at-these-photographs-and-answer-some-questions variety. Some useful and not necessarily obvious results have emerged, such as that one determinant of beauty is facial symmetry.

But what would really help is a breeding experiment which allowed the shapes of faces to be followed across the generations to see how those shapes relate to variations in things that might be desirable in a mate. These might include fertility, fecundity, social status, present health, and likely resistance to future infection and infestation. Correlations between many of these phenomena and attributes of the body-beautiful have, indeed, been established. But in a pair-forming, highly social species such as Homo sapiens, you also have to live with your co-child-raiser or, at least, collaborate with him or her. So other things may be important in a mate, too, such as an even temper and a friendly outlook.

It would be impossible to do such a breeding experiment on people, of course. But as Irene Elia, a biological anthropologist at Cambridge, realised, it has in fact been done, for the past five decades, on a different species of animal. Dr Elia has published her analysis of this experiment in the Quarterly Review of Biology. The animals in question are foxes.

Foxy ladies, vulpine gents

The story starts in 1959, in Novosibirsk, Russia. That was when Dmitry Belyaev, a geneticist, began an experiment which continues to this day. He tried to breed silver foxes (a melanic colour variant, beloved of furriers, of the familiar red fox) to make them tamer and thus easier for farmers to handle. He found he could, but the process also had other effects: the animals’ coats developed patches of colour; their ears became floppy; their skulls became rounded and foreshortened; their faces flattened; their noses got stubbier; and their jaws shortened, thus crowding their teeth.

All told, then, these animals became, to wild foxes, the equivalent of what dogs are to wild wolves. And this was solely the result of selection for what Belyaev called “friendly” behaviour -- neither fearful nor aggressive, but calm and eager to interact with people.

The link appears to be hormonal. Hormones such as estradiol and neurotransmitters such as serotonin, which regulate behaviour, also regulate some aspects of development. Change one and you will change the other. So in a species where friendliness is favoured because that species is social and the group members have to get on with each other -- a species like Homo sapiens, for example -- a “friendly” face is a feature that might actively be sought, both in mates and in children, because it is a marker of desirable social attitudes. And there is abundant evidence, reviewed by Dr Elia, both that it is indeed actively sought by Homo sapiens, and that it is such a reliable marker.

What men look for in the faces of women, and vice versa, is so well known that research might seem superfluous. Suffice to say, then, that features like those seen in Belyaev’s foxes (flat faces, small noses, reduced jaws and a large ratio between the height of the cranium and the height of the face) are on the list. People with large craniofacial ratios are, literally, highbrow.

More intriguingly, the presence or absence of such features skews parents’ attitudes to their offspring. At least 15 studies have shown that mothers treat attractive children more favourably than unattractive ones, even though they say they don’t and may actually believe that. At least one of these studies showed this bias is true from birth.

Some of the details are extraordinary. One researcher, who spent a decade observing how mothers look after young children in supermarkets, found that only 1% of children judged unattractive by independent assessors were safely secured in the seats of grocery carts. In the case of the most attractive the figure was 13%. Another researcher studied police photographs of children who had been abused and found such children had lower craniofacial ratios than those who had not been.

In a state of nature, this sort of behaviour would surely translate into selective death and thus the spread of the facial features humans are pleased to describe as “beautiful”. If such features do indicate a propensity to friendly, sociable behaviour, as they do in foxes, then such behaviours will spread too.

Crucially for Dr Elia’s hypothesis, they do indeed indicate such a propensity. Even as children, according to 33 separate studies, the attractive are better adjusted and more popular than the ugly (they also have higher intelligence, which assists social skills). And of course, they have less difficulty finding a mate -- and as a result have more children themselves. One study found that the most beautiful women in it had up to 16% more offspring than their less-favoured sisters. Conversely, the least attractive men had 13% fewer than their more handsome confrères.

The beholder’s eye

An appreciation of what is “beautiful”, moreover, seems innate -- as Dr Elia’s hypothesis requires it should be. Babies a few days old prefer pictures of the faces of people whom their elders would define as beautiful to those they would not, regardless of the sex and race of either the baby or the person in the photo.

People also seem to be more beautiful now than they were in the past -- precisely as would be expected if beauty is still evolving. This has been shown by assessing the beauty of reconstructions of the faces of early humans. (Such reconstructions, sometimes used in murder cases where only skeletal remains of the victim are available, produce reliable depictions of recently dead people, so the assumption is that ancients really did look like the reconstructions made of them.)

None of this absolutely proves Dr Elia’s hypothesis. But it looks plausible. If she is right, facial beauty ceases to be an arbitrary characteristic and instead becomes a reliable marker of underlying desirable behaviour. It is selected for both in the ways beautiful children are brought up, and in the number of children the beautiful have. Face it.

From the print edition: Science and technology

Are We Still Evolving?

Yep, but there's a catch: Our identities might be too fluid for any advantageous mutations to take hold.

Michael White, 10/30/13

Our evolutionary trajectory over the last three million years took us from small-brained walking apes who lived in East African grasslands to modern humans who have colonized just about every type of environment of every major land mass on the planet. So what's next? Are we still evolving? If so, have our culture and our technology changed our evolutionary trajectory? Using new genetic inventories of world populations, researchers are now tracing our recent evolutionary path in remarkable detail. They are discovering that our culture and our general restlessness as a species have had a big impact on our genetic makeup.

A human living in Africa 50,000 years ago wouldn't look out of place groomed and dressed up in a business suit, sipping coffee at a Starbucks in Manhattan. Yet while fully modern humans evolved in Southern Africa, a glance around a Manhattan Starbucks is enough to show you that human evolution has continued since we migrated out of Africa and settled the rest of the world: our stature, skin color, hair, eye color, and other facial features clearly show where in the world at least some of our ancestors lived. Modern humans began branching out into the Near East, Asia, Europe, and Australia by about 40,000 years ago, finally arriving in South America by 12,000 years ago. As our species colonized new environments around the world, we confronted new foods, new pathogens, and other new challenges posed by differences in sunlight, temperature, and altitude. Different populations around the world evolved in response to their unique environmental challenges; as a result, we differ from each other not only in our outward appearance, but also in the inner workings of our bodies. The effects of different evolved adaptations among humans in different parts of world can be seen today in the strong influence our ancestry can have on our health.

To get a better understanding of the changes in our recent evolutionary past, scientists have been looking under the hood at the genetic workings of those evolutionary changes. They're using large genetic inventories of different world populations, such as the Human Genome Diversity Project, to look for mutations that show signs of being actively promoted by evolution. Among the findings are mutations that cause lighter skin color in northern human populations. Lighter colored skin may have evolved in response to the need to maintain sunlight-activated vitamin D synthesis as humans migrated northward. Scientists have discovered different mutations in Europeans and East Asians that are responsible for the lighter skin color in these populations. Other studies have uncovered mutations responsible for straight hair in Asians and blue eyes in Europeans; the evolutionary basis for the short stature of “Pygmy” populations that live in the tropical forests of Africa, Asia, and South America; and the different genetic adaptations of Andean, Tibetan, and Ethiopian high-altitude societies to low oxygen levels that would make the rest of us sick. These changes may seem subtle when you consider what can happen over millions of years, but there is no question that humans have continued to evolve.

There is also no question that we've managed to influence the course of our own evolution. One of the biggest cultural changes we've undergone as a species has been to settle down into villages and cities, and support ourselves by raising crops and livestock. In the process, we've altered the evolution of our immune system and our metabolism. The clearest example of a diet-induced evolutionary change is adult lactose tolerance in dairy-consuming Europeans and African Maasai, a useful trait to have before the availability of Lactaid.

Our species' wanderlust has also had a profound impact on how we've experienced evolutionary change. Much of our genetic makeup is due to what geneticists call founder effects, meaning that our genes reflect the chance membership of the small band of colonists that we've descended from, rather than evolutionary pressure to adapt. The fact that Scots commonly have red hair, while Norwegians have blond hair is likely due to founder effects and not because red hair is better suited to the Scottish climate. Our long tradition of pulling up stakes and seeking our fortunes elsewhere has also had the effect of putting the brakes on natural selection in many cases. One research team studied the fate of seemingly favorable mutations worldwide and concluded that human "populations may be too mobile, or their identities too fluid" for advantageous mutations to spread completely through a population. By moving around so much, we stir up the human gene pool and alter how evolutionary pressures act on our genes.

The recent evolutionary changes studied by scientists all occurred well before a few game-changing developments that include antibiotics, vaccines, mass-produced food, fertility drugs, and online dating services. We've raised the odds that, in most areas of the world, children will live to adulthood and go on to have their own children. Does this mean that we've transcended the messy process of evolution and made ourselves largely immune to natural selection? Not quite -- just because our children aren't eaten by predators or don’t succumb to childhood diseases does not mean that evolution has lost its power over our species. For the past 40,000 years, we've been adapting to the local environments that we've colonized; in the future, we will adapt to the social and physical environment we are making for ourselves. We'll face the uncertain new challenges of climate change, but we also continue to confront the questions of how to successfully choose a mate and whether and when to have children. More people are choosing to have children later in life or not at all, a choice that generally wasn't an option for most women not too long ago. The well-being of our children today depends less on the chance occurrence of a famine or epidemic, and more on the choices we make as parents. These kinds of decisions clearly influence whose DNA ends up in the next generation. Our future evolutionary trajectory depends on how billions of people resolve these choices over the next 40,000 years.

http://www.psmag.com/science/still-evolving-69121/

Are Americans Getting Smarter?

Lauren Lyster, Daily Ticker, 03/04/13

Are we getting smarter? If you look at IQ test results over the last few generations, it appears to be the case.

James Flynn, academic and author of Are We Getting Smarter, became famous for finding a massive increase in IQ test scores from one generation to the next. His research has come to be known as the “Flynn Effect.”

But Flynn tells The Daily Ticker we’re not necessarily smarter, but more modern.

First the facts. Flynn says only 3% of our ancestors had cognitively demanding jobs. Today, that number is 35% in America. Schooling has developed too. Nowadays, educators teach students how to reason logically, something that wasn’t taught to our ancestors (they learned more literal skills to prepare them for a life of say, farming or working in a factory).

The evolution to a more complex, modern existence for more people is something that has translated into higher IQ scores, according to Flynn. He’s documented gains of three points a decade on the Stanford-Binet test, amounting to 30 points in 100 years. In addition, women have closed the gender gap in IQ scores.

Related: Why Men are Failing in this New Economy

"If you took the scores literally, either we're all at 130 and are all gifted, or they're all at 70 and are all at the border of mental retardation,” Flynn says, putting the scores in perspective. “Now that's not true of course."

Flynn argues that our ancestors' intelligence was adequate to deal with what their world demanded. Nowadays, modern society simply demands more cognitive flexibility.

So we’re not necessarily more intelligent in Flynn’s view, we’ve just adapted to the times. He has no doubt our “dumber” ancestors would have adjusted similarly if they were transported to this day-and-age.

Related: How to Be a "Superachiever"

For people wanting more than the generational IQ gains, is it possible to raise your IQ?

Flynn says living and working in the modern world will automatically increase one's IQ test scores. But even as humans are getting smarter in some respects, they're becoming less intelligent in others.

“Where we've fallen behind is not in terms of our ability to reason scientifically or our ability to profit from tertiary education,” he says. “We've made no progress whatsoever in terms of our political sophistication, and indeed, young people today may be worse because, thanks to their visual environment, they've stopped reading history and they've stopped reading the world's great literature."

Related: Are Millennials a “Lost Generation”?

There may be a silver lining though for a life spent watching TV. Flynn has documented what he calls a “bright tax": The brighter you are, the bigger the decline in your analytic abilities over time.

http://finance.yahoo.com/blogs/daily-ticker/americans-getting-smarter-143840511.html

What We Learned About Humanity in 2012  

Charles Choi, LiveScience Contributor, 12/27/12

The controversial extinct human lineage known as "hobbits" gained a face this year, one of many projects that shed light in 2012 on the history of modern humans and their relatives. Other discoveries include the earliest known controlled use of fire and the possibility that Neanderthals or other extinct human lineages once sailed to the Mediterranean.

Here's a look at what we learned about ourselves through our ancestors this year.

We're not alone (族繁不及備載)

A trove of discoveries this year revealed a host of other extinct relatives of modern humans. For instance, researchers unearthed 3.4-million-year-old fossils of a hitherto unknown species that lived about the same time and place as Australopithecus afarensis, a leading candidate for the ancestor of the human lineage. In addition, fossils between 1.78 million and 1.95 million years old discovered in 2007 and 2009 in northern Kenya suggest that at least two extinct human species lived alongside Homo erectus, a direct ancestor of our species. Moreover, fossils only between 11,500 and 14,500 years old hint that a previously unknown type of human called the "Red Deer Cave People" once lived in China.

Bones were not all that scientists revealed about modern humans' extinct relatives in 2012. For instance, scientists finally put a face on the hobbit, a nickname for a controversial human lineage. Anthropologist Susan Hayes at the University of Wollongong in Australia reconstructed the appearance of the 3-foot (1-meter) tall, 30-year-old female member of the extinct humans officially known as Homo floresiensis, which were first discovered on the remote Indonesian island of Flores in 2003. [Image Gallery: A Real Life 'Hobbit']

DNA extracted from a recently discovered extinct human lineage known as the Denisovans -- close relatives of Neanderthals -- also revealed new details about this group, which once interbred with modern humans. The Denisovan genome that was sequenced belonged to a little girl with dark skin, brown hair and brown eyes, and displayed about 100,000 recent changes in our genome that occurred after the split from the Denisovans. A number of these changes influenced genes linked with brain function and nervous system development, leading to speculation that we may think differently from the Denisovans.

Genetic analysis also suggested the only modern humans whose ancestors did not interbreed with Neanderthals were apparently sub-Saharan Africans. These findings are just one tidbit regarding the closest extinct relatives of modern humans that was revealed this year. Scientists also found that the unusually powerful right arms of Neanderthals might not have been due to a spear-hunting life as was previously suggested, but rather one often spent scraping animal skins for clothes and shelters. Archaeologists also suggested that Neanderthals and other extinct human lineages might have been ancient mariners, venturing to the Mediterranean Islands millennia before researchers think modern humans arrived at the isles.

Humans' tool use (工具的使用)

Ancient artifacts revealed this year also have shown how tool use has helped humanity reshape the world -- and perhaps inadvertently reshape humanity as well.

For instance, ash and charred bone, the earliest known evidence of controlled use of fire, reveal that human ancestors may have used fire 1 million years ago, 300,000 years earlier than thought, suggesting that human ancestors as early as Homo erectus may have begun using fire as part of their way of life. Controlled fires and cooked meat may have influenced human brain evolution, allowing our ancestors to evolve to have larger, more calorie-hungry brains and bodies.

Discoveries involving ancient weapons also revealed that humans learned to make and use these tools far earlier than scientists thought. For instance, what may be ancient stone arrowheads or lethal tools for hurling spears suggest humans innovated relatively advanced weapons about 70,000 years ago, while a University of Toronto-led team of anthropologists found evidence that humans in South Africa used stone-tipped weapons for hunting 500,000 years ago, which is 200,000 years earlier than previously suggested.

Even the seemingly innocuous discovery this year of the first direct signs of cheesemaking from 7,500-year-old potsherds from Poland might help reveal how animal milk dramatically shaped the genetics of Europe. Most of the world, including the ancestors of modern Europeans, is lactose intolerant, unable to digest the milk sugar lactose as adults. However, while cheese is a dairy product, it is relatively low in lactose. Transforming milk into a product such as cheese that is friendlier to lactose-intolerant people might have helped promote the development of dairying among the first farmers of Europe. The presence of dairying over many generations may then, in turn, have set the stage for the evolution of lactase tolerance in Europe. As such, while cheese might just seem to be a topping on pizza or a companion to wine, it might have changed Western digestive capabilities.

Other clues regarding the diet of ancient relatives also emerged. For example, 2-million-year-old fossils suggest humans' immediate ancestor may have lived off a woodland diet of leaves, fruits and bark, instead of a menu based on the open savanna, as other extinct relatives of humanity did. In addition, fragments of a 1.5-million-year-old skull from a child recently found in Tanzania suggest that later members of the human lineage weren't just occasional carnivores but regular meat eaters, findings that help build the case that meat-eating helped the human lineage evolve large brains.

Humans still evolving (仍在演化中)

When it comes to the future of humanity, research this year added to accumulating evidence that natural forces of evolution continue to shape humanity. Church records of nearly 6,000 Finns born between 1760 and 1849 showed that despite humans radically altering their environments with behavior such as farming, human patterns of survival and reproduction were comparable with those of other species.

One researcher at Stanford University has even suggested that humans are getting dumber over time, having lost the evolutionary pressure to be smart once we started living in densely populated settlements several millennia ago. However, other scientists dispute this notion, pointing at geniuses such as Stephen Hawking, and suggest that rather than losing our intelligence, people have diversified, resulting in a number of different types of smarts today.

Follow LiveScience on Twitter @livescience. We're also on Facebook & Google+.

• Top 10 Mysteries of the First Humans
• Denisovan Gallery: Tracing the Genetics of Human Ancestors
• Image Gallery: Our Closest Human Ancestor

Copyright 2012 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Why Humans Prevailed

Natalie Wolchover, LiveScience.com, 06/05/12

NEW YORK -- One hundred thousand years ago, several humanlike species walked the Earth. There were tribes of stocky Neanderthals eking out an existence in Europe and northwest Asia, and bands of cave-dwelling Denisovans in Asia. A diminutive, hobbitlike people called Homo floresiensis inhabited Indonesia. What were essentially modern humans roamed Africa.

Then, about 60,000 years ago, a few thousand of those humans migrated out of Africa. As they slowly moved into new territories over the course of generations, they encountered the Neanderthals, the Denisovans and the hobbit people -- all of whom descended from hominin groups that had left Africa during prior waves of migration. DNA analysis shows the humans interbred with these strangers, but other details of the encounters are lost to history. One thing is clear: only humans remain.

Why did we prevail? A panel of experts discussed their latest interpretations of genetic and fossil evidence Saturday (June 2), at the fifth annual World Science Festival here in New York. Humanity's success, they said, appears to be a "revenge of the nerds" story of global proportions.

First, although Neanderthals had as big a brain as anyone, the shapes of their fossilized skulls indicate humans had slightly larger frontal lobes, said Chris Stringer, a paleoanthropologist at the Natural History Museum in London. That brain region controls decision-making, social behavior, and such uniquely human tendencies as creativity and abstract thought. Meanwhile, Neanderthals were broader and stronger than us, with especially powerful upper bodies, and their robustness made them better adapted to Europe's cold climate. "In a sense, we're wimps," Stringer said. "Physically, we didn't have any advantage over the Neanderthals -- quite the opposite."

This would suggest brains won out over brawn, and that rather than destroying our enemies in some epic battle, our ancestors may simply have been savvier survivors, steadily growing our numbers while our burlier brethren met their demise.

Braininess helped us broaden our diets, for example. We had smaller teeth than Neanderthals, suggesting we put some of those superior abstract thinking skills toward processing food (such as pounding cooked yams), which would have conferred a major survival advantage. "The more processing you do before it goes in your mouth, the more energy you save," Stringer said. "If you want your kids to survive, you can process the food for them as well."

Ancient hunting tools such as snares and fishing nets suggest we may also have been more efficient hunter-gatherers. "Modern humans had technology that allowed them to get a more consistent, reliable and balanced diet," said Alison Brooks, an anthropologist at George Washington University. [Top 10 Technologies that Changed the World]

Another handy cognitive capacity allowed the rapid spread of new technologies, as well as the sharing of knowledge and information relevant for survival: We were -- and clearly still are -- adept social networkers. According to Brooks, excavations of ancient human settlements in Africa have turned up stashes of stone tools located as many as 100 kilometers from where the stones were quarried, implying the presence of a sophisticated and multidirectional trade network. "You're seeing a completely different approach to social organization in modern humans … than we're seeing in the Neanderthals," Brooks said. "Neanderthals simply did not do this."

Why didn't they? Such activities would have required the ability to communicate in great detail, which raises an important question in terms of the other hominins' demise: Were Neanderthals, Denisovans and Homo floresiensis capable of language, and if so, how well-developed was their system of communication? "If they could talk, then perhaps that's not the reason why we beat them, but if they couldn't, it's an obvious reason," said Ed Green, a genome biologist at the University of California, Santa Cruz, and a member of the team that sequenced the Neanderthal genome in 2010 using DNA from fossils. "If you think about all the things that you know, and calculate how much of that you figured out yourself versus what was told to you, it's obvious how important speech and language is and being able to communicate." [The Original Human Language Like Yoda Sounded]

Neanderthals probably did have some form of language. They appear to have had a gene that is crucial to language in humans, and they buried their dead, which seems too complex an idea to have arisen among a tribe of mutes. But Brooks argues they may have lacked the vocal cords necessary for complex communication. "The sounds they made would have been a little bit less distinct" -- somewhat like the speech of a 2-year-old, she said. That would imply they communicated in small groups, but not with others in a network; they simply wouldn't have been able to make sense of individuals with different accents.

Strangely coinciding with human beings' ability to cooperate is our tendency to be extremely aggressive. That, too, may have helped us prevail. "William James said 'history is a bloodbath.' And we should see that as a powerful generating force for what we are," said the Harvard evolutionary biologist E.O. Wilson. "If that trait is specific to our species as opposed to those competitors that fell before us, that could explain a lot."

Some combination of these cognitive and behavioral advantages led us to out-compete the other hominins, setting us on our uncontested path to world domination. "It's the really big brain 'Revenge of the Nerds' story," Green said. "There are 7 billion of us and maybe 100,000 of the most populous great apes. We've not only crowded out all the other hominin forms, but we're also on our way to crowding out all the other great apes."

In fact, we're so darn smart, we're in a bit of a pickle. "Our biggest danger right now is really our success," Green said. "We're taxing the world in a way that's never been done before, and so hopefully we're smart enough to figure out a solution to that problem."

Follow Natalie Wolchover on Twitter @nattyover. Follow Life's Little Mysteries on Twitter @llmysteries, then join us on Facebook.