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Hopp til: Medisin, Helse og sykdom, Mikrobiota, Ernæring, Psykologi

Evolusjon

Is evolution a theory, a system, or a hypothesis? It is much more -it is a general postulate to which all theories, all hypotheses, all systems must henceforward bow and which they mnust satisfy in order to be thinkable and true. Evolution is a light which illuminates all facts, a trajectory which all lines of thought must follow-this is what evolution is.

Pierre Teilhard de Chardin (Kilde)

Man with all his ‘ingredients’ has not ‘fallen from the sky’, but every molecule, every metabolic pathway and every organ system has its evolutionary history, which must be taken into account if the state of man today is to be understood.

Florian Horn (Kilde)

Considering that we live in an era of evolutionary everything – evolutionary biology, evolutionary medicine, evolutionary ecology, evolutionary psychology, evolutionary economics, evolutionary computing – it was surprising how rarely people thought in evolutionary terms. It was a human blind spot. We look at the world around us as a snapshot when it was really a movie, constantly changing.

Michael Crichton

An organism’s structure, physiology, and metabolism best serve the organism’s primary biological imperatives (survival and mating) when the organism lives in the environment described by its genes.

Anthony Sebastian et al. (Kilde)

There are two kinds of unit of natural selection, and there is no dispute between them. The gene is the unit in the sense of replicator. The organism is the unit in the sense of vehicle. Both are important. Neither should be denigrated.

Richard Dawkins (Kilde: The Selfish Gene)

Once upon a time, natural selection consisted of the differential survival of replicators floating free in the primeval soup. Now, natural selection favours replicators that are good at building survival machines, genes that are skilled in the art of controlling embryonic development.

Richard Dawkins (Kilde: The Selfish Gene)

Evolutionary bioogists have come to consider natural selection to be even more important than it was thought to be in Darwin’s day.

Richard Morris (Kilde: The Evolutionists: The Struggle for Darwin’s Soul)

All biological phenomena are the consequences of millions of years of evolution through the action of natural selection.

Daniel A. Boullosa og Fábio Y. Nakamura (Kilde)

If we are thinking in a Darwinian way, we should be starting from the hypothesis that any organism that has been consistently present for a significant part of mammalian evolution might have been ‘written into’ the mammalian genome, because ‘Evolution turns the inevitable into a necessity’; or, to put it more simply, anything that was always there must continue to be there (an extreme example is oxygen: when it started to appear on planet earth, some organisms adapted to its presence, and now cannot do without).

Graham Rook (Kilde)

Darwinian man though well behaved, at best is only a monkey shaved!

Arthur Sullivan og William S. Gilbert (Kilde: Princess Ida)

While biologists have revealed many phenomena that Darwin never imagined—how to discern evolutionary relationships from DNA sequences, for one thing—the theory presented in The Origin of Species has, in the main, held up steadfastly. Today scientists have as much confidence in Darwinism as they do in the existence of atoms, or in microorganisms as the cause of infectious disease.

Jerry Coyne (Kilde: Why Evolution Is True)

Like all species, today’s humans are genetically adapted to the environment in which their ancestors survived and in which their genetic makeup was selected.

Wolfgang Kopp (Kilde)

We are apes descended from other apes, and our closest cousin is the chimpanzee, whose ancestors diverged from our own several million years ago in Africa. These are indisputable facts. And rather than diminishing our humanity, they should produce satisfaction and wonder, for they connect us to all organisms, the living and the dead.

Jerry Coyne (Kilde: Why Evolution Is True)

Natural selection is the only evolutionary force that is capable of creating complexly organized machines.

Leda Cosmides & John Tooby (Kilde)

Evolution confers greater Darwinian fitness on those organisms that have greater reproductive success at lower energy expenditure. Organisms therefore optimize energy consumption and maximize energy extraction and efficiency of energy conversion to ATP.

Wan-Hui Lao et al. (Kilde)

Natural selection’s explanatory power is not just about life on this planet: it is the only theory so far suggested that could, even in principle, explain life on any planet.

Richard Dawkins (Kilde)

In biology, the greatest organizational idea created by our species is Darwin’s theory of evolution through natural selection.

Loren Cordain

An organism’s phenotypic structure can be thought of as a collection of «design features» — micro-machines, such as the functional components of the eye or liver. Over evolutionary time, new design features are added or discarded from the species’ design because of their consequences. A design feature will cause its own spread over generations if it has the consequence of solving adaptive problems: cross-generationally recurrent problems whose solution promotes reproduction, such as detecting predators or detoxifying poisons. If a more sensitive retina, which appeared in one or a few individuals by chance mutation, allows predators to be detected more quickly, individuals who have the more sensitive retina will produce offspring at a higher rate than those who lack it. By promoting the reproduction of its bearers, the more sensitive retina thereby promotes its own spread over the generations, until it eventually replaces the earlier-model retina and becomes a universal feature of that species’ design.

Hence natural selection is a feedback process that «chooses» among alternative designs on the basis of how well they function. It is a hill-climbing process, in which a design feature that solves an adaptive problem well can be outcompeted by a new design feature that solves it better. This process has produced exquisitely engineered biological machines — the vertebrate eye, photosynthetic pigments, efficient foraging algorithms, color constancy systems — whose performance is unrivaled by any machine yet designed by humans.

By selecting designs on the basis of how well they solve adaptive problems, this process engineers a tight fit between the function of a device and its structure.

Leda Cosmides og John Tooby (Kilde)

Every aspect of an organism’s phenotype is the joint product of its genes and its environment. To ask which is more important is like asking, Which is more important in determining the area of a rectangle, the length or the width? Which is more important in causing a car to run, the engine or the gasoline? Genes allow the environment to influence the development of phenotypes.

Indeed, the developmental mechanisms of many organisms were designed by natural selection to produce different phenotypes in different environments. Certain fish can change sex, for example. Blue-headed wrasse live in social groups consisting of one male and many females. If the male dies, the largest female turns into a male. The wrasse are designed to change sex in response to a social cue — the presence or absence of a male.

Leda Cosmides og John Tooby (Kilde)

Natural selection is a slow process, and there just haven’t been enough generations for it to design circuits that are well-adapted to our post-industrial life.

Leda Cosmides og John Tooby (Kilde)

Biological machines are calibrated to the environments in which they evolved, and they embody information about the stably recurring properties of these ancestral worlds.

Leda Cosmides og John Tooby (Kilde)

Natural selection is an historical process. Phenotypic adaptations have arisen by the differential reproductive success of ancestors, and complex adaptations can arise only by gradual modification which requires many thousands of generations. Therefore, the distinctive adaptations of humans were not ‘designed’ by natural selection for our current environment—which is rapidly changing and has existed for too short a duration—but for the environment which existed in the past few million years over which our ancestors evolved. This is sometimes known as the environment of evolutionary adaptedness (EEA).

Bruce G. Charlton (Kilde)

Medisin

Nothing in medicine makes sense, except in the light of evolution.

Ajit Varki (Kilde)

The near complete absence of evolution in medical school curricula is a historical anomaly that needs correction. Otherwise, we will continue to train generations of physicians who lack understanding of some fundamental principles that should guide both medical practice and research.

Ajit Varki (Kilde)

When evolution is included [in medical curriculum], it will give students not only a new perspective on disease but also an integrating framework on which to hang a million otherwise arbitrary facts. Darwinian medicine could bring intellectual coherence to the chaotic enterprise of medical education.

Randolph M. Nesse og George C. Williams (Kilde: Why We Get Sick: The New Science of Darwinian Medicine)

One can only wonder how many lives might have been saved if Darwin’s Origin of Species had been incorporated into medical school curricula when it was published in 1859. Or even, alas, a century later.

Melvin Konner (Kilde)

The doctor of the future will give no medicine, but will instruct his patient in the care of the human frame, in diet and in the cause and prevention of disease.

Thomas Edison

The study of medicine often strikes students as an unsystematic conglomeration of information and skills- relevant to medicine, but gathered from a wide variety of domains and without any linking theoretical rationale. The curriculum coheres only in terms of its common focus upon the health of the human organism. This ad hoc convergence is reasonable from a purely pragmatic, vocational perspective; but the curriculum lacks the intellectual structure that ought to characterize a scholarly discipline.

Bruce G. Charlton (Kilde)

The advent of evolutionary medicine has been a total game-changer when it comes to understanding best practices in the health professions. The basic principle of evolutionary medicine is pretty straightforward. The idea is that best practices in health care should always include some understanding of the evolutionary biology that underlies the particular issue at hand.

Glenn Geher og Nicole Wedberg (Kilde: Positive Evolutionary Psychology: Darwin’s Guide to Living a Richer Life)

Evolutionary thinking helps to understand and manage most health challenges in the modern world, including emerging infectious disease, evolution of antimicrobial resistance, aging, reproductive health, increasing prevalence of autoimmune diseases and immune function, obesity epidemics, threats to food safety and diet, neurodegenerative diseases, behavioral disorders and mental health, cancer, microbiomes, veterinary medicine, inflammation, among others.

Olga Dolgova og Oscar Lao (Kilde)

In new medicine everything is connected. There is no need for specialists. The seat of health is in the gut.

Kelly Brogan

Mismatch resolution should be the No. 1 priority of modern health care! Only by acknowledging that Homo sapiens were designed, via natural selection, to survive and reproduce under conditions that differ markedly from the conditions we – contemporary humans – find ourselves in can we make some headway towards restoring the health of our species.

Eirik Garnås

Besides biota alteration, chronic psychological stress, sedentary lifestyles, inflammatory diets, and vitamin D deficiency need to be the highest priorities for our health care system. If we don’t address all of these issues, the best we can ever hope for is a sick-care system that treats disease, not a health care system that protects the population health.

William Parker (Kilde)

Helse og sykdom

I don’t think it is possible to overemphasize just how important mismatch diseases are. You are most likely going to die from a mismatch disease. You are most likely to suffer from disabilities caused by mismatch diseases. Mismatch diseases contribute to the bulk of health-care spending throughout the world.

Daniel Lieberman (Kilde: The Story of the Human Body: Evolution, Health, and Disease)

Long-standing chronic inflammatory diseases over months and years with a high energy demand did not exist during most of our evolutionary time (including our primate and non-primate ancestors). Thus, genes and molecular networks have not been positively selected to serve long-standing, highly-energy consuming, chronic inflammation.

Rauber H. Straub (Kilde)

It has become clear that most, if not all, typically Western chronic illnesses find their primary cause in an unhealthy lifestyle and that systemic low grade inflammation is a common denominator. From an evolutionary point of view, the current conflict between environment and our Paleolithic genome traces back to our brain growth and the ensuing intimate relationship between inflammation and metabolism. The present disbalance between inflammatory and anti-inflammatory stimuli does not originate from a single cause and can consequently also not be solved by a single “magic bullet”. Resolution of the conflict between environment and our ancient genome might be the only effective manner to arrive at “healthy aging” and to achieve this objective we might have to return to the lifestyle of the Paleolithic era according to the culture of the 21st century.

Begoña Ruiz-Núñez et al. (Kilde)

If you want to live a healthy life, you ignore ideas inspired by Darwin to your own peril. 

Glenn Geher og Nicole Wedberg (Kilde: Positive Evolutionary Psychology: Darwin’s Guide to Living a Richer Life)

Living organisms thrive best in the milieu and on the diet to which they were evolutionarily adapted; this is a fundamental axiom of biology.

James H O’Keefe Jr. og Loren Cordain (Kilde)

Stratification of health according to status was something that emerged in its present form alongside economic stratification, and after the historical development of agriculture (or other types of delayed-return and storage economies).

Bruce G. Charlton (Kilde)

The ultimate cause of health is natural selection: this is the most fundamental health-creating force. This applies even though reproductive success, not health creation, is that which is selected for.

Bruce G. Charlton (Kilde)

Health advice based on epidemiological data and mechanistic research has clearly failed to achieve the desired societal impact. This suggests that a new approach, perhaps one integrating physical activity (and nutrition) within an overarching paradigm, deserves consideration. Obesity, type 2 diabetes, many cancers, hypertension, osteoporosis, atherosclerosis, and numerous other disorders conform to the same general rule: deviation from our ancestors’ way of life increases susceptibility, while reincorporating the essentials of that lifestyle reduces risk.

Boyd Eaton et al. (Kilde)

Using the lens of evolutionary medicine allows us to understand that we are facing a mismatch between our old-physiology and the rapid, radical and still ongoing changes in lifestyle and diet. Darwin said that natural selection and the conditions of existence are the forces behind evolution, the latter being more powerful. We need to realize that constantly changing the conditions of existence (our environment) has many adverse consequences.

Pedro Carrera Bastos (Kilde)

Hundreds of genes and a myriad of regulatory factors interact with lifestyle to determine whether or not an individual develops complex degenerative disease. Nearly all these genes and also the mechanisms regulating their expression were selected for the circumstances of life in the Paleolithic. An aggressive health promotion campaign based on this rational, easily-understood formulation might energize the public and lead a greater proportion to act on recommendations which have hitherto had disappointingly little effect.

Boyd Eaton

Mikrobiota

We cannot truly promote health without widening our view to the wider dysbiosis of Earth’s ecosystems and the reality that NCDs [non-communicable diseases] will be increasingly driven by loss of, or degradation of, these ecosystems at the macrobiological and microbiological levels. As we learn more about the microbiome it is obvious that personalized medicine must move toward a new clinical ecology, in which the external world (of our lifestyle within and around our habitat) matters to the ecosystems of our skin, intestinal and other personal habitats.

Susan L. Prescott et al. (Kilde)

On the larger scale, social determinants of health extend beyond the well-recognised lifestyle risk factors (diet, exercise) for disease, to the ecological determinants of health. This calls for integrated approaches that span all aspects of urban design and city planning, and which encourage human interaction with nature, plants, soils and clean air – making cities into microbe-friendly environments.

Susan L. Prescott et al. (Kilde)

Significant data suggest that a variety of microorganisms (frequently referred to as the «old friends») were tasked by coevolutionary processes with training the human immune system to tolerate a wide array of non-threatening but potentially proinflammatory stimuli. Lacking such immune training, vulnerable individuals in the modern world are at significantly increased risk of mounting inappropriate inflammatory attacks on harmless environmental antigens (leading to asthma), benign food contents and commensals in the gut (leading to inflammatory bowel disease), or self-antigens (leading to any of a host of autoimmune diseases). Loss of exposure to the old friends may promote MDD [major depressive disorder) by increasing background levels of depressogenic cytokines and may predispose vulnerable individuals in industrialized societies to mount inappropriately aggressive inflammatory responses to psychosocial stressors, again leading to increased rates of depression.

Charles L. Raison et al. (Kilde)

You can eat the healthiest food on the planet, exercise every day, and get 8 hours of sleep every night; it’s not going to be sufficient to make you healthy if your microbiome is in a sorry state.

Eirik Garnås

In order to function correctly the immune system needs «data» from biodiverse microbial inputs. The most important sources of these essential microbial inputs are the microbiota of our mothers, and the microbiota of the natural environment. These inputs are absolutely crucial in early life, but continue to be important in adulthood and old age. Without appropriate microbial inputs the regulation of the immune system is faulty, and the risk of chronic inflammatory disorders increases.

Graham Rook (Kilde)

The health of your gut flora (the interacting trillions of bacteria of a couple of hundred different species that make up the pound of bacteria that you carry primarily in your large intestines) is more important than your genetics to your overall health.  Thus, your health is a result of diet, gut flora adapted to your diet and exercise.  Everything else, your genetic risks, environmental toxins, etc. are of only minor impact.

Art Ayers (Kilde)

Highly diverse gut microbiotas tend to be more resistant to invasion by pathogenic species than less diverse microbiotas. In addition, a phylogenetically diverse community will likely contain competing groups whose influences may counteract each other. Furthermore, in a diverse microbial environment, microbes will likely expend resources on competing and cooperating (e.g. via cross-feeding), rather than on manipulating their host.

Joe Alcock et al. (Kilde)

The Darwinian approach has taught us that we are ecosystems containing humans and numerous categories of microbes with which the human component of the ecosystem has co-evolved. We are not individuals. Looking at the problem in a Darwinian way immediately points to the organisms that we must have evolved to encounter, and enables us to understand why these organisms have the functions in our physiology that we observe.

Graham Rook (Kilde)

Ernæring

Nature is the cure of illness. Leave thy drugs in the chemist’s pot if thou can heal the patient with food.

Hippocrates (Kilde)

The past 10,000 years – less than one percent of hominid evolutionary time – has afforded natural selection insufficient time to generate adaptations and eliminate maladaptations to the profound transformation of the human diet that occurred during that period consequent to the inventions of agriculture and animal husbandry, and more recently, to the development of modern food production and distribution technologies.

Lynda Frassetto et al. (Kilde)

A species’ most intimate contact with its natural environment occurs when the species eats it.

Felipe Fernandez-Armesto (Kilde)

Our modern enrvironment, complete with industrial agriculture, burdens our bodies in ways never expected based on our evolutionary history. We are adapted to a meager diet and strenous activity, and now we eat excessively and exercise too little. We are adapted to a low-salt environment, and yet we now eat excesssive amounts of salt. We are adapted to eating lean game, and instead fatten our domesticated animals and then fry our food in yet more fat. We are adapted to eating high fiber and no simple sugars, and yet now we eat processed foods loaded with high-fructose corn syrup. We are not adapted to drinking alcohol, and yet many of us drink to excess. We have easy access to cheap tobacco, and many of us smoke it. A consequence of becoming fat, hypertensive, diabetic, hypercholesterolemic drinkers and smokers is the epidemic of heart disease we now face.

E. Jennifer Weil (Kilde: Evolutionary Medicine and Health: New Perspectives)

Western diets significantly distort the fine-tuned metabolism that has evolved over a very long period of human evolution in adaptation to Paleolithic nutrition.

Wolfgang Kopp (Kilde)

The typical eating pattern in modern societies of three meals plus snacks every day belies the fact that humans are adapted over millions of years of evolutionary history to sporadic eating patterns. The evolutionary pressure of food scarcity resulted in selection for individuals whose cognitive capabilities were heightened in a food deprived state, suggesting that cognition of modern day humans might be enhanced by a change from eating three meals plus snacks every day to an intermittent fasting (IF) eating pattern.

Mark Mattson (Kilde)

We can mend the fissure between the deepest desires of our physiology and the persistent degradation rooted in our modern environment. We can reconnect. We can realign. We can offset the imbalances. The answer is so simple, and it’s right under our noses: elements of origin — those pristine reservoirs of natural nutrition that our ancestral environment once provided, but that are sorely lacking in our industrialized world.

Originating from earth, plant, and animal sources, elements of origin are naturally derived — not artificially fabricated — and provide a full array of nutritional factors perfectly balanced to meet the needs of our inherited physiology. When we reintroduce these elements of origin, we alter systemic imbalances to close the rift between how we are and how we’re meant to be.

(Kilde)

Millions of years of the successful existence of ours and related species in a salt-free environment is sufficient proof that a low-salt diet is man’s original and natural diet, is compatible with normal physiology, and is safe. The modern man while well adapted to low-salt diet is poorly equipped to cope with the salt surfeit imposed on him in recent times.

Vecihi Batuman (Kilde)

Like all other terrestrial life forms, humans evolved in a salt-free environment under intense evolutionary pressure for the selection of salt-conserving genes. Hypertension is a prototypical evolutionary maladaptation disorder of the modern man—a species exquisitely well adapted to low salt conditions suddenly confronted with salt excess.

Vecihi Batuman (Kilde)

The nutritional needs of organisms are shaped by the selective pressures imposed by the nutritional environments in which the organisms evolve. All nutritional concepts that don’t have this fundamental evolutionary idea incorporated into them are flawed.

Eirik Garnås

The results of calcium balance studies have suggested that man can adapt to relatively minute calcium intake by increasing calcium absorption and decreasing urinary excretion when vitamin D is supplied. Using evolutionary logic, this finding suggests that modern people, like primates and hominine ancestors, are capable of adjusting to changing dietary calcium.

Ze’ev Hochberg og Irit Hochberg (Kilde)

Our diet is composed of millions of substances that are part of a biological network. In fact, we eat “biological systems” like a banana, a fish or a piece of meat. There is a connection between the various nutrients in these systems. In other words, there is a balance and an interaction that is part of a living organism.

Begoña Ruiz-Núñez et al. (Kilde)

One of the greatest deviations away from our ancestral diet is the amounts and types of fat found in modern grain fed animals vs. the amounts and types of fats found in grass fed or wild meat, fowl and fish. What we observe is wild meat is remarkably lean, and has relatively low amounts of saturated fats, while supplying significant amounts of beneficial omega-3 fats such as EPA and DHA.

Robb Wolf

Milk is for babies.

Arnold Schwarzenegger

With the introduction of bovine microRNAs into the human food chain, which are able to regulate human gene expression, humans got under gene control by another species, the dairy cow. The microRNA system of cow´s milk has the natural purpose to promote anabolism and growth of the calf, but not of human beings for life time.

Bodo Melnik (Kilde)

Psykologi

The Darwinian perspective on behavior has the capacity to shed light on all aspects of the human experience.

Glenn Geher

Every last bit of psychology can be understood in terms of how the processes that characterize us now had some kinds of benefits for survival and/or reproduction under ancestral conditions.

Glenn Geher (Kilde)

Evolutionary psychology, informed fully by Darwin’s great insights into the nature of life, has proven to be a powerful approach to understanding the full suite of human behaviors.

Glenn Geher og Nicole Wedberg (Kilde: Positive Evolutionary Psychology: Darwin’s Guide to Living a Richer Life)

Human brains require physical activity to function optimally because their physiology evolved among individuals who were rarely able to avoid regular physical activity. Moreover, because energy from food was limited, human brains, like most energetically costly physiologic systems, evolved to require stimuli from physical activity to adjust capacity to demand.

Ian J. Wallace et al. (Kilde)

Humans in modern environments are, essentially, like monkeys in cages at the zoo. As you will see in a broad array of examples in this book, our modern environments are mismatched from the conditions that our bodies and minds were shaped to experience in many ways.

Glenn Geher og Nicole Wedberg (Kilde: Positive Evolutionary Psychology: Darwin’s Guide to Living a Richer Life)

If you want to understand what factors lead to happiness, then you have to understand what kinds of outcomes under ancestral conditions led to feelings of positive affect – outcomes such as positive relationship outcomes, success in obtaining resources, success in the lives of kin (such as the birth of a niece or a nephew), and so forth. Further, if you want to understand factors that lead to problems in the modern day, you can easily look to instances of mismatch between modern conditions and ancestral conditions.

Glenn Geher og Nicole Wedberg (Kilde: Positive Evolutionary Psychology: Darwin’s Guide to Living a Richer Life)

To some extent, selfish genes in humans have created altruistic apes who focus largely on what they can do to help others and build strong and positive communities.

Glenn Geher og Nicole Wedberg (Kilde: Positive Evolutionary Psychology: Darwin’s Guide to Living a Richer Life)

From a Darwinian perspective, wealth is not based on money – rather, wealth is based on the connections that you have and the mark that you leave on the world.

Glenn Geher og Nicole Wedberg (Kilde: Positive Evolutionary Psychology: Darwin’s Guide to Living a Richer Life)

Religion likely evolved to keep behaviors within a community in check to cultivate behavioral patterns in which people would work toward the common good.

Glenn Geher og Nicole Wedberg (Kilde: Positive Evolutionary Psychology: Darwin’s Guide to Living a Richer Life)

Because positive moods seem to influence multiple behaviors that are relevant to reproduction and survival, it is a reasonable hypothesis that positive moods were selected for during our evolutionary history.

Ed Diener et al. (Kilde)

In ancestral times, integration of inflammatory responses and behaviours of avoidance and alarm provided an evolutionary advantage in managing the microbial world. In the absence of the temporizing influence of commensal organisms that were rife in environments in which humans evolved, the inflammatory bias of the human species in the civilized world has been increasingly engaged in the complex world of psychosocial interactions and the inevitable stress it engenders. Responding to these sterile insults with activation of the inflammasome and mobilization of myeloid cells to the brain, the resultant release of inflammatory cytokines impinges on neurotransmitters and neurocircuits to lead to behaviours that are poorly suited for functioning in modern society. This inevitability of our evolutionary past is apparent in the high rates of depression that are seen in society today.

Andrew H. Miller og Charles L. Raison (Kilde)

Our neural circuits were designed by natural selection to solve problems that our ancestors faced during our species’ evolutionary history.

Leda Cosmides og John Tooby (Kilde)

We are able to solve problems that no hunter-gatherer ever had to solve — we can learn math, drive cars, use computers. Our ability to solve other kinds of problems is a side-effect or by-product of circuits that were designed to solve adaptive problems. For example, when our ancestors became bipedal — when they started walking on two legs instead of four — they had to develop a very good sense of balance. And we have very intricate mechanisms in our inner ear that allow us to achieve our excellent sense of balance. Now the fact that we can balance well on two legs while moving means that we can do other things besides walk — it means we can skateboard or ride the waves on a surfboard. But our hunter-gatherer ancestors were not tunneling through curls in the primordial soup. The fact that we can surf and skateboard are mere byproducts of adaptations designed for balancing while walking on two legs.

Leda Cosmides og John Tooby (Kilde)

Natural selection, the process that designed our brain, takes a long time to design a circuit of any complexity. The time it takes to build circuits that are suited to a given environment is so slow it is hard to even imagine — it’s like a stone being sculpted by wind-blown sand. Even relatively simple changes can take tens of thousands of years.

The environment that humans — and, therefore, human minds — evolved in was very different from our modern environment. Our ancestors spent well over 99% of our species’ evolutionary history living in hunter-gatherer societies. That means that our forebearers lived in small, nomadic bands of a few dozen individuals who got all of their food each day by gathering plants or by hunting animals. Each of our ancestors was, in effect, on a camping trip that lasted an entire lifetime, and this way of life endured for most of the last 10 million years.

Generation after generation, for 10 million years, natural selection slowly sculpted the human brain, favoring circuitry that was good at solving the day-to-day problems of our hunter-gatherer ancestors — problems like finding mates, hunting animals, gathering plant foods, negotiating with friends, defending ourselves against aggression, raising children, choosing a good habitat, and so on. Those whose circuits were better designed for solving these problems left more children, and we are descended from them.

Leda Cosmides og John Tooby (Kilde)

These stone age priorities produced a brain far better at solving some problems than others. For example, it is easier for us to deal with small, hunter-gatherer-band sized groups of people than with crowds of thousands; it is easier for us to learn to fear snakes than electric sockets, even though electric sockets pose a larger threat than snakes do in most American communities. In many cases, our brains are better at solving the kinds of problems our ancestors faced on the African savannahs than they are at solving the more familiar tasks we face in a college classroom or a modern city.

Leda Cosmides og John Tooby (Kilde)

Next time somebody tells you something that sounds important, think to yourself: ‘Is this the kind of thing that people probably know because of evidence? Or is it the kind of thing that people only believe because of tradition, authority or revelation?’ And, next time somebody tells you that something is true, why not say to them: ‘What kind of evidence is there for that?’ And if they can’t give you a good answer, I hope you’ll think very carefully before you believe a word they say.

Richard Dawkins