I highly recommend investing an hour into watching this video. It’s a great archaeology/anthropology introduction for everyone interested in modern diets. It touches on a lot of the main concepts necessary to understand what the heck is being talked about when referencing the methods used to figure out what was going on during the paleolithic era. The talk is super-approachable for intro purposes, but Teresa Steele is also an actual scientist, so more advanced folks will probably appreciate some of what she discusses.

The Australopithecus afarensis to Agriculture Talk (3.4 million – 10,000 years ago)

One concept that seems obvious, but I’d never consciously considered is the size of animals eaten by humans vs. other primates. It’s easy to look at a timeline of the paleolithic and see that human ancestors ate some meat, but there’s a key distinction. Humans eat animals much larger than themselves, while all other primates eat animals much smaller than themselves. Thus, talking about primates as “meat eaters” is factually true, but it ignores a huge difference between Homo sapiens and other surviving species. Hunting large game necessitates a degree of cooperation that is on an entirely different level than the individuality of hunting small game. Since we know Homo neanderthalensis also hunted in groups, we can start to make some interesting comparisons with the rest of the Homo lineage.

“I’d like to add to that one of the things that’s unique about humans among primates is how much meat we consume. A large percentage of our calories come from meat on average – compared to other primates. Amongst primates, chimpanzees eat the most amount of meat. And humans on average eat about 10x the amount of meat as other primates.”

The interesting question professor Steele attempts to address in her research and in this talk is: “When did the differences in human and chimpanzee diets evolve?” The implications of this answer impact us in terms of social organization, evolved behavior, and optimal diets in the modern context. A big factor in determining this is that there is little evidence of hominin plant consumption during the Acheulean (~1.6 m – 100,000 years ago) period of the paleolithic. Admittedly, part of this is because plant evidence doesn’t fossilize as well as bones, but it’s interesting that the plant eating assumption persists on such small amounts of evidence. As usual, this refutes the vegetarian position in terms of evolutionary biology.

“Humans specialize in nutrient dense, hard to extract sources, while chimpanzees specialize in ripe fruits and plants that have low nutrient density which are also easily collected.”

The relative difficulty of resource extraction also carries implications for human society versus primates. This impacts the necessity of tool use and social organization to sustain expanding populations. Thomas Malthus’ famous prediction that human population would be restricted by a linear growth in the food supply compared to an exponential growth in population comes to mind. The Malthusian limit suffers from an assumption that humans are stuck in the chimpanzee mode of resource collection. To be fair to Malthus, it’s still possible that there is a limit on production that is simply beyond the date he predicted. Thus, the growth in production and population since his prediction doesn’t completely refute his hypothesis. The questions raised by Malthus remain at the foundations of geopolitical debates to this day.

Looking at this from the perspective of adaptive evolution, we also see foundations for hypotheses to explain the explosive growth in human brain size over the paleolithic. Dealing with the problems of tools and groups certainly placed different pressures on the evolution of humans. In other words, the information in this video underpins everything I write about on evolvify. Watch it. Love it.

Methods of study

1. Archaeological record (tools, artifacts, bones)
2. Skeletal morphology (bone mechanics & dental structure)
3. bone chemistry

[cft format=0]

• Human Diet Unique in High Meat Content
• Australopithecus afarensis Diet
• Cut-Marked Bones 2.5 Million Years Ago
• Evidence of Ancient Hominids Eating Aquatic Animals
• Acheulean Hunting and Scavenging (Homo erectus)
• Exceptional Preservation Sites with Wood Spears
• Neandertals in Europe
• Bone Chemistry Findings
• Hunting Technology
• Middle Stone Age in Africa
• Modern Humans in Europe
• Plant Use
• Intensification of Resource Extraction
• Why Humans Replaced Neandertals
• Conclusive Evidence of Cut Marks
• Ratio of Fatty Acids in Diet and Brain Size

I hate postmodern feminism. As a man by birth, not by choice, I call shenanigans on the idea of a vast male conspiracy in which I’m hopelessly complicit. The charge that I am conditioned from birth to oppress all of the women I love, all of the women I know, and all of the women on the planet is not one with which I’m likely to acquiesce. The notion that I’m doomed to omni-directional socialization smacks of Christianity’s putrid communicable mind-disease of “Original Sin”. But while Christianity offers potential salvation through authoritarian subjugation of our minds and the rest of our human nature after a life of guilt, postmodern feminism offers nothing more than perpetual guilt and a labryinthian trial of futility that would lead Josef K to rejoice in the relative clarity of his nightmare of Kafka’s prison. Like the magical monotheisms’ strategic defense by placing its rules outside the observable world and beyond the understanding of feeble brains, postmodern feminism holds its truths just on the other side of spectacular society’s aim or grasp. We are all inside the conspiracy, and thus, forever powerless to question its pervasive hold with our tainted minds.

But let’s get to the bad news…

Apparently, I am guilty as charged. I openly view women as different from men… and I like it. What’s worse, I have been known to love women precisely because of their femininity. And I probably shouldn’t admit this, but I have been successful in being smitten by oppressing women to degree that they have appreciated my undying appreciation of said femininity. Thus, I have apparently pulled off the masterstroke of Pavlovian conditioning by convincing women that there is something special different about them worthy of distinction, and that that inherent beauty defect is a point of delineation warranting irrepressible affection and admiration objectification.

Yet despite my actual loathing for postmodern feminism, and tongue-in-cheek embrace of their accusatory program, I consider myself a Darwinian feminist. Let’s be clear… that is a political position of feminist bias influenced by Darwinian science. This is not to be confused with the scientific position of feminist Darwinism, in which scientific hypotheses are formed through the perspective gained by freeing oneself from the scientific community’s irrepressible patriarchy (Vandermassen 2008). I take this position of political bias because since the agricultural revolution, feminists have an indisputable point (generally speaking). One of the first sociopolitical developments of agricultural society was property. Besides land, women were subjected to the forefront of the legal ownership construct. It’s difficult to disentangle the development of agriculture, writing, law, oppression, and theistic religion. This difficulty is explained in their mutually supportive natures (the Matrix beta version?).

In my overlap into the paleosphere, I wonder about the influence of gendered conflagrations of caveman romanticism. I think the first of Melissa McEwan’s posts I ever read was on the question of ‘Sexism and Paleo‘. Though I disagree with a few of the points in that piece, I share a disdain for the popularized caveman stereotype. On one level, I’ve wandered around a lot of wilderness looking for caves, and I can verify that they’re not a reliable strategy for shelter from the elements or protection from predators. Thus, I vote for burying the “caveman” concept along with agricultural dominance hierarchies and the vegetarian myth. On the psychosocial level, I see the caveman image of a clubbed woman being dragged off to be used as a reproduction machine as an overt misogynistic cultural amplification of testosterone-drunk wish-thinking. As a man, I’m also not going to pretend that I can’t imagine where that impulse comes from. If you take that last sentence as a justification, you don’t understand me and should probably stop reading now.

*Much of what follows was influenced by a 4-participant, 5-article throwdown in the “Feminist Forum” feature on the intersection of feminism and Darwinism in a 2008 issue of Sex Roles…  a peer-reviewed, openly feminist leaning journal. The journal is offering free and direct access through December 31, 2010. Rebecca Hannagan wrote the target article which was reponded to by feminists Laurett Liesen, Griet Vandermassen, and Celeste Condit. Hannagan also provides a follow-up on the others’ comments.

“Ignorant” Evolutionary Psychology vs. “Ignorant” Feminism

And thus begins the typical impasse between evolutionary psychology and feminism. Feminists charge evolutionary psychologists with indiscriminate justification of evil, and evolutionary psychologists accuse feminists of misunderstanding that the “job of scientists is to find out how things work, to try to be evenhanded with the evidence, and to present their findings…” (Vandermassen 2008). The project of science is understanding. The project of evolutionary psychology is understanding psychology in the context of evolution. Beware anyone who conflates understanding with justification.

“Evolutionary psychologists’ continued ignorance of feminism and their ongoing failure to recognize the vast contributions by feminist evolutionists is at worst the continuation of male bias, and at best scholarly negligence.” (Liesen 2008)

“[P]reviously considered an “archaic debate” [, genetic determinism], turned out to be a real concern still in the minds of many feminists. As Jonathan Waage and Patricia Gowaty (1997) write in their conclusion, “[t]erminology, politics, and ignorance are, inretrospect, major barriers to the dialectic of feminism and evolutionary biology” (p. 585).” (Vandermassen 2008)

Darwin: More Feminist than the Feminists

Darwin’s world-view was certainly steeped in a world of Victorian ideals. As such, he tended to ethnocentrize, anthropomorphize, and Victorianify a bit too frequently. However, behind the now anachronistic veneer, his wisdom was potent.

“Darwin also attributed a more important evolutionary role to females than did most evolutionists for nearly a century after him: female choice in sexual selection. Since females bear the greater parental investment through pregnancy and lactation, they have more to gain from being highly selective about with whom to mate than do males. As a result, certain traits are selected for in males if, over time, females choose to mate with the males that bear those traits more than those who do not.” (Hannagan 2008)

That first sentence could have also read, “Darwin also attributed a more important evolutionary role to females than did most feminists for nearly a century after him.” In the concept of sexual selection, we have a solid foundation from which to sweep away all attempts to legitimize gendered patriarchy. In the concept of sexual selection, we have a power structure that, excepting violence, is nearly irrefutable for men. Across the millions of species of the animal kingdom, females exercise ultimate say in selecting with whom to reproduce. The whims of females have given us everything from the peacocks’ tail (Darwin 1972) to the bowerbirds fantastic nests and 12 foot antlers of the Irish elk (Coyne 2009) to our very creativity and intelligence (Miller 2001). Sexual selection is almost universally ignored, and when it is considered, is often misunderstood as a patriarchal mechanism for herding women. Competition between men acts as a fitness cue that aids women in selecting mates (intrasexual sexual selection). Direct displays by men to women also act as fitness cues to aid women in selecting mates (intersexual sexual selection). This isn’t to say that dominance hierarchies don’t exist in various species, but it is necessary to question the assumption that intrasexual selection is a dominance hierarchy rather than a fitness cue. Intersexual selection is always the latter.

The positive implications of sexual selection for a Darwinian feminism are many. Yet ironically, and to the detriment of their program, postmodern feminism has attacked evolutionary biology after missing the point.

Another area that’s often ignored or assigned to the evils of patriarchy is competition between females. It would be naive to assume that sexual selection is unidirectional. It is true that females have the highest degree of choice, but men also gain reproductive advantage by choosing the “best” mate. Intrasexual female competition has serious negative consequences. Stereotypically female behaviors from fashion to makeup to anorexia have been attributed to competition between females (Li, et al. 2010). Interestingly, Li, et al also found this intrasexual competition functioning similarly in homosexual men. Activities motivated by intrasexual female competition have traditionally been prime targets for postmodern feminists to assign to patriarchal power structures. However, it seems that this may be a misguided confusion of intrasexual and intersexual competition.

Men and Women Are Different

That is not a claim or implication that a male brain or a female brain is better, it is a statement of fact. While – Top 5 target of anti-evolutionary psychology deniers – Steven Pinker had already convincingly refuted “blank slate” conflagrations in his 2001 book, “The Blank Slate” (linked below), neuroscience has since been demonstrating differences via fMRI and other brain studies. Sexual dimorphism (differences) in brain development have been observed to be directly influenced by differences in XX vs. XY chromosome factors (that is at the genetic, pre-hormonal level), and by gonadal hormone differences (e.g. testosterone) (Arnold 2004).

“Genes that are found on the sex chromosomes influence sexually dimorphic brain development both by causing sex differences in gonadal secretions and by acting in brain cells themselves to differentiate XX and XY brains. Because it is easier to manipulate hormone levels than the expression of sex chromosome genes, the effects of hormones have been studied much more extensively, and are much better understood, than the direct actions in the brain of sex chromosome genes. Although the differentiating effects of gonadal secretions seem to be dominant, the theories and findings discussed above support the idea that sex differences in neural expression of X and Y genes significantly contribute to sex differences in brain functions and disease.” (Arnold 2004) [emphasis mine]

“Many neurological and psychological diseases vary in incidence or severity between the sexes. Some of these diseases are known to involve X-linked genes. The vulnerability of males to mutations of X-linked genes is an obvious source of sex differences in diseases. However, more subtle variation of the same loci probably accounts for some of the differences in psychological and neural function among populations of males and females.Recent improvements in methods to manipulate and measure gene action will lead to further insights on the role of X and Y genes in brain gender.” (Arnold 2004)

Recent theoretical developments in neuronal plasticity have given the postmodern feminists and other blank-slaters a new angle to make us all the same. Some now claim that the overarching and nefarious social construct causes brains to physically develop gender identities based on patriarchal domination by way of language faculty alteration (Kaiser, et al. 2009). That’s right folks, males are so crafty that we’ve figured out how to physically alter the neuronal structure of women’s minds to do our bidding as hapless automatons. To say that gender bias goes deep is apparently an understatement of mind-bending proportions. Curiously, all such studies seem to recognize, or ignore, sex differences in the brains of all other animal species, but resort to neck-down Darwinism when considering humans. Again, the postmodern feminist position parallels that of religion in its insistence that evil forces corrupt us on unseen levels, and by excluding the human brain as the one thing Darwinian considerations can’t mustn’t be applied to.

Years after Pinker’s work, Hannagan is still comfortable enough about sex differences to say: “Broad personality constructs, such as neuroticism, extraversion, openness, agreeableness and conscientiousness, are heritable and there are small but consistent differences between men and women on two of the big five personality constructs—extraversion and agreeableness.” (Hannagan 2008b) [emphasis mine]

This is only the tip of the proverbial iceberg regarding physical (brain included) and psychological differences.

Against the Caveman Mystique

It’s hard for me to imagine the caveman stereotype existing without the logically flawed, but evolutionarily advantageous, human cognitive availability bias (or heuristic). In short, since we find evidence of humans in many caves, but not out in the open, we tend to assume humans were more often inhabiting caves than out in the open. The art and human remains found in caves are not found there because a majority of our ancestors were “cavemen”. They are found there because caves offer protective value for preservation, and because caves are geographically obvious places to look. Thus, the probability we’ll look in caves multiplied by the probability of evidence being preserved in caves skews cave evidence to secure an artificially elevated place in our consciousness. It’s also the case that human remains are dragged to caves by whatever ate them, or humans died in caves by becoming trapped. All of this is further multiplied by the caveman narrative in culture… it’s easy to picture, and therefore remember, and therefore spreads.

The following excerpt is from a review of the apparently poorly received book, ‘The Caveman Mystique‘ by Martha McCaughey. While it’s directed at the McCaughey’s view of the caveman stereotype, I suggest that it should also be tested against feminist theory.

Perhaps the most curious omission in the book is any discussion of the evolutionary psychological view of the human female. We are repeatedly told the dubious notion that the evolutionary view of the male is that of the stereotypical caveman who drags women off by the hair for sex. But what is the corresponding picture of the female? Evidently McCaughey doesn’t think this is informative. If men are interested in having sex with as many women as possible, what does this say about women? It is a fact of simple arithmetic that the average number of sexual partners must be identical for males and females (assuming a 50-50 sex ratio). So if men have X female partners on average, the average woman must also have X male partners. What does this logic imply about the female side of mating? (McBurney 2009)

Hunter-Gatherers: Hierarchy vs. Egalitarianism

The hunter-gatherer stereotype often does no better than the caveman tripe. Rather than the overt “masculinity” of clubbing all women of one’s choosing, it’s replaced by the overt “masculinity” of killing a wily beast and the implied “masculine” domination associated with bestowing such a gift upon the rest of the band. Unfortunately, the “Man the Hunter” hypothesis that was forwarded to explain human cognitive development has been considered inaccurate almost consistently since the 1970s (Hannagan 2008).

In discussing sexual selection above, I argued that there is a fundamental refutation of patriarchy inherent in the Darwinian framework. That itself should sound the death knell for any attempts at misogyny or gendered political dominance. However, pre-agricultural hunter-gatherer existence takes that a step further. It is likely that the prevailing form of social arrangement for the bulk of human evolution was social anarchism in the context of small hunter-gatherer bands. It is important not to assume contemporary stereotypes of socialism and anarchy here.

As found by anthropological studies of recent hunter-gatherer bands, hunter-gatherer bands exhibit high levels of communitarian and cooperative behaviors combined with an often explicit rejection of hierarchy. To observe this clearly, we also need to make a distinction between immediate-return hunter-gatherers and delayed-return hunter-gatherers. The immediate vs. delayed distinction refers initially to the timeframe in which they consume hunted and gathered food. With immediate-return bands, we see daily consumption of most food, little storage, and a tendency to an almost perpetually nomadic existence. Delayed-return hunter-gatherer bands tend to differ in that they are geographically isolated, or have borders imposed upon them by surrounding populations . In this transitional stage between ancestral hunter-gatherer existence and agriculture, we see more evidence of hierarchy, despite a lack of private property relative to modern agrarian cultures (Gray 2009).

Overall, we see a general lack of ownership or conceptions of private-property within hunter-gatherer social arrangements. The division of labor is an economic strategy that benefits both individuals and the group. Value is not necessarily assigned a priori to male or female, or to hunter or gatherer.

In some examples, anthropologists have noted a significant degree of male group control over “marriages”. This is often imposed not by potential suitors, but by the male family members of the woman. This is misleading as it’s often an ethnocentric assignment of our notions of monogamy on cultures which don’t necessarily share the same sexual norms. Even in societies with supposed marriages, females exercise a high degree of mate choice when it comes to actual reproduction:

“Having high status as a good hunter has been shown to raise a man’s reproductive success everywhere the relationship has been investigated, one of the pathways being that it gains him sexual access to more and higher quality women, whether officially or in extra-marital affairs.” (Vandermassen 2008) [emphasis mine]

At first glance, this would seem to refute my comment a couple paragraphs back about non-assignment of value to the hunter role. However, it merely reinforces my qualification that such value is not assigned a priori. Hunters, as a category, do not automatically benefit. Hunters who excel are assigned a higher fitness value and therefore tend to be selected by females to father offspring. This does however, refute the claim that arranged marriages act as true control over women’s reproduction.

Autonomy

In another word, freedom. Why is every sovereign individual (by that I mean every individual) in the 21st century born not as a human, but as a proprietary asset on the balance sheet of a nation-state? Why do all agricultural societies suffer from drastically diminished levels of freedom? Why do geographically and otherwise isolated delayed-return hunter-gatherer bands tend toward political hierarchy while their immediate-return analogues do not? The atomization of individuals within the supra-organism of culture has been elevated over the autonomy our ancestors were born with, but why?

For 99%+ of human evolution, every able-bodied human has had the option of leaving oppressive regimes. Every individual had the choice to opt out of social games stacked against them. The fact of human migration across the totality of earth is proof that this strategy was employed many times. However, it would have happened more rapidly if remaining in a group was not generally more advantageous for each individual. The ability to round up a group of like-minded individuals to leave was somewhat balanced by the group’s recognition of a general strength in numbers. Call it the invisible hand of exploration, or call it migration, but it acted as a perpetual check on all forms of unwelcome domination. Their complete lack of the geographical and legal boundaries we’re faced with today allowed an entirely different paradigm for human social interaction. This concept is not new. The right to cross all borders to leave oppression is legitimized in the United Nations’ Universal Declaration of Human Rights. However, it is ignored by every country on earth for reasons beyond the scope of this piece. Further, the concept loses its actual value when there is no more frontier, but only trading one domination hierarchy for the flag of another.

The temptation to form in-groups and out-groups along lines of gender, ethnicity, education, running skills, or other coin flips is a curse of a stone age brain in an information age world. Yielding to such temptations will invariably lead to error. The unbearable lightness of paranoia that accompanies postmodernist cynicism is a direct path to your own distracted energy. You’re all formally invited to ditch the postmodern feminist doomsday machine for a refreshing trip to the history of the Galapagos…

Hey! I finished in under 4,000 words! Is this the part where I get called a misogynist then burned at the altar of Margaret Mead, or… perhaps you have other thoughts? (If you have questions or comments that you think are too far off topic, you can also post ’em in the forum.)

References
Arnold, Arthur P. “Sex chromosomes and brain gender..” Nature reviews. Neuroscience 5, no. 9 (September 2004): 701-8.
Curry, Oliver. “Who’ s Afraid of the Naturalistic Fallacy?”. Evolutionary Psychology (2006): 234-247.
Gray, Peter. “Play as a Foundation for Hunter- Gatherer Social Existence s.” The American Journal of Play 1, no. 4 (2009): 476-522.
Hannagan, Rebecca J. “Gendered political behavior: A Darwinian feminist approach.” Sex Roles 59, no. 7/8 (2008).
Hannagan, Rebecca J. “Genes, Brains and Gendered Behavior: Rethinking Power and Politics in Response to Condit, Liesen, and Vandermassen.” Sex Roles 59, no. 7-8 (September 2008): 504-511.
Kaiser, Anelis, Sven Haller, Sigrid Schmitz, and Cordula Nitsch. “On sex/gender related similarities and differences in fMRI language research..” Brain research reviews 61, no. 2 (October 2009): 49-59.
Li, N. P., Smith, A. R., Griskevicius, V., Cason, M. J., & Bryan, A. (2010). Intrasexual competition and eating restriction in heterosexual and homosexual individuals. Evolution and Human Behavior, 31(5), 365-372.
Liesen, Laurette T. “The Evolution of Gendered Political Behavior: Contributions from Feminist Evolutionists.” Sex Roles 59, no. 7-8 (July 2008): 476-481.
McBurney, Donald H. “REVIEW – The Caveman Mystique: Pop Darwinism and the Debates over Sex, Violence, and Science.” Sex Roles 62, no. 1-2 (June 2009): 138-140.
Trivers, R.L. . Parental investment and sexual selection. In B. Campbell (Ed.), Sexual selection and the descent of man, 1871-1971 (1972) : 136-179. Chicago, IL: Aldine. ISBN 0-435-62157-2
Vandermassen, Griet. “Can Darwinian Feminism Save Female Autonomy and Leadership in Egalitarian Society?.” Sex Roles 59, no. 7-8 (August 2008): 482-491.
Waage, J., & Gowaty, P. (1997). Myths of genetic determinism. In P. Gowaty (Ed.), Feminism and evolutionary biology: Boundaries, intersections, and frontiers (pp. 585–613). New York: Chapman & Hall.
Walter, Alex. “The Anti-naturalistic Fallacy : Evolutionary Moral Psychology and the Insistence of Brute Facts.” Evolutionary Psychology, no. 1999 (2006): 33-48.
Wilson, David Sloan, Eric Dietrich, and Anne B Clark. “On the inappropriate use of the naturalistic fallacy in evolutionary psychology.” Evolutionary Psychology (2003): 669-682.

What is the “Adventure Gene”?

The science on the genetics of personality is still in its infancy. It landed on the world in 1996, with two papers attempting to link Novelty Seeking (NS) and Extraversion with the DRD4 gene coding for a particular dopamine receptor in the brain (Ebstein 2006). It’s important to consider that the interaction of particular gene expressions within individuals is quite complex. The interaction of multiple genes can yield a range of results. Therefore, we can’t say the gene discussed here is an on or off switch that says people with one variant will necessarily act a certain way and those with another variant will necessarily act according to another set of expectations. So literally… there is no single, binary adventure gene that determines whether or not you’ll be boring or awesome. However, links to personality traits that would tend to bias an individual toward certain personality traits that would lead someone to be more adventurous are starting to pop up. Enough of the scientifically required equivocation… back to DRD4…

Novelty Seeking

The problem with science is that somebody has to pay for it. Don’t get all “it’s all a drug company conspiracy” on me now! What that means for this discussion is that most of the early research on the genetics of personality has involved “disorders” such as ADHD. Thus, we need to parse a bit of the jargon. “Novelty Seeking” is a specific personality used by researchers and professionals to make comparisons from one person to the next. The research here talks about it like crazy, but let’s go colloquial.

The Non-Technical Guide to Novelty Seeking

• Tendency to respond strongly to novelty
• Exploratory activity in pursuit of rewards
• Active avoidance of monotony
• Active avoidance of punishment
• Less influenced by emotion (especially fear) in risk assessment (Roussos et al. 2009)

Say what? Novelty seeking means seeking novelty? Shocker… I know. The trouble is that if you read the literature, much of it discusses NS in terms that may make you think of depraved gambling addicted meth fiend crack head zombies (see Igor, science fun). As it turns out, novelty, and the other tendencies, have serious implications when we start to talk about how this relates to human evolution and the spirit of adventure required to populate the entire planet.

When we start looking at DRD4, it turns out that a specific variant significantly correlates with NS. In such individuals, those with the “adventure gene” present by using less emotion to make decisions and are less impacted by the negative emotions of others when forced to make decisions. Some people are more inclined to be “response ready” when faced with tough decisions in situations of uncertainty and emergency. (Wang et al. 2004)

Consistent with this “response ready” behavior hypothesis is the significantly better performance of DRD4 knockout mice on tests of complex coordination and the observed faster reaction times exhibited by individuals with [the adventure gene], in comparison to [the boring gene] individuals (Roussos et al. 2009).

Humans with the adventure gene also tend to be startled less. What I found interesting about that is not only do they seem less startled physically (they don’t tend to jump and squeal with shock), but their emotional response to being startled is also attenuated. This tendency is true on a short-term scale, but also holds up when stretched over time. These individuals maintained their ability to plan, make decisions, and undertake complex problem solving in the face of direct threat or in novel environments (Roussos et al. 2009).

We’re starting to get a pretty solid picture of the type of person you might want to turn to when things get ugly. For now, we’ll go ahead and ignore the fact that this sort of behavior can be problematic when my ex-girlfriends others have to deal with me these relatively detached wayward souls on a day-to-day basis… when nothing dramatic is afoot.

Paleo Exit from Africa

So much happened in the paleolithic! Not only did our favorite species, Homo sapiens, hit the scene, but the travel industry was born! The migration of humans across the globe had such an impact on our psychology that, to this day, we can simply put “travel” in a list of things we like and all the sexy people in a hundred mile radius will feel an irresistible attraction to us.

Sure, Homo erectus had the travel industry cornered a few hundred thousand years before us, but hey… they’re kind of us too. Current estimates for the last out-of Africa exodus focus on 44,000-47,000 years ago. And wouldn’t you now it, the explosion of the adventure gene in the population has been dated to 40,000-50,000 years ago by completely different methods (Wang et al. 2004; Roussos et al. 2009).

“The simplest explanation, then, for this worldwide [spread] is the most straightforward: the [adventure gene] was strongly selected for at about the time of the last major out-of-Africa exodus (Wang et al. 2004)”.

Now why oh why would something christened “the adventure gene” by hyperbolic determinism have been strongly selected for during a global migration?

Evolutionary Considerations

Make no mistake about it, we’ve ventured well beyond evolutionary biology to get to this point. We’re talking about genes that directly influence behavior and cognition for favorable survival and reproductive success. That’s right confused minions… evolutionary psychology. Before long, we’ll all be automatons controlled by our genes making us tell everyone we want to be astronauts and firemen! Oh Noes!

“It has been suggested that [the adventure gene] would have great evolutionary importance contributing to major human migratory expansions in the past. Indeed, it is conceivable that risk taking with efficient problem solving, under-reactivity to unconditioned aversive stimuli and low emotional reactivity in the face of preserved attentional processing of emotional stimuli may have been advantageous phenotypic characteristics fostering migration and expansion. Low emotional reactivity is associated with high emotional endurance which can afford physical, emotional and mental resilience in the face of adversity in perilous environments. The disadvantageous decision making in [the adventure gene], high NS individuals does not necessarily result in dysfunctional behavior, since all our subjects were normal healthy volunteers, with no history or presence of psychiatric illness. It may even be that [the adventure] genotype may be protective against stress, anxiety and depression by moving attention away from emotional adversity, as an analogue to the psychological termof “denial” (Roussos et al. 2009).”

In other words… “[The adventure gene] appears to be favoured by selection (1) when benefits can be gained from migrating to new environments , and (2) under resource-rich environmental conditions (Penke et al. 2007 )”. And the extra bonus is that it may protect individuals from downward emotional spirals in adverse situations. So maybe you get accused of a little misanthropy from time to time. Ah well… it will probably seem worth it when you’re having more fun than everyone else.

What could be the behavioral differences that are selected for? By observing current genetically influenced differences in human personality, it has been suggested that resource-depleted, time-critical, or rapidly changing environments might select for individuals with “response ready” adaptations, whereas resource-rich, time-optimal, or little-changing environments might select against such adaptations . We have speculated that such a “response ready” adaptation might have played a role in the out-of-Africa exodus and that allele frequencies of genes associated with such behavior certainly would be influenced, subsequently, by the local cultural milieu (Wang et al. 2004).

Referring to these findings, [others] noted that under conditions of environmental harshness and resource scarcity (as is common in hunter-gatherer societies), intensive cooperation, strong family ties, stable pair bonds, and biparental investment are necessary for survival and successful reproduction. These ancestrally typical conditions would maintain the more risk-averse, ancestral form of the [the adventure gene] (Penke et al. 2007)

In this model, the 4R variant has been honed for hundreds of thousands of years to function optimally, whereas [the adventure gene] variants are suboptimal yet confer a behavioral advantage in some environments. Though the “response ready” hypothesis was proposed as an environmental adaptation, sexual selection has long been proposed as another source of human variation (Darwin 1871). (Wang et al. 2004)

The next question for me is… “So what do we do with this information?” If you have any thoughts, I’d love to hear them below. To my mind, it would be an act of violence (in the parlance of Foucault) for society to place constraints on this group of people. If some of us suffer rapt elation at the prospect of adventure and exploration, wouldn’t herding such children into pens of monotony be a “tyrrany of the majority” of a serious flavor? Or is it better to reign in such impulses… to keep them in hibernation until such characteristics are needed?

And… Why is adventure so damned sexy that it’s the foundation of memes?

Please leave a minimum of 3 comments (yes, 3 each ya slackers) below.

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But under more luxuriant environmental conditions, when children can survive without so much paternal support (as in most agricultural and modern societies), the more risk-seeking 7R allele should be favoured by selection, as it leads to a personality more prone to sexual promiscuity and intrasexual competition (Penke et al. 2007).

and… Your paleo brain in the modern world…

We have speculated that the same traits that may be selected for in individuals with a DRD4 7R allele also may predispose behaviors that are deemed inappropriate in the typical classroom setting and hence diagnosed as ADHD. In this environmental-mismatch hypothesis (Hartman 1993; Jensen et al. 1997), the DRD4 7R subset of individuals diagnosed with ADHD is assumed to have a different, evolutionarily successful behavioral strategy, rather than a disorder. It is also possible, however, that DRD4 7R, although selected for in human populations, could have deleterious effects when combined with genetic variants in other genes. (Wang et al. 2004)

Oh your heart is pounding just thinking about it! I can almost feel it. No, seriously. You didn’t feel that?

References

Ebstein, R. P. (2006). The molecular genetic architecture of human personality: beyond self-report questionnaires. Molecular psychiatry, 11(5), 427-45. [Link]

Penke, L., Denissen, J. J., & Miller, G. F. (2007). The evolutionary genetics of personality. European Journal of Personality, 21, 549-587. [Link]

Roussos, P., Giakoumaki, S. G., & Bitsios, P. (2009). Cognitive and emotional processing in high novelty seeking associated with the L-DRD4 genotype. Neuropsychologia, 47(7), 1654-9. [Link]

Wang, E., Ding, Y., Flodman, P., Kidd, J. R., Kidd, K. K., Grady, D. L., et al. (2004). The genetic architecture of selection at the human dopamine receptor D4 (DRD4) gene locus. American journal of human genetics, 74(5), 931-44. [Link]

Robert Wright

The best-selling author of “Nonzero,” “The Moral Animal” and “The Evolution of God,” Robert Wright draws on his wide-ranging knowledge of science, religion, psychology, history and politics to figure out what makes humanity tick — and what makes us moral.

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