Presentation on theme: "Biological Theory of Morality"— Presentation transcript:
1Biological Theory of Morality Jonathan Haidt:Biological Theory of Morality
2How do people come to know what is right and wrong? Haidt: Biological Theory of MoralityHow do people come to know what is right and wrong?Haidt: moral knowledge fundamentally intuitive or emotional.Social Intuitionist Model: moral emotions/intuitions and moral reasoning work together to produce moral judgments. Moral judgments are like aesthetic judgments – we make them quickly, intuitively, automatically. We know what is right and wrong much the same way we know what is beautiful and ugly. When called on to explain ourselves, we make up reasons after the fact. Moral reasoning does affect judgment, but this happens primarily in a social context, as people talk, gossip and argue.
3Chapt 1: Where Does Morality Come From 1. Re the origin of morality, what, according to Haidt, is the difference between nativism, empiricism and rationalism? Which, if any, of these theories does Haidt favor?nativism (inborn)empiricism – we learn them (thus morals vary extensively from one culture to another)rationalism – we construct them on the basis of our (social) experiences, but only as on the mind develops (Piaget, Kohlberg, Turiel)2. Note 7 (p 7) – Haidt: infants may actually react to violations of fairness as early as 15 months (Schmidt & Sommerville 2011). That’s our seminar paper for Thursday (I will present it, as an example of the kind of presentation I want folks to give).3. What is Kohlberg’s view of moral development? What is the difference between the pre- conventional, conventional, and post-conventional stages? How does his view relate to Piaget’s developmental theory?4. What does Haidt mean when he says that American and W. European cultures have ‘stripped down and thinned out the thick, all-encompassing moral orders [typical of original cultures]”?5. What is the distinction Turiel makes between moral rules and social conventions?
4Chapt 1: Where Does Morality Come From 6. What is the distinction Shweder makes between individualistic and sociocentric cultures? In his study, in what ways did individuals in in Hyde Park, Chicago differ from those in Orissa, India?Shweder, Mahapatra & Miller 1987 “Culture and Moral Development” –Shweder: “all societies must resolve a small set of questions about how to order society, the most important being how to balance the needs of individuals and groups … seem to be just two primary ways of answering this question – – individualistic vs sociocentric cultures – latter is much more common – “no bright line separated morel rules (preventing harm) from social conventions (regulating behaviors not linked directly to harm). Study compared individuals who lived in Hyde Park, Chicago, and Brahmins in a town in Orissa, India (Brahmins and untouchables).7. What is Turiel’s major criticism of the Shweder et al study? In Haidt’s research, how did he deal with this criticism?That Shweder used ‘trick’ questions – didn’t control by asking subjects about harm (e.g., wife is hurting her husband by eating a ‘hot’ food which could lead her into having sex)– would they condemn actions that were harmless? Haidt used harmless taboo violations (eating your dead dog, sex with chicken) – most involve disgust or disrespect (but action done in private, no one harmed)
5Chapt 1: Where Does Morality Come From 8. What were the results of Haidt’s research. Did they favor Turiel or Shweder? What was the biggest surprise in these results?9. What is ‘moral dumbfounding’?Person rendered speechless or searching for explanations when asked to explain verbally what they knew intuitively.10. What does Hume mean by “reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them”?That reason find the means to achieve whatever ends are chosen by the passions (emotional intuitions).In sum: Morality doesn’t come primarily from reasoning, but some combination of innate reactions and social learning.
6Chapt 2. The Intuitive Dog and the Rational Tail (Intuitions come first, reasoning follows)1. How do (1) the rationalists, e.g., Plato, Kant and Kohlberg), (2) Jefferson, and (3) Hume differ on the relative roles of reason and ‘the passions’ in determining our behavior?viewed ‘sacrilized’ reason, thought that reason did (or should) rule the passions. Jefferson perceived them as co-equals. Hume: reason the servant of the passions.2. What were Darwin’s views on morality?A nativist about morality. Thought that “natural selection gave us minds that were preloaded with moral emotions”.3. What is Social Darwinism?Richest, most successful individuals, races, nations were the fittest [and thus deserved what they had]. Giving charity “interferes with the natural process of evolution”.4. What does E. O. Wilson mean by ‘consilience’?5. de Waal: chimps have the ‘building blocks’ of morality. See reading by de Waal.
7Chapt 2. The Intuitive Dog and the Rational Tail (Intuitions come first, reasoning follows)6. According to Damasio, why does damage to the vm prefrontal cortex, which seems to rob individuals of emotions, also significantly impairs their judgment:?Can’t murder someone, for example, because feelings of horror rush in – without the emotional basis, person knows right from wrong but its all academic. Thus every option – good or bad – was as good as every other. Decision making was impaired in every area, even ones that appeared to be purely rational (like picking the best washing machine).7. What is the point of the ‘cognitive load’ tasks? What did Haidt conclude from his studies using these methods?8. Would you drink roach juice? What you sell your soul even if it was a non-binding contract?9. Look carefully at Haidt’s social intuitionist model (summarized in Fig. 2.4). What is the most likely route by which a person might change his or her moral judgment? How does ‘confirmation bias’ figure in here?10. So, according to Haidt (and Dale Carnegie), what is the best way to try and change someone’s mind on a moral issue?
9Chapt 3. Elephants Rule 1. What is meant by ‘affective primacy’? 2. If you haven’t already, try an Implicit Association Test: https://implicit.harvard.edu/implicit/demo/3. Check out the Bloom Lab puppet shows: right-from-wrong.html4. How do psychopaths, discussed in this chapter, compare with Damasio’s patients with damage to their vm prefrontal cortex, discussed in chapter 2?5. What is the philosopher’s ‘trolley problem’? What is the utilitarian solution? What is the deontological solution?6. How can science possibly work if scientists are ruled by their elephants and inevitably prone to confirmation bias?7. The old saw about how to avoid argument (e.g., with your spouse) was “count to 10 before you say (or do) something”. What would Haidt give us a reason this may work (at least some of the time)?
12Fig. 2. Schematic representation of the timing and anatomical localization of brain microstates in response to accidental harm (top left) in the right posterior superior temporal sulcus (STS)/temporoparietal junction (62–140 ms) and to intentional harm (bottom left) in the right amygdala/temporal pole (122–180 ms)and ventromedial prefrontal cortex (182–304 ms). Stimulus exemplars of the 2 classes of stimuli (intentional and accidental harmful actions) are shown at right. Three transverse brain sections show the estimated localization of the intracranial brain generators of the 3 main microstates.
13Chapt 4: We are all intuitive politicians Glaucon: most important principle for designing an ethical society is to make sure that everyone’s reputation is on the line all the time, so that bad behavior will always bring bad consequences.“When you see 100 insects working together toward a common goal, it’s a sure bet they’re siblings. But when you see 100 people working on a construction site or marching off to war, you’d be astonished if they all turned out to be members of one large family. Human beings are the world champions of cooperation beyond kinship, and we do it in large part by creating systems of formal and informal accountability”.Accountability: (Tetlock) Explicit expectation that one will be called upon to justify one‘s beliefs, feeling or actions to others, coupled with an expectation that people will reward or punish us based on how well we justify ourselves. When nobody in answerable to anybody, when slackers and cheaters go unpublished, everything falls apart”.
14Chapt 4: We are all intuitive politicians Tetlock’s view (we are all intuitive politicians striving to maintain appealing moral identities in front of our multiple constituencies) vs. view Kohlberg , Turiel, rationalists (children are little scientists who use logic and experimentation to figure out the truth for themselves)In physical world, we are rationalist, do converge on the truth.But social world is different, Glauconian: appearance is usually far more important than reality.Exploratory thought: an evenhanded consideration of alternative points of viewConfirmatory thought: a one-side attempt to rationalize a particular point of viewMost of our thinking is confirmatory!
15Chapt 4: We are all intuitive politicians TetlockA central function of thought is make sure that one acts in ways that can be persuasively justified or excused to others. Indeed, the process of considering the justifiability of one’s choices may be so prevalent that decision makers not only search for convincing reasons to make a choice when they must explain that choice to others, they search for reasons to convince themselves that they have made the “right” choice.
16Confirmation Bias in Action? Wason Selection Task: Subject is asked to look for violations of a conditional rule of the form If P then Q.Rule: "If a card has an even number on one face, then its opposite face is red”.Which card(s) must be turned over to see if this rule has been violated.‘8’ and brown cards – only ~25% of subjects get this right!‘8’ and ‘red’ = most common answer
17We lie, cheat, and justify so well that we honestly believe we are honest Ariely (2008):When given the opportunity, many honest people will cheat. In fact, rather than finding a few bad apples weight the averages, we discovered that the majority of people cheated, and that they cheated just a little bit.
18We can believe almost anything that supports our team Neural Bases of Motivated Reasoning: An fMRI Study of Emotional Constraints on Partisan Political Judgment in the 2004 U.S. Presidential ElectionDrew Westen, Pavel S. Blagov, Keith Harenski, Clint Kilts & Stephan HamannResearch on political judgment and decision-making has converged with decades of research in clinical and social psychology suggesting the ubiquity of emotion-biased motivated reasoning. Motivated reasoning is a form of implicit emotion regulation in which the brain converges on judgments that minimize negative and maximize positive affect states associated with threat to or attainment of motives. To what extent motivated reasoning engages neural circuits involved in ‘‘cold’’ reasoning and conscious emotion regulation (e.g., suppression) is, however, unknown. We used functional neuroimaging to study the neural responses of 30 committed partisans during the U.S. Presidential election of 2004.
19Westen et al: Neural Bases of Motivated Reasoning
20Westen et al: Neural Bases of Motivated Reasoning We presented subjects with reasoning tasks involving judgments about information threatening to their own candidate, the opposing candidate, or neutral control targets. Motivated reasoning was associated with activations of the ventromedial prefrontal cortex, anterior cingulate cortex, posterior cingulate cortex, insular cortex, and lateral orbital cortex. As predicted, motivated reasoning was not associated with neural activity in regions previously linked to cold reasoning tasks and conscious (explicit) emotion regulation.These findings provide the first neuroimaging evidence for phenomena variously described as motivated reasoning, implicit emotion regulation, and psychological defense. They suggest that motivated reasoning is qualitatively distinct from reasoning when people do not have a strong emotional stake in the conclusions reached.
21In SumFirst principle of moral psychology: Intuitions come first, strategic reasoning second.We are obsessively concerned about what others think of us, although much of the concern in unconscious and invisible to us.Conscious reasoning function like a press secretary who automatically justifies any position taken by the president.With the help of our press secretary, we are able to lie and cheat often, and then cover it up so effectively that we convince even ourselves.Reasoning can take us to almost any conclusion we want to reach, because we ask “Can I believe it?” when we want to believe something, but “Must I believe it” when we don’t want to.In moral and political matters we are often groupish, rather than selfish. We can believe almost anything that supports our team.
22We can believe almost anything that supports our team Bill Moyers talkstart at ~2:30
23Part II. There’s More to Morality than Harm and Fairness Chapt 5. Beyond WEIRD MoralityHaidt tells the dead chicken story and then asks “Can you tell me why that was wrong?”Customer at McDonald’s (after a long pause): “You mean you don’t know why it’s wrong to do that to a dead chicken? I have to explain this to you? What planet are you from?”Penn students typically judged the behavior in this story as ok (if strange): “It’s his chicken, he’s eating it, nobody is getting hurt”.WEIRD cultures: Western, educated, industrialized, rich and democratic. The WEIRDer you are the more you see a world full of separate objects, rather than relationships.Similar to Shweder’s distinction of sociocentric vs. individualistic cultures.
24Part II. There’s More to Morality than Harm and Fairness Chapt 5. Beyond WEIRD MoralityWEIRDNON-WEIRDIndividualisticSociocentricAutonomyInterdependency“I am…happy, outgoing, interested in jazz…”a son, a husband, an employee of…”AnalyticHolisticPhilosophersKant, MillDurkheim (Chapt 8)PsychologistsKohlberg, TurielShwederPredominant moral concernHarm & fairnessMore than harm & fairness: community, divinity
25Part II. There’s More to Morality than Harm and Fairness Chapt 5. Beyond WEIRD MoralityShweder: “Yet the conceptions held by others are available to us, in the sense that when we truly understand their conception of things we come to recognize possibilities latent within our own rationality ... and those ways of conceiving of things become salient for us for the first time, or once again. In other words, there is no homogenous “backcloth” to our world. We are multiple from the start.”
26Part II. There’s More to Morality than Harm and Fairness Chapt 5. Beyond WEIRD MoralityHaidt: “Our minds have the potential to become righteous about many different concerns, and only a few of these concerns are activated during childhood. Other potential concerns are left undeveloped and unconnected to the web of shared meanings and values that become our adult moral matrix.If you grow up in a WEIRD society, you become so well educated in the ethic of autonomy that you can detect oppression and inequality even where the apparent victims see nothing wrong...Conversely, if you are raised in a more traditional society, or within an evangelical Christian household in the U.S., you becomes so well educated in the ethics of community and divinity that you can detect disrespect and degradation even where the apparent victims see nothing wrong...”[may be]
27Part II. There’s More to Morality than Harm and Fairness Chapt 5. Beyond WEIRD MoralityComing up:Catalog of moral intuitions (more than harm and fairness)How a small set of innate and universal moral foundations can be used to construct a great variety of moral matricesTools for understanding moral arguments emanating from matrices that are not your own
28Part II. There’s More to Morality than Harm and Fairness Chapt 6. Taste Buds of the Righteous MindMorality is rich and complex, multifaceted, internally contradictory.“Pluralists such as Shweder rise to the challenge, offering theories that can explain moral diversity within and across cultures”.Others “reduce morality to a single principle, usually some variant of welfare maximization or fairness, rights, respect for individuals”.Utilitarian Grill – serves only sweeteners (welfare)Deontological Diner – serves only salts (rights)Haidt & Shweder: “moral monism – the attempt to ground all of morality on a single principle – leads to societies that are unsatisfying to most people and at high risk of becoming inhumane because they ignore so many other principles”.
29Chapt 6. Taste Buds of the Righteous Mind “The righteous mind is like a tongue with six taste receptors. In this analogy, morality is like cuisine: it’s a cultural construction, influenced by accidents of environment and history, but it’s not so flexible that anything goes … Cuisines vary, but they all must please tongues equipped with the same five taste receptors. Moral matrices vary, but they all must please righteous minds equipped with the same six social receptors”.Hume (according to Haidt): “Philosophers who tried to reason their way to moral truth without looking at human nature were no better than theologians who thought they could find moral truth revealed in sacred texts”.“In the decade after Hume’s death the rationalists claimed victory over religion and took the moral sciences off on a 200-year tangent”.
30Chapt 6. Taste Buds of the Righteous Mind Systemizers versus EmpathizersEmpathizing: drive to identify another person’s emotions and thoughts, and to respond to these with the appropriate emotion”.Systemizing: drive to analyze the variables in a system, to derive the underlying rules that govern the behavior of the system”.Autism: individual high on systemizing, low on empathizing.Bentham and Kant: high on systemizing, low on empathizing.
31Chapt 6. Taste Buds of the Righteous Mind Jeremy Bentham’s principle of utility: approves or disapproves an action depending on whether it augments or diminishes the individual's happiness. When multiple individuals are affected, law should maximize the utility of the community (= Σ of all the individual utilities).Consequentialist: moral worth of act judged by its consequences.Immanuel Kant’s categorical imperative: Act only according to that maxim whereby you can, at the same time, will that it should become a universal law. ( Golden Rule)Deontological ethics: position that judges the morality of an action based on the action's adherence to moral rules. Sometimes described as "duty" or "obligation" or "rule"-based ethics.Bentham and Kant both rationalists. Kohlberg too a rationalist and his theory of moral development is Kantian.Utilitarianism.
32Chapt 6. Taste Buds of the Righteous Mind S. Baron-Cohen
33Chapt 6. Taste Buds of the Righteous Mind Moral Foundations Theory: an account of how five six innately-based psychological systems form the foundation of an “intuitive ethics,” and how each culture constructs its own sets of virtues on top of these foundations.Modular: mechanisms that are switched on by patterns that were important for survival in a particular ecological niche (in the EEA), and when they detect that pattern, they send out a signal that changes the animal’s behavior in a way that is (usually) adaptive (e.g., snake detectors, face detectors).Moral receptors draw person’s attention to certain kinds of events (such as cruelty or disrespect), and trigger instant, intuitive reactions, perhaps even specific emotions (such as sympathy or anger).Role of cultural learning: Culture can modify, shrink or expand the triggers. Distinguish between original and current triggers.
34The Five Moral Foundations 1. Care/harm: Related to our long evolution as mammals with attachment systems and an ability to feel (and dislike) the pain of others. Underlies compassion, empathy, kindness, nurturance.2. Fairness/cheating: Related to the evolutionary process of reciprocal altruism. Generates ideas of justice, rights, and autonomy.3. Loyalty/betrayal: Related to our long history as tribal creatures able to form shifting coalitions. Underlies virtues of patriotism and self-sacrifice for the group. “One for all, and all for one!"4. Authority/subversion: Shaped by our long primate history of hierarchical social interactions. Underlies virtues of leadership and followership, including deference to legitimate authority, respect for traditions and the fulfillment of role-based duties.5. Sanctity/degradation: Shaped by the psychology of disgust and contamination. Underlies religious notions of striving to live in an elevated, less carnal, more noble way, idea that the body is a temple which can be desecrated by immoral activities and contaminants.
35Chapt 7. The Moral Foundations of Politics Homo economicus versus Homo Sapiens“Behind every act of altruism, heroism and human decency you’ll find either selfishness or stupidity. That at least is the view long held by man social scientists who accepted the idea that Homo sapiens is really Homo economicus”.
36Chapt 7. The Moral Foundations of Politics Homo economicus versus Homo Sapiens
37Chapt 7. The Moral Foundations of Politics Sidebar on Innateness (from Haidt “The Righteous Mind”)“It used to be risky for a scientist to assert than anything about human behavior was innate. To back up such claims, you had to show the trait was hardwired, unchangeable by experience, and found in all cultures. With that definition, not much is innate, aside for a few infant reflexes ... If you proposed that anything more complex than that was innate – particularly a sex difference – you’d be told that there was a tribe somewhere on Earth that didn’t show the trait, so therefore it’s not innate … We’ve advanced a lot since the 1970s in our understanding of the brain, and now we know that that traits can be innate without being hardwired or universal. As the neuroscientist Gary Marcus explains,Nature bestows upon the newborn a considerably complex brain, but one that is best seen as prewired – flexible and subject to change – rather than hardwired, fixed and immutable.
38Chapt 7. The Moral Foundations of Politics “To replace wiring diagrams, Marcus suggests a better analogy: The brain is like a book, the first draft of which is written by the genes during fetal development. No chapters are complete at birth, and some are just rough outlines waiting to be filled in during childhood. But not a single chapter – be it on sexuality, language, food preferences, or morality – consists of blank pages on which society can inscribe any conceivable set of words. Marcus’s analogy leads to the best definition of innateness I have ever seen:Nature provides a first draft, which experience then revises…. ‘Built-in’ does not mean unmalleable; it means organized in advance of experience.
39The Moral FoundationsCuteness primes us to care, nurture, protect, and interact. It gets the elephant leaning … the Care foundation can be triggered by any child.
42Baby schema modulates the brain reward system in nulliparous womenGlocker et al PNAS 2009Ethologist Konrad Lorenz deﬁned the baby schema as a set of infantile physical features, such as round face, high forehead and big eyes, that is perceived as cute and motivates caretaking behavior in animals including humans, with the evolutionary function of enhancing offspring survival.
43Baby schema modulates the brain reward system in nulliparous womenGlocker et al PNAS 2009
44Baby schema modulates the brain reward system in nulliparous womenGlocker et al PNAS 2009“Using functional magnetic resonance imaging and controlled manipulation of the baby schema in infant faces, we found that the baby schema activates the nucleus accumbens, a key structure of the mesocorticolimbic system mediating reward processing and appetitive motivation, in nulliparous women. Our ﬁndings suggest that engagement of the mesocorticolimbic system is the neurophysiologic mechanism by which baby schema promotes human caregiving, regardless of kinship.”
45Baby schema modulates the brain reward system in nulliparous womenGlocker et al PNAS 2009
56Figure 8.3. The flag of Virginia, illustrating the Liberty/oppression foundation.
57Figure 8.4. Liberal liberty: Interior of a coffee shop in New Paltz, New York. The sign on the left says “No one is free when others are oppressed.” The flag on the right shows corporate logos replacing stars on the American flag. The sign in the middle says “How to end violence against women and children
58Figure 8.5.Conservative liberty:Car at a dormitory at Liberty University, Lynchburg, VA.The lower sticker says: “Libertarian: More freedom, less government.”
59Figure 8. 6. Fairness as proportionality Figure 8.6. Fairness as proportionality. The right is usually more concerned about catching and punishing free-riders than is the left. (Campaign poster for the Conservative Party in the U.K. parliamentary elections of 2010.)
60Figure 8.7. A car in Charlottesville, Virginia, whose owner prefers compassion to proportionality.
61Chapt 9. Why are we so Groupish? To this point, Haidt’s portrait of human nature somewhat cynical – Glaucon: we care more about looking good than being good.“I do believe that you can understand most about moral psychology by viewing it as a form of enlightened self- interest”.We may be altruistic, but we are strategically altruistic, not universally altruistic.If moral psychology is fundamentally selfish then, it can be explained by natural selection working at the level of the individual.
62Chapt 9. Why are we so Groupish? But this portrait is incomplete:But this portrait is incomplete: we are also groupish.Although some mental modules designed to further our own selfish interests, others are designed to further our group’s interests (perhaps at a cost to ourselves).“We are not saints, but we are sometimes good team players”.“Do we have groupish mechanisms…because groups that succeeded in coalescing and cooperating outcompeted groups that couldn’t get it together? If so, then I’m invoking a process known as ‘group selection’, and group selection was banished as a heresy from scientific circles in the 1970’s”.
63Chapt 9. Why are we so Groupish? Haidt argues that “group selection was falsely convicted and unfairly banished”.Chapter plan: to present four pieces of new evidence that he believes “exonerate group selection (in some but not all forms)”.The new evidence demonstrates the value of thinking about groups as real entities that compete with each other.”“Evidence leads directly to the third and final principle of moral psychology: Morality binds and blinds”.
64Chapt 9. Why are we so Groupish? Haidt: “human nature mostly selfish, but with a groupish overlay that resulted from the fact that natural selection works at multiple levels simultaneously ”.Individuals compete with individuals within groups – which favors selfishness (including strategic cooperation),Groups compete with groups – between group competition favors true team players.“These two processes [individual-level and group-level selection] pushed human nature in different directions and gave us the strange mix of selfishness and selflessness that we know today”.
65Chapt 9. Why are we so Groupish? Haidt: “A gene for suicidal self-sacrifice would be favored by group-level selection (it would help the team win), but it would be so strongly opposed by selection at the individual level that such a trait could evolve only species such as bees, where competition within the hive has been nearly eliminated and almost all selection is group selection13”.Footnote 13: Bees “perfectly consistent with inclusive fitness theory … but [some] people who work with bees, ants [etc.] sometimes say that multilevel selection helps them see phenomena that are less visible when they take the gene’s eye view”.
66Chapt 9. Why are we so Groupish? Most groupish groups fare best. But how did early humans get these groupish abilities? According to Darwin:Social instincts (hang with the group)ReciprocityConcern with reputation (Glaucon) – moral sentiments sense of shame and love of glory evolved by individual-level selectionCapacity to treat duties and principles as sacred (part of our religious nature)Free-riding no longer so attractive. Group-level selection now becomes more potent. Groups now outcompete – and replace – other groups.
67Chapt 9. Why are we so Groupish? Willliams: Morality is “an accidental capability produced, in its boundless stupidity, by a biological process that is normally opposed to the expression of such a capability”.Williams: “only by a theory of between-group selection could we achieve a scientific explanation of group-related adaptations.”Haidt takes up this challenge.
68Chapt 9. Why are we so Groupish? Evidence for Group Selection (Exhibits):Major TransitionsShared IntentionalityGenes and Cultures Co-evolveEvolution can be FastLactose tolerance as example of C and DBelayev’s foxes as example of DTomasello: you’ll never see 2 chimps carrying a log
69Chapt 9. Why are we so Groupish? Evolution can be FastBelayev’s foxes
70Lactose IntoleranceMammals stop drinking milk at weaning. They also stop producing lactase, the digestive enzyme that breaks down lactose (the main carbohydrate in milk) into glucose and galactose (sugars that are easily absorbed in the bloodstream and provide energy). Cessation of both lactase production and milk drinking characterizes most human populations, especially those of African and Asian descent. In the majority of non-European populations, fresh milk is considered an unpleasant substance to be consumed only as a last resort. Lactose intolerance is the rule, and it is now clear that lactose tolerant Europeans are atypical among humans (as well as among all mammals).Why do some humans, however, retain the ability to digest lactose? A genetic mutation that maintains lactase production into adulthood occurs among certain populations that practiced cattle domestication. These individuals have the lactase persistence trait.
73% of Population Lactose Tolerant Age of Gene When nutrient rich nonhuman milk became widely available in pastoralist societies, the rare genetic variations that allowed some adults to easily digest lactose were selected for and this trait became more common.Lactase persistence gene that has evolved in Africa has evolved independently of the gene variants predominant in Europe.Region% of Population Lactose TolerantAge of GeneAge of Domestication of CattleWest Africa5 to 20%6000 to 7000 years ago7700 to 9000 years agoEast Africa26 to 88 %2700 to 6800 years ago3300 to 4500 years agoSouthern Europe50%8000 to 9000 years ago8000 years agoNorthern Europe90%2000 to 20,000 years ago
74Chapt 9. Why are we so Groupish? “Group-related adaptation” (= ?) requires group selection, i.e., this adaption may be disfavored within the group, but groups with this adaptation fare better than groups without it. Altruists suffer within the group, but groups with altruists outcompete groups without altruists. Note: ‘group selection’ still talking about gene-based traits.Cultural selection is a form of group selection but it is not gene-based. Good ideas concerning making tools, making foods, avoiding poisons, keeping young alive, fighting, etc., will spread with dispersal of individuals with this knowledge into new groups. It’s not genes that are selected, but the ideas (memes).The gene-based traits that are selected are mechanisms for intelligence, having good ideas, learning and teaching.
75It’s Not All About War“I’ve presented group selection so far in its simplest possible form: groups compete with each other as if they were individual organisms, and the most cohesive groups wipe out and replace the less cohesive ones during intertribal warfare. That’s the way that Darwin first imagined it. But … Lesley Newson points out:I think it is important not to give readers the impression that groups competing necessarily meant groups being at war or fighting with one another. They were competing to be the most efficient at turning resources into offspring. Don’t forget that women and children were also very important members of these groups.Of course she’s right. Group selection does not require war or violence. Whatever traits make a group more efficient at procuring food and turning it into children makes that group more fit than its neighbors. Group selection pulls for cooperation, for the ability to suppress antisocial behavior and to spur individuals to act in ways that benefit their groups. Group-serving behaviors sometimes impose a terrible cost on outsiders (as in warfare). But in general, groupishness is focused on improving the welfare of the ingroup, not on harming an outgroup.