I have been reading the excellent book ‘The mind of an ape‘ by David and Ann Premack and also enrolled in a MOOC tiled ‘Origins of the human mind’ offered by Dr. Matsuzawa, so apes have been on top of my mind recently.
Prof Matsuzawa describes an experimental procedure where numerals from 1 to 9 are very briefly displayed on the screen and then masked and the chimpanzee is required to touch the numerals, displayed randomly on the screen briefly, and now invisible as are masked, in ascending order. The chimpanzee is able to perform the task at 80% accuracy, a feat at which if human subjects try they can never succeed (humans perform at 0% accuracy).
We typically pride ourselves as being the epitome of civilization and cognitive abilities, but its humbling to find that there are tasks at which the chimpanzee can excel! This task, in particular, requires immediate memory (sensory/short-term memory) which it seems is better in the chimp.
The different experiments on the chimp also made me think about the underlying structure of memory and reasoning systems. Like humans, it seems chimps too have two different reasoning systems- one tuned to physical world and the other to social/agentic world.
The physical reasoning system is attuned to thinking about causal reasons between psychical objects and events. The question of concern is ‘what caused what?’ . One needs to have a (rudimentary) theory of cause and effect. Some basic understanding of physics is necessary and is instrumental in the development of the capacity of tool use. As a matter of fact too use is one of the ways this physical reasoning system is studied.
The social /agentic reasoning system is attuned to thinking about other con-specifics/ living creatures. It attributes intentions to people and answers ‘who did what to whom?’. One needs to have a (rudimentary) theory of mind to know that others have intentions/ beliefs/ desires etc. A simple paradigm to measure this is whether one understands the visual gaze of a person and can take his/her perspective and know whether the other is able to see something or not.
The physical and social reasoning systems have been show to be different and dissociated in humans and as per one theory are differently accentuated in autistic (more physical reasoning) and schizophrenic (more social reasoning) mind.
Another ability where chimps and humans markedly differ is in their abstract/symbolic representations and linguistic abilities. While chimps can be taught language to a great extent, they don’t develop symbolic language naturally. Language requires abstract and symbolic representation. One can contrast this with the immediate/imaginal representation.
Again, while autistic people have a good immediate/imaginal (thinking/seeing in images instead of words/ symbols) representation system (for e’g’ like in movie ‘rain man’ they can tell the exact number of matchsticks dropped on the floor without counting), their language development is typically hampered , perhaps due to deficits in the abstract/semantic/symbolic representation system.
Thus we see two sets of cognitive functions, and the two sets seem to be slightly at odds with each other: Physical reasoning and concrete/ immediate/imaginal representation; and social reasoning and abstract/semantic/ symbolic representation.
The species (chimps/humans) who are good at imaginal and physical reasoning system may not be as good at symbolic and the social reasoning system. Similarity within the human family, autistic and schizophrenics may excel at different such functions. While we lost or never gained the ability for highly accurate imaginal system since around 5 MYA when we diverged from chimps and bonobos, we gained the ability for abstract/ symbolic representation. Given the limited real estate that the brain can occupy in any body, its inevitable that as you evolve you lose some and you gain some abilities. Like we lost the ability to use four hands that chimpanzee has.
To summarize, one can associate and link the above to human memory systems. One can conceive of four such memory/reasoning systems:
Visuo-spatial/ short term/ sensory memory: related to immediate memory and imaginal representation.
Procedural memory: related to Physical reasoning/ tool use /physical skills etc and objects representations.
Episodic memory: related to social reasoning and agent representations.
Semantic memory: related to language and symbolism and abstract representations.
Its easy to see how we can apply the same memory/reasoning model to chimps/ other apes without necessarily anthropomorphism. And its equally hard to see and admit that chimps may be better than us at certain cognitive functions and tasks.
In my last post I hinted at how primate evolution may be an example of eight stage evolutionary process in action and today I’ll try to support my first prediction that the prosimian stage evolution was dominated by predatory concerns.
Prosimian evolution and branching within the primate order took place 55 million years ago or a bit earlier, near the beginning of the Eocene Epoch. These first primates , it is safe to assume were nocturnal just like today’s prosimians like lemurs, bushbabies, tarsiers etc are. Why they were nocturnal remains a question to be answered. Species turn nocturnal usually to avoid predation by day predators. Crypsis is the mechanism that even today is used by prosimians to avoid predation.
It is instructive to note here that though predation in primates has not been considered a big force, in pro-simians it is important. A whole book Primate anti-predator strategies has been written which focuses more on pro-simian anti-predator strategies than on other primates. It is testament to the fact that predation was/ remains important for prosimian evolution. Here I quote from the preface of the book:
The impact of predation on the morphology, behavior, and ecology of animals has long been recognized by the primatologist community (Altmann, 1956; Burtt, 1981; Curio, 1976; Hamilton, 1971; Kruuk, 1972). Recent thorough reviews of adaptations of birds and mammals to predation have emphasized the complex role that predation threat has played in modifying proximate behaviors such as habitat choice to avoid predator detection, degree and type of vigilance, and group size and defense, as well as ultimate factors including the evolution of warning systems, coloration, and locomotor patterns (Thompson et al., 1980; Sih, 1987; Lima & Dill, 1990; Curio, 1993; Caro, 2005).
We have conducted research on nocturnal primates for more than ten years. Immersed as we have been in the literature of nocturnal primatology we recognize a spectrum of diversity amongst the nocturnal primates in their social organization, cognitive behavior, and ecology (Charles-Dominique, 1978; Bearder, 1999; M¨uller and Thalmann, 2000). Our studies on tarsiers and lorises showed that these species were highly social and that resource distribution was not sufficient to explain why they defied the supposed “stricture” of being solitary (Gursky, 2005a; Nekaris, 2006). Furthermore, our animals defied another supposed “rule” — namely, that all nocturnal primates should avoid predators by crypsis (Charles-Dominique, 1977). Even recent reviews of primate social organization and predation theory included one-sentence write-offs, excluding nocturnal primates from discussions of primate social evolution on the basis that crypsis is their only mechanism of predator avoidance (Kappeler, 1997; Stanford, 2002).
An analysis of the mammalian literature shows this type of generalization to be crude at best. Small mammals are known to have extraordinarily high rates of predation, and a plethora of studies of rodents, insectivores, and lagomorphs, among others, have shown that predation is a viable and powerful ecological force (Lima & Dill, 1990; Caro, 2005). Furthermore, although researchers have long considered it critical to include prosimian studies in a general theoretical framework concerning the evolution of the order Primates (Charles-Dominique & Martin, 1970; Cartmill, 1972; Oxnard et al., 1990), a pervading view contends that prosimians are too far removed from humans for the former’s behavior to shed any light on the patterns of behavior seen in anthropoids (Kappeler & van Schaik, 2002; Stanford, 2002).
However, an excellent review by Goodman et al. demonstrates the dramatic effect predation can have on lemurs, and it remains the most highly quoted resource on lemur predation, despite that it was published in 1993. Studies of referential signaling aid in dispelling the view that prosimians are primitive and not worthy of comparison with monkeys and apes (Oda, 1998; Fichtel & Kappeler, 2002). A handful of studies further reveal that prosimians are not always cryptic and may engage in social displays toward predators (Sauther, 1989; Sch¨ulke, 2001; Bearder et al., 2002; Gursky, 2005b).
Leaving for the time-being the fact that prosimains too engage in social behavior as a defense against predation, and sticking to the traditional view that crypsis best defines their defense mechanism, the thing to be noted is the relative abundance of predatory strategies on prosimian evolution. A whole book has been written keeping that in mind!!
So my thesis is that for the very first stage of evolution when a leap was made, prosimains got left behind, still struggling with predation; while the common ancestor of new world and old world primates somehow solved/ reduced the problem of predation and became diurnal and maybe started living in large social groups and thus exhibiting social defenses against predators. This evolutionary successful completion of the first developmental/ evolutionary task of avoiding predators, then enabled these ancient primates to focus their energies on finding food and thus from insectivores become fruit-eating and move towards a rich diet and focus on acquisition of resources. but that takes us to stage II marked by focus on food and the new world monkeys. More on that later!
I have been looking at primate evolution and taxonomic tress for quite some time and am aware that different scholars parse the same tree in different ways, specifically people try to avoid being anthropocentric. I , on the other hand , will focus exclusively on the primate tree as it relates to humans and try to to show that it might be a living proof of the eight stage theory of evolution/ development.
First let me show you a popular way of portraying the primate tree from Philadelphia Inquirer’s Going Ape website.
Now, let me show you an alternative classification (just slightly different from this, but based on cladistics) . It is hard to see the figure (I’ve lost the original full -kleght versions), but the idea is that the first level branching happens at the level of suborder, then infraorder, then family etc within the order of primates.
Here is a similar diagram from the The Third Chimpanzee by Jared Diamond.
It is instructive to note that here barnching within primate tree is as follows:
Suborder branching: Prosimians: I hypothesize that prosimian evolution be driven by first adaptive problem that of hiding from / avoiding predators. (lemurs etc)
Infraorder branching: Platyrrhine (flatnosed) or New World Monkeys: I hypothesize that these would be most adventurous of all and would be focussed on finding food and resources, having mastered the predation problem. Maybe the main factor here would be their range size etc. This family is as opposed to Catarrhine (down-nosed) or Old World primate to which humans belong.
Superfamily branching: Cercopithecoidea: Old World Monkeys. Lets say we focus on old world monkeys here. The hypothesis is that they would be specialized for forming alliances and territorial hierarchical behaviors. This superfmaily is as opposed to hominoidea superfamily.
Family branching: Hylobatidae or Gibbons: the hypothesis is that Gibbon evolution may be driven by parental investment conflicts. this family is as opposed to Hominidae to which humans belong.
Subfamily branching: Ponginae or Orangutans : Orangutan evolution may be driven by kin selection concerns.
Tribe branching: Panini or gorillas: Gorilla evolution may be driven by theory of mind considerations. Maybe the driving force behind gorilla evolution is reading others mind and we would find good evidence for the same in gorillas.
Species branching: pan of chimpanzees and bonobos and humans: may be driven by communication or language concerns. Of course language or communication in Humans is phenomenal; but may be of equal importance for the other two also.
This species may be a branching of humans later on along sexual selection lines or assortative mating considerations along the lines of Elois and Morlocks.
I am not a primatologists and the above appears too simplistic and fishy to me; but is there evidence for any of the hypothesis presented above; if so do let me know! Meanwhile I will be on the lookout for any confirmatory evidence!!
This post is regarding the evolution of Life-forms on earth. I’ll start from the primordial soup/ sandwich and try to show how life developed in stages and how development of a particular life-form was an adaptation to a particular adaptive problem. My thesis is that life should evolve in eight stages each , with each evolutionary stage solving one adaptive problem.
For reference, I have heavily used this post titled ‘The Making of Cat‘ by Roger Berton and Nancy Creek. I would however present the finding in my own idiosyncratic way , using as my reference the eight-fold evolutionary/ developmental stages. I have also used the 21 major animal phyla classification as present on Wayne’s Word site.
Co-Evolution of genes and proteins/ amino-acids: Life first originated in the primordial soup/sandwich of molecular compounds. Proteins may be thought of as chemicals (enzymes) that helped speed up the chemical process in desired direction and provided stability to the gene-protein complex, while at the same time destabilizing other combination of compounds; while genes as replicators that ensured that the gene-protein complex could not only survive but reproduce or help make copies of oneself. Here the first problem was that of how to avoid being broken-up by other proteins/ enzyme that worked to break other chemical compounds in the soup. Thus the evolution of genes and proteins was primarily driven by how they could become stable and get into such stable configurations that the corrosive influence of the primordial soup could be withstood and an identity asserted!
Evolution of the chromosome or two strands of DNA: Once stable gene-protein couplings could come together the next problem was how to extract the maximum from the primordial soup for self-maintenance and self-enhancement. The problem was solved by genes and non-genetic code coming together to form a DNA strand and then two DNA strands and a layer of water coming together to form a chromosome. A similar approach was taken by viruses, but it contained RNA instead of DNA and hence juts a single strand, which proved ineffective against the double helix. Eventually, though viruses continue to evolve, life evolved in the direction of DNA.
Evolution of a simple unicellular prokaryotic-bacteria-like cells: Once chromosomes outwitted viruses, the next problem facing them was how to maximally defend against predators (other destabilizing compounds) and also eat or grow maximally (use the soup maximally). Here they thought that forming alliance was a good step. So a few chromosomes came together and the chromosomes and the proteins they made, especially the outer cellular wall, gave rise to simple prokaryotic cells. These cells were simple- no nucleus, no specialized organelles. The key was that 2 or 24 chromosomes were better than single chromosomes.
Evolution of simple unicellular Archea-like cells: It is assumed that Archea is just a type of bacteria or Prokaryotes, but it has been proposed that these are more similar to Euaryotes than prokaryotes and may be the missing link in evolution and may have been the common ancestor of eukaryotes. Anyway, the problem facing the primordial animal after the first three problems had been faced was how to share resource optimally between one and one’s offspring. The reproduction was still asexual but different asexual techniques like binary fission, multiple fission, fragmentation, budding etc were tried. Techniques like horizontal gene transfer came into picture. The whole idea being what is the best parental investment while reproducing asexually. Here also for the first time, DNA contained introns or non-coding DNA (whose significance, we still do not know!!).
Evolution of simple uni-cellular Eukaryotic like cells: It is generally agreed that eukaryotes evolved from simple prokaryote-like cells, or better still Archaea like cells. These cells are more specialized and have a nucleus as well as other specialized structures enclosed in membranes. It is my thesis that this centralization of DNA in nucleus and also concurrent appearing of different specialized organelles like mitochondria was key step in evolution, that for the first time made permissible a central command system (nucleus). The adaptive problem to be solved was how to help those specialized structures that were related or kin-like from conflicting demands on the cytoplasm (the common pool) and a central command center (nucleus ) evolved!
Evolution of simple colonies of cells (first animal phylum: the porifera or sponges) : Once a central command (nucleus) originated that could control the organelles within, it’s command was turned outwards to manage conflicts with other similar cells and form a co-operating colony of identical cells. This was the biggest leap-to-date and gave rise to multi-cellular organisms.These were simple in the sense that all cells were the same : there was no specialization: no digestive tract. There was also radial symmetry. The problem to be solved was how to know which cells would co-operate and which not (akin to reading the cells mind or having a theory-of-cell-mind module) . Somehow, I believe that having radial symmetry sort of solved this trust problem.
Evolution of multi-cellular organisms with digestive tracts (second animal phyla coelenterate): These are the modern day jelly fishes and corals. They solved the internal communication problem that was facing them. How to tell each cell what to do. Some cells specialized as digestive tract based on signaling during development. There are three classes : Hydrozoa (Hydra),Scyzophoa (jelly fish), Anthozoa (anemones and corals ) of these. Reef corals may form (1) fringing reefs extending out to 0.4 kilometers from shore; (2) barrier reefs separated by a lagoon of considerable width and depth from a shore; and (3) atolls or circular reefs that encircle a lagoon of water and not enclosing an island. this is just to highlight the importance of number three at stage seven of evolution! I also believe that for the first time reproduction sexually became paramount and gave rise to germ-line gametes of sperms and eggs and also soma cells that reproduced by mitosis and not meiosis. Specialization of cells into structures like Gonads became possible; just like the digestive tract, once the problem of internal communication and command was solved. Please also note that for the first time we have a polyp type or medusa like stage.
Evolution of multi-cellular organisms moving towards a CNS( bilaterality) (third animal phyla :Ctenophora (Comb Jellies)): These have biradially symmetric bodies. It is my contention that a move from radial to biradial may have arisen just by chance and due to sexual selection and may have ultimately kled to bilaterally symmetric bodies, which somehow necessitated or gave rise to the CNS. Externally there are eight plates of fused cilia that resemble long combs; the rows of ciliated comb plates are used for locomotion. These are also bio-luminescent , perhaps another property to make them attractive to mates and arose out of sexual selection. The problem to be solved : attracting ‘right’ mates; the solution bio-luminescence and move towards bilateral symmetry. These are also solitary creatures and have no polyp stage.
This brings us finally to the completion of first round of evolution, with the move from genes to fully-functional multi-cellular animals; but still simple and not having a CNS. After this CNS somehow developed along with bilaterality and a new chain of evolution started. I’ve thus reset the count of evolutionary stage to 1.
Phylum Platyhelminthes (Flatworms): bilateral symmetry with CNS,No body cavity.
Phylum Nemertea (Ribbon Worms)
Phylum Rotifera (Rotifers): Coelem incomplete.
Phylum Gastrotricha (Gastrotrichs).
Phylum Nematomorpha (Horsehair Worms).
Phylum Nematoda (Nematodes): a special level of evolutionary jump and that is why we scientists study this a lot.
Phylum Acanthocephala (Spiny-Headed Worms).
Phylum Bryozoa (Bryozoans): body with, for the first time, a true coelom.
And of course this paves way for the next wave of evolution of protosomians: Blastopore forms mouth, schizocoelom present. Their list goes as follows: again evolutionary stage reset to 1.
Phylum Tardigrada (Tardigrades).
Phylum Brachiopoda (Brachiopods).
Phylum Mollusca (Mollusks).
Phylum Annelida (Segmented Worms).
Phylum Sipunculoidea (Peanut Worms).
Phylum Arthropoda (Arthropods): Evolutionary jump. Body consisting of three parts: head, thorax and abdomen.
Phylum Chaetognatha (Arrow Worms). Phylum Echinodermata (Echinoderms).I’ll like to club these two together.
Phylum Hemichordata (Acorn Worms):
And then we come to another major evolutionary jump or invention: the spinal chord: the phylum chordata or vertebrates, having a spinal chord. The classes within vertebrates (chordata):
Class Osteichthyes (bony fishes) : driven by avoiding predation
Class Amphibia (Amphibians): driven by exploring surrounding
Class Reptilia (Reptiles): driven by forming alliances between small groups
Class Aves (Birds): driven by best reproductive/parental strategy
Class Mammalia (Mammals): driven by kin-related concerns?/ specialization/ division of labor??
From the above it seems that much more good things (than mere humans/mammals) are in the offing!! I have bought (and actually generated the argument) the argument hook , line and sinker, what about you!
Today I discovered a new blog called The Amazing world of Psychiatry, and this book review of Introducing Evolutionary Psychology by Evans and Zarate caught my eye. As I own a copy, so I had a quick look and indeed found the book very pleasurable to read (Its in comic book format) and recommend it wholeheartedly.
In it Dylan Evans and Oscar Zarate claim that all animals, and especially humans face a few adaptive problems and have developed modular adaptions in the brain to handle those problems that were encountered in the EEA. now , the massive modularity hypothesis is a topic for another day; today I’ll restrict to how they had organized their typical adaptive problems into seven groups and how I propose to modify it by introducing an eighth group to make it more in line with my eight stage evolutionary and developmental theory.
So what are the adaptive problems faced by our hominid ancestors? Various considerations drawn from Biology, Primateology, Archeology and Anthropology suggest what the most important adaptive problems would have been:
Eating the Right Food
Forming Alliances and Friendship
Providing help to Children and other Relatives
Reading other people’s minds
communicating with other people
They then go on to describe each problem and the corresponding modules that evolved to serve these needs.
I’ll now elaborate a bit on the thesis and would like to split the 4th level into two: one for parental investment and parent-offspring related issues and second with kin-selection issues. I’ll draw heavily on their work. Its also my thesis that most of these (at least the first five issues ) are faced by most higher animals , like all mammals.The evolutionary problems and the specific modules they give rise to are described below:
Avoiding Predators:The first need for a gene to be successfully passed in further generations, and thus be selected for, is that it enables the possessing organism to survive (against predators) and avoids them being eaten away. Thus the prime importance of this adaptive problem to be solved cannot be stressed enough. This problem can be solved by a) detecting predators b) detecting false alarms and c) taking action (running away (flight), freezing or fighting it).
Eating the right food: The second problem, once you have avoided being eaten and wiped out of the gene pool, is to exploit your environment to the fullest such that you can enhance and maintain the robot (organism) that is carrying you (the gene). In other words, find food to sustain oneself and meet metabolic needs. Here not only rich sources of food need to be detected, but bad and poisonous sources avoided. Emotion of Disgust as well as the sweet tooth are result of adaptations to this problem. To generalize it, you need to discover, exploit and protect resources that could nourish you and avoid those that can harm you. I would club territoriality behavior and food ranges also as another module related to this same adaptive problem. You have to exploit your environmental niche to the fullest and be the fittest.
Forming alliances and friendships : The third problem, for those animals that are not solitary, and are social in nature, is to form alliances and friendships within the group to which they belong. Group avoidance of predators (which may be big for an individual) and group sharing of food (big game hunting/ unpredictable foraging/ agriculture etc) is more beneficial than solitary hunting/ predator avoidance/food gathering. But with group formation comes the problems of group living – co-operation evolution and maintenance and the free-rider problem. Basically, how to detect cheaters and free-riders who take benefits from the group but do not pay back. If unchecked, the genes conferring such free-riding behavior will proliferate in the gene pool and destabilize co-operation and thus effective groups. It has been proposed by Robert Axelrod, that co-operation can evolve only if a) organisms encounter each other repeatedly (live in a group) b) they can recognize those they have met before and distinguish them from strangers and c) organisms can remember how those they have met before have treated them on previous occasions. Thus we need modules for recognizing con-specifics and for remembering their past actions, for solving this adaptive problem; many animals including elephants, who live in large groups, have solved this problem to an extent. This model is called reciprocal altruism and the strategy used is called tit-for-tat strategy in a repeated prisoners dilemma game of whether to co-operate or to defect. This also lays the foundation for a social exchange module whereby one calculates the costs and benefits keeping in mind the context under which the favor was given/ received.
Helping Children / Parental investment: Most of the animals reproduce and that too sexually. In case of sexual reproduction, the child contains only half the genes of each parent and thus from gene’s point of view an offspring’s welfare is only half as important as one’s (parents ) own welfare. So it might be conceived that the selfish gene would juts work towards prolonging the life of the organism that contains it, but at some point the benefits of reproducing and passing the genes to future generations may become more cost-effective in the long run. But, reproduction is not a child’s play! The mother (in most animals) usually invests a lot of her energy and resources while gestating or lactating. The father too, in many species, including humans has to expend considerable resources to the well-being of his dependent children. Parent-offspring conflict arises as for parents all children are equivalent (in terms of gene value), but for siblings a sibling is only half as worth as self. A parent has to decide how many offspring to have to maximally pass on the genes. One approach could be to have a big litter; but this reduces the individual care or investment the parent can make in a child; thus leaving many to die or in hands of fate. The other strategy could be to have a few children , but to invest heavily in them so that most of them do live to reproduction themselves and are able to pass the genes forward. These two strategies are known as the r-strategy and the K-strategy of mating and parental care and apartment investment respectively. However along with strategies for parent investment , the most prominent problem to be solved by this adaptive problem of helping children, is to be sure that they are your children! Thus, mate guarding , jealousy , sticking to monogamy (and love which makes you monogamous in the critical parental investment period) , a mothering/fathering caregiver module may be some modules that are brought forth as a measure of solving this adaptive problem of how best to reproduce and let ones genes pass on through direct descendants.
Helping Kin or Kin-selection: While ensuring survival of individuals and direct descendants is beneficial to the gene; it also benefits from inclusive fitness i.e. if some other related / unrelated organism that contains the gene survives at the cost of the original organism carrying the gene. Hamilton first formulated this using his famous equation that an organism will act altruistically to help another member (that is benefit other at cost to oneself) if r> c/ b; where r is how related you are to the individual in question (r is 1 for self, 0.5 for siblings/ children who share half the genes, 0.25 for first cousins etc ) , c is cost to yourself and b is benefit to the individual in question. Thus as it is difficult (though not impossible ) to determine from overt behavior/ phenotype, the genotype of the organisms (the famous green beard problem) , the only clue one has to whether one shares anthers genes is the degree of relatedness. Thus, other things being equal, one would favor one’s kin above others leading to nepotism. But more than that the chief feature of this level of selection is captured by the phrase that one could die to save two siblings, four first cousins, eight second cousins etc. Thus, though one would get nothing in return, one would still co-operate and help. This mechanism is definitely different from reciprocal altruism that we discussed in the context of social exchange. However, with this level of selection comes the additional problem of how to identify kin and people carrying similar genes. I don’t think people have asked this question much, (except for relatedness coefficients) , so there is scope for much work here. I propose that a minimum one would need a family-stability and family-institution-concept module to ensure that indeed whom one encounters the most are one’s blood relatives. Similarly, a trust module would be present to trust the fidelity of your parents, uncles, aunts , grandparents, children etc, so that what you believe as blood relatives are indeed blood relatives. I also believe that biases may be build into us, such that we treat people more similar to us favorably and this could be the working of this module. We all know this bias that we have that if someone is like us or mirror our actions/ accent etc, we tend to favor him over others. This could be a result of this mechanism whereby we try to ascertain or make an approximation of the genotype of the individual from his phenotype and try to see how similar it is to our genotype. In short, we favor those who look and behave like us; or are related to us by blood ties.
Reading other minds: Till now we have looked at how genes work at the level of individual (avoiding predators, eating food) , level of a few close fiends/ alliances , at the level of nuclear family (parents -offspring) and at the level of extended family (kin-selection) to ensure that they are passed on. Although in each case it is the genes that are selected for, they act at a level of an organism or a unit of organisms and show their effects most in interactions amongst that unit. Now its time to move a notch higher and move towards group-selection mechanisms whereby genes show their effects at the group level where the group is big enough (say the society/ population in which one lives). For humans this group size of a day-to-day interactions is supposed to be 150. (the size of our ancestor bands). Despite not being related to someone by way of kinship, alliance or friendship, when one lives in a group one has to work with other people with which one may or may not have good relations. To ensure survival of ones kin/ friends over ones enemies one needs to indulge in a bit of Machiavellian intelligence. This involves keeping track of who is sleeping with whom (and using that information to ones advantage) or indulging in some social politics. Information becomes paramount and thus rumor, reputation management and gossip is important!! It is presumed that this social intelligence was a driver for human large brain evolution. It is important to keep track of who is allied with whom and to use this knowledge well in forming alliances with an enemy of a common enemy. However, at the same time it is important to tolerate enemies, when one is not in a strong position and in general not to reveal ones true intentions, desires, beliefs etc to others. Information(social) is advantage. At the same time realization dawns that others may be concealing things from oneself and thus a need to know their true intentions, thoughts, beliefs. Thus a need for a Theory of Mind module that would keep track of what others are thinking or about what has been left unstated (by way of behavior). Thus, to be able to compete with one’s con specifics , who may not be related or friendly and may have hidden, selfish intentions, it becomes important to read their minds properly and to mislead them, even using deception or lies to ensure that one is helped even by those who might not have the best interests in their heart.
Communicating with others: This level of selection would ensure a generalized-reputation-based -reciprocity wherein the individual helps others based on how this individual has helped others in the past. If one can ensure that reputation of an individual correctly reflects his co-operative nature, then this sort of co-operation based on reputation can emerge. However, one needs to solve the problem first of what the reputation of an individual is. This is usually using the gossip mill mechanism, wherein having a good communicative ability is essential. In short, problem to be solved: correct reputation or credibility: modules involved: gossip, language etc.- level of selection: society or whole group that can properly ascertain correct reputations and benefit from reputation-based altruism will thrive/ flourish. Typical module: the language acquisition device.
Mate-selection: This is sexual section and I believe is self-explanatory. This however can lead to arbitrary features developing that are not adaptive in the traditional sense; so this is a whole new level of evolution. This also leads to runaway evolution and emergence of beauty like the peacocks tail which are non-utilitarian . This via assortative mating may also lead to speciation. The idea is to improve the genotype and not just survive/ reproduce/ thrive; so one mates with another individual having ‘best’ compatible genes. Problem to be solved: best compatible genotype that will result in best offspring . Best is relative as the only best thing about them may be that the offspring can find a mate and thus ensure that the lineage continues. A recursive definition of best.
As you can make out , I am quite excited by this line of work. My thesis has always been that evolutionary/ developmental constraints have lead to the eight stages that we see in most phenomenon. I can readily map most of the eight stage phenomenons to these evolutionary problems. By way of an example consider the eight basic story plots. These enduring myths or basic plots are embedded in our memory becuase the hero solves a particular evolutionary problem and that acts as a parable for all others. Consider this:
Overcoming the Monster plot ( avoiding predator)
Rags to Riches plot (finding food/ resources): how one successfully gets resources like money.
Quest plot ( forming friends and alliances) : the most important element of such plots is the journey in which a hero is accompanied by some friends and allies.
Voyage and return plot( might be related to parental investment conflicts) :one goes on a journey in a different land and returns. cant fit this in, sorry about that!
Comedy plot: (kin selection): the typical plot involves family disjointed, twins to create confusions, disguised identities etc: overall recognizing similar people and kin.
Tragedy plot (might be related to Machiavellian manipulations and theory of mind confusions) : tragedy normally follows because one did not understood the unsaid correctly and made false premises.
Rebirth (communicating with others) ; haven’t read Christopher Booker’s book till here so cant comment!!
I have been reading, of late, some articles that have invoked the concept of intentionality and its orders. More specifically, this has been with respect to Social Brian hypothesis of Robin Dunbar, whereby he claims that humans evolved intelligence to be able to cope with your in-laws (and other social members of one’s groups). Leaving asides the main premise of the social brain hypothesis, which I find convincing to an extent, he also claims that monkeys have only first order intentionality, while apes have second order and humans are able to function at about fifth order of intentionality, with some like Shakespeare being able to work on the sixth order. To quote at length form the ‘beginner’s guide to intentionality’:
Computers can be said to know things because their memories contain information; however, it seems unlikely that they know that they know these things, in that we have no evidence that they can reflect on their states of ‘‘mind.’’ In the jargon of the philosophy of mind, computers are zero-order intentional machines. Intentionality is the term that philosophers of mind use to refer to the state of having a state of mind (knowing, believing, thinking, wanting, understanding, intending, etc).
Most vertebrates are probably capable of reflecting on their states of mind, at least in some crude sense: they know that they know. Organisms of this kind are first-order intentional. By extension, second-order intentional organisms know that someone else knows something, and third-order intentional organisms know that someone else knows that someone else knows something. In principle, the sequence can be extended reflexively indefinitely, although, in practice, humans rarely engage in more than fourth-order intentionality in everyday life and probably face an upper limit at sixth-order (‘‘Peter knows that Jane believes that Mark thinks that Paula wants Jake to suppose that Amelia intends to do something’’).
A minimum of fourth-order intentionality is required for literature that goes beyond the merely narrative (‘‘the writer wants the reader to believe that character A thinks that character B intends to do something’’). Similar abilities may be required for science, since doing science requires us to ask whether the world can be other than it is (a second-order problem at the very least) and then ask someone else to do the same (an additional order of intentionality).
I find the above definitions (and other I have found on the web), slightly problematic, so I’ll attempt my own synthesis on the matter:
Zeroth order or No intentionality: Having knowledge but no ‘awareness ‘ of knowledge. Mere representation of information, but no meta awareness of that representation. Computers and machines , and even simple life forms like bacteria etc, may have this (no) intentionality, wherein they have ‘facts’ about the world, but no beliefs, desires etc.
First Order Intentionality: Awareness of knowledge that is distinct from mere knowledge. A belief system. Knowing that something you know may be incorrect from the actual world scenario. You know what you know and you know what you don’t know. Meta cognition. Beliefs, desires etc. Important thing to note is that only ‘I know’ is covered in this definition. A limited ‘You know as I know’ may be covered at this order as one may be aware of other people as being intentional agents , but whose beliefs are congruent with one’s own! ‘You know something that may be different from what I know’ is not possible yet. Most mammals including rats and monkeys are at this level. Awareness ta this level may be that others too have facts of world at their disposal.
Second order intentionality: Awareness of a belief-system that is distinct from the belief system itself. A Theory of Mind. You know that someone else may know things differently from both as they are and as you think they are. Awareness that others have a mind or a belief-system. Ability to keep two different belief systems in the mind- one of your own and the other of another third person. Apes and children age 4 demonstrate this level and order of intentionality. They have a theory of mind as to the fact that others have beliefs and that these are after all beliefs and can be false too. Awareness that others have beliefs, but still no awareness that they have a ToM too!
Third order intentionality: Awareness of a ToM that is distinct from the ToM itself. A communicative intent. Joint attention. Language. symbol grounding. Knowing that someone else may have different views regarding what you yourself believe and thus it is important to communicate your internal intentions, beliefs , desires etc to others so that there is common ground on which communication and speech acts can proceed. this also enables grounds for lies and deceptions in the sense that one can deliberately lead someone to believe what one oneself does not believe. As per this source , communication requires third order of intentionality. To quote:
Suppose my little brother intends for me to jump. He might (and sometimes does) achieve this by sneaking up behind me and yelling “Boo!”. But that’s not communication, in the fullest sense of the word. It would be quite a different sort of action were he to instead request of me, “please jump.” (I don’t think he’d find that nearly so fun, for one thing.) Such a speech-act would show not only that he intends me to jump, but also that he intends for me to recognize that he wants me to jump.
Purposive communication requires an intentional state of at least third-order complexity. The speaker wants his audience to recognize what the speaker intends by his utterance. Put another way, you don’t just communicate ‘X’, you rather communicate, “I am trying to convey ‘X'”. (This is the difference between discreetly insulting someone, or making it clear to him that you want him to know you’re insulting him.) Anything less would fail to qualify as ‘communication’, in the fullest sense of the word.
Fourth-order Intentionality: Awareness of a communicative act that is distinct from the communicative act itself: A narrative or story telling/ story understanding capability. An ability to weave experiences into a running narrative such that it incorporates different communicative acts or ‘scenes’. An understanding of ‘roles’ that one is playing that give shape to all the communicative acts one participate sin and the narrative one weaves for oneself. A limited awareness that others are also communicative agents , but not a full awareness , that like oneself, they are also acting a script/ playing a role/ having a running narrative using which they interpret events. It is important to emphasize that story telling requires one to visit a new world in which the protagonist is separate, but also one is in a state of willful suspension of disbelief and thus one feels along-with the protagonist, but still retains one’s own narrative: separate, and quite distinct, form the story-teller’s narrative. Story-telling, and story understanding and the interpreter module of humans that gives rise to stream of consciousness to me are the hallmarks of fourth order of intentionality and most of us juts stop there. One may mistakenly believe that there is only one role / narrative and that everybody shares the same narrative.
Fifth order intentionality: Awareness of roles and narratives that are distinct from the role or narrative. An organizing system of religion/ myths using which one interprets stories. Awareness that others too have their own narratives and are playing a script/ performing their roles. Awareness that one’s role/ stance / understanding of world can be radically different from someone having the same experiences but using a different interpretation. A culture . A worldview. It is instructive to note that Dunbar considers that religion and story telling are higher level intentional activities.
I’ll leave things as they are for now as this fits nicely with my obsession with 5 + 3 stage developmental process. Higher orders of intentionality may exist, but probably we humans are not yet evolved to appreciate their subtleties/ find practical examples.
The blogosphere and the news tabloids are abuzz with the latest discovery that Vasoprassin may serve a similar role in humans as it does in prairie voles, when it comes to pair bonding. While , it might be true that ‘if you love someone , set him free’ a more strategic and evolutionary sound strategy is to keep him bound in a pair-bond. The females do this, by somehow , releasing Vasporossin in their partners brain and when this vasporossin binds to its receptors in the Brain, it leads to more bonding and pro-social behavior by the male.
A recent PNAS paper has implicated the vasoprassin receptor gene alleles for some variation in the marital bond. Read the excellent Not Exactly Rocket Science post for more details. Interestingly the gene variant , while conferring lower marital bond probability, also ups the risk for Autism. The mechanism underlying this must therefore be social – as social difficulties in Autistics may be related to this. This leads to the interesting hypothesis that people with Psychosis may have a stronger version o this pair-bonding receptor gene and thus may be less prone to depart ways, once a pis bond has been formed, and this may explain why despite low chances for procreation, the genes for schizophrenia may be carried out as the limited number of offspring’s are more heavily invested in by parents due to a stable pair bond.
But I digress, let this Post be about Love and what better way to celebrate that with a ‘Prairie voles in Love’ poem by Scicurious!
There is a new article by John Horgan, in the Discover Magazine regarding the eternal question of whether aggressiveness is in our genes and inevitable or can be done away with and lead to peaceful human existence.
I was introduced to psychology by reading Eric Fromm’s excellent treatise on the same titled The Anatomy of human destructivity, in which he passionately argues that the animals are not cruel or destructive; but that it is a uniquely human trait. that book is a classic and I recommend it whole heartedly to anyone who has interest in the matter.
The Discover magazine article in particular quotes too of my favorite scientists: Robert Sapolsky and Frans De walls and they are on the side of ‘peaceful humans’ . It also has discusses those hwo belive in a darker view of human nature.
Some excerpts follow:
Frans de Waal stands in a watchtower at the Yerkes National Primate Research Center north of Atlanta, talking about war. As three hulking male chimpanzees and a dozen females loll below him, the renowned primatologist rejects the idea that war stems from “some sort of blind aggressive drive.” Observations of lethal fighting among chimpanzees, our close genetic relatives, have persuaded many people that war has deep biological roots. But de Waal says that primates, and especially humans, are “very calculating” and will abandon aggressive strategies that no longer serve their interests. “War is evitable,” de Waal says, “if conditions are such that the costs of making war are higher than the benefits.” De Waal acknowledges that “we have a tendency, and all the primates have a tendency, to be hostile to non–group members.” But he and other experts insist that humans and their primate cousins are much less bellicose than the public has come to believe. Studies of monkeys, apes, and Homo sapiens offer ample hope that we can overcome our aggressive tendencies and greatly reduce or maybe even eliminate warfare.
Biologist Robert Sapolsky is a leading challenger of what he calls the “urban myth of inevitable aggression.” At his Stanford University office, peering out from a tangle of gray-flecked hair and beard, he tells me that primate studies contradict simple biological theories of male belligerence—for example, those that blame the hormone testosterone. Aggression in primates may actually be the cause of elevated testosterone, rather than vice versa. Moreover, artificially increasing or decreasing testosterone levels within the normal range usually just reinforces previous patterns of aggression rather than dramatically transforming behavior; beta males may still be milquetoasts, and alphas still bullies. “Social conditioning can more than make up for the hormone,” Sapolsky says.
De Waal suspects that environmental factors contribute to the bonobos’ benign character; food is more abundant in their dense forest habitat than in the semi-open woodlands where chimpanzees live. Indeed, his experiments on captive primates have established the power of environmental factors. In one experiment, rhesus monkeys, which are ordinarily incorrigibly aggressive, grew up to be kinder and gentler when raised with mild-mannered stump-tailed monkeys.
De Waal has also reduced conflict among monkeys by increasing their interdependence and ensuring equal access to food. Applying these lessons to humans, de Waal sees promise in alliances, such as the European Union, that promote trade and travel and hence interdependence. “Foster economic ties,” he says, “and the reason for warfare, which is usually resources, will probably dissipate.”
Fry has also identified 74 “nonwarring cultures” that—while only a fraction of all known societies—nonetheless contradict the depiction of war as universal. His list includes nomadic hunter-gatherers such as the !Kung in Africa and Aborigines in Australia. These examples are crucial, Fry says, because our ancestors are thought to have lived as nomadic hunter-gatherers from the emergence of the Homo lineage just over 2 million years ago in Africa until the appearance of agriculture and permanent settlements about 12,000 years ago. That time span constitutes 99 percent of our history.
Lethal violence certainly occurred among those nomadic hunter-gatherers, Fry acknowledges, but for the most part it consisted not of genuine warfare but of fights between two men, often over a woman. These fights would sometimes precipitate feuds between friends and relatives of the initial antagonists, but members of the band had ways to avoid these feuds or cut them short. For example, Fry says, third parties might step between the rivals and say, “‘Let’s talk this out’ or ‘You guys wrestle, and the winner gets the woman.’”
First, let me tell you how, the book got its name. It got its name from a quote by Darwin, while he was contemplating the debate between empiricists (we gain knowledge from experiences- tabula rasa) and rationalists (we have innate schema, intuition and logic that is independent of experiences) as to how we acquire knowledge, and how evolutionary theory might provide the answers.
With growing excitement, Darwin began to see that his theory might allow him to reconstruct the evolution of the human mind and thereby resolve the great debate between rationalism and empiricism. The modern human mind must acquire information, organize it, and generate behavior in ways that have been shaped by our evolutionary past. Our metaphysics must be the product of evolution. And just as the key to reconstructing the evolution of a whale’s fin or a bird’s beak comes from comparative research on similar traits in closely related species, the key to reconstructing the evolution of the human mind must come from comparative research on the minds of our closest animal relatives. “He who understands baboon would do more towards metaphysics than Locke.”
The authors then go on to confront behaviorist thoughts with experimental results that show that many animals come pre-programed in this world.
Song sparrows (Melospiza melodia) and swamp sparrows (Melospiza georgiana) are two closely related North American birds with very different songs. Males in both species learn their songs as fledglings, by listening to the songs of other males. But this does not mean that the mind of a nestling sparrow is a blank slate, ready to learn virtually anything that is written upon it by experience. In fact, as classic research by Peter Marler and his colleagues has shown, quite the opposite is true. If a nestling male song sparrow and a nestling male swamp sparrow are raised side-by-side in a laboratory where they hear tape-recordings of both species’ songs, each bird will grow up to sing only the song of its own species.
The constraints that channel singing in one direction rather than another cannot be explained by differences in experience, because each bird has heard both songs. Nor can the results be due to differences in singing ability, because both species are perfectly capable of producing each other’s notes. Instead, differences in song learning must be the result of differences in the birds’ brains: something in the brain of a nestling sparrow prompts it to learn its own species’ song rather than another’s. The brains of different species are therefore not alike. And the mind of a nestling sparrow does not come into the world a tabula rasa—it arrives, instead, with genetically determined, inborn biases that actively organize how it perceives the world, giving much greater weight to some stimuli than to others. One can persuade a song sparrow to sing swamp sparrow notes, but only by embedding these notes into a song sparrow’s song. It is almost impossible to persuade a swamp sparrow to sing any notes other than its own. Philosophically speaking, sparrows are Kantian rationalists, actively organizing their behavior on the basis of innate, preexisting schemes.
They then go on to discuss studies by Tolman and his students that gave a blow to behaviorism and introducing knowledge as an intermediary between stimulus and response.
In 1928, Otto L. Tinklepaugh, a graduate student of Tolman’s, began a study of learning in monkeys. His subjects were several macaques who were tested in a room in the psychology department at the University of California at Berkeley (sometimes the tests were held outdoors, on the building’s roof, which the monkeys much preferred). In one of Tinklepaugh’s most famous experiments, a monkey sat in a chair and watched as a piece of food—either lettuce or banana—was hidden under one of two cups that had been placed on the floor, six feet apart and several feet away. The other cup remained empty. Once the food had been placed under the cup, the monkey was removed from the room for several minutes. Upon his return, he was released from the chair and allowed to choose one of the cups. All of Tinklepaugh’s subjects chose the cup hiding the food, though they performed the task with much more enthusiasm when the cup concealed banana.
To illustrate the difference between behaviorist and cognitive theories of learning, pause for a moment to consider the monkey as he waits outside the experimental room after seeing, for example, lettuce placed under the left-hand cup. What has he learned? Most of us would be inclined to say that he has learned that there is lettuce under the left-hand cup. But this was not the behaviorists’ explanation. For behaviorists, the reward was not part of the content of learning. Instead, it served simply to reinforce or strengthen the link between a stimulus (the sight of the cup) and a response (looking under). The monkey, behaviorists would say, has learned nothing about the hidden food—whether it is lettuce or banana. His knowledge has no content. Instead, the monkey has learned only the stimulus-response associations, “When you’re in the room, approach the cup you last looked at” and “When you see the cup, lift it up.” Most biologists and laypeople, by contrast, would adopt a more cognitive interpretation: the monkey has learned that the right-hand cup is empty but there is lettuce under the left-hand cup.
To test between these explanations, Tinklepaugh first conducted trials in which the monkey saw lettuce hidden and found lettuce on his return. Here is his summary of the monkey’s behavior:
Subject rushes to proper cup and picks it up. Seizes lettuce. Rushes away with lettuce in mouth, paying no attention to other cup or to setting. Time, 3–4 seconds.
Tinklepaugh next conducted trials in which the monkey saw banana hidden under the cup. Now, however, Tinklepaugh replaced the banana with lettuce while the monkey was out of the room. His observations:
Subject rushes to proper cup and picks it up. Extends hand toward lettuce. Stops. Looks around on floor. Looks in, under, around cup. Glances at other cup. Looks back at screen. Looks under and around self. Looks and shrieks at any observer present. Walks away, leaving lettuce untouched on floor. Time, 10–33 seconds.
It is impossible to escape the impression that the duped monkey had acquired knowledge, and that as he reached for the cup he had an expectation or belief about what he would find underneath. His shriek reflected his outrage at this egregious betrayal of expectation.
Later they move on to their central premise, that baboons offer a good model to study the evolution of (human) mind.
Moreover, the conservation status of baboons confers neither glamour nor prestige on those who study them. Far from being endangered, baboons are one of Africa’s most successful species. They flourish throughout the continent, occupying every ecological niche except the Sahara and tropical rain forests. They are quick to exploit campsites and farms and are widely regarded as aggressive, destructive, crop-raiding hooligans. Finally, baboons are not particularly good-looking—many other monkeys are far more photogenic. Indeed, through the ages baboons have evoked as much (if not more) repulsion than admiration.
Baboons are interesting, however, from a social perspective. Their groups number up to 100 individuals and are therefore considerably larger than most chimpanzee communities. Each animal maintains a complex network of social relationships with relatives and nonrelatives—relationships that are simultaneously cooperative and competitive. Navigating through this network would seem to require sophisticated social knowledge and skills. Moreover, the challenges that baboons confront are not just social but also ecological. Food must be found and defended, predators evaded and sometimes attacked. Studies of baboons in the wild, therefore, allow us to examine how an individual’s behavior affects her survival and reproduction. They also allow us to study social cognition in the absence of human training, in the social and ecological contexts in which it evolved.
This same theme, of baboons having a greater social/group IQ is also touched upon by fellow ScientificBlogger Howard Bloom in a series of fascinating articles at the Scientificblogging.com, where I also blog. specifically Bloom refers to baboons and how they are smarter than chimpanzees, by being able to adapt to any environment (a more plausible definition of intelligence, instead of the usual anthropomorphic one we are accustomed to).
The ultimate test of intelligence is adaptability—how swiftly you can solve a complex problem, whether that problem is couched in words, in images, in crises, or in everyday life. The arena where intelligence is most important is not the testing room, it’s the real world. When you measure adaptability by the ability to turn disasters into opportunities and wastelands into paradises, bacteria score astonishingly high. But how do big-brained chimpanzees and small-brained baboons do? Or, to put it differently, how adaptable, clever, mentally agile, and able to solve real-world problems have chimpanzees and baboons proven to be?
He illustrates the above with a real world field study case example that showed the high adaptability of baboons.
Baboons have been called “the rats of Africa.” No matter how badly you desecrate their environment, they find a way to take advantage of your outrage. One group, the Pumphouse Gang, was under study for years by primatologist Shirley Strum. When Strum began her baboon-watching, the Pumphouse Gang lived off the land in Kenya and ate a healthy, all-natural diet. They ate blossoms and fruits when those were in season. When there were no sweets and flowery treats, the baboons dug up roots and bulbs.
Then came disaster—the meddling of man. Farmers took over parts of the baboons’ territory, plowed it, built houses, and put up electrified fences around their crops. Worse, the Kenyan military erected a base, put up homes for the officers’ wives and kids, and trashed even more of the baboons’ territory by setting aside former baboon-land for a giant garbage heap. If this had happened to a patch of forest inhabited by chimps, the chimpanzee tribes would have been devastated. But not the baboons.
At first, the Pumphouse Gang maintained its old lifestyle and continued grubbing in the earth for its food. Then came a new generation of adolescents. Each generation of adolescent baboons produces a few curious, unconventional rebels. Normally a baboon trip splits up In small groups and goes off early in the day to find food. But one of the adolescent non-conformists of the Pump House Gang insisted on wandering by himself. His roaming took him to the military garbage dump. The baboon grasped a principle that chimps don’t seem to get. One man’s garbage is another primate’s gold. One man’s slush is another animal’s snow cone.
The baboon rebel found a way through the military garbage heap’s barbed wire fence, set foot in the trash heap, and tasted the throwaways. Pay dirt. He’d hit a concentrated source of nutrition. When they came back to their home base at the end of the day, the natural-living baboons, the ones who had stuck to their traditional food-gathering strategies, to their daily grind digging up tubers, came home dusty and bedraggled, worn out by their work. But the adolescent who invented garbage raiding came back energetic, rested, strong, and glorious. As the weeks and months went by, he seemed to grow in health and vigor. Other young adolescent males became curious. Some followed the non-conformist on his daily stroll into the unknown. And, lo, they too discovered the garbage dump and found it good.
Eventually, the males who made the garbage dump their new food source began to sleep in their own group, separated from the conservative old timers. As they grew in physical strength and robustness, these Young Turks challenged the old males to fights. The youngsters’ food was superior and so was their physical power. They had a tendency to win their battles. Females attracted by this power wandered outside the ancestral troop and spent increasing amounts of time with the rebel males—who continued to increase their supply of high-quality food by inventing ways to open the door latches of the houses of the officers’ wives and taught themselves how to open kitchen cupboards and pantries and who also Invented ways to make their way through the electrified fences of farmers and gather armloads of corn. The health of the males and females in the garbage-picking group was so much better than that of the old troop that a female impregnated in the gang of garbage-pickers and farm-raiders was able to have a new infant every eighteen months. The females in the old, conservative, natural-diet group were stuck with a new infant only every 24 months. The innovators were not only humiliating the conservatives in pitch battles, they were outbreeding them.
I find the above anecdote very appealing. It seems we got to learn a lot from the social species and baboons may just be the ones we should look at more closely.