Category Archives: evolution

Primate evolutionary tree: a case of eight stage evolution leading to humans?

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:

  1. Suborder branching: Prosimians: I hypothesize that prosimian evolution be driven by first adaptive problem that of hiding from / avoiding predators. (lemurs etc)
  2. 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.
  3. 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.
  4. 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.
  5.  Subfamily branching: Ponginae or Orangutans :  Orangutan evolution may be driven by kin selection concerns.
  6. 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. 
  7. 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.
  8.   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!!

The eight major evolutionary transitions

Regular readers of this blog can vouch for my fascination with the eight stage  theories and would no doubt be sympathetic when I report my exhilaration of finding that none other than Maynard Smith himself has proposed that there are eight major evolutionary transitions till date in the evolution of life. Maynard Smith and  Szathmary in their book The Major Transitions in Evolution had proposed for the following eight transitions :

More details are available at this wikipedia page . now I , independent of any knowledge that this has already been proposed by Maynard Smith as back as in 1995, a few days ago had come up with similar eight transitions in evolution of life forms . Of course there are some differences, but the important thing to note is the similarities(great minds think alike) and of course my model is far more accurate and realistic than Maynard smiths who I believe leap from multi-cellular organisms to humans quite arbitrarily leaving all the phylum in between un addressed.

I’ll now briefly note the similarities and also highlight the dissimilarities in our approaches:

The first three stages are identical (first description of Maynard Smith stage and that is followed by my description in a few days ago post) :

1. Transition from Replicating molecules to “Populations” of molecules in compartments
1. Co-Evolution of genes and proteins/ amino-acids

2. Transition from Independent replicators (probably RNA) to Chromosomes
2. Evolution of the chromosome or two strands of DNA

3. Transitions from RNA as both genes and enzymes to DNA as genes; proteins as enzymes (Prokaryotes)
3. Evolution of a simple unicellular prokaryotic-bacteria-like cells

In the fourth stage I differ a bit from Maynard Smith, in that I propose for an intermediate archea type life-feom evolution while they jump straight to prokaroyotes)
4. Trasition from Prokaryotes to Eaukaryotes
4. Evolution of simple unicellular Archea-like cells

In the fifth stage they stress the importance of sex. I stress the importance of organalles, mitochondria and nucleus (specialized cell structures) instead.
5.Transition from Asexual clones to Sexual populations
5.Evolution of simple uni-cellular Eukaryotic like cells

In the sixth stage they move directly to multi-cellular organisms while I introduce intermediate colonies. I believe their fifth stage sexual populations are a substitute for my colonies (both map to protists)
6. Transition from Protists to Multicellular organisms — animals, plants, fungi
6.Evolution of simple colonies of cells (first animal phylum: the porifera or sponges)

In the seventh stage they make a leap and go directly to full-fledged solitary individuals (animals, plants fungi) while I take a more conservative approach and introduce multi-cellular organisms now from colonies.
7. Transition from Solitary individuals to Colonies with non-reproductive castes
7. Evolution of multi-cellular organisms with digestive tracts (second animal phyla coelenterate)

In the eighth and final stage they leap from primates to humans while I stay with multi-cellular organisms but introduce a CNS for the first time.
8.Transition from Primate societies to Human societies with language, enabling memes
8. Evolution of multi-cellular organisms moving towards a CNS( bilaterality) (third animal phyla :Ctenophora (Comb Jellies)):

I believe that after multi-cellular organisms they have made big leaps (which may be justified in some contexts), but I have worked more on micro level and believe that we can gain much more by studying the intermediate phyla too. The important thing to note is the common evolutionary and taxonomic approach and the guiding principles as outlined below for each transition:

Maynard Smith and Szathmary identified several properties common to the transitions:

  1. Smaller entities have often come about together to form larger entities. e.g. Chromosomes, eukaryotes, sex multicellular colonies.
  2. Smaller entities often become differentiated as part of a larger entity. e.g. DNA & protein, organelles, anisogamy, tissues, castes
  3. The smaller entities are often unable to replicate in the absence of the larger entity. e.g. Organelles, tissues, castes
  4. The smaller entities can sometimes disrupt the development of the larger entity e.g. Meiotic drive (selfish non-Mendelian genes), parthenogenesis, cancers, coup d’état
  5. New ways of transmitting information have arisen.e.g. DNA-protein, cell heredity, epigenesis, universal grammar.

Hat Tip: Shared Symbolic Storage blog

The big fight: The Big Five or The Big Eight?

The big question of the day is whether to overthrow the last 40-yrs mature conventional wisdom that there are only five personalty traits or factors. The introduction of Big Five or FFM model of personality had spawned a big research paradigm and there are many independent confirmations; so before I try to throw the baby out with the bath-water, let me just say at the outset that just like the big five model is not incompatible with Eysneck’s PEN model, so is my proposed eight factor model not inconsistent with the Big Five model- it just extends it and introduces a few new traits or dimensions. I have written in the past about personality, so it may help to read a few articles to know where I am coming from. I especially recommend this one related to perfectionism and personality.

First a quick review. the big Five personality dimensions are (in no particular order): Openness, Conscientiousness, Extraversion, Agreeableness and Neuroticism. It is to be recalled that these traits were discovered by lexical analysis of adjectives/ nouns and then doing factor analysis on the data to discover the minimum number of factors required to account for the variation in the data set. This way five factors have been discovered by exploratory Principal component analysis in many languages.

Recall that in PCA, factors are ordered. First factor is more important and can explain most of the variance. Second is less important/ responsible for variance and so on. It is my thesis that these personality traits would occur in a factor analysis in the order in which they evolve/develop , with the most evolved/ developed trait , which is most under hereditary control, reflected more in language and accounting for more variance in the data set.

Now, I do not have access to the original Goldberg or any McRae and Costa factor analysis results , so cannot say what the order of factors was. I propose, from my theoretical leanings and ordering of eight basic adaptive problems, the order would be (in order of less importance) : Neuroticism, conscientiousness, Extraversion, Agreeableness and Openness.

I have done some quick lookup on Google , but could not find much data related to how the five factors are ordered. One source I found, found support for NECAO ordering if only items from NEO-PI were analyzed; but NCEAO i.e. my order when additionally Zuckerman scales were also taken into account.

Let me delineate this further:

  1. Neuroticism (N): personality more focused towards solving the adaptive problem of avoiding predators. marked by negative emotionality, worry etc. Nettle calls these Worriers. The plot that works for them is ‘overcoming the monster’: everything apprised as a monster. primary mode of being: emotional.
  2. Conscientiousness (C): personality more focused on optimally finding and utilizing resources (or finding food) Nettle calls them controller. The plot that works for them is Rags to riches. How to become successful. Primary mode of being: motivational.
  3. Extraversion (E): personality more focused on forming alliances/friendships and thus issues of dominance- hierarchy. Nettle calls them wanderers. The plot for them a Quest, where they wander adn on the way make alliances/ friends to reach the illusive goal. The Journey , and the energy imbued with travel, becomes more important than the Goal. Primary mode of being: behavioral/social.
  4. Agreeableness (A): personality more focused on care of close ones; be it friends or children. Nettle calls them Empathizers. not sure if voyage and return is an apt plot for them. Primary mode of being: attachment/ care/ responsibility.
  5. Openness (O): Here I’ll like to re-categorize this as rebelliousness vs social conformity: adaptive problem to be solved : who am I and who are like-minded people / roles that I should help. Nettle calls them Poets. The plot that works for them is comedy wherein one has to find true identities of disguised people or become reunited with twins/ kin etc. Primary mode of being: cognitive and self-appraisal

I’ll like to add three more factors to the above based on CPS scales and any other theoretical as well as factor-analytic considerations:

6. Trust vs defensiveness (T): personality more focused on who can be trusted and who cannot. trying to see behind someones apparent persona.
7. Activity (Act) : personality more focused on being active, communicative, lively and humorous.
8. Masculinity- femininity (M-F): personality more focused on becoming desirable to the opposite sex.

The reasons I extend this are:

I) The evidence for Comrey Personality scales:

  1. Trust vs. Defensiveness ; A new factor (T above)
  2. Social Conformity vs. Rebelliousness: same as O
  3. Emotional Stability vs. Neuroticism: same as N
  4. Mental Toughness vs. Sensitivity: Same as Masculinity- femininity above
  5. Orderliness vs. Lack of Compulsion: Same as C
  6. Activity vs. Lack of Energy: A new factor (Act above)
  7. Extraversion vs. Introversion : same as E
  8. Empathy vs. Egocentrism : Same as A

II) when Nouns are factor analyzed we get eight factors (in the order of importance of factors)

  1. Social Unacceptability (Scum, tarsh, mororn): N (negative emotion)
  2. Intellect (philosopher, artist,nonconformist): C? (not conscientious person?)
  3. Egocentrism (snoop, busybody, know-it-all): E (not extarverted person)
  4. Ruggedness (tough, gentleman, fighter) : A (not agreeable person)
  5. Delinquency (law-breaker, googdy-ggody, innocent): O (more rebellious person)
  6. Attractiveness (babe , doll, hero) : T ??(a trustworthy person is attractive??)
  7. Liveliness (joker, chatterbox, loudmouth): Act ( a more active/ communicative person)
  8. Disorientation: (klutz, novice, daydreamer): M-F ? (are we being sexually selected for more ‘orientation’?)

III) Goldberg, who had originally proposed the Big five has revised them to include two more ; he calls them Religiosity and WYSIWYG respectively.

Goldberg (Goldberg 1992b) has identified the “next two” factors that might be used to augment the big five. The first, tentatively called Religiosity, includes adjectives ranging from prayerful and reverent at the north pole to irreligious and unreligious at the south pole. The second, tentatively called what you see is what you get, includes adjectives ranging from undevious and unsly at the north pole to slick and aristocratic at the south pole. He goes on to point out that “there are no additional domains with anywhere near the breadth of the Big-Five factors”.

IV) Wikipedia entry says that others have also proposed more traits (and presumably also found in their factor analytic studies evidence for such traits)

Some psychologists have dissented from the model precisely because they feel it neglects other domains of personality, such as Religiosity, Manipulativeness/Machiavellianism, Honesty, Thriftiness, Conservativeness, Masculinity/Femininity, Snobbishness, Sense of humour, Identity, Self-concept, and Motivation.

See this also on personality research:

Saucier and Goldberg (1998) presented evidence that nearly all clusters of personality-relevant adjectives can be subsumed under the Big Five. Paunonen and Jackson (2000), however, argued that this study used too loose a criterion for inclusion in the Big Five–namely that the Big Five account for at least 9% of the variance in the adjective cluster. Reanalyzing the same data using a stricter criterion of 20% explained variance resulted in nine clusters of traits that fell outside of the Big Five: Religiosity, Honesty, Deceptiveness, Conservativeness, Conceit, Thirft, Humorousness, Sensuality, and Masculinity-Femininity. These analyses do not imply that the clusters are unrelated; for example, Honesty and Deceptiveness may be highly (negatively) related as opposite sides of the same dimension. Nevertheless, these results suggest that several important personality traits lie beyond the Big Five.

Considering all the above factors , especially keeping in mind the fact that Goldberg;’s new proposed religiosity may be more close to the now-traditional openness which I have re-characterized as rebellious- conformity ; and that Goldberg’s unsly, slick, aristocratic and undevious may correspond to trust-defensiveness dimension; what we see is that the traditional intellect that Goldberg uses may be better thought of as Activity dimensions which relates to how lively, communicative and active a person is . Also he completely misses the last factor related to masculinity / femininity.

For the other proposed dimensions by Johnson et al , it is easy to see that religiosity can be subsumed under my definition of Opennnes; honesty/deceptiveness are opposite poles of the trust-defensiveness (T) trait); Conservativeness, Conceit, Thirft, Humorousness are better conceptualized as per me into Activity trait (Act) and that leaves us sensuality and Masculinity-Femininity as the last trait with these being two poles: at one end the role is more gender conformant; at the other it is more open and sensual in nature. If ever Humans speciate, it would because of this dimension!! It has been my thesis that we have been developing in diversity along these personality dimensions, but speciation would most likely happen only when assortattive mating and sexual selection acts at the eighths trait and the eighth trait is under more and more genetic control. Such a scenario may, thankfully, be far away!!

Evolution of Life: the eight stage process repeating again and again?

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 Catby 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.

  1. 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!
  2. 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.
  3. 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.
  4. 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!!).
  5. 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!
  6. 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.
  7. 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.
  8. 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.

  1. Phylum Platyhelminthes (Flatworms): bilateral symmetry with CNS,No body cavity.
  2. Phylum Nemertea (Ribbon Worms)
  3. Phylum Rotifera (Rotifers): Coelem incomplete.
  4. Phylum Gastrotricha (Gastrotrichs).
  5. Phylum Nematomorpha (Horsehair Worms).
  6. Phylum Nematoda (Nematodes): a special level of evolutionary jump and that is why we scientists study this a lot.
  7. Phylum Acanthocephala (Spiny-Headed Worms).
  8. 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.

  1. Phylum Tardigrada (Tardigrades).
  2. Phylum Brachiopoda (Brachiopods).
  3. Phylum Mollusca (Mollusks).
  4. Phylum Annelida (Segmented Worms).
  5. Phylum Sipunculoidea (Peanut Worms).
  6. Phylum Arthropoda (Arthropods): Evolutionary jump. Body consisting of three parts: head, thorax and abdomen.
  7. Phylum Chaetognatha (Arrow Worms). Phylum Echinodermata (Echinoderms).I’ll like to club these two together.
  8. 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):

  1. Class Osteichthyes (bony fishes) : driven by avoiding predation
  2. Class Amphibia (Amphibians): driven by exploring surrounding
  3. Class Reptilia (Reptiles): driven by forming alliances between small groups
  4. Class Aves (Birds): driven by best reproductive/parental strategy
  5. 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!

The (eight) basic adaptive problems faced by all animals (esp humans)

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.

To quote:

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:

  1. Avoiding Predators
  2. Eating the Right Food
  3. Forming Alliances and Friendship
  4. Providing help to Children and other Relatives
  5. Reading other people’s minds
  6. communicating with other people
  7. selecting mates

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:

  1. 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).
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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:

  1. Overcoming the Monster plot ( avoiding predator)
  2. Rags to Riches plot (finding food/ resources): how one successfully gets resources like money.
  3. 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.
  4. 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!
  5. Comedy plot: (kin selection): the typical plot involves family disjointed, twins to create confusions, disguised identities etc: overall recognizing similar people and kin.
  6. 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.
  7. Rebirth (communicating with others) ; haven’t read Christopher Booker’s book till here so cant comment!!

I’m convinced! What about you?

Movement and perception disorders : a case for dissolution?

I have touched upon the work of Hughlings-Jackson earlier, albeit very obliquely, and readers familiar with with his work will know the immense contributions he has made to the understanding of epilepsy and other neurological disorders. I was recently reading the Croonian Lectures on the Evolution and dissolution of human nervous system and I encourage my readers to read the 3 lectures in their entirety. Let me briefly try to summarize his approach to brain first:

Hughligs Jackson believed that the brain had evolved. Also that the human brain is heterogeneous with three distinct evolutionary distinct components that were perfected in evolutionary dissimilar times: in this sense he sort of laid the groundwork for the Triune Brain theory of Paul MacLean.

He also believed that these three evolutionary distinct (logical) components of the human brain were hierarchical in nature and that all that these centers really did was representation of impressions and movements or re-representation of that initial representation (in successively higher centers). He also proposed that lower centers were more simple, more organized, more automatic and more reflexive in nature; while the highest centers were the least automatic, least organized , but the most complex and the least reflex-like in nature.

As these centers evolved one after the other, each such center has a positive function that only it can provide and it also inhibits some of the functions that were earlier provided by the lower layers; or in other words keeps the lower layers in check.

He also believed in the concept of dissolution: whereby when a higher center is not working properly then this would result in the lower centers asserting their autonomy. The loss of the higher layer/ center would not only result in the loss of function associated with that center (negative symptoms) ; but by freeing the autonomic activity of lower center from higher inhibition, it would also lead to some new functions to be experienced (positive symptoms). Thus a dissolution that affects the third or highest layer , would free the intermediate layer to produce some positive effects, and because of unavailability of the higher layer function would also lead to loss of some functionality.

He most fully developed these ideas in association with epilepsy patients, in which he believed, that the epileptiform seizure or discharge leads to inactivity of higher layers (1, 2 or all 3) and inappropriate activity in lower layers, thereby produce different degrees of negative and positive symptoms/ behaviors. My earlier post did contain references to this.

We find evidence for the truth of most of his ideas in today’s neuroscience developments.

This time I will like to touch upon how he himself had, sort of extended the triune brain, to an eight stage brain and how he delineated eight different levels of dissolution, each progressively of a more severe level than the earlier one , while he related the concept of dissolution in the Croonian lectures (lecture 1) with the help of movement disorders.

Before we proceed, it is instructive to note that Jackson believed in two levels of consciousness: subject and object- the former related to awareness of impressions; while the latter to movements. In simpler terms , he believed that we could discuss, movement (and volitional) related stuff separate from perceptual stuff and I’ll stick to that distinction in this post.

I’ll first quote at length from him (I have reformatted the stuff, so please read the original lecture for a balanced view):

I now come to give examples of dissolution. I confess that I have selected cases which illustrate most definitely, not pretending to be able to show that all the diseases of which we have a large clinical knowledge exemplify the law of dissolution. However, I instance very common cases, or cases in which the pathology has been well worked out; they are cases dependent on disease at various levels from the bottom to the top of the central nervous system. Most of them are examples of local dissolution.

  1. Starting at the bottom of the central nervous system, the first example is the commonest variety of progressive muscular atrophy. We see here that atrophy begins in the most voluntary limb, the arm; it affects first the most voluntary part of that limb, the hand, and first of all the most voluntary part of the hand; it then spreads to the trunk, in general to the more antomatic parts. To speak of a lower level of evolution in this case is almost to state a barren truism. At a stage when the muscles of the hand only are wasted, there is atrophy of the first or second dorsal anterior horn; the lower level of evolution is made up of the higher anterior horns for muscles of the arm. This statement, however, is worth making, for it shows clearly that by higher and lower is meant anatomico-physiologically higher or lower.
  2. Going a stage higher we come to hemiplegia, owing to destruction of part of a plexus in the mid-region of the brain. Choosing the commonest variety of hemiplegia, we say that there is loss of more or fewer of the most voluntary movements of one side of the body; we find that the arm, the more voluntary limb, suffers the more and longer; we find, too, that the most voluntary part of the face suffers more than the rest of the face. Here we must speak particularly of the lower level of evolution remaining; strictly we should say collateral and lower. We note that although unilateral movements (the more voluntary) are lost, the more automatic (the bilateral) are retained. Long ago this was explained by Broadbent. Subsequent clinical researches are in accord with his hypothesis. The point of it is that the bilateral movements escape in cases of hemiplegia in spite of destruction of some of the nervous arrangements representing them; the movements are doubly represented—that is, in each half of the brain. Hemiplegia is a clear case of dissolution, loss of the most voluntary movements of one side of the body with persistence of the more automatic movements.
  3. The next illustration is paralysis agitans. Apart from all speculation as to the seat of this disease, the motorial disorder illustrates dissolution well. In most cases the tremor affects the arm first, begins in the hand, and in the thumb and index-finger. The motorial disorder in this disease becomes bilateral; in an advanced stage paralysis agitans is double hemiplegia with rigidity—is a two-sided dissolution.
  4. Next we speak of epileptiform seizures which are unquestionably owing to disease in the midregion of the brain (middle motor centers). Taking the commonest variety, we see that the spasm mostly begins in the arm, nearly always in the hand, and most frequently in the thumb or index-finger, or both; these two digits are the most voluntary parts of the whole body.
  5. . [The next illustration was by cases of temporary paralysis after epileptiform seizures.]
  6. Cborea is a disease in which the limbs (the most voluntary parts) are affected more than the trunk (the more automatic parts), and the arms (the more voluntary limbs) suffer more than the legs. The localization of this disease has not been made out;symptomatically, however, it illustrates dissolution. Chorea has a special interest for me. The great elaborateness of the movements points to disease “high up” —to disease on a high level of evolution. Twenty years ago, from thinking on its peculiarities, it occurred to me that some convolutions represent movements. A view I have taken ever since.
  7. Aphasia. This well illustrates the doctrine of dissolution, and in several ways. We will consider a case of complete speechlessness. (a) There is loss of intellectual (the more voluntary) language, with persistence of emotional (the more automatic) language. In detail the patient cannot speak, and his pantomime is of a very simple kind; yet, on the other hand, he smiles, frowns, varies the tones of his voice (be may be able to sing), and gesticulates as well as ever. Gesticulation, which is an emotional manifestation, must be distinguished from pantomime, which is part of intellectual language. (b) The frequent persistence of “Yes“ and “No“ in the case of patients who are otherwise entirely speechless is a fact of extreme significance. We see that the patient has lost all speech, with the exception of the two most automatic of all verbal utterances. “Yes“and “No“ are evidently most general, for they assent to or dissent from any statement. In consequence of being frequently used, the correlative nervous arrangements are of necessity highly organized, and, as a further consequence, they are deeply automatic. (c) A more important, though not more significant, illustration is that the patient who cannot get out a word in speech nevertheless understands all that we say to him. Plainly this shows loss of a most voluntary service of words, with persistence of a more automatic service of words. We find illustrations in small corners. (d) There are three degrees of the utterance “No“ by aphasics. A patient may use it emotionally only—a most automatic service; another patient may also be able to reply correctly with it—a less automatic, but still very automatic service. (Here there is some real speech.) There is a still higher use of it, which some aphasics have not got. A patient who can reply “No“ to a question may be unable to say ‘No“ when told to do so. You ask the aphasic, “is your name Jones?“ he replies “No.“ You tell him to say “No,“ he tries and fails. You ask, “Are you a hundred years old ?“ He replies “No.“ You tell him to say “No.“ He cannot. Whilst not asserting that the inability to say “No“ when told is a failure in language, it is asserted that such inability with retention of power to use the word in reply illustrates dissolution. (e) A patient who is speechless may be unable to put out his tongue when told to do so; that he knows what is wanted is sometimes shown by his putting his finger in his mouth to help out the organ. That the tongue is not paralyzed in the ordinary sense is easily proved. The patient swallows well, which he could not do if bis tongue were as much paralysed as “it pretends to be.“ Besides, on other occasions he puts out his tongue, for example, to catch a stray crumb. Here is a reduction to a more automatic condition; there is no movement of the tongue more voluntary than that of putting it out when told. [The lecturer then remarked on swearing and on the utterance of other and innocent ejaculations by aphasics, remarking that some of these utterances had elaborate propositional structure but no propositional value. The patients could not repeat, say, what under excitement they uttered glibly and well. He spoke next of the frequent retention of some recurring utterance by aphasics, such as “Come on to me.“ These were not, from the mouth of the aphasic, of any propositional value, were not speech. He had no explanation to offer of these, but stated the hypothesis that they were the words the patient was uttering, or was about to utter, at the time he was taken ill.]
  8. . So far I have spoken of local dissolution occurring on but one half of the nervous system on different levels. Coming to the highest centers I speak of uniform dissolution—of cases in which all divisions of these centers are subjected to the same evil influence. I choose some cases of insanity. In doing this I am taking up the most difficult of all nervous diseases. I grant that it is not possible to show in detail that they exemplify the principle of dissolution, but choosing the simplest of these most complex cases we rnay show clearly that they illustrate it in general. I take a very common-place example—delirium in acute non-cerebral disease. This, scientifically regarded, is a case of insanity. In this, as in all other cases of insanity, it is imperative to take equally into account not only the dissolution but the lower level of evolution that remains. The patient‘s condition is partIy negative and partly positive. Negatively, he ceases to know that be is in hospital, and ceases to recognise persons about him. In other words, he is lost to his surroundings, or, in equivalent terms, he is defectively conscious. We must not say that he does not know where he is because he is defectively conscious; his not knowing where he is is itself defect of consciousness. The negative mental state signifies, on the physical side, exhaustion, or loss of function, somehow caused, of some highest nervous arrangements of his highest centers. We may conveniently say that it shows loss of function of the topmost layer of his highest centers. No one, of course, believes that the highest centers, or any other centers, are in layers; but the supposition will simplify exposition. The other half of his condition is positive. Besides his not knowings, there are his wrong knowings. He imagines himself to be at home or at work, and acts as far as practicable as if he were; ceasing to recognize the nurse as a nurse, he takes her to be his wife. This, the positive part of his condition, shows activity of the second layer of his highest centers; but which, now that the normal topmost layer is out of function, is the then highest layer; his delirium is the “survival of the fittest states,“ on his then highest evolutionary level. Plainly, he je reduced to a more automatic condition. Being (negatively) lost, from loss of function of the highest, latest developed, and least organized, to his present “real,“ surroundings, he (positively) talks and acts as if adjusted to some former “ideal“ surroundings, necessarily the more organized.

This to me seems very promising: I am a die-hard fan of the eight stage evolutionary/ developmental model whereby the first five stages are more similar, the next two on a qualitatively different level; while the last or eighth one takes one a notch higher up the octave to a different qualitative level altogether, although resembling or analogous to the first stage to an extent.

I keep mapping analogies between the different stages evident in different developmental / evolutionary processes and this piece of puzzle fits in nicely.

I’ll now like to speculate a bit. I’ll first restrict myself to movement/action planning, execution and control. I believe that the regions of the brain involved in this activity are (in a heirarchichal order) :

  1. Frontal Cortex (supplementary motor area) : decides which action to initiate/ plans and co-ordinates with respect to complex actions involving say both hands. More involvement in ‘voluntary’ actions
  2. Primary Motor cortex : Actual execution of the intended/ chosen action.
  3. Pre-motor cortex:responsible for motor guidance of movements especially with respect to external cues
  4. Parietal cortex:responsible for transforming visual information into motor commands
  5. Somatosensory cortex: this too is involved in motor circuits ; see this too.(synapses to and from this go to cerebellum/ basal ganglia): probably involved in triggering visual information related to the action. I am tempted to replace this with Thalamus and I just might do that after some more research!!
  6. Basal Ganglia: a set of structures that are involved in gross motor control
  7. Cerebellum: a structure involved in fine motor control
  8. Brain Stem: a structure involve in controlling vital involuntary movements like breathing, heart beat etc. these movements are neither voluntary nor automatic; they are involuntary and thus a notch different.

Now coming back to the disorders of the movement delineated by hughlings-Jackson, we can readily see some correspondences. The Basal Ganglia abnormality leading to Huntington’s Chorea is clearly at level 6. The primary motor cortex lesion leading to stage 2 hemiplegia is also well established. The epileptofm seizure related spasms and temporary paralysis just after that may be plausibly related to lesions of parietal and somatosnesory cortices. The lesion of pre-motor area may give rise to alien hand syndrome (to be distinguished from Anarchic hand syndrome), whereby you grab any object in sight compulsively. The hughlinghs-jackson description of Parkinsonisms at level 3 does not really gel here as Parkinsonism is more of a basal ganglia problem. Similarly PMA (progressive muscular atrophy) is no longer a valid diagnosis, so it may not map to SMA lesion or dysfunction. SMA dysfunction or lesion may instead produce syndromes like the mirror hand syndrome , in which both hands are used for the same action, though only one hand would have sufficed. It is interesting to note that this mirror hand syndrome is conceptualized today as freeing of SMA inhibition of PMA, thus allowing parallel planning of the same action. Similarly level 7 lesions of cerebellum may be more related to Ataxia rather than aphaisas.

Despite the above problems with the above conceptualization, I find the efforts of Jackson is the right direction and ahead of hist time.

I’ll now end with a teaser of things to come. It is related to disorders of phenomenal consciousness classified by Thomas Metzinger in Being No One, and they are as follows :

Deviant phenomenal models of reality

  1. Agnosia
  2. Neglect
  3. Blindsight
  4. Hallucinations
  5. Dreams

To me they follow the same 5 stage process, with each stage analogous to the movement related disorder.More about that later.

Psychosis and Autism as Diametrical Disorders of the Social Brain: converging evidence!!

Readers of this blog will be familiar with my model of Autism/ Schizophrenia and I recently found an online article by Crespi et al that elegantly summarizes the theory that autism and Schizophrenia are on a continuum of phenotypic variations related to cognition and the social brain.

I will be using images and text from that article heavily, so go ahead and read the original article too, which is very well-written and thought provoking.

The Authors contend that autism and schizophrenia are on a continuum where cognition is concerned with Autistics leaning towards mechanistic cognition, while schizophrenics leaning towards mentalistic cognition. This should be a familiar story to readers of this blog.

They discuss the various contrasting features of Autism and Schizophrenia. They contend that Autism is made up of three dimensions: language and communication difficulties, social reciprocity difficulties and creative or imaginative difficulties (which they term as repetitive and restricted behavior) .

They contrast this with the psychotic spectrum in which they include the three corresponding dimensions as Unipolar depression, bipolar disorder and Schizophrenia.

They then go ahead and list a variety of evidence from studies of growth, development, neuroanatomy, cognition, behavior, and epidemiology for diametric phenotypes in autism and psychosis. I reproduce below the table (click to enlarge – the tables are a must read!!) which highlights salient differences in phenotypes:

The authors have their own theory (which seems very plausible to me) regarding why Autism and Schizophrenia are diametrically opposite. This they contend is due to evolutionary arms race between the child and mother for scarce resources mediated by maternal and paternal imprinting genes.

They do a brilliant job of describing their theory so I quote from them:

Further hints that imprinted genes may have something to do with autism and psychosis come from the finding that autistics have heavier birth-weight(especially males) while schizophrenics are lighter – just as you would expect if paternal genes were more prominent in autism. Again, more paternal and/or less maternal genetic influence is sometimes implicated in cancer(another form of over-growth) and here the striking finding is that schizophrenics have less cancer than autistics despite the fact that the former smoke much more. Again, there is evidence that autistics by contrast to psychotics show early brain growth at the expense of the mother.

The article’s discussion is enlightening as it also throws light on other previous researchers who have hypothesized along similar lines. Alas The Mouse Trap doesn’t get a mention, But Nettle , regarding whom I have blogged before gets a mention.

Our hypothesis can be conceptualized at two interacting levels: (1) the diametric architecture of autistic and psychotic-spectrum conditions (Badcock 2004), and (2) the underpinnings of this structure in dysregulated genomic imprinting. A diametric structure to autism and schizophrenia has been considered for some traits before: thus, Abu-Akel (1999) and Abu-Akel & Bailey (2000) suggested that autism and schizophrenia represent extremes on a continuum of theory of mind skills from hypodevelopment to hyper-development, Frith (2004b) described ‘under-mentalizing’ in autism and ‘over-mentalizing’ in schizophrenia, and Nettle (2006) anticipated an autism psychosis spectrum in noting that “autistic traits are in many ways the converse of the unusual experiences component of schizotypy”. However, most previous research on autism and psychosis has considered the disorders to be etiologically unrelated (or has considered the negative symptoms of schizophrenia in terms of autism), although both disorders are believed to be underlain by dysregulated development of the social brain (Broks 1997; Emery 2000; Burns 2004, 2006). By our hypothesis, autism and psychosis represent extremes on continua of human cognitive architecture from mechanistic to mentalistic cognition, with balanced cognition at the center (Figure 4). Each set of conditions is extremely heterogeneous but also highly convergent, in that diverse genetic, epigenetic and environmental effects can generate similar cognitive phenotypes (Happé 1994, p. 2; Keverne 1999; Seeman et al. 2005; Badcock & Crespi 2006; Happé et al.2006). These striking convergences are mediated, in our view, by the dynamics of social brain development, with under-development in autistic conditions and hyperdevelopment in psychotic conditions (Badcock 2004), Further tests of this hypothesis should focus on assessing the breadth and depth of diametric phenotypic structure to autistic and psychotic spectrum conditions, and testing for tradeoffs between mentalistic and mechanistic thought and ability.

I am thrilled to see my theory also being investigated in parallel and worked on by distinguished scientists and am grateful for the scientific work going in this area. I am sure we will soon see more research supporting my thesis.

The eight-fold structure of evolutionary biology/ cultural evolution

Regulars readers of this blog will know that I am sold on the eight-fold developmental theory that assumes that there are eight stages of development/evolution of any feature and I have explored this extensively. Five of these lower stages are at a different level and the upper 3 at a different level explain the development of the same phenomenon. for a quick summary and links to my eight-fold fascination please see this the first paragraph of this post. So it is no surprise that I was fascinated when I discovered that evolutionary biology is conceptualized as eight subjects or methods of inquiry and they also follow a 5 +3 pattern with 5 lower levels referring to within species evolution and the last 3 referring to between species evolution. This structure of evolutionary biology I discovered via a fascinating artcile that tries to find parallels between cultural evolution and biological evolution. The article is by Mesoudi et al (2006) and I will be heavily quoting from that paper.

First a very beautiful figure that shows the structure of evolutionary biology and draws parallels to cultural evolution. Explanation of figure follows.

The left hand side of Figure 1 illustrates the overall structure of evolutionary biology, as described by Futuyma (1998, pp. 12-14) in what is, perhaps, the most widely used undergraduate textbook in the field. The study of biological macroevolution deals with change at or above the species level, while biological microevolution concerns changes within populations of a single species. The former comprises systematics, paleobiology and biogeography, while the latter involves population genetics (theoretical, experimental and field-based), evolutionary ecology and molecular genetics. In Sections 2 and 3 we examine each of the sub-disciplines of evolutionary biology in turn, first outlining their general methods then briefly describing examples of recent studies to illustrate how those methods are applied and the kind of results they yield. This is followed in each case by a discussion of existing analogous or equivalent methods within the social sciences regarding human culture, again describing recent key studies. These cultural disciplines, and the way in which they map onto the structure of evolutionary biology, are illustrated on the right hand side of Figure 1. While there may be no obvious precedent for two distinct fields to exhibit the same internal structure, the similarity of underlying processes leads us to expect a correspondence.

Now let me come to the central theme of the paper that cultural evolution has parallels in evolutionary biology and the sub disciplines and methodologies from one can inform the other.

Parallels or analogies between biological and cultural evolution have been noted by a number of eminent figures from diverse fields of study.The implication of this growing body of theory is that culture exhibits key Darwinian evolutionary properties. If this is accepted, it follows that the same tools, methods and approaches that are used to study biological evolution may productively be applied to the study of human culture, and furthermore that the structure of a science of cultural evolution should broadly resemble the structure of evolutionary biology. In the present paper we attempt to make this comparison explicit, by examining the different approaches and methods used by evolutionary biologists and assessing whether there is an existing corresponding approach or method in the study of cultural evolution. Where such an existing correspondence is not found, we explore whether there is the potential to develop one. We also explore potential differences between biological and cultural evolution.

They also elaborate on benefits of the evolutionary eight-fold approach.

Second, and particularly relevant to this article, the theory of evolution encompasses and integrates a multitude of diverse sub-disciplines within biology, from behavioural ecology to paleobiology to genetics, with each sub-discipline stimulating and contributing to several others (see Mayr, 1982 for further details of this ‘evolutionary synthesis’). The social sciences, in contrast, have no such general synthesising framework, and the greater part of disciplines such as cultural anthropology, archaeology, psychology, economics, sociology and history remain relatively insular and isolated, both from each other and from the biological and physical sciences. Adopting an evolutionary framework can potentially serve to highlight how these disciplines are, in fact, studying complementary aspects of the same problems, and emphasise how multiple and multidisciplinary approaches to these problems are not only possible but necessary for their full exposition. At present, many of the individual studies considered below are the result of independent developments at the fringes of separate fields of study. Placing these disparate studies side-by-side within a broader evolutionary framework, as is done here, will hopefully contribute towards creating a coherent unified movement and bring evolutionary analyses of cultural phenomena into the mainstream. They then go on and explore each of the subdivision in detail and draw parallels to cultural evolution and show how methods of evolutionary biology when applied to culture have helped solve many problems there.

They also analyze psychology as equivalent to experimental population genetics. Reproducing the relevant sections below:

One parallel with this work lies in laboratory based psychological experiments simulating cultural transmission. Where population genetic experiments simulate biological evolution by studying the transmission of genetic information from generation to generation through the reproduction of individuals, psychological experiments can potentially simulate cultural evolution by studying the transmission of cultural information (e.g. texts or behavioural rules) from one individual to another through social learning.

One method for simulating cultural evolution was developed by Gerard, Kluckhohn and Rapoport (1956) and Jacobs and Campbell (1961). A norm or bias is established in a group of participants, usually by using confederates, and one by one these participants are replaced with new, untrained participants. The degree to which the norm or bias remains in the group after all of the original group members have been replaced represents a measure of its tansmission to the new members.

For example, Baum et al. (2004) studied the transmission of traditions using a task in which participants received financial rewards for solving anagrams. Groups of individuals could choose to solve an anagram printed on either red or blue card: the red anagrams gave a small immediate payment, while the blue anagrams gave a larger payoff but were followed by a ‘time-out’ during which no anagrams could be solved. By manipulating the length of this time-out, the experimenters were able to determine which of the two anagrams gave the highest overall payoff (i.e. where the blue time-out was short, blue was optimal, and where the blue time-out was long, red was optimal). Every 12 minutes one member of the group was replaced with a new participant. It was found that traditions of the optimal choice emerged under each experimental condition, with existing group members instructing new members in this optimal tradition by transmitting information about payoffs and timeouts, or through

Key similarities exist between this study and the experimental simulations of natural selection described above. In Kennington et al.’s (2003) study with Drosophila, where the experimentally determined conditions of low humidity favoured small body size, smaller individuals out-reproduced larger individuals. Hence genetic information determining ‘small body size’ was more likely to be transmitted to the next generation through biological reproduction, and the average body size of the population became gradually smaller. In Baum et al.’s (2004) study, where the experimentally determined conditions favoured red anagrams (when the blue time-out was relatively long), choosing red anagrams gave a larger payoff to the participants. Hence the behavioural rule ‘choose red’ was more likely to be transmitted to the new participants through cultural transmission, and the overall frequency of choosing red
gradually increased.

Baum et al.’s (2004) method could easily be adapted to study the cultural evolution of attitudes or beliefs. Groups of participants could be asked to discuss a contentious issue, then every generation the participant with the most extreme opinion in a certain direction removed and replaced with a random participant. After a number of generations the group should hold more extreme views (in the opposite direction to those of the removed participants) than average members of the larger population.

Finally they discuss psychology in relation to evolutionary ecology and neursocience / memetics in relation to molecular biology.

While genetic information is represented in sequences of DNA molecules, cultural information is represented primarily in the brain. Viewing culture as comprised of discrete units of information, or memes, can potentially make a complex system theoretically and empirically tractable, in the same way as the gene concept advanced biologists’ understanding of biological evolution. Although memes can be characterised as vague entities with flexible and fuzzy boundaries, so can the modern concept of the gene. It should be remembered that there was at least 50 years of productive investigation into biological microevolution before the molecular basis of genetic inheritance was determined, and even now it is only partly understood.
A deeper understanding of the neural and molecular basis of culturally acquired information must rely on technological advances in, for example, neuroimaging techniques. However, we should also reserve the possibility that the same cultural information is specified by different neural substrates in different brains, severely limiting such methods for studying cultural transmission. In this case there may be no cultural equivalent to molecular biology, although models and methods examining cultural transmission at the behavioural and cognitive levels can still provide important insights.

To me all this seems very interesting and I end with their conclusion:

The evidence discussed in this paper suggests that much potential exists for a comprehensive science of cultural evolution with broadly the same structure as the science of biological evolution, as outlined in Figure 1. This potential is already being realised for the study of cultural macroevolution and the mathematical modelling of cultural microevolution, with methods developed within evolutionary biology, such as phylogenetic analyses and population genetic models, being applied to cultural data. A number of opportunities exist for psychologists, sociologists and experimental economists to adopt the experimental methods and tools developed in population genetics to simulate cultural microevolution, and detect cultural evolution ‘in the wild’. Finally, the study of the neural basis of cultural transmission is seemingly dependent on advances in new technologies that should reveal how culturally acquired information is represented in the brain.

In short, we submit that the argument that culture exhibits a number of key Darwinian
properties is well-supported, and advocate taking advantage of this in order to use evolutionary biology as a model for integrating a multitude of separate approaches within the social sciences, and, where appropriate, borrowing some of the methods developed by evolutionary biologists to solve similar problems. Putting disparate studies from presently unconnected disciplines together into a broad evolutionary context adds value to each of the individual studies, because it illustrates that the degree of progress in this area is far more impressive than hitherto conceived. We suggest that these studies can now be said to be aligned within a unified ‘movement’, and that if this Darwinian evolutionary movement could be better co-ordinated, a more persuasive and important direction could be put on much work in the social sciences.

Hat tip: Natural Rationality

The eight-fold devlopmental model stretched to cover evolutionary ground

Regular readers of my blog will know how I am memserised by the eight-fold developmental model . I have applied that model to Cognitive Maps, linked it to Moral Development, development of perspective-taking, to language and universal moral grammar development, to language and stages of pretend play, to evolution of languages (color terms), evolution of language faculty (general), to personality and the BIG FIVE, and to evolution of color vision.

Just to recap, I believe in a 5 +3 = 8 step development/ evolutionary model, wherein the first 5 stages are qualitatively different from the last 3 ; but the stages of development / evolution are analogous in widely different faculties.

thus, I was quite surprised to discover a model of Consciousness, as proposed by Timothy Leary, that I was till now not aware of . Thanks to Mind Hacks, I spent a better part of my day on the net reading about Leary’s and RAW, eight circuit theory and I find it quite plausible and fascinating. Some links worth checking.

Although I do not buy the left-brain/ right-brain distinction in totality, I do find the fact that the first five stages are related to embodied consciousness, while the last three mark a departure and closely parallel other higher level stages quite interesting.

The evolutionary and developmental stages of Leary are :


The imprinting of this circuit sets up the basic attitude of trust or suspicion which will ever after trigger approach or avoidance

This is clearly the trust vs distrust development task identified by Erikson for infants. Leary though applies it to the living race (invertebrates ) on an evolutionary scale.


Again the first imprint on this circuit remains constant for life (unless brainwashed) and identifies the stimuli which will automatically trigger dominant, aggressive behavior or submissive, cooperative behavior.

This maps closely to Erikson’s second toddler stage, whereby the toddler has to master Autonomy (a sense of power) vs Shame and Doubt


It is no accident, then, that our logic (and our computer-design) follows either-or, binary structure of these circuits

Here the preschooler of Erikson, starts taking initiative. related to Initiative vs Guilt developmental task.

The fourth brain, dealing with the transmission of tribal or ethnic culture across generations, introduces the fourth dimension, time.

This is the traditional Social background process, stretched over the whole school life of the child, wherein he develops a sense of industry and a sense of skills that can be refined with hard work over time. Time if of essence here.


When this fifth “body-brain” is activated, flat Euclidean figure-ground configurations explode multi-dimensionally. Gestalts shift, in McLuhan’s terms, from linear VISUAL SPACE to all-encompassing SENSORY SPACE. A hedonic turn-on occurs, a rapturous amusement, a detachment from the previously compulsive mechanism of the first four circuits.

The fifth stage is a transforming stage that enables a rite of passage. In Erikson.s model it is transcendence of adolescence and taking on an adult role. One solves the problem of Identity vs Role Confusion. In my view this stage is also linked to Schizophrenia , which may result from role confusions and results in hallucinations. It is orthwhile to note here that many hallucinogens, as per Leary, lead to this stage.


The sixth brain consists of the nervous system becoming aware of itself apart from imprinted gravitational reality-maps (circuits I-IV) and even apart from body-rapture (circuit V).The evolutionary function of the sixth circuit is to enable us to communicate at Einsteinian relativities and neuro-electric accelerations, not using third circuit laryngeal-manual symbols but directly via feedback, telepathy and computer link-up. Neuro-electric signals will increasingly replace “speech” (hominid grunts) after space migration.

This meeting and communication between inter-stellar civilizations, bodes well on a human level with Erikson’s marriage as the sixth developmental milestone with Intimacy vs Isolation as a core developmental task


The seventh brain kicks into action when the nervous system begins to receive signals from WITHIN THE INDIVIDUAL NEURON, from the DNA-RNA dialogue. The first to achieve this mutation spoke of “memories of past lives,” “reincarnation,” “immortality,” etc. The “akashic records” of Theosophy, the “collective unconscious” of Jung, the “phylogenetic unconscious” of Grof and Ring, are three modern metaphors for this circuit.

this also bodes well with the collectivist nature of Erikson’s seventh developmental task, wherein , as a group of individual (member of society) one feels Generativity vs Stagnation.


When the nervous system is turned on to this quantum-level circuit, space-time is obliterated. Einstein’s speed-of-light barrier is transcended; in Dr. Sarfatti’s metaphor, we escape “electromagnetic chauvinism.” The contelligence within the quantum projection booth IS the entire cosmic “brain,” just as the micro-miniaturized DNA helix IS the local brain guiding planetary evolution. As Lao-tse said from his own Circuit VIII perspective, “The greatest is within the smallest.”

This too bodes well as the eights stage again being the ultimate stage of transcendence, coming to terms with one’s inevitable (human) death and either having Integrity vs Despair as one reflects on life and prepares to transcend it

I know that a lot of the above my sound nonsensical to the regular readers of this blog, but we know so little about consciousness, that it may be best to keep an open mind about it and about evolution and our fate as human race.

Darwinian Linguistic Evolution

There is a paper by Oudeyer and Kaplan, which discusses the evolution of languages in Darwinian terms. That is a refreshingly new (to me!) take on how languages may evolve. It applies the same Darwinian principles of heritability, variation and selection to individual phonetic words as well as associations between words and meanings.

The article makes use of computer simulations to inform their theory. Some of the take home from that article are:

  • For Linguistic coherence to evolve (that is one word referring to same meaning for different agents), the replication principle most suited is whereby the most frequently encountered word is repeated and thus gets fixated in the population. This scores over the use-the-last-heard phoneme rule and use-the-phoneme-as-per-frequency-in-usage rules.
  • The phonemes that can be easily confused (are liable to mutate more) with nearby phonemes get selected against and thus, selection leads to implicit evaluation whereby those phonemes that do not mutate (or mutate less) are preferred and get fixated.
  • In a population with agents coming and leaving, the population flux ensures that optimal words are used and sub-optimal done away with.
  • The linguistic phonemes (or words) that are used to represent concepts, break the acoustic space in such a way that their is least scope for confusion amongst the phonemes.
  • A trade-off happens between linguistic distinctively and robustness. Some words are long enough that they can mutate more, but are not easily confusable. Other frequently used words are short and do not mutate easily, but if they mutate than more confusion of meaning arises.

There are more such interesting information nuggets in the paper. So why don’t you have a look at the original paper itself.

Hat tip: Babel’s Dawn.