Friday, September 12, 2008

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?

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Ward said...

great post. I really like your tie in with storytelling and evolution. I will have to read your other posts.


joshyMinor said...

Wow, absolutely amazing! very nice indeed.