Saturday, February 8, 2014

The arrival of the frequent: how bias in genotype-phenotype maps can steer populations to local optima

Stephen Schaper and Ard A. Louis
(Link)

Abstract:

 
 
Figures:

 
 
 



 
 
Excerpts of interest:
 
Response when the population is too small compared to large populations:
 
 
Responses to environmental change:

 Phenotypes with a local high frequency fix at the expense of rare phenotypes:
 

7 comments:

  1. Wow, Marnie. This posting really taxes my capacity for analytical thinking! I almost feel like a dotard trying to understand the article. I can only think of an example. I have avoided behavioral genetics because of the implications that phenotypic behavioral traits could be linked to racial/ethnic differences. But there is one trait that mystifies me--that of the phenotype, empathy, that is associated with genotypic differences in oxytocin receptors. I noticed that that the "empathic" genotype is frequent among Africans and diminishes in frequency as one leaves Africa--Africans>Europeans>Asians. What if oxytocin receptor variants were adaptive in African societies and became less adaptive in Northern climates where individualism held sway? Now that we are globalized, we see that the preponderance of entrepreneurs and technical experts demands an individualized set of cognitive attitudes, which are frequent, but that the future preservation of the earth needs more empathic values. Maybe, our genotypes are stuck in individualistic behaviors and it is difficult (genotypically) to return to altruism and empathy. I could just be ignorant of the technical details of this fascinating paper, but I just don't know.

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  2. Roy,

    I don't think that empathy is regionally or genetically encoded. I do think that empathy is perhaps cultural and that certain cultures suppress empathy. However, having lived in Ghana, West Africa, and long having observed African culture, political events and outlook, I don't think I could say that people who live in Northern climates are less empathetic than others.

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  3. Marnie,
    Very good point. This is why I shy away from (actually viscerally hate) behavioral genetics. Finding genotype/phenotype associations presupposes that we understand or can measure phenotype. Empathy is so culturally conditioned, fuzzily measured and cultivable that small lab based psychological/genetic studies of empathy belie its complexity. I prefer studying patterns of migration, extinction and demography under neutral evolution. I can say that the field of biological psychology/psychiatry is obsessed with reductive explanations of behavior and experience to the detriment of interpersonal understanding.

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  4. " I prefer studying patterns of migration, extinction and demography under neutral evolution. I can say that the field of biological psychology/psychiatry is obsessed with reductive explanations of behavior and experience to the detriment of interpersonal understanding."

    Migration, extinction, demography . . . me too.

    It may sound goofy and very unscientific, but just based on my long observation of several very empathetic dogs, in particular my dog I had when I was growing up, it is pretty hard to argue that empathy has any recent evolutionary basis in humans.

    I even had a cat, Peter, who had an uncanny empathetic ability.

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  5. Maybe phenotypic space itself is of high dimension, at least as high as genotypic space. Love your example of empathic dogs and cats. Same here--I find pets to be extremely empathic if I remove my human-centric blinders. Perhaps terms such as empathy are very multi-determined, as in all roads lead to Rome. It would be difficult to measure empathy in a dog; the usual human-centered measures employ "theory of mind" models which don't really fit a non-verbal animal. So the terms empathy or intelligence or aggression merely reduce the complex space of phenotypes into a linear measure, convenient for psychologists, but ultimately a reductive trick of the eye to simplify that which is ineffable.

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  6. A good book about dog social behavior:

    The Hidden Life of Dogs
    by Elizabeth Marshall Thomas

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  7. Page viii:

    "After all, thoughts and emotions have evolutionary value. If they didn't, we wouldn't have them. Thought is an efficient, effective mechanism that we, and many other animals, would be hard put to do without. With intellect, which is to say the ability to learn and reason, an organism such as a person or dog can cope with a wide variety of problems that would require an enormous amount of hard-wiring if the behavioral solution to each problem were pre-programmed. When we relegate animal thought to instinct, we overlook the fact that instinct is merely an elegant matrix for the formation of an intellect, a fail-safe device that guides each species to form thoughts. When shaped by education, our thoughts enable us to do what we do, and even to be what we are, not only as members of our species, but as individuals.

    .....


    "A dog who adopted a human mannerism is my husband's dog, who amazed us all one hot day this past summer after my husband had bought himself an ice cream cone. As my husband took the first taste, he noticed that his dog was watching. So he offered the cone, expecting the dog to gobble it. But to everyone's astonishment, the dog politely licked a little ice cream just as my husband had done. My husband then licked a little more, and again offered it to the dog, who also licked a little more. In this way, taking turns, they ate the ice cream down to the cone. Then my husband took a bite. The dog watched him. Assuming that the dog would bolt the rest of the cone, my husband passed it on for what he thought would be the last time. But drawing back his lips to expose his little incisors, the dog took the most delicate of nibbles. Twice more my husband and the dog took turns biting the cone, until only the tip remained."

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