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Politics : Evolution -- Ignore unavailable to you. Want to Upgrade?

To: 2MAR$ who wrote (21289)	2/16/2012 12:49:33 PM
From: average joe	Respond to of 69300

Misunderstanding Evolutionary Theory Common misunderstandings of evolutionary theory. Published on March 8, 2010 by Robert L. Leahy, Ph.D. in Anxiety Files Some time ago I posted a blog proposing that many of the most common fears are related to evolutionary adaptation, Are we Born to be Afraid? I attempted to show how specific fears-that are universally distributed--- have survival value in a primitive environment. This includes fears of heights, water, closed spaces, open fields, etc. A recent comment on that post will give me an opportunity here to clarify some common misunderstandings of evolutionary theory. I want to thank the commentator for his or her critical points, because they deserve attention. Comment: First of all, not everyone fears open spaces, or heights, or even spiders. If this is evolutionary, then why are there so many exceptions? Response: I never said everyone has these fears. Evolutionary theory proposes wide variation within a trait-such as height, metabolic rate, intelligence, fear. Indeed, if there were no variation there could be no evolution. Keep in mind that evolution is about "selection" which means that you need variation to select the trait that is adaptive to the environment. Moreover, environments change-as Darwin noticed---and, therefore, traits that are useful in one environment confer little advantage in a different environment. In regard to universal distribution, I am simply indicating that the most common fears are found in all cultures, largely in the same proportion. There are some cultural differences in certain fears but many of the most common fears are found everywhere-and, in some degree, similar distribution. Comment: Your post claims that certain fears require hormones or events to activate, but this suggests learning rather than the activation of genes. Response: The commentator does not understand the difference between a genotype and a phenotype. Genes interact with other biological processes and with the environment. An example is Phenylketonuria (PKU) which is an inherited trait characterized by a deficiency in phenylalanine hydroxylase (PAH) which can be managed by dietary control of phenylalanine (Phe) levels. Another genetically determined trait-height--- is also affected by nutrition. The phenotype (height) is not the same thing as the genotype. In regard to the role of learning, we can think of different kinds of fear-and of fear itself-as genotypic but as interacting with the environment in various ways. This is what is meant by "constraints" on learning (Seligman). We can think of certain fears as examples of "prepared learning". Thus, it is far easier to learn to be afraid of dogs than flowers. It might be better to think of genetic determination as "preparedness" rather than as inevitability. Comment: Lastly, your theory on agoraphobia lacks basic logic: if humans are afraid of closed spaces, then why did they live in caves? And if humans are afraid of open spaces, why are there large atriums built all the time? These ideas are contradictory. Response: The concept of agoraphobia has "evolved" over the last forty years. We now view agoraphobia in terms of specific stimuli or situations that are feared and that might trigger, for some, a panic attack. Not all agoraphobics have panic attacks. We view agoraphobia as a fear of specific stimuli, such as open spaces, closed spaces, traveling, and places or situations where exit might be blocked (e.g., crowded places). The question of why some humans might fear closed spaces is interesting. Of course, fear of closed spaces-or spaces where exit is blocked---can trigger hyperventilation symptoms and a feeling of suffocation. Indeed, evolutionary theory suggests that those ancestors living in caves were especially vulnerable to being trapped by predators at night and exposed to poisonous gases emanating from the cave. Open fields also confer vulnerability, since bipedal humans crossing an open field are vulnerable to attack from predators. Agoraphobia often reflects vulnerability to danger or attack-whether it is an open field during daytime or a closed space or crowded room where exit is blocked. There is no contradiction if you can see that vulnerability to attack or other dangers is the key.