A story about snakes
October 29, 2013 | James Kohl
My comment to The Scientist site was pulled, perhaps because it referenced reporting from another source.
My comment to Science Magazine follows, in an attempt to address the story-telling that I abhor.
Did Snakes Help Build the Primate Brain? 28 October 2013
Excerpt: “Even if we carry these “leftovers from evolution” in the form of snake-sensitive neurons deep in our visual system, higher brain processes, such as learning and memory, may influence our behavior just as much as this deep and instinctive snake sense.”
My comment: The context of adaptive evolution in which the spontaneous binding between congruent olfactory and visual information forms a multimodal saliency map in species with adaptively evolved eyes and individual humans who are not congenitally blind has been removed.
Instead, in two primates, the saliency of the visual input is automagically established outside the context of any model organism that might otherwise link the evolution of the human response to snakes to any of the basic principles of biology or levels of biological organization required to link epigenetic cause to effects on hormones that affect behavior.
Thus, instead of nutrient-dependent pheromone-controlled adaptive evolution, or even the mutation-driven evolution of invertebrate and vertebrate brains and behavior, we have a snake-centric approach to human development associated with visual input.
Excerpt 2: “…another primate-specific skill: using vision to guide reaching and grasping movements. (Example: Reach for a banana, but don’t reach toward a slumbering snake.)”
My comment: Given the repeated indications that any theory will suffice for some people as an acceptable approach to evolution, this snake-centric theory should probably compared to the perspective of those called “Creationists” by some evolutionary theorists. If snakes were intimately involved in human adaptations, the report of the snake that caused Bibilical Eve to reach for the apple, makes as much sense as snakes ensuring our monkey-like ancestors reached for a banana, instead of something that looked like a snake.
Brain has specific radar for snakes
October 28th, 2013 in Biology / Plants & Animals
Article excerpt: “I pulled together indirect evidence,” she told AFP.
My comment: Direct evidence of cause and effect for use in a story about snakes would include an epigenetic link from the sensory environment to gene expression in hormone-secreting cells of the vertebrate brain that link the epigenetic “landscape” to the physical landscape of DNA in the organized genomes of species that exhibit hormone-affected behaviors. For example, the behavior attributed to the visual imagery of snakes in some primates but not others is hormone-affected behavior. I think that pulling together indirect evidence about hormone-affected behavior is akin to story-telling that includes the parts of the story you like, but leaves out anything that doesn’t quite fit in an attempt to ensure the story-teller’s credibility.
Article excerpt: Previous research has even shown that some primates, such as the Malagasy lemurs of Madagascar where there are no venomous snakes, do not express fear of them they way other apes and monkeys do. Why not? The fact that they don’t makes the indirect evidence pulled together for this story yet another example of selecting “factoids” that fit the story being told.
Article excerpt: “Snakes are largely responsible for the origin of primates. Vision is what separates primates from other mammals. A lot of the structures in our brain are devoted to vision,” said Isbell, who wrote a book on the topic in 2009 called “The Fruit, the Tree, and the Serpent: Why We See So Well.”
My comment: The primacy of vision in humans is one of the stories that’s been so frequently told that many people believe there is scientific evidence to support the story. Instead, this author admits from the start of this article that “I pulled together indirect evidence,” she told AFP. Indirect evidence is not scientific evidence. Experimental evidence is scientific evidence.
My comment: Who would have guessed that research done on two monkeys of one primate species would support the story told and the claims made here (and probably made in her book)? Does anyone else think that this story is typical of the “Just-So” stories common among evolutionary theorists who pull together indirect evidence and present it as if it included biological facts?