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Nobody Needs to Learn Any More

If all the knowledge is in the genes

All of us know what a slog it is for every new generation to memorise the times tables, history dates, and to learn how to read and write. Why can the acquired knowledge not be stored in our genetic code and then be available to our children and their children, and so on? After all, the skill how to walk upright and the fear of heights, some scientists claim even the fear of spiders and snakes, need not be learned. Mothering, nest building in mammals and vocalizations, i.e. singing in many (but not all species) of birds, are instinctive skills, but the times table in humans, to the chagrin of all the children of the world, ain’t.

Everybody knows that if you take a caterpillar from a tomato plant and place it on an apple tree it would rather starve to death than consume the apple tree leaves. Often one tiny bite into the wrong leaf is sufficient for the caterpillar to reject the food. It does not have to have had the experience of getting sick and developing a stomach-ache; it simply seems to “know” its proper food plant from birth. But there are exceptions: I have taken the eggs of a gum emperor moth in New Zealand and prior to hatching transferred the eggs from a gum tree to a birch or even apple tree: a considerable portion of the young caterpillars will feed on the wrong tree leaves, grow to maturity and turn into an adult moth, which in all probability (but I cannot confirm that) will seek out a birch or apple tree again for depositing its eggs. After all, it had already been shown in the 1970s that memory in insects can “survive” metamorphosis from larva into adult.

Another example: the monarch butterfly is poisonous to birds and it has been observed innumerous times that a bird that attempts to swallow a monarch will immediately drop it and may even vomit out everything it contains in its stomach at that time. Since the monarch has such a distinctive coloration, it has always been assumed that this aided its recognition by birds, which had experience its disgusting taste and that such birds would leave the butterfly alone if they encountered it for a second time. However, research (in Sweden, I believe it was), has shown that some birds, naïve chicks for example, which had never experienced a poisonous species of butterfly, would avoid the sickness-causing species given a choice of different butterflies to eat. Since smell due to the experimental set-up could be ruled out, it appears as if the learning experience would only reinforce an already existing innate avoidance trait. This is why some scientists believe that the image of a snake or a hairy tarantula could well cause repulsion in humans without having had to be learned.

To test what is an innate (=instinctive) behavioural reaction, scientists use the Kaspar Hauser approach, named after the sad case of the boy Kaspar Hauser, who was thought to have grown into a teenager deprived of almost all contact with humans and kept in a small darkened room throughout his childhood. Would a songbird, for example, deprived of ever hearing another bird’s song, later know and sing its own song? Would a kitten reared only on commercial cat food later know how to catch a mouse, and would a child growing up in a circular hut or yurt have a concept of squares and cubes when adult? Although the Kaspar Hauser approach has been very successful when it comes to unravelling what an animal “knows” from birth and what it has to learn (and then attempt to remember) during its life, the method can, of course, not be used with humans. As far as is known only some basic instincts and reactions in humans (crawling, closing the eyes at the approach of an object, crying, laughter, etc.) need not be learned. Unfortunately, the times table, languages and history dates are not among them and the same dreary stuff (to the delight of teachers, because otherwise they’d be out of a job) has to be learned again and again by every new generation.

parasite manipulation biology science

Are you in control? click for another story : “Parasitic manipulations”

© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2017.
Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to V.B Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com with appropriate and specific direction to the original content.

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