Argument:
On page 35 Shenk talks about london taxi drivers who have "a greatly enlarged posterior hippocampus” (35). In 1999 an experiment by Eleanor Maguire discovered that
“the longer the driving career, the larger the posterior hippocampus”
(35). This means that as taxi drivers drove longe,r through
the streets of London, they were learning the streets leading a part of the brain to enlarge for the specializing for spatial skills.
With this in mind how does the GPS affect the brains for the new generation of
taxi drivers, who might not need to memorize or learn as much information as those who did not have access to GPS? Does having a larger hippocampus help an individual learn another skill better? Does having a large hippocampus give better advantage to those in a foreign setting? Do the taxi drivers merely memorize the streets are they create a map in their mind to aid themwhen driving? Relate these back to the idea of different learning processes from class and from outside sources.
(Christine Park go2chritine@hotmail.com)
The term that is used to describe the ability to change proficiency in skills or the ability for the brain to change to match the individual’s demand of it is plasticity. Maguire concluded that the longer that the career of a London taxi driver was, the larger the size of the posterior hippocampus. This clearly shows the plasticity of the brain in action as the brain in London taxi drivers must enlarge its hippocampus in order to memorize the thousands of streets in London. Similarly, our brain changes form in order to meet the demands that we make of it. For example, in a study done at Harvard in 1979, scientists took a cat that had use of both eyes since birth and a cat which had one eye sutured since birth and measured the bands formed in the visual cortex from radioactive amino acids. They found that in a normal cat the columns were equal in width, while those of the cat without vision in one of its eyes had the columns representing the active eye expanded and the columns for the deprived eyes reduced (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2841150/)
ReplyDeleteAccording to Yale psychologist Robert Sternberg, “intelligence represents a set of competencies in development” (51). Shenk further states that, “intelligence is a dynamic, diffuse, and ongoing process” (51) and therefore, intelligence changes with every passing day and new experience. The human muscles and brain regions adapt to the demands that we make of it. Therefore, the way someone can increase his or her intelligence is by simply being in an environment that contains challenges, like the complicated roads of London, elicit change in the brain. Associative learning also serves as an example to prove that intelligence is a process. There are two types of associative learning: classical condition and operant conditioning. Classical conditioning is when a “stimulus becomes associated with a particular outcome” (Campbell 1127). Operant conditioning is also called trial-and-error learning where “an animal learns to associate one of its own behaviors with a reward or punishment and then tends to repeat or avoid that behavior” (Campbell 1127). Both methods shows that animals can constantly improve their intelligence through these experiences and proves that intelligence cannot be a fixed quantity as animals increase their intelligence constantly as organisms learn more and more about their surrounding environment. Taxi drivers in London of the past, who did not have GPS, would have been undergoing more operant conditioning because they would have to constantly experiments with the routes they take. But, this does not mean the newer drivers with GPS, who would be undergoing more classical conditioning as they would respond to the stimuli of the GPS, would increase their intelligence levels any less. Even if they are told where to go, the mere fact that they actually gain the experience of driving through these roads is still adding to their intelligence. Therefore, while their hippocampuses may not be as enlarged, I think new taxi drivers of London, even with their GPS, would constantly be adding knowledge of the road system their and almost identical brain development as old drivers did.
The brain’s plasticity clearly supports Shenk’s GxE model which clearly hurts the credibility of the old idea of evolution: that organisms whom have a certain selective advantage can survive and reproduce pass along their genes while the ones who cannot die out, natural selection. However, this idea of plasticity shows that even if one doesn't have “innate” intelligence in their genes, an individual’s brain will alter its form in order to alter its function so that it can better fit the needs of the individual’s environment. This also relates to the biological theme of structure and function since as the structure of the brain changes, so does its function in order to adapt to the environmental requirements.
Neil Edat(neil.edat@gmail.com)
When the taxi drivers memorize the roads, they utilize cognition learning through cognition maps, a representation in the nervous system of the spatial relationships between objects in an animal’s surroundings, and landmarks (spatial learning: the establishment of a memory that reflects the environment’s spatial structure). Therefore, the drivers can make connections between landmarks to recognize where he/she is and how to get from one landmark to another. In addition, associative learning is displayed, especially operant conditioning, because of the trial and error gone through to find the fastest way to get to a destination .The many trials and errors will lead to the formation of a more effective and efficient route. Also, cognition learning skills (the process of knowing represented by awareness, reasoning, recollection, and judgment) are developed, like problem solving, in order for the drivers to reason out routes and recall street names and places (Campbell 1126-1129). Mostly, this all works within the hippocampus, which is involved in the functioning of the consolidation of new memories, emotional responses, navigation, and spatial orientation. It “acts as a memory indexer by sending memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrieving them when necessary” (http://biology.about.com/od/anatomy/p/hippocampus.htm). Lately, research has found that a regular exercising of the hippocampus leads to an enlargement of it, which can actually prevent certain effects of Alzheimers. It was found that “the volume of the hippocampus part of the brain was 20 percent greater in the cognitively intact group compared to the Alzheimer's disease group with dementia” (http://www.sciencedaily.com/releases/2008/04/080415154223.htm). Those who rely solely on GPS do not take the time to challenge and stimulate their brain through processes of concentration, memorizing, and taking in perceptions to develop spatial learning and cognition and make their hippocampus more active, storing more memory (http://www.audiblox2000.com/learning-ability.htm ). Therefore, their hippocampuses will be smaller and less effective than those of the London taxi drivers (or Sherlock Holmes).
ReplyDeleteThis is a good example of Shenk’s point of genetics not being alike to total blueprints. The hippocampus is not a set size, but can enlarge due to activity. Relating to structure and function, the larger the hippocampus, the stronger and more effective it is in its functions of consolidating memories and spatial orientation. However, these “specific parts of the brain adapt and organize themselves in response to specific experiences” (35). Therefore, a taxi driver with a large hippocampus doesn’t directly correlate to them being able to play the piano better (http://www.fil.ion.ucl.ac.uk/Maguire/Maguire_CORE_2000.pdf ). Their large hippocampus is due to activation of a specific function, like spatial orientation. So maybe the cabbie will be able to adapt to a foreign setting in terms of being able to more easily identify pathways because of his enlarged hippocampus adapted to spatial learning. But, this doesn’t guarantee that the larger hippocampus will give the cabbie an advantage in wine tasting or any other skill not specific to spatial learning. Of course, that doesn’t necessarily mean humans cannot adapt to learning another skill faster by taking advantage of the “plasticity” of the human brain, where one brain does not have the same potential as another, but “guarantees that no ability is fixed” (Shenk 36 & http://faculty.washington.edu/chudler/plast.html ). Cognitive skills and learning abilities can be expanded and developed through concentration, memorizing, problem solving, and taking in different perceptions of situations (http://www.audiblox2000.com/learning-ability.htm ). The complexity and adaptability of the human brain has evolved through natural selection because of its ability to allow easier survival and reproduction. From very early, humans learned to hunt through the learning of skills by the brain. Nowadays, the plasticity of the brain is pushed and challenged with new technologies and studies, learning new skills and building off older ones. The brain and gene expression can alter in response to different genes as well as the environment, changing phenotypic expression in response to interactions between genotype and the environment (interdependence in nature). Thus, one can very early develop skills and traits that can help them in survival. Being able to learn and having a growing capacity to adapt is one of the many wonders of the human brain and its powers.
ReplyDelete(Lea Nowack, lea.nowack123@gmail.com)