In his book, The Ravenous Brain, Daniel Bor spends a good amount of time discussing the history and evolution of the animal brain in relation to it's principle job of perceiving and reacting to important information. To put it more succinctly, "the main purpose of the brain is to sense the outside world and move accordingly." (Bor, pg. 67) In the same vein, Bor brings up the incredible complexity that exists in what he calls the brain's internal environment. Animals, especially humans, have incredibly large and detailed stores of information about the world around us readily available in our minds at all times. This allows us to entertain endless varieties of ideas, test theories, make plans, and react to the world with minimal physical work and remarkable mental ease. As an example, Bor offers his own ability to plan a midnight snack and where it could be procured, all without leaving his bed. This inner world, and the extreme specificity that it contains, is what seems to set animals and humans apart from other organisms that are capable of learning and adapting. While it is a feature that formed relatively early in our own evolutionary spectrum (at least from the viewpoint of someone on a human timeline), there are still many parts of this inner environment of the brain that are being discovered, particularly as it relates to their corresponding physical structures.
While scanning the New York Times I happened upon a silly sounding article, proclaiming that humans' (and monkeys') almost innate fear of snakes is the result of a specific group of neurons in a specific brain region. Yes, according to researchers exactly 91 neurons located in the pulvinar are solely responsible for identifying snakes. The pulvinar as a whole is said to be responsible for quickly directing attention to specific objects. Because of the neurons located in it that are specific to recognizing snakes, we have the ability to notice snakes faster than we recognize other objects, contributing to our fear of them (researchers say that people who like snakes are experiencing the same effects, but their experience with snakes resulted in love instead of fear). At one point, this specificity for snakes was almost certainly evolutionarily advantageous, as snakes were a serious threat to the safety of ancient humans and primates.
This ability to single out snakes also speaks to Bor's idea of a highly specific and complex inner concept of the world. Given our ability to imagine and detect so many specific things, it is hardly surprising that part of our brain is solely devoted to snakes, especially given their importance as an age old threat. Our mere ability to conceptualize, identify and respond so many specific things is amazing, and it is even more unbelievable that we can now pinpoint the exact location that allows us to recognize something as specific as a snake. What started out as a seemingly silly article, takes on a much more meaningful tone when examined through the lens of Bor's "inner world."
This blog post refers to the following New York Times article: http://www.nytimes.com/2013/10/31/science/afraid-of-snakes-your-pulvinar-may-be-to-blame.html?ref=science
This is a very interesting post. I appears that our fear of snakes is not learned knowledge but instead is implicit knowledge which we are born with. If all of our brains have a predetermined fear of snakes due to a specific group of neurons, I wonder what other survival specific neuron groups reside in our brains that helped us survive and evolve. I wonder if there is a similar neuron group devoted to spiders as well. This study brings the field of neuroscience together with evolutionary biology, psychology, anthropology and others. These types of studies that encompass multiple fields of science are extremely important and extremely interesting because they lead to a deeper more holistic understanding.
ReplyDeleteI thought this was a little funny (but cool) study that you found, especially given that most people don't really encounter a lot of snakes in the day-to-day anymore. I guess it's just an evolutionary artifact now, but I liked how you tied it into the general process of perception and adaptation. I wonder how the neurons react to snake-like objects, like low-hanging vines or, more commonly (thanks to our technological world) bundles of wires, etc? Also, I thought it was interesting that it was snakes, of all things-- not because they're not scary, but because it reminded me of this type of caterpillar that can puff up its body to resemble a snake to ward of predators. (http://www.whatsthatbug.com/images/amazon_caterpillar_snake.jpg). I just thought it was interesting that this animal has adapted itself to mimic something that we are neurologically inclined to be afraid of!
ReplyDeleteI really enjoyed reading about how we have evolved and found it very interesting the traits that we have kept over the time. Goosebumps, for example, is something that is a trace of evolution. It makes sense that we have neurons specific to snakes, although I had never thought about that before. We have been learning in class about how we have sympathetic nervous system reactions to things such as a lion growling at the zoo even though there is no chance of it getting to us. I always wondered why I am scared of snakes, spiders, and other bugs, but now I know that they were things that my ancestors were afraid of and stuck around. In the case of snakes, we even have 91 neurons to show for it.
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