This is the final blog in a series that addresses a recent article by cracked.com entitled "Five Seemingly Random Factors That Control Your Memory" (http://www.cracked.com/article_19518_5-seemingly-random-factors-that-control-your-memory_p2.html). The article starts off with point number five: "walking through doorways." In which we learned that our memory divides information into compartments, and those compartments are divided much as the rooms of the house are divided by doorways. Point number four: "ridiculous fonts" demonstrates that human memory is largely visual, and visual novelty assists in creating the context allowing information to be more easily remembered. Point number three: "deep voices" reveals that our emotional state, attraction and sex appeal, also contribute to the context which allows information to be more easily remembered. In the previous blog we addressed point number two: "faces" in which we learn that the visual system, and hence memory, are particularly care and to complex visual objects. There are even neurons in the brain that specifically respond to faces.
This brings us at last to cracked.com's number one factor that controls our memory: "hand gestures." From the article:
The article goes on to explain that learning and remembering portions of the brain are connected to the portions of the brain that move our hands. As we discussed in the previous blogs. This is the correct explanation but doesn't go quite far enough. All of these "seemingly random factors" are really getting back to the issue that I have stated many times with respect to memory: memory is dependent on association. When information is associated with movement: whether that's movement of the hands only, or movement of the entire body, more regions of the brain contribute to the association or context of the memory. In addition to the simple context of of movement, hand gestures also involve what is known as "kinesthetic sense." Kinesthetic senses an important component of memory, since your brain needs to know how your body is positioned and where everything is located before you make a new movement. Much of this information is not processed in the temporal lobe like specific event memory, but in the basal ganglia and cerebellum. In fact, this is one reason why it is possible to learn skills to the point where performing them requires no conscious thought at all. Athletes and soldiers call this "muscle memory" even though the memory itself has little to do with the muscles and everything to do with brain.
"Here's something you've probably never wondered: Why do people talk with their hands? Almost everyone gestures when they're talking -- when they're counting down something, they hold up a hand and point to a finger to tick off each point. During an argument, most people can't illustrate their point without almost accidentally karate chopping you in the throat."
One of the amazing capabilities of the classic amnesia patient H.M. is the fact that even though his memory for events and facts did not last more than 10 min., he showed evidence of being able to learn and remember a skill even though he could not recall ever having learned it. As you may recall from an earlier blog (http://teddysratlab.blogspot.com/2011/07/curious-things-we-learned-from-epilepsy.html), the patient that history records simply as H.M. had epilepsy, which was not treatable by medication. A neurosurgeon removed the medial temporal lobe, including hippocampus, from both sides of his brain. After the surgery, H.M. was able to remember events that had occurred in his childhood, or well before the onset of his epilepsy and his surgery, but was unable to form new memories. However, when therapists presented H.M. with puzzle which required a certain level of skill to complete, he showed evidence of continually improving performance, even though he would tell doctors each time that he had never seen the puzzle before. The studies led to our current understanding of skill learning including the phenomenon of "muscle memory." Again, this should come as no surprise that muscle movements and body movements are associated with memory. Even though they involve two different memory systems, one requiring the hippocampus while the other does not, in a healthy individual the two systems interact in the formation of new memories.
I owe a debt of gratitude both to the article for bringing up these interesting concepts, and to the friend who asked my opinion of the article - thus prompting this series of blog posts. As always, I'm very interested in analyzing and interpreting science in the public media and in the news. If you see an article you wish to suggest for future topic, please feel free to bring it to my attention.
There are many other tricks for improving memory that do not require one to have what is commonly referred to as a "photographic memory." . Many of these tricks involve repetition, association and tapping into the normal brain mechanisms which are contributing to the formation of memory all of the time. as you can see from this series, there are many different factors which both assist and impair the function of memory. The best way to improve our memory, is to better understand the distractions and the benefits that we can get from context and association.
Until next time, keep using your brain, make associations and observe the context. You'll be glad you did!