Cascades: A Neurological Waterfall
In class, we have discussed information cascades and the meaning behind a series of stages in the processing chain of a signal where each operates the next in turn. Knowledge of cascades has been applied to markets, financial systems, and the general decision making process of electing to accept or reject. Can this knowledge be expanded to more complex concepts that are just as incorporated in our lives, if not more, than the models we have discussed thus far? Do cascades necessarily have to be based on physical, visual theories? By putting a little bit of spin on the ideas we have learned, it is easy to see how cascade theories appear in many other situations, both macroscopic and microscopic in comparison with our day-to-day lives. A major microscopic existence of cascades lies in psychology, the brain, and how it processes chains of events to create and recall memories.
As we all know, extensive research has been performed for many years now to observe and record brain activity regarding how each person’s thoughts and emotions are formed, stored, and remembered. According to New York Times writer Benedict Carey, a recently conducted study gave evidence and conclusions about specific individuals who were awaiting surgery for epilepsy. The study, called “Oscillatory Patterns in Temporal Lobe Reveal Context Reinstatement During Memory Search,” was performed by a group of research scientists from the University of Pennsylvania and Vanderbilt University. Specifically, the study measured neurological activity that occurs when a memory is recalled or presented to an individual in order to determine whether events surrounding a given target memory may serve as a kind of context reinstatement of memories.
Each patient in the study was given a list of words to study and recall while their brain activity was observed and recorded for the entire process. After studying the list, patients were asked to recall certain words by calling the memories with framework clues in order to recollect the actual memory of studying the word. The brain activity recorded during this part of the study supported the study’s hypothesis by revealing that upon remembering a certain item, the patient’s pattern of neuron activity was not only very similar to that which was recorded during the time over which the word was originally studied, but was also extremely similar to the patterns observed when studying the neighboring list items of the target word. In simpler terms, when the patient recalled a certain memory, the brain activity indicated that memories closely related with respect to time were also closely associated with the specific memory being recalled. The effect was such that the patients tended to remember the words in clusters that were in the same order as they were originally presented in.
Upon the first analysis of this study, the actual psychological facts may seem mind-boggling, but when the specifics are pushed back and the idea of a cascade is applied, it is easier to understand how this study relates to this networks concept. The study essentially concludes that memories, whether stimulated by the mention of them by someone else or by a familiar scene or sense of smell, can start a cascade of memories. The cascade effect occurs due to the fact that memories are recalled along with closely neighboring memories that took place around the same time. As Carey suggests, “memory is like a streaming video that is bookmarked by facts, scenes, characters, and thoughts.” In other words, memories are recalled by analyzing the surrounding context memories to help organize chronology and perspective.
For example, many college students have experienced a hangover on a Sunday morning: The brain attempts to reconstruct the previous night’s activities by remembering broad physical details such as a broken piece of furniture, recollecting surroundings such as dance floors or bar areas, and recalling who else was there. The brain starts with these basic facts and uses them to remember details that correspond to each event, thus creating a cascade of memories as each memory forms another piece to the puzzle. As Dr. Kahana of the University of Pennsylvania says, “When you activate one memory, you are reactivating a little bit of what was happening around the time the memory was formed, and this process is what gives you that feeling of time travel.”
http://www.nytimes.com/2011/07/05/health/05memory.html?_r=1&ref=memory
http://memory.psych.upenn.edu/files/pubs/MannEtal11a.pdf