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The Brain as Prediction Computer

In recent years a theory has been developed describing the brain as actively employing memory against incoming sensory data in order to avoid focusing on known factors and to try to predict instantaneously what is going to happen next. The brain has thus been called “a prediction computer.” It has also been called the “top-down prediction theory.” It rose through evolution and it allows our brains to function and not be overwhelmed by the amount of incoming sensory information.

A very interesting example of this can be shown on a YouTube clip (see Hollow Face Optical Illusion). There, we see something that is virtually never seen in the real world, namely a hollow face, which our brains “interpret” as a normal face, based upon 100% of our past experience. This shows how the “top-down” prediction model of how the brain works can actually alter our perceptions of what is really coming in through out sensory organs. Our brain is saying “this can’t possible be a hollow face” so it recreates what we see as a normal face. We have perception of an object, our brain’s instantaneous attempt to understand it, and to predict what it means. In the vast majority of instances, we sense things that we have previously sensed. In that way, scientists have described the way the brain works as “saving band width” or not sending along sensory data that is or has been well predicted. Another example would be comparing your memories of a random day in the past thirty days with your memories of, say a vacation to Europe. Because your brain is less able to “predict” what is around the corner in a new and novel place, the experience is much better remembered than a day through the daily routine.

These theories and studies (Friston 2010; Bubic 2010; Keraga, 2007) also lead us into some interesting directions regarding rehabilitation of an injured brain and perhaps methods to utilize during our lives to strengthen the brain against the ravages of old age and dementia. Neuro-regeneration of brain cells is known to be enhanced by confronting “novelty.” It is obvious how this might occur – new connections and memories must be developed to accommodate confronting sensory data (visually, through sounds or taste) that is novel as unpredictable.

Thus, persons who are hardwired to seek novelty (neophilia) would tend to strengthen their brain over time when compared to individuals who stay within the confines of the very well known parameters of life. Likewise, it would seem that experiencing “avant garde” art and the added effort on the part of the brain, should be promotional of neuro-regeneration since, by its nature, it will confront the brain with new and unexpected sensory input, whether it be new modes of music, painting or even food. Studies have shown that the uncomfortable feeling people have when experiencing atonal or novel music is in part created by the brain sending out signals that it is confronting something unexpected. Further studies need to be done to confirm this connection.

The unexpected, the new, the novel, the challenging – all of these should be part of a regular diet for a healthy brain. Try to fool the prediction computer, shake it up a little bit.