Top Down Processing

Extra Credit Paper

The cognitive system is organized hierarchically. The most basic perceptual systems are located at the bottom of the hierarchy, and the most complex cognitive (e.g. memory, problem solving) systems are located at the top of the hierarchy. Information can flow both from the bottom of the system to the top of the system and from the top of the system to the bottom of the system. When information flows from the top of the system to the bottom of the system this is called "top-down" processing. The implications of this top to bottom flow if information is that information coming into the system (perceptually) can be influenced by what the individual already knows about the information that is coming into the system (as information about past experiences are stored in the higher levels of the system). Extreme versions of top-down processing argue that all information coming into the system is affected by what is already known about the world. In his theory of modularity, it is argued that top-down processing occurs only in some parts of the cognitive system at certain times. When information flows from the bottom of the system to the top of the system this is called "bottom-up" processing. Lower level systems categorize and describe incoming perceptual information and pass this descriptive information onto higher levels for more complex processing. Usually in perception processing, the top-down and bottom-up process match, creating a perception. However sometimes they don't coincide and create "mismatch" which results in hypnosis. In the NY Times article "This Is Your Brain under Hypnosis", Sandra Blakeslee states that according to recent studies people whom are susceptible to suggestion process information in their brain quite differently than people whom are not. The suggestions actually change a person's perception of reality, in what they hear, feel, and believe to be true. The experiments used to derive this information use a process called brain imaging. Brain imaging is a fairly recent discipline within medicine and neuroscience. Brain imaging falls into two broad categories -- structural imaging and functional imaging. The