Mental Representations in the Cognitive Approach
There are two key concepts that guide the cognitive approach. The first is: how we process information depends on what we know and the second: mental representations change over time. The Posner experiment showed that we can determine many representations of a stimuli (the physical aspect of the stimulus, the stimuli's identity and finally the category that the stimulus belongs too).
Another goal of cognitive psychology is to figure out how we perform tasks. Sternberg proposed four primary mental operations:
1. Encode: identify the object
2. Compare: the object with the objects stored in memory
3. Decide: if the object matches the items in memory
4. Respond: make a decision
How efficient is our brain at retrieving information? Two ideas were proposed: (1) if this is a parallel process then the reaction time should be independent of the number of objects in your memory (2) if it is a serial or sequential process reaction time should slow down as the memory set increases. Sternberg found that reaction time increased as the memory set increased.
Computer Modeling
Computer simulations are used to mimic the cognitive processes and that support a particular behavior. In order for this to be successful the creator must be very specific about how the information is represented and changes. Computer models show that minor changes in the brain could result in big behavior changes. People are even able to damage areas in the computer model to see how that affects behavior.
Animals in Experiments
Single-cell recording was a big breakthrough for Cognitive Psychology. In order to do single-cell recording, one must stick an electrode into a single. However, it may be hard to observe behavior because this technique may kill the cell. This technique has been used to study most regions of the brain. Many studies have looked into the visual systems. All cells that are visually sensitive can only respond to a stimuli in a certain region of space; this is called the receptive field.. The receptive field for cells vary; the smallest are in the primary visual cortex and the largest are in the association visual cortex.
Genetics play a role in cognitive function. Right now, neuroscientists are working with animals to identify the genetic mechanisms in both the brain structure and function. Some are performing knockout procedures. This means that certain genes are manipulated so that they are know longer able to function.
Neurology
Most neurological studies see how much damage has been done and how it was done. Then they measure electrical activity and changes in behavior. Diffusion tensor imaging is done with an MRI scanner. It looks at how big and active pathways are.
How does cognitive psychology play into neurology? If a patient has damage cognitive psychology can define the nature of the impairment. Obviously, if damage is done in a certain brain area and a behavior depends on that area the damage should disrupt the behavior. Single a double dissociations are helpful in studying damaged brain areas and cognitive tasks. In a single dissociation, two groups are tested on two tasks and there should be a difference between the groups. In a double dissociation, three groups are compared. One is a control group, group one is impaired at task A and group two is impaired at task B.
Localizing a certain area for a specific deficit is harder to do in groups. This is because no one has damage in the exact same area, psychologists have to isolate the a common area in order to pinpoint a certain damaged area for a certain deficit. However, with individuals you are able to focus on the one brain area that is damaged and understand that specific damaged area. Many wonder if the damage is specific to the individual or are you able to generalize it across people.
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