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Cognitive Approaches to Consciousness

Contributors: 
Matthew Hunzinger: Author
J. S. Jordon: Author
Additional Credits:
Funding
This module was supported by National Science Foundation Grant #0127561.

 

As was stated above, during the first half of the 20th century, American psychology tended to ignore consciousness as a topic of investigation and, instead, focused on measuring behavior. After World War II however, and the advent of the computer and other communication technologies, researchers once again began to discuss conscious states. Within this approach, what is best known as the cognitive approach, the brain was modeled as an information-processing system, and consciousness was treated as an effect of the information processes of the brain (although the word 'consciousness' was not used all the much). This led to two major approaches to the conscious content of such information. In attention-based approaches, researchers ask how it is that the mind determines which information from the environment is actually allowed to enter into consciousness. In imagery-based approaches, researchers ask how it is that the information in consciousness is manipulated and controlled.

Attention-based Approaches

As stated above, the purpose of attention-based research is to investigate how information gets into consciousness. In what are called visual search experiments, participants are presented visual displays and are asked to look for a particular type of stimulus within the display. Researchers have found that certain aspects of a stimulus (i.e., its form, color, and orientation) enter consciousness rather easily (i.e., participants can quickly identify differences between stimuli based on these dimensions); that is, they seem to 'pop-out' of the display. If however, participants have to search for a stimulus that constitutes a combination of dimensions (e.g., the 'red' L -- a conjunction of color and form) it takes much longer to find the more complex stimulus. This finding has lead to the well-accepted notion that the visual system 'processes' different dimensions (i.e., color, form and orientation) simultaneously; what information processing theorists refer to as "parallel" processing. It takes longer to identify a more-complex stimulus because one has to focus attention on each individual stimulus in the display to determine whether or not it contains the right combination of both dimensions; what information-processing theorists refer to as serial-processing. According to information-processing theory therefore, whether and when stimulus information enters consciousness depends on the complexity of the stimulus as well as the attentional filter one has in place.

     At present, the most popular attention-based theory of consciousness is Bernard Baars' 'Global-Workspace Theory' (GWT). According to GWT, stimulus information enters into consciousness when it enters a massively distributed neural network that Baars calls the Global Workspace. Information is entered into the workspace in order to make it simultaneously available to many distributed processing systems. In short, the information is conscious because it is so widely available. As things change from moment to moment (i.e., the organisms location in the environment, things in the environment, and other locations in the organism's brain) the contents in the workspace change as needed to complete the current task. Attention is the mechanism by which these changes take place.

Imagery-based Approaches

Once a bit of information has come and gone in our consciousness, we are often able to 're-enter' it (i.e., remember it) some time later. For example, you can now sit here and re-construct the visual images you generated while reading the opening section in this module. You can also skip portions of the event or start certain portions over and over if you like. This skill is known as mental imagery, and as you are conscious of the images as you work through them, how you are able to do this is a well-investigated phenomenon.

     Initial experiments in mental imagery discovered that people tend to work with mental images the same way they do with physical images. For example, if you are shown two similar figures and are asked to indicate whether or not they are the same, it takes longer to say 'yes' the larger the difference in their orientation. Researchers referred to this as 'mental rotation' and argued participants were answering the question by rotating a mental image of one of the objects, just as they would if the images were on pieces of paper.

     In another line of imagery research, participants memorized the locations of objects (e.g., a tree or a hut) on a map. They were then asked to imagine a ball moving from one location on the map to another, and to indicate when the ball reached the second location. The results indicated the further the distance between two locations, the longer it took for the 'ball' to travel the distance between them, even though the map, the locations, and the dot were all imagined. Recent neurophysiological data indicate that when people engage in mental imagery, they actually use the same parts of the brain they use when actually 'seeing' a physical version of the image. In short, people seem capable of generating and manipulating their own conscious visual experiences, and they do so by actively controlling the parts of the brain involved in normal conscious perception.

     To be sure, attention and imagery are not the only phenomena studied by cognitive psychologists interested in consciousness. Rather, I discussed attention and imagery in order to represent two approaches cognitive psychologists use to study consciousness. In each case, the scientists were investigating patterns in consciousness. And even though cognitive psychology developed to explore patterns in the mind, it also seems well suited for studying patterns in conscious experience.

THE END

 


Copyright: 2006


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