Active Symbols and Internal Models: Towards a cognitive connectionism

 

Please read starting with the section labeled The Active Symbol (page 57) and up to the section Higher-level Processes (page 60).

For many years psychology was dominated by behaviorism. Behaviorists do not believe in what we would normally call "thinking" but rather conceived that humans are essentially a large collection of behaviors. These behaviors were accessed by environmental stimuli (the paradigm is also called stimulus-response). Probably the most famous example of a behaviorist-style experiment is Pavlov’s dogs which learned to salivate upon hearing the sound of a bell because food normally followed soon after the bell. In this selection Kaplan, et al. recount the development of the cell assembly as an alternative to behaviorism. One of the key ideas is the possibility that neural activity can be held in the brain after a stimulus is gone (this was both a revolutionary idea and a difficult problem to solve). It is likely that we will return to the rest of the model later in the course.

 

Mechanisms of Learning and Development (continued)

 

In this passage Hebb directly tackles the challenge of building a neural structure capable of sustaining activity after stimulation has ceased. Cell assemblies and their properties will dominate the rest of the course and serve as the basis of virtually everything we talk about from this point on.