Two dissociable updating processes in working memory
More recent evidence has shown that language too is computed by widely distributed and domain-general neural circuits, and Broca’s area may also be involved in other computations (see here for more on this).Difference # 4: Processing speed is not fixed in the brain; there is no system clock The speed of neural information processing is subject to a variety of constraints, including the time for electrochemical signals to traverse axons and dendrites, axonal myelination, the diffusion time of neurotransmitters across the synaptic cleft, differences in synaptic efficacy, the coherence of neural firing, the current availability of neurotransmitters, and the prior history of neuronal firing.“A good metaphor is something even the police should keep an eye on.” – G. Lichtenberg Although the brain-computer metaphor has served cognitive psychology well, research in cognitive neuroscience has revealed many important differences between brains and computers.
For example, one of the primary mechanisms of information transmission appears to be the rate at which neurons fire – an essentially continuous variable.
(See here for more about “attentional pointers” in short term memory).
Unlike RAM, the capacity limit of short-term memory is not fixed; the capacity of short-term memory seems to fluctuate with differences in “processing speed” (see Difference #4) as well as with expertise and familiarity.
Similarly, one could imagine there being a “language module” in the brain, as there might be in computers with natural language processing programs.
Cognitive psychologists even claimed to have found this module, based on patients with damage to a region of the brain known as Broca’s area.